Bendigo-Ophir Gold Project - Pre-Feasibility Study
Santana Minerals Ltd
Level 1, 371 Queen St
Brisbane, QLD 4000
ABN 37 161 946 989
GPO Box 1305
Brisbane, QLD4000
T: +61 7 3221 7501
15 November 2024
BENDIGO-OPHIR GOLD PROJECT
PRE-FEASIBILITY STUDY (+/-15%)
Long life, high margin gold development with low capex
and significant upside
PRE-FEASIBILITY (PFS) HIGHLIGHTS:
• The project produces 147,000oz per annum (first 3 years of production) and an average of 125,000oz per annum from an initial
9.2 years of Reserves, from Rise & Shine (RAS) and Srex (SRX) deposits only.
• The PFS enables a Probable Mining Reserve of 15.5Mt at 2.37g/t Au for 1.18Moz of gold to be reported. Open pit mining
produces approximately one million ounces whilst the remainder comes from the initial phase of underground mining.
• A further ~770,000oz of Inferred resources at RAS and ~150,000oz at SRX and Come-in-Time (CIT) offer further known potential
growth.
• The PFS estimates total production of 1.15Moz of gold from open pit and underground mining at an average All-in-Sustaining-
Cost (ASIC) of A$1,416/oz, at the current spot price of gold (A$4,000/oz).
• A conventional 1.5Mtpa CIL process plant is designed to achieve an average 92.4% metallurgical recovery.
• Tailings are neutralised and stored in a waste-rock buttressed dam with closed circuit, process-water recirculation.
• The project generates revenue of A$4.60 billion at the current spot price of gold (A$4,000/oz) with an EBITDA of A$3.05 billion
and free cash flow of A$1.78 billion after tax and royalties.
• Capex for plant and all associated mine infrastructure estimated at A$208M, whilst pre-production capex for the enlarged
39.5Mt pre-strip, to enable higher initial gold production, is A$132M. Total negative cash drawdown is estimated at A$340M.
• At the current spot price of gold (A$4,000/oz), an after-tax Net Present Value (NPV
8
) of A$1.06 billion is generated over the
initial term with an IRR of 68% and a simple payback period of less than one year from the commencement of production.
• At the base case price of gold (A$2,894/oz), an after-tax Net Present Value (NPV
8
) of A$0.535 billion is generated over the initial
term with an IRR of 42% and a simple payback period of 1.7 years from the commencement of production.
• At the current spot price of gold (A$4,000/oz) the New Zealand (NZ) government royalty payments are estimated at A$296M
(NZ$325M) with corporate tax payments (28%) of a further A$728M (NZ$800M). These exclude payroll taxes and other indirect
taxes which add up to show the fiscal significance of the project to NZ and the Central Otago regional economy.
Santana CEO, Damian Spring said:
“We are pleased that our Pre-Feasibility Study with a higher level of accuracy has confirmed the robustness of the Bendigo-Ophir
Gold Project previously outlined in our Scoping Study.
We have upscaled the initial years of gold output commensurate with a deliberate decision to enlarge the mine pre-strip. Our
detailed geotechnical works have recommended more conservative pit wall slopes than our scoping study resulting in higher strip
ratios. However, our high-grade deposit combined with strong gold prices gives effect to a vastly improved post-tax NPV, valuing
the project at multiples of the current market cap. We still believe we can improve the project from here and will be working to
that end whilst advancing permitting.
Our team has worked tirelessly with detailed and diligent technical and baseline studies in line with previous Resource
Management Act consenting. We are pleased that the certainty and significance of this project have now secured an opportunity
to participate in the Fast-track Approvals process laid out by the New Zealand government. While we are confident we have
met—and will continue to meet—all previously expected standards, the overwhelmingly positive economics of our proposed
development add significant weight to our inclusion in this process and highlight the many benefits it brings to both the region
and the nation. With around 40% of the company owned by Kiwis and nearly all of our employees residing in New Zealand, this
project is truly shaping up to be a home-grown success story.”
ASX RELEASE
ASX:SMI
NZX:SMI
2
Bendigo-Ophir PFS 2024
Development timetable post PFS:
Based on the robustness and large financial headroom as estimated in the PFS, the Board has elected to move onto a detailed
construction plan with commencement of financing discussions.
Activities related to resource consents and mine permitting will continue with a view to applying into the Fast-track Approval process
in February 2025.
Webinar
The Company’s CEO Damian Spring will be hosting a webinar to present the outcomes of the PFS to investors at 10:30am
(AEDT)/12:30pm (NZDT) on Friday, 15 November. Registration is required prior to entry into the webinar, which can be accessed by
following this link: WEBINAR LINK.
Ore Reserve Statement
The Santana Board is pleased to announce an Ore Reserve Estimate (ORE) at the wholly owned Bendigo-Ophir Gold Project
(BOGP) in New Zealand. The BOGP JORC 2012 compliant ORE is 15.5 million tonnes @ 2.37g/t Au for 1.181 million ounces of
gold. This ORE is based on a Mineral Resource Estimate (MRE) of 40.3 million tonnes @ 1.9g/t Au for 2.46 million ounces reported
at a 0.25g/t cut-off grade. The July 2024 MRE of 36.8 million tonnes @ 2.1g/t Au for 2.46 million ounces was reported at a cut-
off grade of 0.5g/t. The lower cut-off grade at 0.25g/t reflects the economic outcomes of this PFS.
The BOGP ORE is tabled below:
Ore Reserve Statement
Note 1: RAS Open pit cut-off grade 0.3 g/t at $US1,650/oz Au price
Note 2: RAS Underground cut-off grade 1.75 g/t at $US1,650/oz Au price
Note 3: SRX Open pit cut-off grade 0.35 g/t at $US2,100/oz Au price
Note 4: Underground Reserves are from the quoted Open pit Resources area
Note 5: The effective date of the Mineral Reserve is 1 November 2024, estimated by Rodney Redden (MAusIMM and CP-Mining), a contractor to Santana
Minerals Ltd.
Note 6: Approved consents and required permits are yet to be granted to enable mining of the RAS and SRX deposits.
Cautionary Statement
Of the Mineral Resources planned for extraction under the PFS production model approximately 94% is within the Indicated Resource
category, with the balance (6%) being classified within the Inferred Resources category. There is a low level of geological confidence
associated with Inferred Mineral Resources and there is no certainty that further exploration work will result in the determination of
Indicated Mineral Resources or that the production target itself will be realised.
Area Proven Probable Total
Mt Au g/t Mt Au g/t Mt Au g/t Au koz
RAS (open pit) - - 11.9 2.42 11.9 2.43 928
RAS
(Underground)
2.3 3.03 2.3 3.03 223
SRX 1.3 0.70 1.3 0.70 30
Total - - 15.5 2.37 15.5 2.37 1,181
RAS Long Section Looking North - Open Pit Stages 1 to 5
RAS Plan View – Open Pit Stages 1 to 15
3
Bendigo-Ophir PFS 2024
Key PFS Data
The key outcomes of the PFS are summarised in the following tables and charts with full cost and input information in the PFS
Summary attached. Financial projections are presented using a spot gold price of A$4,000/oz. A robust base-case study using
A$2,894/oz is also presented and compared in Table 3.
Total mining physicals underpinning all financials can be seen below in Table 1.
Key Project Mining Physical Targets and Assumptions
Mine Life
Years
9.17
Plant Throughput
ktpa
1,835
Open Pit Ore Mined
kt
14,404
Open Pit Mill Feed
kt
14,404
Open Pit Mill Feed Grade
Au g/t
2.19
Open Pit Contained Gold
kOz
1,014
Open Pit Recovered Ounces
kOz
935
Underground Ore Mined
kt
2,413
Underground Mill Feed
kt
2,413
Underground Mill Feed Grade
Au g/t
2.99
Underground Contained Gold
kOz
232
Underground Recovered Ounces
kOz
215
Total Ore Mined
kt
16,817
Total Mill Feed
kt
16,817
Au Grade - Mined
g/t
2.30
Total Contained Gold
koz
1,245
Overall Plant Recovery
%
92.38%
Gold Production
kOz
1,151
Table 1. Key mining physicals
Table 2 below shows the ‘per tonne’, ‘per ounce’, and total combined cost for open pit and underground mining, with processing
costs, G&A, selling costs, royalties, and sustaining CAPEX, to show the average project C1 cash costs and average AISC costs per
ounce when using the spot price for gold of A$,4000/oz.
Operating Costs breakdown AUD '000 AUD /T Milled
AUD /Oz
Produced
Mining Cost
'000
771,984 45.9 671
Processing Costs
'000
288,943 17.2 251
General and Admin Costs
'000
55,633 3.3 48
C1 Cash Cost
'000
1,116,559 66.4 970
Selling Cost
'000
8,357 0.5 7
Royalties - Govt
'000
296,305 17.6 258
Royalties - Others
'000
123,887 7.4 108
Closure Capex (see note 1)
'000
- - -
Sustaining Capex
'000
83,663 5.0 73
All-in Sustaining Cost (AISC)
'000
1,628,771 96.9 1,416
Note 1: Conceptual mine closure costs netted to zero against mine salvage value.
Table 2. Gold production costs in C1 and AISC, per tonne, per ounce, and total A$.
4
Bendigo-Ophir PFS 2024
Table 3 below follows the Scoping Study cash flow template (announced 17 April 2024), splitting out open pit mining costs and
underground mining costs and building up totals to show a Total Production Cost per ounce, which includes all pre-production
CAPEX. The Total Production Cost per ounce in the PFS, at spot gold prices is A$1,818/oz, as compared to the Scoping Study of
$1,265/oz. The increase includes a government royalty of $186/oz, based on the higher profitability of the project at current
spot gold prices, and by applying the royalty rate at the higher 10% of accounting profits (previously 2% NSR rate applied in the
Scoping Study).
A base-case scenario underpinned the PFS at an Australian dollar gold price of A$2,894/oz, a ~28% discount to current spot gold
prices, as at 12 November 2024. Financial projections at the spot gold price of A$4,000/oz are also reported in NZD and USD:
Key Financial Assumptions Base Case AUD Spot AUD Spot NZD Spot USD
Gold Price
$/oz
2,894 4,000 4,406 2,626
Exchange Rate
USD:$
0.66 0.66 0.60 1.00
Key Project Metrics
Gold Produced
Oz
1.15 million
Initial Mine Life
Yr(s)
9.17
Gold Revenue
'000
3,330,018 4,602,435 5,069,319 3,021,314
Open Pit Mining Cost
'000
619,237 619,237 682,054 406,504
Underground Mining Cost
'000
152,747 152,747 168,242 100,272
Processing Costs
'000
288,943 288,943 318,254 189,679
General and Admin Costs
'000
55,633 55,633 61,276 36,521
Selling Cost
'000
8,357 8,357 9,204 5,486
Royalties - Govt
'000
170,173 296,305 326,363 194,512
Royalties - Others
'000
89,636 123,887 136,454 81,327
Total Cash Operating Cost
'000
1,384,725 1,545,108 1,701,848 1,014,301
Total Cash Operating Cost per Ounce
$/oz
1,203 1,343 1,479 881
Project EBITDA
'000
1,945,292 3,057,327 3,367,471 2,007,013
Depreciation and Amortisation (exc Rehab PPE)
'000
546,067 546,067 601,462 358,471
Total Production Cost (incl. all CAPEX)
'000
1,930,793 2,091,175 2,303,310 1,372,773
Total Production Cost per Ounce
$/oz
1,678 1,818 2,001 1,193
Net Profit Before Tax (NPBT)
'000
1,399,225 2,511,260 2,766,009 1,648,541
Tax Payable (28.0%)
'000
(424,010) (728,094) (801,954) (477,965)
After Tax Profit
'000
975,215 1,783,166 1,964,055 1,170,577
Capital
Initial Development Capex (inc. OP & Capitalised Opex)
'000
340,609 340,609 375,161 223,596
Underground Initial Development Capex
'000
121,795 121,795 134,151 79,954
Sustaining Capex
'000
83,663 83,663 92,151 54,922
Closure Capex (see note 1)
'000
- - - -
Total CAPEX over Mine Life
'000
546,067 546,067 601,462 358,471
DCF Outcomes
Initial NPV (unleveraged and after-tax) @8.00%
'000
534,975 1,058,104 1,165,441 694,603
IRR
%
41.66% 68.23% 68.23% 68.23%
Payback Period from production start (unleveraged and after-tax)
years
1.67 Yr(s) 0.92 Yr(s) 0.92 Yr(s) 0.92 Yr(s)
Note 1: Conceptual mine closure costs netted to zero against mine salvage value.
Table 3. Base Case vs Spot Gold and Currency Values
5
Bendigo-Ophir PFS 2024
The chart below shows the gold production profile and AISC in the main production years, after the pre-production and
commissioning phase, applying the spot gold price scenario. Approximately 150koz is produced from years one to three,
bolstering upfront cash flows:
Figure 1. Production Profile OP/UG w/AISC at Spot Gold Price
At the spot gold price of A$4,000/oz, the project generates nearly A$1.8 billion in free cash flow over the initial mining term. The
chart below shows the max cash draw down in the pre-production period, followed by very high returns in the first years of gold
production, allowing a <1yr payback from first production.
Figure 2. Project Free Cash Flows at Spot Gold Price
Gold Production OP/UG (oz per annum) w/ AISC Yr1 to Yr9 (AUD)
Project Free Cash Flows (including conceptual closure provisions for Yr 10/11)
152
151
138
129
98
185
119
129
45
1,268
1,213
1,287
1,641
2,044
1,302
1,604
1,130
1,709
-
500
1,000
1,500
2,000
2,500
-
20
40
60
80
100
120
140
160
180
200
Year 1Year 2Year 3Year 4Year 5Year 6Year 7Year 8Year 9
AISC $/oz
Production (kOz)
Open PitUndergroundAll-in-Sustaining Cost
(137)
(204)
341
267
234
178
155
391
212
263
76
20
(14)
(137)
(341)
0
267
501
679
834
1,226
1,438
1,701
1,777
1,797
1,783
(1,500)
(1,000)
(500)
-
500
1,000
1,500
2,000
2,500
(300)
(200)
(100)
-
100
200
300
400
500
Year -2Year -1Year 1Year 2Year 3Year 4Year 5Year 6Year 7Year 8Year 9Year 10Year 11
Cumulative net cash flow ($'000)
Cash Flow ($'000)
Project Free Cash Flow (inc tax)Cumulative FCF (RHS)
6
Bendigo-Ophir PFS 2024
The PFS targeted Indicated resources to forecast the mine’s economics. Approximately 94% of tonnes constituting ore feed are
in the Indicated resource category, as seen in Figure 3 below:
Figure 3. Indicated vs Inferred Ore Feed
The tornado chart below shows the NPV sensitivity analysis at the Base-Case gold price scenario.
Figure 4. NPV
8
sensitivity analysis on the Base-Case gold price scenario at A$2,894/oz
The table below shows the NPV, IRR and Payback metrics at price steps above and below the Base-Case and Spot price scenarios
applied in the PFS:
-A$200/oz Base-Case Spot Price +A$200/oz
A$2,694/oz A$2,894/oz A$4,000/oz A$4,200/oz
NPV8 $440M $535M $1.06b $1.15b
IRR 36% 42.00% 68% 73%
Payback 1,83Yrs 1.67Yrs 0.92Yrs 0.83Yrs
Table 4. Sensitivities on NPV, IRR and Payback metrics based on gold price movements.
(36,591)
(38,359)
(46,598)
(68,188)
(136,315)
(137,041)
36,591
41,312
46,598
68,149
136,097
137,041
(200,000) (150,000) (100,000) (50,000) - 50,000 100,000 150,000 200,000
Capex (+/-10%)
Discount Rate (+/-1%)
Operating Cost (+/-10%)
Recovery (+/-5%)
Grade (+/-10%)
Gold Price (+/-10%)
Indicated vs Inferred Ore Feed (94% Indicated resources into PFS schedule)
-
500
1,000
1,500
2,000
2,500
-
500
1,000
1,500
2,000
2,500
3,000
3,500
Year 1Year 2Year 3Year 4Year 5Year 6Year 7Year 8Year 9
AISC $/oz
Ore Tonnes Mined (kt)
IndicatedInferredAll-in-Sustaining Cost
NPV
8
Sensitivity analysis ($’000) based on the Base-Case gold price scenario at A$2,894/oz
7
Bendigo-Ophir PFS 2024
Please see the PFS Executive Summary appended below for more detail. This announcement has been authorised for release by
Santana’s Board of Directors.
Enquiries:
Damian Spring
Exec. Director & CEO
dspring@santanaminerals.com
Sam Smith
Exec. Director Corp Affairs & IR
ssmith@santanaminerals.com
Cautionary Statement
The Preliminary Feasibility Study (PFS) discussed in this ASX announcement has been conducted to assess the potential
development of the Bendigo-Ophir Gold Project in New Zealand. Of the Mineral Resources planned for extraction under the PFS
production model, about 94% are categorized as Indicated, with the remaining 6% classified as Inferred over the 9.17-year
assessment timeframe. The Company believes it has a reasonable basis to disclose a production target that includes some Inferred
Mineral Resources as the Inferred Resources are not a determining factor in the viability of the Project. However, it acknowledges
that there is a low level of geological confidence associated with Inferred Resources and that there is no certainty that further
exploration will result in the determination of Indicated Mineral Resources or that the production target itself will be realised.
Importantly, the feasibility of the development scenario outlined in the PFS does not hinge on the Inferred Mineral Resources.
Additionally, Ore Reserves are based solely on Indicated resources.
This announcement includes forward-looking statements. The Company has concluded that it has a reasonable basis for those
forward looking statements, including the production target set out in the PFS and the financial information on which it is based.
This basis is detailed throughout the release, with all critical assumptions, including the JORC modifying factors, on which the
forward looking statements rely, is fully disclosed in this release. Nonetheless, several variables could cause actual outcomes to
vary significantly from those suggested by the forward-looking statements. Given these uncertainties, investors are cautioned
against making investment decisions based purely on the PFS findings.
To achieve the range of outcomes anticipated in the PFS, the PFS estimates that financing on the order of A$340 million will be
required. Santana believes that there are reasonable grounds for the assumptions it has made in satisfying itself that the requisite
funding for the development of the Project will be available when required. However, Shareholders and prospective investors
should be aware that there is no guarantee Santana will be able to secure this funding as required, and it is possible that the terms
available may be dilutive or adversely otherwise impact the value of Santana’s current shares. Additionally, Santana may explore
alternative value-creating strategies, such as divesting some or all potential revenue streams from precious metals or a full or partial
sale of its interest in the Bendigo-Ophir project.
Previous ASX Disclosures - 2012 JORC Code
Information relating to Mineral Resources, Exploration Targets and Exploration Data associated with the Company’s projects in
this announcement is extracted from the following ASX Announcements:
• ASX announcement titled “Bendigo-Ophir Gold Resources Increased 155% to 643k Oz” dated 28 September 2021
• ASX announcement titled “1.3m ounces upgraded to Indicated category from RAS drilling” dated 16 February 2024
• ASX announcement titled “Outstanding Economics - RAS Scoping Study (First 10 Years)” dated 17 April 2024
• ASX announcement titled “Infill drilling increases RAS Indicated category to 1.45Moz” dated 2 July 2024
A copy of such announcements are available to view on the Santana Minerals Limited website www.santanaminerals.com. The
reports were issued in accordance with the 2012 Edition of the JORC Australasian Code for Reporting of Exploration Results,
Mineral Resources and Ore Reserves. The Company confirms that it is not aware of any new information or data that materially
affects the information included in the original market announcements referenced above and, in the case of the Mineral Resource
estimates, that all material assumptions and technical parameters underpinning the Mineral Resource estimates in the relevant
announcements continue to apply and have not materially changed. The Company confirms that the form and context in which
the Competent Person’s findings are presented have not been materially modified from the original market announcements.
8
Bendigo-Ophir PFS 2024
Current Disclosure - Competent Persons Statement
The information in this report that relates to the July 2024 RAS Mineral Resource Estimates (MRE) and to this November 2024
SRX and SRE MRE, is based on work completed by Mr Kerrin Allwood, a Competent Person (CP) who is a Member of The
Australasian Institute of Mining and Metallurgy (AusIMM). Mr Allwood is a Principal Geologist of GeoModelling Limited, Petone,
New Zealand and has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration
and to the activity which is being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the “Australasian
Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves”. Mr Allwood consents to the inclusion in this
report of the matters based on his information in the form and context in which it appears. Mr Allwood and GeoModelling Limited
are independent of Santana Minerals Ltd.
The information in this report that relates to the prior 2021 Mineral Resource Estimates (2021 MRE) for the CIT deposit completed
by Ms Michelle Wild (CP) (ASX announcement on 28 September 2021) continue to apply and have not materially changed.
The estimated Ore Reserves underpinning the production target set out in this Announcement have been prepared by a
Competent Person as defined in the 2012 Edition of the “Australasian Code of Reporting of Exploration Results, Mineral
Resources and Ore Reserves”, estimated by Rodney Redden (MAusIMM and CP-Mining), a contractor to Santana Minerals Ltd.
The information in this report that relates to the Ore Reserves for Rise and Shine (RAS), Srex (SRX) and Srex East (SRE) is based
on and fairly represents information and supporting documentation compiled by Mr Rodney Redden. Mr Redden is an Associate
of Redden Mining Limited, a full time contractor to Matakanui Gold Limited (a wholly owned subsidiary of Santana, and is a
Chartered Professional Mining Engineer of the Australian Institute of Mining and Metallurgy. Mr Redden has sufficient experience
that is relevant to the style of mineralisation and type of deposit under consideration and to the activity currently being
undertaken to qualify as a Competent Person as defined in the 2012 Edition of the “Australasian Code of Reporting of Exploration
Results, Mineral Resources and Ore Reserves”. Mr. Redden consents to the inclusion in this report of the matters based on the
information in the form and context in which it appears. The Company confirms that the form and context in which the
Competent Persons’ findings are presented have not been materially modified.
Forward Looking Statements
Forward-looking statements in this announcement include, but are not limited to, statements with respect to Santana’s plans,
strategy, activities, events or developments the Company believes, expects or anticipates will or may occur. By their very nature,
forward-looking statements require Santana to make assumptions that may not materialize or that may not be accurate.
Although Santana believes that the expectations reflected in the forward-looking statements in this announcement are
reasonable, no assurance can be given that these expectations will prove to have been correct, as actual results and future events
could differ materially from those anticipated in the forward-looking statements. Accordingly, viewers are cautioned not to place
undue reliance on forward-looking statements. Santana does not undertake to update publicly or to revise any of the included
forward-looking statements, except as may be required under applicable securities laws.
BENDIGO-OPHIR
PRE-FEASIBILITY
STUDY SUMMARY
2
Bendigo-Ophir Gold Project Pre-Feasibility Study | Disclaimers
Disclaimer
All information contained in this presentation is of a general nature. Potential investors are cautioned against using the content of this presentation, in
isolation, for making investment decisions and should also refer to Santana Minerals Limited (‘Santana’) Annual Reports and ASX:SMI releases. For further
information about Santana visit our website at www.santanaminerals.com.
Best efforts have been made to ensure the accuracy of information contained (at the time of preparation). Where forward targets and/or assumptions
have been included – all such instances are indicative only and subject to alteration and/or cancellation as and when the management of Santana
determines.
Research and advice of a qualified financial advisor or accountant are strongly recommended to anyone considering investing in listed company securities,
including those of Santana.
The Prefeasibility Study, including the production target and the forecast financial information derived from the production target, referred to in this
Presentation (PFS) was released to the ASX on 15 November 2024. This Presentation includes summary excerpts from the PFS and does not purport to
be all-inclusive or complete.
Forward-Looking Statements
This Presentation contains various forward looking statements. Forward-looking statements in this presentation include, but are not limited to,
statements regarding the production target, financial information based on that production target and statements statements with respect to Santana’s
future plans, strategy, activities, events or developments the Company believes, expects or anticipates will or may occur. By their very nature, forward-
looking statements require Santana to make assumptions that may not materialize or that may not be accurate. The Company has concluded that it has
a reasonable basis for providing these forward-looking statements, including the production target and the forecast financial information included in this
Presentation. The detailed reasons for these conclusions are outlined throughout the ASX releases dated 15 November 2024. However, no assurance can
be given that these expectations will prove to have been correct, as actual results and future events could differ materially from those anticipated in the
forward-looking statements. Accordingly, viewers are cautioned not to place undue reliance on forward-looking statements. Santana does not undertake
to update publicly or to revise any of the included forward-looking statements, except as may be required under applicable securities laws.
To achieve the range of outcomes anticipated in the PFS, the PFS estimates that financing in the order of A$340 million will be required. Santana believes
that there are reasonable grounds for the assumptions it has made in satisfying itself that the requisite funding for the development of the Project will
be available when required. However, Shareholders and prospective investors should be aware that there is no guarantee Santana will be able to secure
this funding as required, and it is possible that the terms available may be dilutive or otherwise adversely impact the value of Santana’s current shares.
Additionally, Santana may explore alternative value-creating strategies, such as divesting some or all potential revenue streams from precious metals or
a full or partial sale of its interest in the Bendigo-Ophir project.
Of the Mineral Resources planned for extraction under the PFS production model approximately 84% is within the Indicated Resources category, with the
balance (16%) being classified within the Inferred Resources category. There is a low level of geological confidence associated with Inferred Mineral
Resources and there is no certainty that further exploration work will result in the determination of Indicated Mineral Resources or that the production
target itself will be realised.
Competent Persons Statement
The production target and the forecast financial information derived from the production target set out in this presentation were first contained in a
public announcement released to the ASX on 13 November 2024. The Company confirms that all material assumptions underpinning the production target
and the forecast financial information derived from it continue to apply and have not materially changed.
The information in this report that relates to Mineral Resources is based on information contained in the following public announcements:
13 November – ASX Announcement titled “Bendigo-Ophir Pre-Feasibility Study”
2 July 2024 – ASX Announcement titled “Infill drilling increases RAS Indicated category to 1.45Moz”
16 February 2024 – ASX Announcement titled “1.3M ounces upgraded to Indicated category from RAS drilling:”
28 September 2021 – ASX Announcement titled “Bendigo-Ophir Gold Resources Increased 155% to 643k Oz”
The information in this report that relates to Ore Reserves is based on information contained in the public announcement made to the ASX on 13 November
2024.
The information in this report that relates to Exploration Results is based on information contained in the following public announcement:
22 August 2022 – ASX Announcement titled “MDD054 Jewellery Box Re-Assays to 1400 g/t Gold”
A copy of these announcements are available to view on the Santana Minerals Limited website www.santanaminerals.com or on the ASX platform
www.asx.com.au.
The reports are issued in accordance with the 2012 Edition of the JORC Australasian Code for Reporting of Exploration Results, Exploration Results, Mineral
Resources and Ore Reserves including the appropriate Competent Person’s statements. The Company confirms that the form and context in which the
Competent Person’s findings are presented have not been materially modified from the original market announcements.
The Company confirms that it is not aware of any new information or data that materially affects the information included in the original market
announcements and, in the case of estimates of mineral resources and ore reserves, that all material assumptions and technical parameters underpinning
the estimates in the relevant market announcement continue to apply and have not materially changes.
Cautionary Statement – Inferred Resources Included in Production Target
Of the Mineral Resources planned for extraction under the PFS production model approximately 94% is within the Indicated Resources category and is
classified Probable Reserves, with the balance (6%) being classified within the Inferred Resources category. There is a low level of geological confidence
associated with Inferred Mineral Resources and there is no certainty that further exploration work will result in the determination of Indicated Mineral
Resources or that the production target itself will be realised.
Competent Persons Statement
The production target and the forecast financial information derived from the production target set out in this presentation were first contained in a public
announcement released to the ASX on 15 November 2024. The Company confirms that all material assumptions underpinning the production target and
the forecast financial information derived from it continue to apply and have not materially changed.
The information in this report that relates to Mineral Resources is based on information contained in the following public announcements:
15 November – ASX Announcement titled “Bendigo-Ophir Pre-Feasibility Study”
2 July 2024 – ASX Announcement titled “Infill drilling increases RAS Indicated category to 1.45Moz”
16 February 2024 – ASX Announcement titled “1.3M ounces upgraded to Indicated category from RAS drilling:”
28 September 2021 – ASX Announcement titled “Bendigo-Ophir Gold Resources Increased 155% to 643k Oz”
The information in this report that relates to Ore Reserves is based on information contained in the public announcement made to the ASX on 15 November
2024.
The information in this report that relates to Exploration Results is based on information contained in the following public announcement:
22 August 2022 – ASX Announcement titled “MDD054 Jewellery Box Re-Assays to 1400 g/t Gold”
A copy of these announcements are available to view on the Santana Minerals Limited website www.santanaminerals.com or on the ASX platform
www.asx.com.au.
The reports were issued in accordance with the 2012 Edition of the JORC Australasian Code for Reporting of Exploration Results, Mineral Resources and
Ore Reserves. The Company confirms that it is not aware of any new information or data that materially affects the information included in the original
market announcements referenced above and, in the case of the Mineral Resource estimates, that all material assumptions and technical parameters
underpinning the Mineral Resource estimates in the relevant announcements continue to apply and have not materially changed. The Company confirms
that the form and context in which the Competent Person’s findings are presented have not been materially modified from the original market
announcements.
has context menu
3
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive
Summary
TABLE OF CONTENTS
Executive Summary .................................................................................................................... 7
ES 1. Introduction, Background and History ....................................................................................... 8
ES 1.1 Introduction .................................................................................................................... 8
ES 1.3 Background and History ................................................................................................ 11
ES 2. Current Permits and Land access ............................................................................................. 11
ES 3. Geology .......................................................................................................................................... 11
ES 3.1 Local Geology ................................................................................................................ 12
ES 3.2 Deposit Geology and Mineralisation .............................................................................. 12
ES 3.3 Rise and Shine ............................................................................................................... 13
ES 3.4 SRX ................................................................................................................................ 15
ES 4. Resources ..................................................................................................................................... 16
ES 4.1 Data .............................................................................................................................. 17
ES 4.2 Interpretation ................................................................................................................ 17
ES 4.3 Estimation ..................................................................................................................... 18
ES 4.4 Classification ................................................................................................................ 18
ES 4.5 Reasonable Prospects .................................................................................................. 19
ES 5. Geotechnical ................................................................................................................................ 20
ES 5.1 Open Pit ........................................................................................................................ 21
ES 5.2 Underground ................................................................................................................. 21
ES 6. Hydrogeology ................................................................................................................................ 22
ES 7. Metallurgical testwork ................................................................................................................. 23
ES 8. Mining ............................................................................................................................................ 25
ES 8.1 Introduction .................................................................................................................. 25
ES 8.2 Pit Optimisations ........................................................................................................... 25
ES 8.3 Pit Design ...................................................................................................................... 31
ES 8.4 Open Pit Production Scheduling .................................................................................... 33
ES 8.5 Mining Fleet and Requirements ..................................................................................... 40
ES 8.6 Engineered Landform (ELF) ........................................................................................... 41
ES 8.7 Rise and Shine Underground ......................................................................................... 43
ES 8.8 Mining Reserves ............................................................................................................ 47
ES 8.9 Relevant Factors ........................................................................................................... 48
ES 9. Plant feed schedule – all sources .............................................................................................. 49
ES 10. Processing .................................................................................................................................. 52
ES 10.1 Run-of-Mine (ROM) Pad and Crushing Circuit .............................................................. 54
ES 10.2 Milling ......................................................................................................................... 54
ES 10.3 Classification .............................................................................................................. 54
ES 10.4 Gravity Concentration ................................................................................................. 54
4
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive
Summary
ES 10.5 Trash Screening ........................................................................................................... 55
ES 10.6 Leach and Adsorption Circuit ...................................................................................... 55
ES 10.7 Elution ......................................................................................................................... 55
ES 10.8 Cyanide destruction .................................................................................................... 55
ES 10.9 Arsenic removal .......................................................................................................... 56
ES 10.10 Tails Thickening ......................................................................................................... 56
ES 10.11 Tailings Pumping ....................................................................................................... 56
ES 10.12 Throughput expansion .............................................................................................. 56
ES 11. TSF .............................................................................................................................................. 58
ES 11.1 Design ......................................................................................................................... 59
ES 12. Infrastructure ............................................................................................................................ 60
ES 12.1 Mining Operations and Processing Plant Site & Infrastructure ..................................... 60
ES 12.2 Project Water Supply ................................................................................................... 61
ES 12.3 Power Supply .............................................................................................................. 61
ES 12.4 Site Access and alternate route for Thomson Gorge Road ........................................... 61
ES 13. Costs .......................................................................................................................................... 62
ES 13.1 Operating Cost Estimates: Open pit ............................................................................ 62
ES 13.2 Operating Cost Estimates: Underground ..................................................................... 62
ES 13.3 Operating Cost Estimates: Processing ......................................................................... 63
ES 13.4 Operating Costs: General and Administration .............................................................. 64
ES 13.5 Capital Cost Estimates ................................................................................................ 64
ES 14. Financial evaluation ................................................................................................................ 67
ES 15. Environment .............................................................................................................................. 72
ES 16. Geochemical ............................................................................................................................ 75
ES 17. Community and iwi .................................................................................................................. 76
ES 18. Permitting .................................................................................................................................. 77
ES 18.1 Mining Permits ............................................................................................................ 77
ES 18.2 Resource Consents ..................................................................................................... 77
ES 18.3 Application .................................................................................................................. 78
ES 19. Closure ...................................................................................................................................... 78
ES 20. Project Implementation .......................................................................................................... 78
ES 21. Risks and Opportunities .......................................................................................................... 79
ES22. Funding ...................................................................................................................................... 80
5
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive
Summary
Figures
Figure ES 1: BOGP general site layout ................................................................................................ 9
Figure ES 2: BOGP Location ............................................................................................................. 10
Figure ES 3: Regional Setting of the Bendigo-Ophir Project Area (BOGP) .......................................... 12
Figure ES 4: Main Prospects Along the RSSZ .................................................................................... 13
Figure ES 5: RAS deposit map .......................................................................................................... 14
Figure ES 6: RAS deposit long section .............................................................................................. 14
Figure ES 7: RAS deposit cross section ............................................................................................ 15
Figure ES 8: SRX deposit geological map ......................................................................................... 16
Figure ES 9: SRX deposit cross section ............................................................................................ 16
Figure ES 10: An orthogonal view looking south of the RAS final pit and Underground workings ....... 26
Figure ES 11: RAS pit by pit optimisation results .............................................................................. 28
Figure ES 12: SRX pit by pit optimisation results .............................................................................. 29
Figure ES 13: RAS sensitivity analysis spider graph .......................................................................... 31
Figure ES 14: RAS staged pit designed long section ......................................................................... 32
Figure ES 15: RAS pit stages in plan view ......................................................................................... 32
Figure ES 16: Total material mined per year at RAS open pit ............................................................. 36
Figure ES 17: Total material mined at RAS open pit per stage per year ............................................. 36
Figure ES 18: Northwest-Southeast Cross-section of the Waste Rock Dump................................... 43
Figure ES 19: Development Design .................................................................................................. 45
Figure ES 20: Panel layout ............................................................................................................... 45
Figure ES 21: Mill feed by source ..................................................................................................... 51
Figure ES 22: Mill feed tonnes by resource class .............................................................................. 51
Figure ES 23: Mill feed ounces by resource class ............................................................................. 52
Figure ES 24: BOGP Process plant – process flow diagram .............................................................. 53
Figure ES 25: Process plant – general arrangement ......................................................................... 57
Figure ES 26: shows the location of the TSF and ELFs ...................................................................... 58
Figure ES 27: TSF and ELF sections .................................................................................................. 59
Figure ES 28: Main BOGP Infrastructure area ................................................................................... 60
Figure ES 29: Project Free cash flow (inc Tax, NZD'000) ................................................................... 71
Figure ES 30: Project NPV Sensitivities (NZD'000) at 8% Post-Tax, Real Discount Rate .................... 71
Figure ES 31: Production Profile OP/UG w/AISC at Spot Gold Price (NZ$4,406/oz) .......................... 72
Figure ES 32: Project Footprint, Ecological Study Area, Dunstan Ecological District and DOC
administered conservation areas .................................................................................................... 73
Tables
Table ES 1: Collated Mineral Resource Estimates ............................................................................ 20
Table ES 2: RAS PFS Level Recommended Pit Slope Design ............................................................ 21
Table ES 3: SRX Scoping Level Recommended Pit Slope Design ...................................................... 21
Table ES 4: Assessed Hydraulic Radii for Stope Walls ...................................................................... 22
Table ES 5: Recommended Stope Dimensions with Cable Bolting in the Backs ............................... 22
Table ES 6: Block model and topography files .................................................................................. 26
Table ES 7: Optimisation input parameters ..................................................................................... 27
Table ES 8: Optimisation mining cost and adjustment factors ......................................................... 27
Table ES 9: Sensitivity analysis top three parameters ranking .......................................................... 30
Table ES 10: Final pit design versus shell 32 .................................................................................... 31
Table ES 11: Pit Stage Inventories .................................................................................................... 33
6
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive
Summary
Table ES 12: SRX final pit design versus shell 33 .............................................................................. 33
Table ES 13: RAS - Pit Design Inventory ............................................................................................ 34
Table ES 14: RAS OP Mining Schedule ............................................................................................. 37
Table ES 15: SRX - Pit Design Inventory ............................................................................................ 38
Table ES 16: SRX (monthly) Mining Schedule ................................................................................... 39
Table ES 17: Open pit drill and blast parameters ............................................................................. 40
Table ES 18: Mining fleet composition ............................................................................................. 41
Table ES 19: Waste Rock Dump Design Capacity ............................................................................ 42
Table ES 20: Break Even Cut off Grade Calculation .......................................................................... 44
Table ES 21: Ore details and Waste by year ..................................................................................... 46
Table ES 22: Development by Type .................................................................................................. 46
Table ES 23: Paste, cabling, trucking, shotcrete .............................................................................. 47
Table ES 24: BOGP Mineral reserve estimate as at 1 December 2024 .............................................. 48
Table ES 25: Annual Processing Schedule ....................................................................................... 50
Table ES 26: LoM open pit mining costs ........................................................................................... 62
Table ES 27: LoM Underground mining operating costs ................................................................... 63
Table ES 28: LoM Processing operating costs .................................................................................. 64
Table ES 29: General and Administration operating costs ................................................................ 64
Table ES 30: Site establishment costs breakdown ........................................................................... 65
Table ES 31: Further detailed breakdown of the 1.5Mtpa plant EPCM cost ...................................... 66
Table ES 32: Full TSF capital costs ................................................................................................... 66
Table ES 33: Underground capital ................................................................................................... 67
Table ES 34: Other capital costs ...................................................................................................... 67
Table ES 35: Key Project Metrics ...................................................................................................... 68
Table ES 36: Key Financial Metrics ................................................................................................... 69
Table ES 37: Summary operating costs ........................................................................................... 70
Table ES 38: Capital cost summary ................................................................................................. 70
7
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive
Summary
8
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive
Summary
Executive Summary
ES 1. Introduction, Background and History
ES 1.1 Introduction
The Bendigo Ophir Gold Project (BOGP) as presented in the Preliminary Feasibility Study (PFS)
will be an open pit and underground mining operation based on the Rise and Shine (RAS) orebody
with satellite feed from the Srex (SRX) orebody.
The study has been prepared by selecting a base-case scenario modelled on a conservative gold
price of US$1,900/oz. To forecast more current economics, a spot gold price scenario was also
modelled at US$2,626/oz. The key inputs, including foreign exchange rates, mining and
processing costs, mining parameters, and all associated financial outcomes of the study can be
found in section ES14 Financial evaluation.
At the current spot price of gold (A$4,000/oz), an after-tax Net Present Value (NPV8) of A$1.06
billion is generated over the initial term with an IRR of 68% and a simple payback period of less
than one year from the commencement of production.
At the base case price of gold (A$2,894/oz), an after-tax Net Present Value (NPV8) of A$0.535
billion is generated over the initial term with an IRR of 42% and a simple payback period of 1.7
years from the commencement of production.
The primary RAS orebody underpins the PFS with grades and thicknesses that support an
underground mining operation beneath the economic limits of the open pit. The processing rate
will initially be 1.5Mtpa, expanding to 2.1Mtpa when the underground is brought into production
in parallel with on-going open pit feed sources. The total processing inventory is 16.8Mt at 2.3g/t
for 1,245koz. 94.9% of the feed ounces are from Indicated resources. Inferred resources mined
are only as a consequence of mine designs optimised to target Indicated resources only.
The RAS orebody is estimated to have a total recovery to doré of 93% of the contained metal. SRX
recovery is 68% through the process flow sheet which is optimised on RAS mineralisation.
Significant Inferred resources remain west of and down dip at RAS, and also at SRX and Come-
in-Time (CIT) deposits that have not been included in this PFS.
Infill drilling at CIT deposit was incomplete prior to the most recent Mineral Resource Estimate
(MRE) update.
The processing flowsheet is a simple single stage crush, grind, gravity concentrate, carbon-in-
leach (CIL), elution to a conventional wet tailings storage facility (TSF). Doré will be the final
product. The TSF will be completely buttressed during and post operations by the engineered
landform (ELF) comprising waste material from the RAS pit.
There is nearby access from the national road network, along with fresh water and high voltage
power, all readily accessible from just outside the project area. An initial construction camp will
be established to cater for temporary personnel involved in establishing the project. Operations
staff will be based in any of the multiple local communities within an hour’s drive of the project.
The overall site layout is shown in Figure ES 1.
9
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive
Summary
Figure ES 1: BOGP general site layout
10
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
The BOGP is sited in the Dunstan Mountains of Central Otago, South Island, New Zealand (NZ)
(see Figure ES 2) within the territorial authorities of Central Otago District Council (CODC) and
Otago Regional Council (ORC).
The local area is known as Bendigo, named in the 1860s by miners arriving from the Australian
(Bendigo, Victoria) goldfields. The Dunstan Mountains comprise large pastoral holdings.
Vineyards and cherry orchards are developed on terraces flanking the northwestern margin of
the Dunstan Mountains.
Figure ES 2: BOGP Location
11
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
The preferred route to the site from Cromwell, the nearest main centre, is via State Highway 8
(SH8) to the Ardgour Road turn-off (24km from Cromwell), then via Ardgour Road, before
travelling along Thomsons Gorge Road (TGR) for 6.5km. Finally, a new road into Shepherds Valley
will provide access to the process plant site.
ES 1.3 Background and History
The area’s mining activity dates back to the Otago gold rush of the 1860s, when the discovery of
gold in Central Otago attracted miners from around the world. Gold mineralisation is widespread
within the Otago Schist, with over 5 million ounces of hard-rock gold, and 8 million ounces of
alluvial gold, being won from Otago goldfields.
The Bendigo field quickly became one of the most significant quartz reef mining areas in Otago,
with approximately 300,000 ounces of gold mined from the Bendigo goldfield and its surrounding
areas up to the 1940s.
In 2012 Depot Corporation Ltd, led by Santana Director, Kim Bunting, began regional exploration
in the RAS valley using track and trail regolith mapping, rock chip sampling, and portable XRF soil
geochemistry. In 2014 Depot Corporation vended its exploration permits to Matakanui Gold
Limited (MGL) and drilling operations were conducted at CIT, RAS and SRX in 2018 and 2019.
In 2020, ASX-listed Santana Minerals Ltd bought MGL with initial diamond drilling commencing
immediately thereafter. Drilling continued in 2021, when the RAS discovery hole (MDD007) was
drilled at 40.3m @ 2.05g/t gold.
ES 2. Current Permits and Land access
The BOGP sits within Mineral Exploration Permit (MEP) 60311.
MEP60311 is owned by Matakanui Gold Limited (MGL) (NZBN 9429041420614) which is a NZ-
registered company, and a fully owned subsidiary of Santana Minerals Limited (SMI) (ACN 161
946 989), an Australian-registered company listed on the Australian Stock Exchange (ASX.SMI)
and the New Zealand Stock Exchange (NZX.SMI).
Land ownership across the project area is freehold, private land, with Bendigo Station to the
southwest (SW) and Ardgour Station to the northeast (NE). Agreements are in place with both
Bendigo and Ardgour stations that allow the project to proceed, subject to project consents and
company approval, through a mix of agreements relating to:
• Purchase;
• Lease agreements; and
• Mining terms with royalty structures.
ES 3. Geology
Gold mineralisation occurs along the Rise and Shine Shear Zone (RSSZ) within the Otago Schist
(Figure ES 3). The Otago Schist is formed from sedimentary and minor intermediate volcanics
and volcaniclastics of the Caples and Rakaia tectono-stratigraphic terranes. Schist protolith
rocks were deposited in a forearc setting along the paleo-Pacific convergent margin of
Gondwana between ca. 250 and 200 Ma.
12
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 3: Regional Setting of the Bendigo-Ophir Project Area (BOGP)
ES 3.1 Local Geology
The Dunstan Mountains are an uplifted block of the Otago Schist, tilted towards the northwest,
with remnants of a Cretaceous peneplain preserved on its northwest slope.
The largely coplanar RSSZ and younger Thomsons Gorge Fault (TGF) cut across the axis of the
Dunstan Mountains. The TGF juxtaposes lower greenschist facies TZ3 and mid to upper
greenschist facies TZ4 schists. Both the TGF and the RSSZ strike northwest and dip
approximately 25° towards the northeast.
The TGF across the RSSZ is an unmineralised 0.3m – 12m thick cataclastic, fault zone separating
biotite zone schists in the southwest (footwall, TZ4) from chlorite zone schists in the north-east
(hanging-wall, TZ3). The TGF is locally extremely planar. Later NE-striking faults (i.e. Norms
Fault) displace the TGF by 10’s to 100’s of metres.
The RSSZ occurs in TZ4 schists of the footwall of the TGF and is a zone up to 200m thick of low-
angle, late-metamorphic, silicified brittle shears within greenschist facies psammitic, pelitic and
meta-volcanic rocks of the Mesozoic Otago Schist Group. The RSSZ silicified shears are termed
silica breccias (SBX).
The RSSZ dips 20-30° to the north-east and generally crosscuts the metamorphic foliation at a
low angle.
ES 3.2 Deposit Geology and Mineralisation
Gold mineralisation is concentrated in four deposits along the shear zone. The deposits known
along the RSSZ are: Come in Time (CIT), Rise and Shine (RAS), Srex (SRX), all approximately 1km
apart, and Srex East (SRE), located about 200m east of SRX.
13
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 4: Main Prospects Along the RSSZ
RAS, SRX and SRE all outcrop in the base of the Rise & Shine Valley and dip north. The CIT deposit
outcrops near the top of the southern face of the Shepherd’s Creek Valley. The gold deposits
identified to date in the RSSZ form 150m to 500m wide shoots plunging to the north.
Mineralisation is generally hosted in breccias or veins.
ES 3.3 Rise and Shine
Mineralisation at RAS has been traced over a width of 350m and down plunge (25 degrees to the
NNE) length of 1.7km. Mineralisation extends up to 90m below the TGF, however is typically 30-
40m. Refer to Figure ES 5, Figure ES 6, and Figure ES 7.
Within the wider zone of mineralisation at RAS, a higher-grade core of approximately 150-200m
width contains most of the gold. The high-grade core is a cataclasite (brecciated) network of
anastomosing, post-metamorphic quartz (SBX), these occur with minor sulphide veins in a halo
around the core mineralisation. Locally, a number of splay faults are interpreted coming off the
main structure which give a sense of structural control. These are also mineralised and are
traceable for 10s to 100s of metres.
The RAS deposit is primarily all fresh rock with subsurface oxidation variably extending from 5-
20m depth.
14
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 5: RAS deposit map
Figure ES 6: RAS deposit long section
15
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 7: RAS deposit cross section
ES 3.4 SRX
The SRX and SRE deposits are located in the upper part of Rise and Shine Creek 1.5 to 2kms
upstream of the much larger RAS deposit. Currently the known mineralisation at SRX covers an
area of 470m x 470m (see Figure ES 8 and Figure ES 9). SRE is offset by 200m from SRX and
covers an area of 350m x 450m. Total mineralised thicknesses are typically 5-15m. The total
thickness is made up of smaller lenses containing economic grades surrounded by sub-grade
material. The mineralised system at SRX is still open to the north and northwest. Micaceous-
carbonate breccia (MCBX} forms the thickest and most extensive zone of strongly deformed rock
within the wider RSSZ at SRX implying it is the principal strand of the RSSZ in this location. The
dominance of MCBX over SBX at SRX implies there was less fluid flow and less intense alteration
at SRX compared with RAS. The abundance of unaltered metamorphic mica in the matrix of
MCBX, unlike in SBX, is consistent with this interpretation.
16
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 8: SRX deposit geological map
Figure ES 9: SRX deposit cross section
ES 4. Resources
The Total Mineral Resource Estimate (MRE) for the Bendigo-Ophir Gold Project using a 0.25 g/t
cut-off for open pit and 1.5 g/t for underground is 40.3 Mt at 1.9 g/t for 2.46 Moz comprised of
RAS open pit, RAS underground, CIT and SRX/SRE resources. All mineral resource estimates
17
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
were prepared by an external consultant using data provided by Santana Minerals. The lower
0.25g/t cut-off grade than the 0.5g/t used in the RAS July 2024 MRE is due to the robust
economics reported in this PFS, additional metallurgical testing and increase gold price. Other
than reporting at a lower cut-off grade there are no other changes from the RAS July 2024 MRE.
A summary of the material information used to estimate the mineral resources for Rise and Shine
(RAS) and Srex (SRX) and Srex East (SRE) is presented in accordance with the Australasian Code
for Reporting of Exploration Results, Mineral Resources and Ore Reserves (the ‘JORC Code’)
2012 edition (refer appended JORC Table 1). For details on the Come in Time (CIT) MRE, please
refer to the announcement dated 28 September 2021.
ES 4.1 Data
The RAS MRE is based on assay sample results from 22 Reverse Circulation Drill (RC) holes
(2,004.5m) and 256 Diamond Drill (DD) holes (71,640.4m). The SRX and SRE MRE is based on
154 RC holes (9,797.3 m) and 66 DD holes (9,445.3 m).
RC samples were collected in the sample box at the base of the cyclone and released into the
riffle splitter at every metre. All diamond core samples were drilled using triple tube methods.
Half-core sampling was completed at predominantly 1m intervals.
All samples were assayed by 50g fire assay at the SGS Laboratories in Westport, Waihi and
Macraes. Routinely, a small number of samples were re-assayed by screen fire assay (SFA),
photon analysis (PA) or accelerated cyanide leach (BLEG) of a 500g sub-sample of the original
coarse rejects as QAQC checks on the original fire assays. The results of these re-assays were
ranked higher than the original fire assay and were used in the MRE
QAQC procedures were completed as per industry standard practices, including blanks,
certified standards, field duplicates, laboratory QAQC and umpire checks.
ES 4.2 Interpretation
At RAS an implicit wireframe model was generated based on a 0.2g/t cut off using surfaces
interpreted from the structural SBX model to control the anisotropy. At the deposit scale no
natural grade breaks have been identified to inform domain boundaries.
At SRX and SRE sectional interpretation was used to generate seven domain wireframes at a
0.25g/t cut off. The nominal interpretation grade was selected because histograms and
cumulative probability plots of the un-domained SRX data showed no natural lower cutoff that
could be used to define mineralisation.
Cross sections for CIT were interpreted on east-west sections at 40m intervals. An assay
boundary of 0.1g/t Au and composite interval using a 0.1g/t Au cut-off grade were used to
delineate the halo of mineralisation on each section. Points were snapped to drillholes,
channels, trenches and underground adit sample points. Subsequent to the mineralised halo
wireframing a higher grade shoot was domained as a discrete zone.
Four oxidation domains were interpreted across the entire project area. The oxidation domains
are intended for use in estimating bulk density and mine planning. The domains include a soil
boundary, notionally 1 m below topography, an oxide domain which varies from 5 to 20 m thick,
a transitional domain which also varies from 5m to 20m thick and is underlaid by a fresh domain.
The bulk of the mineralisation is located within the fresh domain.
18
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 4.3 Estimation
High grade outlier analysis has been completed on 2m composites for each individual
mineralization domain at RAS and SRX. CIT samples were composited to 1m intervals. The
effects of the highest-grade composites on the mean grade and standard deviation of the gold
dataset for each of the estimation domains have been investigated. An upper cut for each
dataset was chosen coinciding with a pronounced inflection or increase in the variance of the
data. RAS outliers were managed by using a distance restriction at a particular grade threshold
to restrict the influence of high-grade values. At RAS gold values greater than the cut off were
restricted to 25 m during the estimation process. At CIT, SRX and SRE, top cuts were used to cut
the composited data.
Wireframed mineralisation domains were used as "hard boundaries" for estimation. Oxide and
transitional mineralisation were estimated together with the fresh mineralisation.
Ordinary Kriging (OK) was selected as the method for estimating the gold grade. Samples at RAS
and SRX were composited to 2m for grade estimation while CIT composites were 1m. At RAS a
single pass was used to interpolate all blocks. Two interpolation passes were used at SRX and
SRE as there are distinct densely and sparsely drilled zones there. CIT used 3 estimation passes
to account for local changes in orientation.
At RAS and SRX block size of 12.5mE by 12.5mN by 2mRL was selected as the appropriate parent
block size given the drill spacing with appropriate sub-celling to ensure adequate volume
representation. CIT parent blocks were 10mE by 20mN by 5mRL.
Variography for the main domains indicate a moderate nugget of 50% with a maximum range of
125m, a semi-major range of 55m and a minor range of 35m for RAS and a high nugget of 80%
with a short range of 30m for Srex. CIT had a lower nugget of 31% and a major range of 50m.
Elliptical search neighbourhoods within domains were applied. The search ellipsoids were
oriented parallel to the variogram model axes and the ratios of the search ellipsoid axis lengths
approximate the ratios in the variogram models. In the main domain at RAS the search ellipsoid
major and semi-major axes were both 150m, reflecting the spatial distribution of the drilling. The
search ellipsoid minor axis was 30 m, the variogram range in that direction. In the steep domain
the semi-major axis of the search ellipsoid was reduced to 75 m to reflect the anisotropy in the
variogram model. The search used a minimum of 4 and a maximum of 15 composites. At SRX
and SRE pass 2 was similar to RAS whereas pass 1 used smaller search axes with a minimum of
10 and a maximum of 20 composites.
Bulk density was interpolated in all block models from density measurements into blocks of the
fresh oxidation domain using inverse distance squared weighting. The fresh oxidation domain
was used as a hard boundary. In blocks where bulk density was not interpolated, bulk density
was assigned to the block model by oxidation domain.
ES 4.4 Classification
Resource categorisation reflects confidence in the estimation of gold grades and is based on
input data quality, geological interpretations, distance to the nearest composite used to
interpolate a block, the average distance to all composites used to interpolate a block and the
kriging slope of regression. The resource estimates have been classified as Indicated and
Inferred Mineral Resources.
19
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 4.5 Reasonable Prospects
Reported resources have all been assessed for Reasonable Prospects of Eventual Economic
Extraction (RPEEE) based on site specific criteria. RPEEE assessments were carried out
sequentially for open pit mining followed by underground mining. Note that detailed Reserve
assessments may move the mining method crossover point based on the economic outcomes.
The portion of the resource considered amenable to open cut mining is reported at lower cutoff
grade of 0.25g/t Au within a RPEEE pit shell. This lower cut-off grade than the 0.5g/t used in the
July 2024 MRE is due to the robust economics reported in this PFS, additional metallurgical
testing and increase gold price. Other than reporting at a lower cut-off grade there are no other
changes from the July 2024 MRE. Outside of this pit shell underground resources are reported at
a lower cutoff of 1.5g/t Au at RAS only. Refer to Table ES 1.
To assess reasonable prospects of economic extraction for mineralisation that potentially could
be extracted by open pit mining methods, the resources have been constrained within a
conceptual Whittle pit shell for each of the deposits.
The conceptual open pit shells for RAS and SRX are based on the following input parameters:
• Gold price NZ$3,250/oz,
• Exchange Rate 0.60 NZD/USD,
• Metallurgical Recovery of 90%,
• Pit slope angles of 45° for all material; and
• Industry correlated mining, ore processing and administration operating costs.
For CIT the following inputs were used:
• Gold price NZ$2,500/oz
• Metallurgical Recovery of 70%
• Processing, NZD$15.00/t
Note that the economic assessment for CIT was at a higher level than RAS or SRX and was based
on earlier extraction investigations.
20
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 1: Collated Mineral Resource Estimates
Deposit
Mining
method
Category
Cutoff
(Au g/t)
tonnes
(Mt)
Au
(g/t)
koz
RAS
open pit
Indicated
0.25
19.6 2.3 1,452
Inferred 9.9 2.0 634
Total 29.5 2.2 2,086
underground
Indicated
1.5
0 1.9 0
Inferred 2.1 2.2 145
Total 2.1 2.2 145
RAS Total
Indicated
19.6 2.3 1,452
Inferred 12 2.0 779
Total 31.6 2.2 2,231
SRX open pit
Indicated
0.25
2.6 0.7 59
Inferred 2.4 0.9 73
Total 5.0 0.8 132
SRE open pit
Indicated
0.25
0.4 0.7 10
Inferred 0.1 0.9 3
Total 0.5 0.8 13
CIT open pit Inferred 0.25 3.2 0.8 81
Total combined
Indicated
22.6 2.1 1,521
Inferred 17.7 1.6 936
Total 40.3 1.9 2,457
Note: totals may not add due to rounding
ES 5. Geotechnical
A mining focussed site investigation was conducted in early 2024, comprising of four
geotechnical purposed boreholes targeting the proposed RAS pit walls.
The typical rock mass conditions at RAS are summarised as follows:
• A thin layer (1 to 2m) of alluvium and colluvium is present across the site. Alluvium located
within the natural streams. This surficial layer is not anticipated to impact the open pit, nor
underground mine designs.
• Weathered schist (Textural zone 3 - TZ3) is located within the top 20m across the site.
Weathering at SRX is deeper than at RAS.
• The highly foliated (Textural zone 3 - TZ3) chlorite schist rock located above the TGF is
generally weak to moderately strong rock (~20 MPa) and is dominated by foliation shears as
well as foliation parallel shear zones, which become more abundant within 30m of the TGF.
• TGF comprises of fractured and fragmented schist within a matrix of clay gouge. The TGF
thickness varies between 0.5 to 3m within the RAS deposit.
• Textural zone 4 (TZ4) situated below the TGF comprises mineralised biotite schist. The rock
mass is generally medium to strong rock (50 to 90MPa).
21
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 5.1 Open Pit
The recommended pit slope design sectors and slope configurations for RAS and SRX are
presented respectively in Table ES 2 and Table ES 3. The level of data available for SRX is scoping
level only.
Table ES 2: RAS PFS Level Recommended Pit Slope Design
Wall
Aspect
(1)
(°)
Unit
IRA
(2)
(°)
BFA
(3)
(°)
Berm
Width (m)
Bench
Height (m)
Controlled By
Southwest
350 to
065
All 30 50 9 15
Foliation/foliation shears
dipping towards
northeast
West
065 to
160
TZ3 35 50 11 15
Planar sliding along the
obliquely dipping TGF
(4)
TZ4 45 60 6.5 15
Planar failure along
faults and shears
identified behind the pit
wall
Northeast
160 to
235
All 45 60 6.5 15
East
235 to
350
TZ3 40 60 9 15
Planar sliding along the
obliquely dipping TGF
(4)
TZ4 47 70 7.5 15
Planar failure along
faults and shears
identified behind the pit
wall
(1) Slope aspect measured as the direction the wall dips towards.
(2) Inter-ramp angle.
(3) Batter face angle.
(4) Opportunity to steepen IRA based on future 3D stability analyses and/or mapping data of the TGF.
Table ES 3: SRX Scoping Level Recommended Pit Slope Design
Wall
Aspect
(°)
IRA
(°)
BFA
(°)
Berm
Width (m)
Bench
Height (m)
Controlled by
Southwest
350 to
065
30 50 9 15
Foliation/foliation shears
dipping towards northeast
West,
Northeast, and
East
065 to
350
45 60 6.5 15
Probable Planar failure along
faults and shears identified
behind the pit wall
ES 5.2 Underground
The empirical assessments conducted assess the potential dimensions of each stope face.
Based on the assessment, the end walls of the stopes are not expected to control the stope
width. Where the stability of the backs is able to be controlled by cable bolting, the requested
15m stope width is expected to be feasible.
22
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 4: Assessed Hydraulic Radii for Stope Walls
Stope Wall
Hydraulic Radii (Recommended Range, typical conditions)
Matthews / Potvin Assessment
Hanging and footwall (TZ4) 4.6 – 5.5
Stope backs (when in TZ3) 1.4
(1)
Stope backs (when in TGF) 0.6
(1)
Stope backs (when in TZ4) 3.2 – 3.8
Stope end wall (TZ4) 5.0 – 5.9
(1) Unsupported.
Table ES 5: Recommended Stope Dimensions with Cable Bolting in the Backs
Depth
(mbgl)
Stope Height
(1)
(m)
Maximum Stope
Length
(2)
(m)
Maximum Stope
Width
(3)
(m)
Notes and Limiting Wall
Mechanism
250
20 25
15
(4)
Assumes heavy support of the
backs is practical and
economic
Potential for footwall planar
slide
25 20
400
20 20
25 15
(1) Vertical height.
(2) Along strike.
(3) Across Strike
(4) Stope width is expected to be controlled by the ability to support the backs.
Development ground support in the TZ3 will be shotcrete with rock-bolts and in the TZ4 it will be
mesh with rockbolts.
ES 6. Hydrogeology
The BOGP sits astride a ridge dividing the Shepherds Creek and Rise and Shine Creek on the
eastern flanks of the Dunstan Mountains, Central Otago. Shepherds Creek is a minor tributary of
the Lindis River, while Rise and Shine Creek is a small tributary of Bendigo Creek, both diminish
and cease flowing as the creeks pass off the hard-rock schist onto the more permeable gravel
deposits forming alluvial aquifers across the valley floors. Regionally, the Clutha River
catchment makes up 67% (⅔) of the Otago region, and the mean flow of the Clutha passing the
Bendigo area is approximately 271 cubic metres per second (23,414 megalitres per day). There
is a strong pluviographic (rainfall) gradient from extremely high runoffs in the Southern Alps
headwaters to specific discharge only a sixth of the Alps in the Bendigo catchments. The gradient
is the result of a drop-off in Alps spill-over precipitation, plus the effect of rain shadowing by
inland Otago ranges.
Shepherds and Bendigo Creeks become intermittent and drain into the ground before meeting
their respective downstream main stems, due to soakage into the creek bed gravel alluvium.
However, groundwater under the mining complex is found within fractured rock comprising
Otago Schist (including textural zone 3, 4, and the Rise and Shine Shear Zone), with very low
permeabilities compared to the alluvial aquifers found on the valley floors. The excavation of the
RAS surface mining pit, and the underground, will each induce the seepage of small volumes of
water from the surrounding rock, requiring it to be pumped away from the working faces. The
23
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
relatively low fracture permeability of all parts of the schist rockmass constrains the rates of
seepage and makes the discharge a relatively small part of the mining complex water balance.
Current model estimates of the ultimate RAS pit inflows lie between 14 and 28 litres per second.
Corresponding RAS underground workings’ groundwater seepage rates approach 24 litres per
second at peak.
The planned mining and processing complex requires a water supply of up to 97 litres per second
for the process plant, mainly for plant make-up water and dust suppression. This would be
obtained from two bores in the Bendigo Aquifer, located 7 kilometres to the west of the mining
complex. Mine water would also be used in a supplemental role in processing and dust
suppression, to offset the need to discharge or use clean water. When in full operating cycle, a
significant amount of water will be recycled from the tailing storage facility. Otherwise, water
mainly leaves the site through evaporation. During and after infrequent rain events, mine
influenced water will be recycled or treated to meet water quality limits before any discharge.
A production bore test in July 2024 has demonstrated the required capacity in addition to
inducing off-site effects, that are in all respects acceptable (i.e., water levels, impacts on surface
water and availability of allocation).
ES 7. Metallurgical testwork
Various historical testwork programmes (Stages 1 through 4) have been completed for the
BOGP, primarily by Kappes Cassidy and Associates (KCA) and ALS Laboratory, during 2018 to
2022.
The PFS testwork programme had the following objectives:
• Composite master sample selection to represent the expected Life of Mine (LOM) ore blend
for the RAS deposit.
• Variability sample selection for RAS to provide spatial variability data.
• Determination of comminution characteristics for the master composite and variability
samples.
• Gravity recovery and intensive leaching of gravity concentrate on all samples.
• Flotation sighter testing on master composite.
• Cyanide leach grind optimisation, reagent optimisation and CIL testing on master composite.
• Cyanidation response based on optimised flowsheet for the variability samples.
As the testwork program proceeded the following steps were included:
• Cyanide destruction testwork on master composite.
• Arsenic removal on master composite.
• Diagnostic leaching of optimised CIL of master composite.
• Thickening testwork.
The SRX deposit was subsequently added to the testwork program, with initial testwork based on
the RAS optimised program.
The following conclusions can be drawn from the current and previous metallurgical and
comminution testwork programmes:
24
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
• The RAS ore is a moderately abrasive and competent ore with moderately high comminution
energy requirements.
o An Abrasion index of 0.3077, indicating the ore exhibits moderate abrasivity.
o Crusher Work index reported a range from 2.96 to 15.24 kWh/t and an average work
index value of 5.15 kWh/tonne.
o A Bond Ball Work index of 19.0 kWh/t (range 17.4 to 21.0 kWh/t) categorising the ore as
moderately hard.
o SAG Circuit Specific Energy values of 9.18 kWh/tonne (range 8.52 to 10.75 kWh/tonne),
indicating a medium to high power input is required for grinding.
• The RAS ore is ‘free-milling’ with a high gravity - recoverable free gold component and high
gold recovery from the gravity tails by cyanidation leach with moderate reagent
consumptions.
o Gravity gold recoveries ranged from 45.4% to 76.3%.
o Testwork at this scale will over account for gravity recovery, and in design a value of 32%
has been adopted.
o Overall gold recoveries ranging from 86.0% to 97.8%.
o Final leach residue grades ranging from 0.07g/t to 0.46g/t.
• A grind optimisation study was undertaken to evaluate the effect of grind size on project
economics. The results of the grind optimisation study indicated:
o The increase in gold revenue (recovery) with fineness of grind is offset by the increase in
operating costs to achieve the finer grind sizes. The net revenue (gold revenue –
operating costs) varies by less than 1% between 75 μm and 106 μm.
o The optimum grind for the RAS ore is 106 μm.
• While leaching is effectively completed in 8 hours preg-robbing behaviour occurs with
increased residence time and so are not suited to a hybrid leach-CIL. Cyanide in the process
water should be minimised as much as possible.
• The RAS ores have demonstrated amenability to cyanide destruction using the air/SO2
system.
• Arsenic is leached in the leach process, and an arsenic removal step is required on the
tailings. Initial testwork has indicated that the ores are amenable to arsenic removal using
ferric chloride precipitation of a ferric arsenate.
• Anticipated lime and cyanide consumptions are typical of operations conducted with good
quality water treating primary ores with a small refractory component. Cyanide
consumptions ranged from 0.33 to 0.56kg/t throughout the tests using tap water. Further
testing using site water is recommended given the high quality.
For the Srex deposit the following conclusions can be drawn:
• The Srex ore is similar in comminution characteristics to RAS, an abrasive, moderately
competent ore with above average comminution energy requirements:
o Abrasion Index – 0.3152;
o Crusher Work index reported a range from 1.80 to 10.70 kWh/t and an average
work index value of 5.25 kWh/t;
o A Bond Ball Work index of 16.9 kWh/t; and
o SAG Circuit Specific Energy values of 8.83 kWh/tonne (range 7.72 to 9.16
kWh/tonne), indicating a medium to high power input is required for grinding.
25
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
• The Srex ore is less free milling than RAS, showing a refractory component that is not
leachable through fine (20 μm) grinding. The Srex deposit shows greater sensitivity to
grind size than RAS.
• Flotation testwork indicated a higher recovery to flotation concentrate than seen with
RAS.
• Gravity recovery for the Srex deposit is lower than that seen for the RAS material, ranging
from 22-23%.
• As with RAS ores, Srex shows some preg robbing behaviour and is not suited to a hybrid
leach-CIL. Overall gold recoveries ranging from 66.8% to 68.7%.
The metallurgical treatment route selected has been based on the results of this test programme
with consideration of results from previous programmes and can be summarised as follows:
• Single stage crushing;
• Single stage SAG milling;
• Gravity concentration;
• Carbon-in-leach (CIL);
• AARL stripping circuit;
• Cyanide destruction; and
• Arsenic removal.
The Srex ore will be treated through the processing route optimised for RAS ore.
ES 8. Mining
The RAS deposit is planned to be mined by staged open pit and underground methods. The two
operations are independent and can be developed in parallel as the topography allows a low
elevation underground portal position, not requiring the open pit to reach a similar location. The
SRX deposit is planned to be mined by staged but shallow open pit only.
ES 8.1 Introduction
Following open pit optimisation analysis on RAS, a final maximum pit size was selected. This was
tested against mining deeper portions of the open pit from underground. This test concluded the
final maximum open pit was preferable to underground mining as gold price increased above the
base case.
ES 8.2 Pit Optimisations
ES 8.2.1 Mineral Resource Models
Open pit optimisations were completed using Whittle Optimisation Software (Whittle®) on the
Indicated Category of the mineral resource estimates (MRE). A third-party consultant group,
Geomodelling Ltd performed the estimates with the RAS outcome for RAS and SRX.
Table ES 6 lists the files utilised in the optimisation process.
26
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 10: An orthogonal view looking south of the RAS final pit and Underground workings
Table ES 6: Block model and topography files
Item File name Description
Topography
TOPO_2021
Lidar_major_contours_filtered.00t
2021 Lidar topography over the Bendigo-
Ophir Gold Project
20240625 RAS PFS Model ext.bmf
Extended RAS model bmf file to cover
enlarged model extents.
20240830 SHRE model.bmf SRX Block model
ES 8.2.2 Open Pit Optimisation Input Parameters
Whittle optimisation was completed utilising input parameters shown in Table ES 7. The
parameters were derived from first principles, and the optimisation was completed on an
operating cost basis. Capital costs, interest, income tax, depreciation, amortisation and closure
costs were not included.
27
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 7: Optimisation input parameters
Parameter Units SRX Value RAS Value
Gold price USD /oz 2,100 1,650
Exchange rate NZD:USD 0.64 0.64
Overall metallurgical recovery % 68 93
Gold price NZD/oz 3,281 2,578
Royalties (varies, average
applied)
%
3.5 3.5
Transport/Refinery cost NZD/oz 8 8
Discount rate % 7.5 7.5
Processing cost NZD/t processed 17.73 17.73
Tailings storage facility cost NZD/t processed 1.42 1.42
Crusher feed NZD/t processed 0.87 0.87
Ore overhaul cost NZD/t processed 1.5 -0.5
General and Admin cost NZD/t processed 3.21 3.21
The resource block models applied are recoverable models with block sizes set as panels that
have an allowance for mining recovery and dilution. A mining recovery of 100% and 0% dilution
was assumed in the pit optimisations for the two deposits due to the block model being re-
blocked to a 2.5m high block from 2.0m high.
Table ES 8: Optimisation mining cost and adjustment factors
Parameter Units SRX Value RAS Value
Base mining cost NZD /t 2.21 3.09
Bench mining cost
adjustment factor
NZD /t
6.0978-0.00047* Bench
mRL
8.086-0.0062*Bench mRL
Dilution
*
% 0 0
Mining recovery
*
% 100 100
Processing throughput Mtpa 1.5 1.5
Mining capacity Mtpa 3 20
Estimated Mine Life Years 1 10
ES 8.2.3 RAS Open Pit Optimisation Results
Optimisation results analysis was completed on the RAS deposit. Pit shell 32 which corresponds
to the revenue factor 0.99 shell, at NZD2,552 /oz (USD 1,633 /oz), has the highest cashflow for
the best case and was selected as the ultimate pit shell.
Figure ES 11 shows pit by pit tonnes, pre-capex cashflow and pre-capex discounted cashflow
values for the best- and worst-case scenarios. Hatched bars show selected shells for pit stage
designs.
* Dilution and mining recovery or losses accounted for by the block model being re-blocked to a 2.5m
high block from 2.0m high
28
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 11: RAS pit by pit optimisation results
ES 8.2.4 SRX Open Pit Optimisation Results
Optimisation results analysis was completed on the SRX deposit. Pit shell 33 which corresponds
to the revenue factor 1 shell, at NZD3,281 /oz (USD 2,100 /oz), has the highest cashflow for the
best case and was selected as the ultimate pit shell.
Figure ES 12 shows pit by pit tonnes, pre-capex cashflow and pre-capex discounted cashflow
values for the best- and worst-case scenarios. Hatched bars show selected shells for pit stage
designs.
29
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 12: SRX pit by pit optimisation results
ES 8.2.5 Sensitivity Analysis
Sensitivity analysis has been completed on the RAS deposit by varying:
• Gold price;
• Metallurgical recovery;
• Pit slope angles;
• Processing cost;
• Mining cost
• Mining dilution; and
• Mining recovery.
Table ES 9 shows results of sensitivity analysis completed by varying the sensitivity parameters
in Whittle. The results show that the project is highly sensitive to gold price and metallurgical
recovery. An increase in gold price or recovery of 10% results in an increase in pre-capex
discounted cashflow of 20%. A decrease in gold prices or recovery of 10% results in a decrease
in pre-capex discounted cashflow of 18%. Mining recovery also has a significant impact with a
decrease of 10% mining recovery resulting in a 15% decrease in pre-capex discounted cashflow.
Pit slope angle is another significant factor with a 10% change in slope resulting in a 12%
increase or 10% decrease in pre-capex discounted cashflow. Results of sensitivity analysis
ranking are shown in Table ES 9 for the top three parameters.
30
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 9: Sensitivity analysis top three parameters ranking
Paramete
r
Rank
Change in
Parameter
%
Parameter
Value
Ore
tonnes
(Mt)
Au
grade
(g/t)
Contained
ounces
(koz)
Pre-Capex
discounted
cashflow (NZD
m)
Price/Met.
Rec
1
20% USD1,980 12.6 2.40 969 1,106
10% USD1,815 11.7 2.47 930 947
Base USD1,650 11.6 2.49 925 791
-10% USD1,485 9.6 2.59 794 650
-20% USD1,320 8.1 2.67 692 511
Mining
Recovery
2
Base 100% 11.6 2.49 925 791
-5% 95% 9.1 2.57 755 732
-10% 90% 8.7 2.57 716 676
-15% 85% 8.2 2.57 676 622
-20% 80% 7.6 2.59 629 562
Slope (
o
) 3
10% Multiple
Sectors
12.0 2.47 948 887
5% Multiple
Sectors
11.5 2.49 924 834
Base Multiple
Sectors
11.6 2.49 925 791
-5% Multiple
Sectors
9.7 2.57 796 752
-10% Multiple
Sectors
9.7 2.57 796 712
The project’s pre-capex discounted cashflow is less sensitive to mining cost, processing cost
and dilution compared to the parameters shown in Table ES 8. A change of 10% in dilution,
mining costs and processing costs results in a 1-7% change in pre-capex discounted cashflow.
Sensitivity analysis spider graph is shown in Figure ES 13.
31
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 13: RAS sensitivity analysis spider graph
ES 8.3 Pit Design
ES 8.3.1 RAS pit
The ultimate pit design was based on shell 32, the highest pre-capex discounted cashflow shell.
The final pit design based on shell 32 is approximately 200 m deep at the highwall, approximately
1,000 m long in a roughly north-south direction and approximately 900 m wide (Refer to Figure
ES 14 and Figure ES 15). The transition from shell to actual workable pit design using
recommended geotechnical and ramp design parameters resulted in a 14% increase in overall
volume, a 3% increase in ore mined and a 3% lower overall grade resulting in slightly more
ounces than the pit shell. A summary of the comparison is shown in Table ES 10.
Table ES 10: Final pit design versus shell 32
Pit Stage Total tonnes
Ore
tonnes
Ore grade Cont. Ounces Waste tonnes
(Mt) (Mt) (g/t) (koz) (Mt)
Shell 32 187.2 11.6 2.49 926 175.6
Final Design 214.0 11.9 2.42 928 202.1
Variance 14% 3% -3% 0.23% 15%
Table ES 11 summarises individual pit stage inventories. Pit stage 1 has the highest grade at
4.06 Au g/t. The grade in subsequent stages decreases with the final stage being the lowest at
1.89 Au g/t.
32
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 14: RAS staged pit designed long section
Figure ES 15: RAS pit stages in plan view
33
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 11: Pit Stage Inventories
Pit Stage
Total
tonnes
Total
volume
Ore
tonnes
Ore
grade
Containe
d Ounces
Ore
volume
Ore bulk
density
Waste
tonnes
Waste
volume
Waste
bulk
density
(Mt) (Mbcm) (Mt) (g/t) (koz) (Mbcm) t/bcm (Mt) (Mbcm) t/bcm
Stage 1 46.8 17.8 1.4 4.06 186 0.5 2.73 45.4 17.3 2.63
Stage 2 29.2 10.9 3.0 2.35 228 1.1 2.73 26.2 9.8 2.66
Stage 3 40.4 15.2 3.0 2.32 226 1.1 2.71 37.4 14.1 2.65
Stage 4 57.6 21.6 2.4 2.13 162 0.9 2.72 55.2 20.7 2.67
Stage 5 40.0 15.2 2.1 1.89 125 0.8 2.72 37.9 14.4 2.63
Total 214.0 80.7 11.9 2.42 928 4.4 2.72 202.1 76.3 2.65
Note: These do not include Inferred mined as a consequence of mining the Indicated blocks. The inferred
resource mined as a consequence of mining Indicated categories totalled 1.1Mt at 1.54 g/t containing approx.
55koz).
ES 8.3.2 SRX Pit
The final SRX pit design based on shell 33 is approximately 88 m deep, 650 m long and 210 m
long. The shell to workable pit design transition resulted in a 11%reduction of both ore and waste
and 9% higher grade resulting in a 5% reduction in ounces compared to the Whittle shell. A
summary of the comparison is shown in Table ES 12.
Table ES 12: SRX final pit design versus shell 33
Pit Stage
Total
tonnes
Ore tonnes Ore grade Cont. Ounces Waste tonnes
(Mt) (Mt) (g/t) (koz) (Mt)
Shell 33 8.2
1.9 0.69
42 6.3
Final Design 7.3
1.4
0.68
31 5.9
Variance -11%
-11%
9%
-5% -11%
ES 8.4 Open Pit Production Scheduling
ES 8.4.1 RAS
An open pit mine production schedule for the RAS deposit has been produced using the pit
stages, final pit and waste rock dump designs.
Table ES 13 below shows the resulting pit inventory which forms the basis of the production
schedule.
34
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 13: RAS - Pit Design Inventory
Unit Quantity
Total Rock (kt) 213,972
Total Waste (kt) 200,996
TZ3 Tonnes (kt) 179,886
TZ4 Tonnes (kt) 18,089
Soil (kt) 3,021
Ore (kt) 12,976
Gold Grade (Au g/t) 2.36
Contained Gold (oz Au) 982,832
All the fresh Indicated and Inferred material above a cutoff grade of 0.3 g/t Au is considered as
ore and planned to be sent either directly to the run-of-mine (ROM) pad or placed on a temporary
ROM rehandling stockpile. The ROM material has been further subdivided into the following
grade bins:
• High Grade (HG) >= 2.6 g/t Au
• Run-of-Mine 2 (ROM2) 1.6 – 2.6 g/t Au
• Run-of-Mine 1 (ROM1) 0.6 – 1.6 g/t Au
• Low Grade (LG) 0.3 – 0.6 g/t Au (primarily processed at the end of the project and makes up
only 2.1% of the metal feed)
The open pit processing break-even grade (BECOG) was determined utilising the 2.1Mtpa
processing and G and A costs plus a rehandle and crusher feed cost to determine what material
mined would at the pit exit contribute to a positive cashflow if treated rather than sent to the
waste dump. (Refer Table ES13A)
For RAS a conservative gold price of NZ$2,578 (US$1,650 and 0.64 NZD:USD exchange rate) per
ounce was used for project evaluation and optimisation works. For SRX a less conservative gold
price of NZ$3,281 (US$2,100 and 0.64 NZD:USD exchange rate) was used due to its small size
and hence pre-stripping commitment.
A break-even cut-off grade of 0.3 g/t was ultimately applied for RAS and 0.35 g/t for SRX (rounding
up to the nearest 0.05g/t from the base calculations.
35
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 13A: Process BECOG calculation
Metric Units RAS SRX Comments
Mining cost $/t $1.11 $1.11
Stockpile rehandle and crusher
feed
Processing Recovery
(Au)
% 93.0% 68.0%
Processing cost $/t ore $17.75 $17.75 Plant at 2.1mtpa
G&A $/t ore $3.08 $3.08 Plant at 2.1mtpa ($6.46M/year)
Total operating Cost $/t $21.94 $21.94
Gold Price USD $/Oz US$1,650 US$2,100
NZD:USD 0.64 0.64
Gold price USD $/oz $2,578 $3,281
Royalty
4.5% 4.5%
Crown (2%), Landowners (varies
- assumed 1%), Venders (1.5%)
Selling cost $/Oz $8.0 $8.0
Effective Gold price $2,454 $3,126
Value 1 gram recovered $/g $78.64 $100.23
Value 1 gram in feed $/g $73.14 $68.16
COG to process plant g/t 0.30 0.32
The scheduling parameters forming the basis for the mine scheduling are as follows.
• Maximum mill feed of 1.5 Mtpa.
• Mill feed commences with an allowance for commissioning ramp-up:
o Month 1: 87.5 kt;
o Month 2: 119 kt; then
o Month 3 (full production) at 125 kt per month for the first two years of production.
• Mill feed includes both the Probable Reserves mined and the Inferred Resource mined as a
consequence of mining the reserves.
• A scale back of mill head grade to a maximum of 3.5 g/t Au has been applied in the
processing plant schedule. It is achieved by blending down the grade in early years.
• 100% of mill feed is re-handled at the ROM pad for crusher feed purposes, ensuring the head
grade not exceeding 3.5 g/t Au.
• Mining generally progresses across multiple benches within the cutbacks, rather than
strictly following a bench-by-bench sequence allowing for quicker ore exposure.
• All the transitional and soil materials are planned to be sent to their own dedicated stockpile
areas.
• Mineralisation below 0.3 g/t Au is sent to the waste rock dump.
ES 8.4.2 Material Movements
36
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Total material movements are shown in Figure ES 16 and Figure ES 17. The annual mining
schedules are shown in Table ES 14. The first 100 kt of ore will be exposed after mining roughly
35 Mt of waste around month 15 of mining, which will be stockpiled. The plant is expected to be
brought into its commissioning phase around this period after which a sustainable supply of ore
is available to start feeding the mill by month 17 of mining.
Figure ES 16: Total material mined per year at RAS open pit
Figure ES 17: Total material mined at RAS open pit per stage per year
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
-2-1123456789
kt
RAS material movement per year
WasteSoilOre
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
-2-1123456789
kt
Total material mined by stage
Stage 1Stage 2Stage 3Stage 4Stage 5
37
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 14: RAS OP Mining Schedule
Year
-2 -1 1 2 3 4 5 6 7 8
Total Rock Mined
(kt)
213,97
2
10,200 30,572 25,859 24,612 24,493 24,300 24,300 24,267 23,112 2,258
Total Waste
(kt)
200,99
6
10,200 30,363 24,437 21,438 22,680 23,060 24,007 21,880 21,575 1,355
TZ3 Tonnes
(kt)
179,88
6
9,417 29,967 20,456 16,804 19,717 20,939 22,636 19,530 19,401 1,019
TZ4 Tonnes (kt) 18,089 0 149 3,139 4,344 2,815 1,613 1,339 2,184 2,171 336
Soil (kt) 3,021 783 247 842 291 148 508 33 166 3 0
Ore (kt) 12,976 0 209 1,422 3,173 1,813 1,240 293 2,387 1,537 902
Gold Grade
(Au
g/t)
2.36 0.00 0.00 3.50 3.37 3.08 2.59 1.11 2.89 1.63 1.67
Contained
Gold
(koz
Au)
983 0 9 185 246 125 98 11 166 80 63
Stripping Ratio (t:t) 15.5 0.0 145.5 17.2 6.8 12.5 18.6 81.9 9.2 14.0 1.5
Note: ROM mined includes Inferred 1.1Mt at 1.54 g/t, therefore 94.4% of the RAS open pit mill feed is from Probable Reserves.
38
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 8.4.3 SRX
An open pit mine production schedule for the nearby SRX deposit has been produced using the
pit stages, final pit and waste rock dump designs. Table ES 15 below shows the resulting pit
inventory which forms the basis of the production schedule.
Table ES 15: SRX - Pit Design Inventory
Unit Quantity
Total Rock Mined (kt) 7,344
Total Waste (kt) 5,916
TZ3 Tonnes (kt) 4,376
TZ4 Tonnes (kt) 710
Soil (kt) 626
Transition Mineralisation (> 0.3 g/t Au) (kt) 204
Ore (kt) 1,428
Gold Grade (Au g/t) 0.68
Contained Gold (oz Au) 30,674
Stripping Ratio
(waste t: ore t)
4.1
Scheduled material is at a 0.3 g/t cut-off grade. Reserves where quoted are at a 0.35 g/t cut-off
grade.
39
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 16: SRX (monthly) Mining Schedule
Months
Unit Total
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Total Rock
Mined
(kt) 7,344
209 209 209 309 350 350 350 350 350 350 350 350 350 350 350 350 350 350 350 350 350 350 108
Waste Rock
Total TZ3 (kt) 4,377
33 79 84 185 209 253 202 214 211 277 199 247 289 162 227 292 211 234 226 205 212 104 21
Total TZ4 (kt) 606
47 42 21 19 28 4 22 14 44 13 17 37 10 29 42 7 28 38 16 30 20 63 14
Total
Economical
WST (>0.30g/t Au)
(kt) 103
0 0 4 2 8 3 9 0 8 1 1 3 4 5 10 2 0 4 2 6 7 18 4
ROM Mined
(>0.30g/t Au Fresh
IND and INF)
(kt) 1,428
0 15 26 34 47 9 75 32 84 27 73 60 38 95 70 47 82 74 94 99 111 164 69
Gold Grade Au g/t 0.68
0.00 0.62 0.76 0.69 0.81 1.03 0.81 0.77 0.67 0.61 0.58 0.69 0.68 0.61 0.63 0.70 0.64 0.57 0.64 0.61 0.68 0.72 0.74
Contained Gold koz 31
0 0 1 1 1 0 2 1 2 1 1 1 1 2 1 1 2 1 2 2 2 4 2
Stockpile
Materials
Total Soil Mined (kt) 625
80 51 49 61 36 59 30 64 3 30 44 3 10 54 0 2 28 0 11 10 0 0 0
Total Transition
Mineralisation
(>0.30g/t Au)
(kt) 204
49 21 25 8 21 21 11 25 0 3 15 0 0 5 0 0 1 0 0 0 0 0 0
40
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 8.5 Mining Fleet and Requirements
ES 8.5.1 Mining Fleet
A mining cost estimate based on an owner mining model has been produced. The cost model is
based on a conventional open pit Drill and Blast, Load and Haul mining method.
ES 8.5.2 Drilling and Blasting
Open pit drilling operations are divided into two distinct zones. These are ore and waste bulk
waste zones.
Ore zone drilling has been modelled on a 7.5 m bench. This zone comprises of ore and inter-
burden waste. There is no separate grade control drilling. Ore blast holes are also used for grade
control sample. Drilling in the ore zone is performed by Atlas Copco L8 RC drills.
Bulk waste drilling has been modelled on 15 m benches and will be carried out by Sandvik D45KS
equivalent drill.
Table ES 17 shows drill and blast parameters for ore and waste zones.
Table ES 17: Open pit drill and blast parameters
Parameter Units Ore zone Waste zone
Drill Atlas Copco L8 RC
Rotary
(Sandvik D40KS)
Hole diameter mm 102 200
Sampling frequency t/sample 128 Nil
Bench height m 7.5 15.0
Burden x Spacing m 4.7 x 4.0 7 x 8
Powder factor kg/bcm 0.32 0.52
ES 8.5.3 Loading
The cost model assumes an equivalent of a 260-t Hitachi EX2600 hydraulic backhoe excavator
for digging in ore and waste (17m
3
bucket capacity). A 120-t Hitachi EX1200 excavator is included
to selectively mine those parts of the orebody that need a balance between productivity, dilution
and recovery.
ES 8.5.4 Hauling
A fleet of 150t class rear-dump trucks, Cat 785 equivalent, have been used in the modelling for
all mine haulage activities. These trucks match with the 17m
3
hydraulic excavators for
approximately five to six passes per truck.
Crusher Feed
A Cat 988 wheel loader will be used to re-handle ore from ROM stockpiles into the crusher bin.
Ancillary Equipment
A fleet of support equipment has been modelled. This fleet supports primary production
equipment in the pit, at the waste rock stacks, haul roads, ROM pad and stockpiles. The fleet
consists of:
• Cat 777 water trucks;
• Cat 834 wheel dozer;
• Cat 16 motor graders; and
41
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
• Cat D10 dozers.
Table ES 18 shows the maximum mining fleet composition during the peak mining periods.
Table ES 18: Mining fleet composition
Description
Numbe
r
Activity
260-t Backhoe Excavator 2 Ore and waste loading
120-t Backhoe Excavator 1
Rehandling ore stockpiles and
backup for primary excavators
Cat 785 150t Rigid Body Dump
Truck
22 Ex-pit and stockpile Ore and waste hauling
Cat D10 Tracked Dozer 3
Mining, waste rock tip management,
rehabilitation and other site dozing
requirements
Cat 16H Motor Grader 2 Haul road and work area maintenance
Cat 834 Wheel Dozer 1 Haul road and work area maintenance
Cat 777 Water Cart 2 Haul road and work area dust suppression
988 Front End Loaders 1 Feeding ore crusher bin
Atlas Copco L8 drills 1 Ore (7.5m)
D40KS Rotary Drill 1 Waste drilling on 15m bench height
ES 8.6 Engineered Landform (ELF)
Overburden waste rock will be stored in the Shepherds Creek engineered landform (ELF).
Several potential waste storage areas have been considered to store the planned waste rock from the
RAS deposit. Areas have been identified that are suitable for use for this PFS study, excluding those
impacted by social and foundational terrain issues, as well as the potential sterilization of nearby
satellite deposits. The selected area is located just downstream of the location of the tailings storage
facility (TSF). Effectively, the waste rock is being planned to act as a buttress of this TSF to enhance
stability downstream of the dam while providing sufficient storage capacity to store all the planned
waste from the pit.
Table ES 19 shows the required and designed capacities in bank cubic metres (bcm) and loose cubic
metres (lcm) for the waste dump. A total swell factor of 25% after compaction (based on the majority
of fresh rock) has been assumed.
42
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 19: Waste Rock Dump Design Capacity
Material Description Requirements Swell Factor Requirements
(‘000 bcm) (lcm:bcm) (‘000 lcm)
TZ3
block model code DTZ = 3
Fresh and Transitional
(excluding Soil), < 0.3 Au
g/t
67,621 1.25 84,526
TZ4
block model code DTZ = 4
Fresh and Transitional
(excluding Soil), < 0.3 Au
g/t
5,555 1.25 6,944
Mineralized
Waste
block model code RSCAT =
0, >= 0.3 Au g/t
1,088 1.25 1,361
Total Waste
Rock
Total Material to be stored
on waste rock dump
74,264 1.25 92,830
A waste rock dump with a total design capacity of 103.6 million loose cubic metres (LCM) of
which 3.2 million LCM from the TSF dam has been produced. The design quantity has a
contingency of roughly 12% which would account for possible changes in the swell factor or the
compaction ratio following further analysis on the actual site-specific parameters.
Waste landform sequencing has been undertaken based on the assumption that background
levels of arsenic are higher in the ore host rock(TZ4) and for precautionary reasons it is planned
to be encapsulated and capped with low/non-arsenic waste rock (TZ3) to mimic its natural
occurrence. A base layer and encapsulating layer of inert material is typically required, with a
core of non-inert material. For this reason, the dump has a base layer of 3 metres which would
only consist of TZ3 material. The TSF dam embankment will also only consist of TZ3 material.
Finally, a 20 m thick capping layer is added consisting only of the TZ3 material. The core will allow
for all material types to be stored. Figure ES 18 shows a cross-section of the dump.
43
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 18: Northwest-Southeast Cross-section of the Waste Rock Dump
ES 8.7 Rise and Shine Underground
The RAS underground targets the continuation of the orebody down plunge and beneath the open
pit. Only the Indicated resource category has been evaluated by the initial underground mine
plan. There remains extensive lower class Inferred mineralisation down-dip that if converted
after infill drilling would allow the underground to:
a. Extend its life; and
b. Increase the annual production rate.
Furthermore, the ore system remains open at depth and deeper extensions are considered likely
to eventuate with deeper drilling.
ES 8.7.1 Mineable package targeting
A conservative gold price of NZ$2,578 (US$1,650 and 0.64 NZD:USD exchange rate) per ounce
was used for project evaluation and optimisation works. Note: The breakeven cutoff grade
(BECOG) was determined at the start of the underground mining process, it assumed a 1Mtpa
operation that is mining stand-alone.
A break-even cut-off grade of 1.70 g/t was ultimately applied for underground mine scheduling.
44
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 20: Break Even Cut off Grade Calculation
Metric
Units
Comments
Mining cost $/t $80.00
SMI estimate
Re-load and haul to
plant
$/t $2.00
Processing Recovery
(Au)
% 93.0%
Processing cost $/t ore $26.60
MIQ at 1Mtpa
G&A $/t ore $4.81
MIQ at 1Mtpa
Total operating Cost $/t $113.41
Gold Price USD $/Oz 1650.0
NZD:USD
0.64
Gold price USD $/oz $2,578
Royalty
4.5%
2% crown, 1.5% vendors, 1% landowners
Refining and Selling cost $/Oz $8.00
Includes freight
Value 1 gram in
recovered
$78.90
Value 1 gram in ground
$73.38
COG to process plant gpt 1.55
COG insitu gpt 1.72
an insitu grade target allowing 10%
dilution
At first the Mineable Shape optimiser tool (MSO) was used to create automated mineable
shapes, that were then used as a guide to prepare manual designs for the stoping outlines as it
was found the MSO tool could not replicate a realistic mining selection package.
The total recoverable Probable Mining Reserve is 2,288 kt at 3.03 g/t containing 223 koz. As a
consequence of extracting this, a further Inferred resource of 124 kt at 2.2 g/t containing 9 koz is
mined. This results in a total underground mine inventory of 2,413 kt.
In total, 96.1% of the underground plant feed is from Probable Mining Reserves generated form
the Indicated Resource blocks with modifying factors applied.
The underground is designed as a mechanised operation with ramp haulage. Extraction is via
open stoping with cemented paste backfill. The relatively constrained Indicated resources at this
point in time constrains the eventual overall annual production rate. If this material can be
converted to indicated category, the underground mining rate could be increased.
Twin portals service a twin ramp development, which leads to a simple haulage (intake) and
egress/return network system.
The underground workings stand off from the selected final Stage 5 Pit by 30m.
ES 8.7.2 Mining Layout, Panels, Design
The mine design layouts are shown in Figure ES 19 and Figure ES 20.
45
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 19: Development Design
Figure ES 20: Panel layout
46
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 21: Ore details and Waste by year
Processing Year Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8
Indicated Ore
Devt Ore (kt)
253
- 76 104 73 - - -
Devt g/t
1.85
- 1.79 1.73 2.08 - - -
Devt (koz)
15
- 4 6 5 - - -
Stope Ore (kt)
2,035
- 92 422 421 483 420 198
Stope g/t
3.17
- 1.97 3.02 3.18 2.90 3.11 4.86
Stope (koz)
208
- 6 41 43 45 42 31
Inferred
Inferred Dev (kt)
110
- 13 53 43 - - -
Inferred Dev g/t
1.83
- 1.24 1.65 2.23 - - -
Inferred Dev (koz)
6
- 1 3 3 - - -
Inferred Stope (kt)
15
15
Inferred Stope g/t
4.82
4.82
Inferred Stope
(koz)
2
2
Total Mill feed -
mined (kt)
2,413
- 181 579 537 483 435 198
Ore g/t
2.99
- 1.84 2.66 2.96 2.90 3.15 4.86
Ore (koz)
232
- 11 49 51 45 44 31
Waste(kt)
565
132 180 179 75 - - -
Total
Movement (kt)
2,974
132 362 757 611 483 435 198
Note 1: Numbers may not add due to rounding.
Note 2: Devt Ore includes 146kt @ 1.4 g/t low grade (between 1.0 g/t and 1.7 g/t)
Note 3: Mined may not correspond to processed schedule timings.
Table ES 22: Development by Type
Total Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8
Development TYPE
Decline 5.5mW x 5.5mH 1,845 791 472 564 17 - - -
Stockpile 5.5mW x 5.5mH 246 87 70 87 - - - -
Level Access 5.5mW x
5.5mH 2,718 36 679 1,189 814 - - -
Return Air Drive 5.5mW x
5.5mH 961 566 131 260 4 - - -
Vent access 5.5mW x 5.5mH 229 85 91 54 - - - -
Sump 5.0mW x 4.5mH 19 11 4 4 - - - -
Level Stockpile 5.5mW x
5.5mH 153 - 30 73 50 - - -
Remote Stockpile 5.5mW x
5.5mH 244 - 82 79 83 - - -
Paste Access 5.5mW x
5.5mH 878 - 466 199 213 - - -
Paste Drives 5.0mW x 4.5mH 1,118 - 591 297 230 - - -
47
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Airleg Drive 3.0mW x 3.0mH 71 18 36 17 - - - -
Escape Drive 2.0mW x
2.0mH 19 - 7 7 6 - - -
TOTAL LATERAL DEVT 8,501 1,594 2,660 2,831 1,416 - - -
Return Air Rise 4.0mW x
4.0mW 59 - 28 31 - - - -
Escape Ladder 2.0mW x
2.0mH 120 - 38 36 46 - - -
TOTAL VERTICAL DEVT 179 - 66 67 46 - - -
Stope Drives 5.0mW x
4.5mH 2,536 - 825 1,357 354 - - -
Robbing Stope 5.0mW x
4.5mH 758 - 24 103 631 - - -
TOTAL STOPE DRIVES 3,294 - 849 1,461 985. - - -
TOTAL LATERAL DEVT 11,795 1,594 3,509 4,291 2,401 - - -
Note: Numbers may not add due to rounding
Table ES 23: Paste, cabling, trucking, shotcrete
Total Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8
Total Devt 11,974 1,594 3,575 4,358 2,447 0 0 0
Total Ore (kt) 2,413 0 181 579 537 483 435 198
Paste (kt) 1,893 0 75 339 372 387 437 283
Cable metres 36,818 900 12,731 9,681 7,170 2,246 2,277 1,813
Shotcrete (m3) 16,750 2,782 7,403 3,468 3,097 0 0 0
TKMS 4,507,634 80,833 459,203 1,128,293 1,057,336 845,851 673,002 263,116
Note: Numbers may not add due to rounding
ES 8.8 Mining Reserves
A Mining Reserve estimate was completed for the RAS and SRX deposits.
The following sections explain the estimation processes for the part of the deposits which can
be economically mined and has had necessary mine planning work completed. Proved and
Probable reserves are based on Measured and Indicated resource blocks. Inferred blocks are not
included in the reserve estimate. Where Inferred blocks are within the pit outlines, they represent
potential minable inventory if confirmed by grade control drilling.
Similarly in the underground mine plan, some Inferred mineralisation is encountered as part of
the mine development sequence.
ES 8.8.1 Open pit
RAS and SRX open pit reserve tonnages and grade are reported from pit designs that are guided
by Whitte 4X Optimisation Software (Whittle®).
48
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
A local currency adjusted gold price from a base of USD1,650/oz was applied for RAS estimates
and similarly USD2,100/oz for SRX. The projected mining and processing costs, pit slope
parameters, processing recovery, a 2% ad valorem royalty payable to the New Zealand
Government and between 2.5 and 3.5% other royalties, and refining and handling charges at NZD
8/oz, have been used in the optimisation
Dilution, mining losses and recovery were incorporated into the mining block model by re-
blocking the resource block model from 2m high blocks to 2.5m high blocks. This is the height of
the planned ore flitches, incorporating adequate dilution and provides a reasonable estimate of
mined tonnage and grades.
Pit optimisation and design inputs and methodologies are discussed in ES 8.2 Pit
Optimisations.
ES 8.8.2 Underground
The underground mineable portion was based on the development and stope designs created
manually.
A gold price of USD1,650/oz for RAS, projected mining and processing costs, processing
recovery, a 2% ad valorem royalty payable to the New Zealand Government and 2.5% other
royalties, and refining and handling charges at NZD 8/oz have been used in the optimisation.
A global 10% dilution was applied to achieve the final cut-off grade.
ES 8.8.3 Reserve Estimate
The open pit Mineral Reserves summarised in Table ES 24 are reported at the cut-off grades
listed below the table.
Table ES 24: BOGP Mineral reserve estimate as at 1 December 2024
Area Proven Probable Total
Mt Au g/t Mt Au g/t Mt Au g/t Au koz
RAS (open pit) - - 11.9 2.42 11.9 2.43 928
RAS
(Underground
)
2.3 3.03 2.3 3.03 223
SRX 1.3 0.70 1.3 0.70 30
Total - - 15.5 2.37 15.5 2.37 1,181
Note 1: RAS Open pit cut-off grade 0.3 g/t at $US1,650/oz Au price
Note 2: RAS Underground cut-off grade 1.70 g/t at $US1,650/oz Au price
Note 3: SRX Open pit cut-off grade 0.35 g/t at $US2,100/oz Au price
Note 4: Underground Reserves are from the Open pit Resources area
ES 8.9 Relevant Factors
• The effective date of the Mining Reserve Estimate is 1 November 2024, estimated by Rodney
Redden (MAusIMM and CP-Mining), a contractor to Santana Resources Ltd.
• There are no approved consents and not all required permits are in place to enable mining
of the RAS and SRX deposits.
49
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 9. Plant feed schedule – all sources
Mining commences at RAS open pit and begins supplying ore from month 15 so that from month 17
processing starts on RAS open pit ore.
The RAS underground commences development in month 19 of processing (36 months after RAS
open pit commencing). Initial underground ore is stockpiled and is timed to commence feed to the
process plant as the processing rate expansion to 2.1Mtpa is complete.
Due to the lower economics, the SRX open pit is mined and processed last F.
All the fresh, Indicated and Inferred material above a cutoff grade of 0.3 g/t Au is considered as
ore and planned to be sent either directly to the run-off mine (ROM) pad or placed on a temporary
ROM rehandling stockpile. The ROM material has been further subdivided into the following
grade bins:
• High Grade (HG) >= 2.6 g/t Au
• Run-of-Mine 2 (ROM2) 1.6 – 2.6 g/t Au
• Run-of-Mine 1 (ROM1) 0.6 – 1.6 g/t Au
• Low Grade (LG) 0.3 – 0.6 g/t Au
Material is fed to the processing plant in the above priority order, whilst maintaining a maximum 3.5
g/t head-grade.
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 25: Annual Processing Schedule
YEAR 1 2 3 4 5 6 7 8 9 10
RAS OP
Probable
Reserves
kt 11,864 1,375 1,466 1,401 1,381 1,414 1,372 1,359 1,639 456 -
g/t 2.43 3.66 3.38 3.09 2.70 1.08 2.97 1.58 1.73 0.49 -
koz 928 162 159 139 120 49 131 69 91 7 -
Inferred
kt 1,112 81 34 99 119 86 128 240 112 213 -
g/t 1.54 0.86 2.84 2.83 1.28 1.65 2.02 1.91 0.77 0.78 -
koz 55 2 3 9 5 5 8 15 3 5 -
Total OP
kt 12,976 1,456 1,500 1,500 1,500 1,500 1,500 1,599 1,751 670 -
g/t 2.36 3.50 3.37 3.08 2.59 1.11 2.89 1.63 1.67 0.58 -
koz 983 164 162 148 125 54 139 84 94 12 -
RAS UG
Probable
Reserves
kt 2,288 - - - 200 600 600 488 327 73 -
g/t 3.03 - - - 2.11 2.70 3.10 2.76 4.11 4.60 -
koz 223 - - - 13,582 52,135 59,840 43,301 43,195 10,812 -
Inferred
kt 124 - - - 0 0 0 13 22 90 -
g/t 2.19 - - - 0.00 0.00 0.00 1.82 1.82 2.33 -
koz 9 - - - 0 0 0 757 1,268 6,720 -
Total UG
kt 2,413 - - - 200 600 600 501 349 163 -
g/t 2.99 - - - 2.11 2.70 3.10 2.74 3.97 3.35 -
koz 232 - - - 13,582 52,135 59,840 44,058 44,463 17,532 -
SRX
Probable
Reserves
kt 1,340 - - - - - - - - 1,216 124
g/t 0.70 - - - - - - - - 0.70 0.70
koz 30 - - - - - - - - 27,226 2,790
Inferred
kt 20 - - - - - - - - 10 10
g/t 0.48 - - - - - - - - 0.48 0.48
koz 0 - - - - - - - - 152 152
Total SRX
kt 1,360 - - - - - - - - 1,226 133
g/t 0.69 - - - - - - - - 0.69 0.69
koz 30 - - - - - - - - 27,378 2,942
Total Inferred 7% 6% 2% 7% 7% 4% 6% 12% 6% 15% 7%
51
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 21: Mill feed by source
Figure ES 22: Mill feed tonnes by resource class
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0
500
1,000
1,500
2,000
2,500
12345678910
Grade (g/t Au)
Mill Feed Tonnes (kt)
Year
Mill Feed by Source
RAS OPRAS UGSRXHead Grade
0%
2%
4%
6%
8%
10%
12%
14%
16%
0
500
1,000
1,500
2,000
2,500
12345678910
% of Mill Feed = Inferred
Mill Feed Tonnes (kt)
Year
Mill Feed -Ore Tonnes
Probable ReservesInferred% Inferred
52
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 23: Mill feed ounces by resource class
ES 10. Processing
The process plant design for the RAS gold deposit is based on a robust metallurgical flowsheet
designed for optimum recovery with minimum operating costs. The flowsheet is based upon unit
operations that are well proven in industry.
The key criteria for equipment selection are suitability for duty, reliability and ease of
maintenance. The plant layout provides ease of access to all equipment for operating and
maintenance requirements whilst maintaining a compact footprint that will minimise
construction costs.
The key project and ore specific criteria that the plant design must meet are:
• 1.5Mtpa of primary ore, easily expandable without plant downtime to 2.1Mtpa;
• mechanical availability of 91.3% supported by crushed ore storage, standby equipment in
critical areas and grid based power supply; and
• sufficient automated plant control to minimise the need for continuous operator interface
and allow manual override and control when required.
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0
50
100
150
200
250
12345678910
Head Grade (g/t)
Mill Feed Ounces (Koz)
Mill Feed -Au Ounces contained
Probable ReservesInferredHead Grade
53
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 24: BOGP Process plant – process flow diagram
54
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 10.1 Run-of-Mine (ROM) Pad and Crushing Circuit
The ROM pad will contain up to 14 days of stockpiled ore to provide a buffer between the mine
and the plant. This will allow the crushing plant to only operate for 12 hours per day.
The primary jaw crushing circuit has been sized based on operating 12 hours per day at 80%
utilisation at a feed rate 128% above the mill feed rate. Ore will be stockpiled so that the
downstream plant can continue operating during the periods that the crushing plant is not
operational.
A run of mine (ROM) grizzly aperture of 700 mm has been selected to minimise oversize material
entering the ROM bin and causing down-stream blockages.
An apron feeder has been selected to draw material from the ROM bin.
A single toggle jaw crusher has been selected for the primary crushing duty due to the moderate
UCS values and the moderately abrasive nature of the ore. In addition, the single toggle crusher
has a higher capacity than an equivalently sized double toggle crusher.
Ore discharged from the jaw crusher will be conveyed to the covered stockpile. An overhead
magnet located on the crusher discharge conveyor will remove magnetic tramp material that
may be present with the ore.
Ore will be withdrawn from the crushed ore stockpile using a variable speed apron feeder that
will discharge ore onto the mill feed conveyor.
ES 10.2 Milling
A single stage SAG mill has been selected to reduce crushed product to the nominal circuit P
80
size of 106 μm.
ES 10.3 Classification
Relatively large diameter cyclones (380 mm) have been selected for the classification duty to
minimise wear and reduce the potential for spigot blockages occurring from coarse ball mill
discharge material.
ES 10.4 Gravity Concentration
Testwork indicates that relatively high gravity gold recoveries (up to 32%) can be expected from
the primary ores, with high gold recoveries and rapid leach kinetics achieved on the gravity tails
material.
The gravity circuit has been designed with two installed centrifugal concentrators. The gravity
concentrator will be fed with cyclone underflow slurry.
The gravity concentrate periodically discharging from the concentrators will be directed to a
storage hopper located in the gold room. The concentrates will be processed through a vendor
supplied Intensive Leach Reactor and dedicated electrowinning cell to recover gold and silver.
Selection of the Intensive Leach Reactor unit has been based on the expected high gravity gold
recovery and the potential impact of returning conventional gravity / shaking table tails to the
leach circuit. The Intensive Leach Reactor will utilise high intensity cyanidation to maximise the
recovery of gold and silver values from the concentrate stream.
A separate pregnant solution tank, pump and electrowinning cell will be provided for the
Intensive Leach Reactor to assist with metallurgical accounting and eliminate any potential
impact on the operation of the carbon elution and electrowinning circuit.
55
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 10.5 Trash Screening
A vibrating trash screen has been selected to prevent oversize particles from entering the
downstream leach and adsorption circuit. Although minimal trash is expected from the primary
ore, good trash screening will be essential for good carbon management.
ES 10.6 Leach and Adsorption Circuit
Metallurgical test work indicated that the primary ore shows minor “preg-robbing”
characteristics. The initial leach kinetics for primary ore are fast, with approximately 85% to 90%
of total CIL gold extraction being achieved in the first 4 to 8 hours of leaching. On this basis, a
circuit configuration utilising six adsorption tanks has been adopted. Six adsorption tanks are the
minimum number required to maintain reasonable overall stage efficiencies.
Due to the minor preg-robbing behaviour a hybrid leach cannot be adopted, reducing the solution
tenor of the first adsorption tank, and driving slightly lower loaded carbon grades than can be
achieved in a hybrid circuit. Lower carbon loadings will increase the batch size and frequency of
carbon elution.
The adsorption tanks will be identical in size with a total circuit residence time of 24 hours at 45%
w/w density in the tanks. The tanks will be arranged such that any one tank can be taken offline
for maintenance without affecting the remainder of the circuit.
ES 10.7 Elution
An AARL elution circuit has been selected based on excellent raw water supply and quality. An
AARL elution circuit separates elution and electrowinning, allowing more batches to be
processed if required. An eight-tonne batch size has been nominated and based on the
calculated carbon movements required to meet the grade variability that is currently predicted
by the production plan. Under nominal conditions a total of six elution cycles are required each
week. The gold room will operate 7 days a week.
Three parallel 12 cathode electrowinning cells are proposed for the gold room to provide a high
pass efficiency (greater than 90%) and ensure a low gold tenor in the spent electrolyte returning
to the strip solution tank.
The high cell pass efficiency will ensure a near barren solution is returned to the strip solution
minimising the gold returned to the column and minimising the number of elution cycles required
to achieve the target barren carbon grade. It is anticipated that the elution electrowinning cycle
will be completed in 8 to 12 hours. This will allow additional strips to be conducted during the
week, if required.
A sludging cell design has been adopted for electrowinning to simplify the cathode handling
process. Sludge will be filtered in a vacuum pan filter and dried in an oven prior to smelting to
produce doré.
ES 10.8 Cyanide destruction
An air/SO
2
circuit has been selected for cyanide destruction based on the relatively lower
operating cost of these circuits, the less hazardous reagents required in comparison to Caros
acid and the amenability shown in the testwork of the ore to this form of cyanide destruction. The
circuit will reduce the weakly acid dissociable cyanide to less than 30 ppm at discharge of the
TSF spigot.
56
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 10.9 Arsenic removal
Ferric chloride precipitation of solubilised arsenic as a ferric arsenate has been selected based
on the amenability of the ore to this removal method, and the anticipated stability of the arsenate
species generated.
ES 10.10 Tails Thickening
A high-rate tails thickener treating the plant tailings has been selected to thicken tails to a density
of 50% w/w solids. This is intended to minimise the volume of tailings being pumped to the TSF
and volume of decant requiring return, as well as the mass of solubilised species entering the
TSF.
ES 10.11 Tailings Pumping
Thickener underflow will be pumped to tailings hopper and will be pumped to the tailings storage
facility using two centrifugal pumps operating in series.
ES 10.12 Throughput expansion
The plant throughput will be expanded from 1.5Mtpa (base case) to 2.1Mtpa as open pit grades
from RAS decline. To facilitate this the following approach has been adopted:
1. Orway Mineral Consultants (OMC) have reviewed the comminution circuit design, and
made the following recommendations:
a. The base case crushing plant design can provide the required feed, however the
stockpile size is too small (residence time will be reduced to 8 hours).
b. During expansion a ball mill with installed power of 2,000 kW should be installed.
c. The cyclone cluster was found to be adequately sized for the increased throughput.
2. Initial installation of slurry and service pumps will allow for the expanded case.
3. Initial screen selections will allow for the expanded case.
4. No change will be made to the CIL tank sizes; however, this must be reviewed once kinetic
data is available for the circuit. Residence time will decrease from 24 hours (allowed in the
base case due to lack of kinetic data) to 17 hours.
5. The period of increased throughput will coincide with decreased head grade, and the
selection of column and electrowinning sizes for plant feed grade variability means that
these circuits will be adequately sized in the initial design.
6. Initial electrical design will allow for the inclusion of the later Project phase.
The decision to utilise equipment sized for the larger case will reduce plant downtime during the
expansion, with the only significant construction works required being the inclusion of the ball
mill. Room has been allowed in the base case design and implementation plan for this to be
done.
The Project execution will therefore proceed in two phases – the initial installation (Phase 1), with
a schedule the same as the base case design but with increased capital cost, and Phase 2, where
the ball mill will be procured, design work undertaken for its installation, installation of the mill
and commissioning.
57
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
The process plant General arrangement together with the run of mine (ROM) pad and other site infrastructure is shown in Figure ES 25.
Figure ES 25: Process plant – general arrangement
58
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 11. TSF
The proposed Shepherds TSF is in the upper reaches of Shepherds Valley with the proposed
Shepherds ELF located immediately downstream (Figure ES 26). The final ELF height will match,
and in places exceed, the TSF embankment and extends downstream of the TSF by 1.4 km.
Figure ES 26: shows the location of the TSF and ELFs
59
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 27: TSF and ELF sections
ES 11.1 Design
The Shepherds TSF is to be formed using a downstream construction embankment using rockfill
from the RAS open pit. The downstream construction embankment is proposed to have a 1
vertical to 2 horizontal downstream slope and 1 vertical to 1.5 horizontal upstream slope. It is
proposed that the tailings are delivered as a conventional slurry from the process plant and
discharged using a combination of spigots and end pipe methods.
The Shepherds TSF is designed to meet the New Zealand Dam Safety Guidelines. The proposed
final crest level allows for the TSF to be managed as a full containment facility (supernatant water
managed onsite). This includes allowance to manage a normal operational decant pond and
inflows from a 72-hour probable maximum precipitation (748 mm depth), with 1m freeboard for
wave action. The uphill diversion channels are conservatively assumed not to function for this
design condition.
Consideration of a probable maximum precipitation event meets the design criteria for a High
Potential Impact Classification Dam under the New Zealand Dam Safety Guidelines. A High
Potential Impact Classification is the highest dam classification under the New Zealand Dam
Safety Guidelines which are in accordance with international practice. For comparison the
average annual rainfall at the top of the TSF catchment is estimated to be approximately 540 mm
including allowance for increased rainfall depths due to topographical effects.
The Shepherds TSF will safely contain tailings when subjected to potential future extreme
earthquakes. It will be designed to withstand a 1 in 10,000 year earthquake including
aftershocks. This includes withstanding a potential rupture on the Alpine Fault or any of the other
active faults in the region. The proposed design has the tailings contained behind the
downstream rockfill embankment, that will also be buttressed by a large volume of rockfill
60
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
placed in the Shepherds ELF. The proposed design will provide safe and robust tailings storage
solution for both operation and post closure of the site.
ES 12. Infrastructure
ES 12.1 Mining Operations and Processing Plant Site & Infrastructure
The Mine Site and supporting infrastructure are located in the lower Shepherds Creek valley,
positioned across two areas. The first is 14 ha in area for the processing plant and mining
operations within the valley that is secluded from the Bendigo and Ardgour Terraces and the
second area of 10 ha positioned outside the valley on the Ardgour Terraces providing non-
operational infrastructure including administration building, high voltage substation and
construction activity support.
To establish the processing plant and mining operations area the valley will be widened to a site
platform of 130m x 1,050m, engineered to accommodate the plant and supporting infrastructure
and buildings. A 7-month period is planned to complete the earthworks establishment of the
lower Shepherds Creek site.
The mining operations area includes heavy vehicle workshops and service infrastructure, a
future paste plant, goods warehouse and office and administration areas to support the open pit
and future underground operations. All supporting infrastructure including power reticulation,
water treatment, stormwater management, parking and circulation are included.
The Ardgour site provides for a temporary 82-person construction camp for the duration of the
construction phase and allocation for the mine administration building and carparking, high
voltage substation, interim heavy vehicle workshop and construction lay down areas.
Figure ES 28: Main BOGP Infrastructure area
61
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 12.2 Project Water Supply
A water supply is required to support project operations, a total supply peak of 97 l/s, or 8,381
m
3
/day at project start-up with future demand declining to a range of 50-70 l/s as more recycled
water becomes available from the processing and mining operations.
A reliable water source from the Bendigo aquifer has been developed, with the first of two bores
constructed in close proximity to the Bendigo Creek and the exploration base, off Bendigo Loop
Road. A dedicated pipeline (315mm HDPE) is to be constructed using in-bore pumps, and a
booster pump station on Matilda Rise, to lift the water approximately 200m vertically and 6.5km,
to the mine site in the lower Shepherds valley. A water permit will be applied for to secure water
rights.
ES 12.3 Power Supply
The electrical load requirements for the new mine site have been modelled based on the known
loads of the mine for the initial stages of operation, 13.8MVA and expected future loads for the
underground phases of the mine’s lifecycle, to a total 19.5MVA.
The new supply distribution is currently connecting to the Aurora Energy owned, Upper Clutha
Network via the Lindis Crossing Substation, installing a new 66kV overhead network
approximately 10km north of the mine, utilising road reserve for the above ground network to a
single 66 /11kV, 24 MVA transformer located at the entrance to the lower Shepherds Creek gorge,
approx. 500m from the process plant and mine operations site. The wider site and plant will be
connected by multiple 11kV networks.
ES 12.4 Site Access and alternate route for Thomson Gorge Road
ES 12.4.1 Site Access
New and upgraded road access is required to provide for personnel and visitor access, delivery
of construction and mine operation equipment, plant and vehicles.
Following an options assessment the preferred route is based on reduced impact to the current
roading network and to neighbouring property owners and businesses. The access will be from
SH8 (Cromwell – Tarras), approximately 24km from Cromwell, via Ardgour Road, then Thomson
Gorge Road (TGR) to the mine site in the lower Shepherds valley, a 7.3km route from the SH8
intersection. The final leg is a 540m extension through existing road reserve in the lower
Shepherds valley gorge.
ES 12.4.2 Thomson Gorge Alternate (TGR) Route – Ardgour Rise
Proposed mining activities will likely disrupt normal use of Thomson Gorge Road.
An alternate 4WD drive diversion access road will be established that follows Ardgour Station
ridge line commencing in the west from the existing TGR in the Lindis Valley and to the east re-
joining close to Matakanui Station.
Chorus telecommunication’s network has a fibre optic cable located in the TGR that will be
reinstated to maintain connectivity within the new Ardgour rise road alignment.
62
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 13. Costs
ES 13.1 Operating Cost Estimates: Open pit
ES 13.1.1 Basis of Estimate
Operating cost estimates have been completed from first principles, based on an owner mining
model generated by the competent person. Physicals are used as drivers and unit rates are
based on demonstrated rates from suppliers and similar style operations such as OceanaGold’s
nearby Macraes Gold Mine. Cost estimates accuracy are expected to be in the range of +/-15%
and are expressed as 2024 NZD.
ES 13.1.2 Mining Operating Costs
The mining unit cost averaged over life-of-mine (LOM) is approximately NZ$3.74 /t and includes:
• Ore and waste drill and blast;
• Ore and waste load and haul;
• Grade control sampling and assaying;
• Crusher feed and stockpile rehandling;
• Ancillary equipment for supporting mining activities;
• Mine management and technical services costs;
• Leasing, maintenance and servicing of all mining and ancillary equipment;
• Pit dewatering and Services (Lighting, work area maintenance, signage, haul road and
access road maintenance); and
• Top soil stripping and surface access haul roads maintenance.
The mining fleet ownership costs are included.
Table ES 26: LoM open pit mining costs
Operating Costs Amount NZD m Unit cost ($/t moved ex-pit)
Loading 76.1 0.34
Hauling 291.0 1.31
Drilling 87.2 0.39
Blasting 51.3 0.23
Grade control 1.70 0.01
Crusher feed 10.3 0.05
Ancillary 109.9 0.50
Mining operations
overheads
189.7 0.86
Stockpile rehandle 7.6 0.03
Pit clear and grub 3.7 0.02
Total Mining Costs 828.4 3.74
ES 13.2 Operating Cost Estimates: Underground
ES 13.2.1 Basis of Estimate
Operating cost estimates have been completed from first principles, based on an owner mining
model. Physicals are used as drivers and unit rates are based on demonstrated rates from
63
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
suppliers and similar style operations such as OceanaGold’s Macraes Gold Mine. Cost
estimates accuracy are expected to be in the range of +/-15% and are expressed as 2024 NZD.
ES 13.2.2 Mining Operating Costs
The total operating costs are estimated at $224.4M and mining unit cost averaged over life-of-
mine (LOM) at NZ$93.01 /t processed and includes:
• Development and stoping direct costs. Ground support, explosives, mine services,
assaying, etc. Driven by metres and tonnes
• Mobile fleet operating costs. Maintenance and running costs for drills, LHD’s, trucks and all
auxiliary fleet
• Infill diamond drilling.
• Power.
• Labour. Management, Mining operations, maintenance and technical services
• Paste. Cement and plant maintenance
• Miscellaneous. Miners tools, technical services, fan and pump maintenance
Post the underground development phase (months 1-24) the unit costs are $78.64/ tonne
processed including on-going mine development.
Table ES 27: LoM Underground mining operating costs
Total LOM
Month 25+ (post mine
development)
$NZD M
Unit cost
($/tonne
processed)
$NZD M
Unit cost ($/tonne
processed)
Direct Operating Cost per
metre (consumables)
20.7 8.57 12.8 5.32
Fleet costs 37.1 15.38 28.9 11.96
Infill Diamond drilling 3.5 1.45 2.5 1.04
Power 16.0 6.63 13.4 5.55
Labour 107.0 44.36 79.4 32.91
Paste Plant Operations
(Directs)
37.2 15.40 35.9 14.87
Miscellaneous 2.9 1.22 2.6 1.06
Total 224.4 93.01 175.4 78.64
ES 13.3 Operating Cost Estimates: Processing
The Processing costs were estimated based on the processing flowsheet for 1.5Mtpa throughout
and 2.1Mtpa throughput. With a breakdown by fixed and variable cost elements.
The LOM unit cost per tonne processed is estimated at $18.92 from a total $318.3M.
64
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 28: LoM Processing operating costs
Rate
$NZD
M
1.5Mtpa - fixed annual $11,637,438 42.7
1.5Mtpa - variable ($/t processed) $11.40 62.2
2.1Mtpa - fixed annual $13,151,033 72.3
2.1Mtpa - variable ($/t processed) $11.49 130.5
Met-lab sampling (annual
1.5Mtpa)
$925,480 10.5
Total
318.3
Unit cost - LOM $18.92
ES 13.4 Operating Costs: General and Administration
The General and Administration costs have been estimated and are broken into three broad
categories:
• Labour. For steady state operations a 25-person support team including General Manager,
Commercial and Administration manager accountants, accounts payable, environmental,
HR, payroll, nurse, OHS.
• General site support. Worker transport, community relations, consultants, light vehicles,
office expenses, legal fees, recruitment and auditing
• Specific site support. Land leases, Site water supply (power), Ecology sanctuary, water
treatment and closure bonding.
Over the LOM this equals $74.0M or $4.40 tonne processed.
Table ES 29: General and Administration operating costs
Cost area $NZD M Unit cost ($/tonne processed)
Operations labour 27.2 1.62
Other - general 20.7 1.23
Other - specific 26.1 1.55
Total 74.0 4.40
ES 13.5 Capital Cost Estimates
Capital cost estimates include project capital, sustaining and closure
ES 13.5.1 Site establishment
The majority of these costs are project (establishment) costs and are summarised below.
Owners team: The labour and support costs for the owners construction team is estimated at
$4.4M.
Land and Landowner costs, which include:
• Land purchases; and
• Payments to landowners on project start-up including up-front royalties.
The estimated costs are $7.2M
65
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Site infrastructure:
• HV power connection to the site from the local 66kV network including a 66kV to 11kV
transformer. ($12.8M)
• Road access upgrades and new roads connecting from the state highway, plus a local public
road diversion (which is a sustaining cost item). ($13.9M)
• Service water system establishment. Borefield, pumps and pipelines. ($5.7M)
• The construction camp establishment and running cost. ($9.9M)
• Site facilities. Administration and mining offices, mobile fleet workshop, refueling,
washdown, warehouse, associated facilities and theservices reticulation. ($23.3M)
Establishment earthworks are required across the terrain. These include:
• Diversion drains. Clean water diversion drains around the TSF and main Shepherds ELF
($1.0M);
• Sediment ponds. This most notably includes a pond in the mid Shepherds valley to contain
mine impacted waters from the upper Shepherds and Jeans Creek basins and would be a
final collector from the RAS pit stripping also ($1.7M); and
• The site haul road network which will involve cuts from the mining locations to the ROM pad,
ore-stockpile and ELF ($13.8M).
Table ES 30: Site establishment costs breakdown
Area Specifics $NZD M
Owners costs 4.4
Land and landowner costs 7.2
Site Infrastructure
Construction camp 9.9
Roads 13.9
Power 12.8
Service water 5.7
Site Facilities 23.3
Establishment earthworks
Diversion drains 1.0
Sediment ponds 1.7
Haul roads 10.5
ELF stripping 2.8
Total 93.2
ES 13.5.2 Process plant
Total process plant costs including preparing the Shepherds valley earthworks is estimated at
$135.2M. With further a further breakdown:
• Shepherds valley earthworks to strip unsuitables, train the creek to the northern bank, drill
and blast in TZ4 to get hard rock foundations for the crusher and milling circuit and building
back up the valley with engineered fill - $5.4M
• The initial 1.5Mtpa process plant build as an EPCM (with minimum disruption later
expansion to 2.1Mtpa) - $128.9M
• Fit out of the laboratory - $0.9M
66
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 31: Further detailed breakdown of the 1.5Mtpa plant EPCM cost
Description $NZD M
Contractor Indirects 3.4
Preliminary & General 0.3
First Fills & Initial Consumables 1.8
Equipment Spares 0.5
EPCM 18.2
Commissioning 1.5
Crushing 15.5
Milling & Classification 23.6
Pebble Crushing & Conveying 1.4
Leach & Adsorption 13.9
Gold Recovery 7.8
Reagents 2.4
Water Services 2.0
Piping 7.6
E&I 17.0
Construction Overheads 3.6
Plant & Equipment 6.2
Plant Buildings 2.4
Total 128.9
The process plant expansion to 2.1Mtpa is $30.3M
ES 13.5.3 TSF
Total TSF construction and closure costs are $58.1M excluding bulk zone fill materials which are
included in the mining costs.
Table ES 32: Full TSF capital costs
Description $NZD M
TSF - Starter 9.5
TSF - Raises 33.5
TSF - Closure 15.1
Total 58.1
ES 13.5.4 Underground
The capital underground costs are $82.2M, not including capitalised operating costs. The
significant cost contributors are the mining fleet including light vehicles ($35.3M) and the paste
plant and associated paste infrastructure ($33.1M).
67
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 33: Underground capital
Description $NZD M
Mining Fleet 35.3
Ventilation 1.3
Dewatering Pumps 1.1
Paste plant and associated infrastructure 33.1
Mine support Infrastructure 8.5
Safety 1.7
Miscellaneous 1.1
Total 82.2
ES 13.5.7 Other
Other specific capital costs are for:
• Water treatment at closure when the site will need to start releasing water ($8.3M);
• Light vehicles not captured elsewhere;
• Provision for ecological offsets; and
• General closure rehabilitation costs not already capture by the TSF or water treatment
Table ES 34: Other capital costs
Description
$NZD
M
Water treatment
8.3
Light vehicles
0.6
Ecological offsets
3.6
Closure (plant-site, infrastructure removal, general)
35.0
ES 14. Financial evaluation
The Financial Evaluation was prepared on the following basis:
• A real discount rate of 8% was applied. This was based on an internal weighted average cost
of capital calculation and a peer analysis of comparative projects.
• All estimated costs are nominal (not adjusted for inflation).
• A corporate tax rate of 28% has been applied, without allowances for New Zealand tax losses.
• All pre-production capital has been capitalised up until the point of commercial production.
• Conceptual mine closure costs have been netted to zero with provisional project salvage
values.
Key financial outputs from the study are as shown in Table ES 35 and Table ES 36.
68
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 35: Key Project Metrics
Description Unit
Base Case
Scenario
Key Project Mining Physical Targets and
Assumptions
Mine Life Years 9.17
Plant Throughput ktpa 1,835
Open Pit Ore Mined kt 14,404
Open Pit Mill Feed kt 14,404
Open Pit Mill Feed Grade Au g/t 2.19
Open Pit Contained Gold koz 1,014
Open Pit Recovered Ounces koz 935
Underground Ore Mined kt 2,413
Underground Mill Feed kt 2,413
Underground Mill Feed Grade Au g/t 2.99
Underground Contained Gold koz 232
Underground Recovered Ounces koz 215
Total Ore Mined kt 16,817
Total Mill Feed kt 16,817
Au Grade - Mined g/t 2.30
Total Contained Gold koz 1,245
Overall Plant Recovery % 92.38%
Gold Production koz 1,151
Modelling of the government or Crown royalty modelling has resulted in the 10% accounting
profits being applied which is higher than the 2% ad valorem.
69
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 36: Key Financial Metrics
Key Financial Assumptions
Base Case
AUD
Spot AUD Spot NZD Spot USD
Gold Price
$/oz
2,894 4,000 4,406 2,626
Exchange Rate
USD:$
0.66 0.66 0.60 1.00
Key Project Metrics
Gold Produced
Oz
1.15 million
Initial Mine Life
Years)
9.17
Gold Revenue
'000
3,330,018 4,602,435 5,069,319 3,021,314
Open Pit Mining Cost
'000
619,237 619,237 682,054 406,504
Underground Mining Cost
'000
152,747 152,747 168,242 100,272
Processing Costs
'000
288,943 288,943 318,254 189,679
General and Admin Costs
'000
55,633 55,633 61,276 36,521
Selling Cost
'000
8,357 8,357 9,204 5,486
Royalties - Govt
'000
170,173 296,305 326,363 194,512
Royalties - Others
'000
89,636 123,887 136,454 81,327
Total Cash Operating Cost
'000
1,384,725 1,545,108 1,701,848 1,014,301
Total Cash Operating Cost per Ounce
$/oz
1,203 1,343 1,479 881
Project EBITDA
'000
1,945,292 3,057,327 3,367,471 2,007,013
Depreciation and Amortisation (exc Rehab
PPE)
'000
546,067 546,067 601,462 358,471
Total Production Cost (incl. all CAPEX)
'000
1,930,793 2,091,175 2,303,310 1,372,773
Total Production Cost per Ounce
$/oz
1,678 1,818 2,001 1,193
Net Profit Before Tax (NPBT)
'000
1,399,225 2,511,260 2,766,009 1,648,541
Tax Payable (28.0%)
'000
(424,010) (728,094) (801,954) (477,965)
After Tax Profit
'000
975,215 1,783,166 1,964,055 1,170,577
Capital
Initial Development Capex (inc. OP &
Capitalised Opex)
'000
340,609 340,609 375,161 223,596
Underground Initial Development Capex
'000
121,795 121,795 134,151 79,954
Sustaining Capex
'000
83,663 83,663 92,151 54,922
Closure Capex (see note 1)
'000
- - - -
Total CAPEX over Mine Life
'000
546,067 546,067 601,462 358,471
DCF Outcomes
Initial NPV (unleveraged and after-tax)
@8.00%
'000
534,975 1,058,104 1,165,441 694,603
IRR
%
41.66% 68.23% 68.23% 68.23%
Payback Period from production start
(unleveraged and after-tax)
years
1.67 Yr(s) 0.92 Yr(s) 0.92 Yr(s) 0.92 Yr(s)
Note 1: Conceptual mine closure costs netted to zero against mine salvage value.
Summary operating costs are shown in Table ES 37.
70
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Table ES 37: Summary operating costs
Operating Costs (Production) NZD '000
NZD /t
Milled
NZD /oz
Produced
Mining Cost 850,296 50.6 739
Processing Costs 318,254 18.9 277
General and Admin Costs 61,276 3.6 53
Selling Cost 9,204 0.5 8
Royalties - Govt 326,363 19.4 284
Royalties - Others 136,454 8.1 119
Total Cash Operating Cost 1,701,848 101.2 1,479
Initial Development Capex (inc. OP &
Capitalised Opex)
375,161 22.3 326
Underground Initial Development Capex 134,151 8.0 117
Sustaining Capex 92,151 5.5 80
Closure Capex - - -
Total Production Cost (inc Closure) 2,303,310 137.0 2,002
Summary capital costs are shown in Table ES 38.
Table ES 38: Capital cost summary
Capital Cost Requirement Estimates
Pre-Production Capital: Open Pit & Initial Dev
Owners Team
NZD '000
3,829
Land
NZD '000
7,225
Infrastructure
NZD '000
56,115
Site Establishment
NZD '000
11,633
TSF
NZD '000
9,473
Process plant
NZD '000
135,218
Open Pit
NZD '000
2,182
Others
NZD '000
562
Capitalised OpEx - Open Pit Mining
NZD '000
146,339
Capitalised OpEx - G&A
NZD '000
2,585
Total Initial OP Pre-Production Cost Estimates
NZD '000
375,161
Underground Infrastructure
NZD '000
78,007
Capitalised OpEx - Underground Mining
NZD '000
56,144
Total UG Pre-Production Cost Estimates
NZD '000
134,151
Sustaining & Closure Capital – Life of Mine Estimates
Underground
NZD '000
4,194
Open Pit
NZD '000
87,956
Closure Capex
NZD '000
-
Total Sustaining & Closure Capital
NZD '000
92,151
Total Capital Cost
NZD '000
601,462
71
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Figure ES 29 below, shows the undiscounted cashflows on an annual basis at the spot gold
price scenario (NZ$4,406/oz).
Figure ES 29: Project Free cash flow (inc Tax, NZD'000)
Sensitivities for gold price, capital and operating costs, discount rate and metallurgical
recoveries at relevant ranges are shown in Figure ES 30 below.
Figure ES 30: Project NPV Sensitivities at spot gold price of NZ$4,406/oz (NZD'000) at 8%
Post-Tax, Real Discount Rate
(150)
(225)
376
294
258
197
171
431
234
290
84
22
(15)
(150)
(375)
0
294
552
748
919
1,350
1,584
1,873
1,957
1,979
1,964
(1,500)
(1,000)
(500)
-
500
1,000
1,500
2,000
2,500
(300)
(200)
(100)
-
100
200
300
400
500
Year -2Year -1Year 1Year 2Year 3Year 4Year 5Year 6Year 7Year 8Year 9Year 10Year 11
Cumulative net cash flow (NZ$'000)
Cash Flow (NZ$'000)
Project Free Cash Flow (inc tax)Cumulative FCF (RHS)
(40,191)
(51,189)
(72,435)
(106,060)
(212,027)
(212,995)
40,180
51,185
77,862
105,993
211,649
212,957
(250,000) (200,000) (150,000) (100,000) (50,000) - 50,000 100,000 150,000 200,000 250,000
Capex (+/-10%)
Operating Cost (+/-10%)
Discount Rate (+/-1%)
Recovery (+/-5%)
Grade (+/-10%)
Gold Price (+/-10%)
72
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Additional sensitivity analysis was undertaken at the base case gold price of NZ$3,204/oz and
is shown in below.
Figure ES 30A: Project NPV Sensitivities at base case of NZ$3,204/oz ($NZD'000) at 8% Post-
Tax, Real Discount Rate
Figure ES 31 shows the overall annual gold production profile and AISC at the spot gold price
scenario (NZ$4,406/oz) for the primary production years.
Figure ES 31: Production Profile OP/UG w/AISC at Spot Gold Price (NZ$4,406/oz)
ES 15. Environment
A comprehensive set of baseline studies have been commissioned to understand the existing
environment across the project area and surrounding landscape. As the project description has
developed the assessment of effects on the environment has also progressed along with
associated considerations of opportunities to address potential negative effects as far as
practical.
Environment related studies include ecology, waterways and wetlands, ground and surface
water, geochemistry, noise, air quality, heritage, closure, visual effects, recreation and traffic.
(40,191)
(51,189)
(72,435)
(106,060)
(212,027)
(212,995)
40,180
51,185
77,862
105,993
211,649
212,957
(250,000) (200,000) (150,000) (100,000) (50,000) - 50,000 100,000 150,000 200,000 250,000
Capex (+/-10%)
Operating Cost (+/-10%)
Discount Rate (+/-1%)
Recovery (+/-5%)
Grade (+/-10%)
Gold Price (+/-10%)
152
151
138
116
50
129
78
88
29
13
48
56
41
41
16
1,397
1,336
1,417
1,807
2,252
1,434
1,767
1,244
1,883
-
500
1,000
1,500
2,000
2,500
-
20
40
60
80
100
120
140
160
180
200
Year 1Year 2Year 3Year 4Year 5Year 6Year 7Year 8Year 9
AISC NZ$/oz
Production (kOz)
Open PitUndergroundAll-in-Sustaining Cost (exc. Closure Capex)
73
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
The project is located in the 90,000 ha Dunstan Ecological District. It is dominated by a mosaic
of native and exotic scrub, native tussockland, mixed depleted herbfields and exotic pasture.
The Ecological Study Area (ESA) for the project covers approximately 5,000 ha. The Project
Footprint (PF) is defined as the area of direct impact of approximately 550 ha. Adjacent to these
areas is land administered by the Department of Conservation (DOC) including the Bendigo
Historic Reserve (459ha) to the west which is contiguous with Bendigo Scenic Reserve (628ha)
further to the west; the Bendigo Conservation Area (1,973ha) to the southwest; and the Ardgour
Conservation Area (303ha) to the east which is contiguous with the Neinei i kura Conservation
Area (1,643ha) to the north. Thus, a total land package of 5,006 ha is under DOC management
adjacent to the project.
A conservation covenant was established over Bendigo Station when it passed from leasehold
into freehold and the DOC areas were established. The conservation objectives broadly seek to
protect the natural character of the land and the ecological character and maintain the
landscape and historic values. The covenant also provides for prospecting or mining of minerals
with the Minister of Conservation’s approval having regard for the objectives. Matakanui Gold
holds the necessary approvals from the Minister to undertake exploration.
Figure ES 32: Project Footprint, Ecological Study Area, Dunstan Ecological District and DOC
administered conservation areas
74
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
The BOGP is located across two freehold working pastoral stations. The indigenous biodiversity
in the ESA is heavily modified by past and current land use practices, along with the ongoing
effects of invasive weeds, introduced mammalian predators, and browsers.
Despite the past and current land use practices the PF contains some areas of high terrestrial
value based on the presence of native-dominated habitats and nationally ‘threatened’ or ‘at-risk’
flora and fauna.
Fifty ‘threatened’ or ‘at-risk’ flora and fauna species (including 16 invertebrates not listed or
assessed) have been identified in the ESA to date. Further surveys to confirm the extent of these
species and search for additional flora species will be undertaken in spring 2024.
Freshwater ecological values of the area are associated with the overall stream habitat and the
macro-invertebrates present. No freshwater fish values were identified within Shepherds nor
Rise and Shine Creeks and macroinvertebrate communities exhibited degradation in areas but
were otherwise considered fair.
A mammalian pest survey of the ESA confirmed the presence of 10 mammalian pests including
deer, pigs, rabbits, hares, ferrets, cats, rats, mice, goats and possums.
Potential effects on the ecology have been identified. Opportunities to avoid and mitigate
negative effects are an integral part of the project design process.
Lengths of waterways and associated streams in Shepherds Creek will be covered by the tailings
storage facility (TSF) and engineered landform (ELF) or realigned to accommodate the process
plant footprint. Loss of waterways will be mitigated by construction of freshwater diversion
drainage channels in the Shepherds valley at or just above the final height of the TSF and ELF.
The channels will be designed to replicate similar flow characteristics to mountain creeks and
streams as far as practical to promote naturalisation over the project life and the return of native
vegetation and invertebrates. Seeding of native species and management of grazing animals will
facilitate naturalisation.
An ecological effects management strategy has been developed which includes rehabilitation
for ecological and pastoral (grazing) outcomes on direct disturbed areas. To offset or
compensate for residual effects that cannot be avoided, minimised or rehabilitated a
combination of broad scale and targeted habitat restoration and enhancement measures will be
employed to deliver improved biodiversity management and uplift.
This approach aims to ensure that at a broad level biodiversity benefits outweigh impacts in
general accordance with regional and national policy requirements. Offsetting and
compensation for residual ecological effects are being considered via land management
programs.
The Central Otago District Plan identifies the Dunstan Mountains as an Outstanding Natural
Landscape (ONL). An ONL requires protection from inappropriate subdivision, use and
development as a matter of national importance in accordance with Section 6(b) of the Resource
Management Act. Landscape and visual effects of the operation are being assessed by
experienced landscape architects considering the physical, perceptual and associative values
of the landscape. Project design work aims to balance the overall disturbance effects across the
landscape values, including ecological, historical and visual values. Potential visual effects are
substantially reduced by locating much of the disturbance within the confines of the Shepherds
75
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
and Rise and Shine Valleys, of which there is limited visibility from key vantage points in the
Clutha / Mata-Au Valley.
The project area has been surveyed for archaeological sites via pedestrian survey, LiDAR
imagery, historical photographs and documents and previous archaeological investigations to
establish detailed maps of archaeological sites. The sites have been further evaluated to
understand their archaeological values. Thirty-three archaeological sites have been mapped in
the project footprint. The majority of the sites are associated with the intensive historic alluvial,
elluvial and hard rock mining in the survey area. These sites include footings of a stamper battery,
tailing areas. water races, huts, dams, culverts, and drains. The predominant archaeological
features are remains of 10 hut sites, of which the majority are associated with mining activity
although several may have also been used by musterers. The heritage structures within the Rise
and Shine Valley are mostly ruinous and at least partially obscured by topography and/or
vegetation, with the exception of the small dam in Rise and Shine valley. Whereas the wider
Bendigo historic areas exhibit residual and visible huts and other buildings which are much more
intact and the mining features are easily identified by the public. No Māori archaeological sites
have been identified in the project area.
Conservative noise modelling has shown that district council noise limits can be readily
achieved. The noise model will be refined as more information comes to hand during detailed
design.
Lighting design aims to minimise night glow and light spill while providing for safe operation of
the plant. The location of the process plant and infrastructure in Shepherds valley greatly
reduces the potential effects of light pollution.
Air quality effects assessment is in progress and indicates that nuisance dust can be managed
within the project footprint.
ES 16. Geochemical
The BOGP gold deposit is located within the Otago Schist and is associated with the mineralised
Rise and Shine Shear Zone (RSSZ) which juxtapose lower greenschist facies Textural Zone 3 (TZ3)
and mid to upper greenschist facies Textural Zone 4 (TZ4) schists in their hanging walls and
footwalls respectively. This mineralisation is dominated by elevated sulphate (SO
4
) and arsenic
(As) (e.g., the mineral arsenopyrite) with other trace metals also being potentially elevated but
at much lower concentrations (e.g., cobalt, (Co), copper (Cu), chromium (Cr), antimony (Sb),
and zinc (Zn)).
The outcropping mineralisation associated with the BOGP area has contributed to baseline
water quality being elevated in some metals, which has been exacerbated by historical legacy
mining activities, leading to streams in the project area containing slightly higher contaminants
of potential concern (COPC) that include for instance, As, cadmium (Cd), Cu, Cr, manganese
(Mn), and Zn leaching at faster rates from exposed mineralisation.
Some soils within the Rise and Shine Creek catchment are elevated in arsenic due to natural
outcropping mineralisation and historic mining spoils. These soils will require management to
avoid adverse effects if they are disturbed (e.g., dust management, stockpile management).
Studies indicate that the rocks associated with the project (TZ3, TZ4, and RSSZ) will not generate
acid rock drainage with >350 samples tested by industry accepted acid base accounting (ABA)
76
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
techniques (e.g., AMIRA, 2002). This is a function of the high acid neutralisation capacity (ANC)
of the rocks associated with carbonate minerals (e.g., dolomite) and a low sulfide mineral
content (e.g., arsenopyrite, pyrite) that can generate lesser acidity. The overall ABA assessment
indicates that the rocks are classified as non-acid forming (NAF).
Data for waste rock indicates that the TZ4 and RSSZ lithologies contain ~97.7% of arsenic and
37.2% of sulfur yet represent only 18% of the waste rock that will be disturbed. Hence,
appropriate management of waste rock to reduce sulfide mineral oxidation and the release of
arsenic is a critical step to minimise any potential deleterious effects of mining, i.e., manage 18%
of the waste rock well to mitigate 97.7% of the arsenic risk in the Engineered Landform ELF) that
will contain the waste rock.
Nitrogenous compounds such as nitrate are also expected to be elevated in seepage from
blasted rock due to the use of ANFO, an ammonium-nitrate fuel oil explosive. This is not an
uncommon problem in the mining industry.
It is expected that mining of the BOGP will affect waters within the project area and these effects
will include:
• Elevated total suspended solids (TSS)
• Neutral metalliferous drainage (NMD) with elevated sulfate and the certain COPCs such as
As, Fe, and potentially lesser amounts of trace metals such as Co, Cu, Cr, Sb, Zn; and
• Nitrate-rich drainage due to the use of ANFO.
Collectively these waters are referred to as mine impacted water (MIW) to acknowledge the
different contributions to poor water quality within the project area. The management of MIW will
involve several engineering controls to minimise the effects on the downstream environment.
These engineering controls have been accounted for in the mine plan, including:
• Materials management and the construction of an Engineered Landform (ELF) to minimise
contaminant loads from the waste rock; and
• Water management and treatment as necessary.
ES 17. Community and iwi
The Bendigo-Ophir Gold Project (BOGP) is located on private farmland in the Central Otago
region, with the closest towns being Tarras and Cromwell. The project is likely to be resourced
by the townships of Cromwell, Tarras, Alexandra, Queenstown, Wanaka, Clyde and Omakau.
Access agreements are in place with both of the station landowners that the project covers,
Bendigo Station and Ardgour Station.
Engagement to date has included regular drop-in sessions in both the Tarras and Cromwell
communities, attendance at community events, community sponsorships, presentations to
community and business groups, site visits, a monthly newsletter, and project information on
Santana Minerals website.
A cultural impact assessment is being undertaken to understand the potential impact on mana
whenua cultural values as identified by iwi in their 2018 statement.
A Social Impact Assessment study is being carried out to assess the social consequences and
community concerns, interviews are currently underway.
77
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES 18. Permitting
ES 18.1 Mining Permits
The project is located within Minerals Exploration Permit (MEP) 60311. To develop the project,
the Company will need to apply for a minerals mining permit (MMP) over the immediate area to
New Zealand Petroleum and Minerals (NZPAM). This is part of the Ministry of Business,
Innovation and Employment (MBIE) and administers the Crown Minerals Act (1991) (CMA).
Section 23 of the CMA provides that the purpose of a minerals mining permit (MMP) is to
authorise the permit holder to mine for the minerals specified in the permit. “Mining” is defined
in the Act as meaning “to take, win, or extract, by whatever means, a mineral existing in its natural
state in land, or a chemical substance from [that mineral].”
The Minister will ordinarily grant a mining permit if satisfied that:
(a) the permit applicant has identified and delineated at least an indicated mineable mineral
resource or exploitable mineral deposit, and
(b) the area of the permit is appropriate, and
(c) the objective of the mining permit is to economically deplete the mineable mineral
resource or deposit to the maximum extent practicable in accordance with good industry
practice.
ES 18.2 Resource Consents
Environmental approvals are predominantly administered under the Resource Management Act
1991 (RMA) the purpose of which is to promote the sustainable management of natural and
physical resources. The Act is administered by the consent authority whose permission is
required to carry out an activity for which a resource consent is required under this Act. In this
case, resource consents will be required from both the Central Otago District Council and the
Otago Regional Council.
Resource consent and building consent are required under New Zealand legislation to construct
the TSF and large dams. This will include the Shepherds Creek Silt Pond. Only resource consent
is required to construct the ELFs. Resource consents relating to environmental effects will be
applied for as part of the wider project application. Building consents for the TSF and Shepherd
Creek Silt Pond will be separately applied for through the building consent authority for dams in
the area.
The NZ Government has introduced a new legislation, Fast-track Approvals Bill (FAB). This Bill
provides a streamlined decision-making process to facilitate the delivery of infrastructure and
development projects with significant regional or national benefits. On 04/10/2024 it was
announced that the Santana Minerals Bendigo-Ophir gold project is included within the list of
projects eligible to access the fast-track consenting framework under the proposed FAB.
The Bill is intended to be a “one stop shop” for consenting projects which would otherwise
require consents under multiple different regimes including resource consents under the RMA,
concessions under the Conservation Act 1987, wildlife permits under the Wildlife Act 1953,
archaeological authorities under the Heritage Pouhere Taonga Act 2014, and land access
provisions of the Crown Minerals Act 1991. The “one stop shop” approach marks a significant
78
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
change in project approvals in New Zealand, and it is hoped that this will significantly reduce
consenting costs, uncertainty, and timeframes.
ES 18.3 Application
Santana Minerals NZ subsidiary Matakanui Gold Ltd is preparing a substantive application for the
Bendigo-Ophir project. The strategy is for the application to include all the necessary
information, from leading technical experts to a high standard to enable robust decision making.
Planned lodgement is Q1 2025.
ES 19. Closure
A conceptual Mine Closure Plan is under development to be submitted as part of the consent
application for the project. The overarching objective of the mine closure plan is a final landform
and site that is safe, stable, and non-polluting at a standard that is acceptable to stakeholders
and regulators. Technical experts have been engaged to develop the conceptual Plan.
The conceptual closure plan will consider the following:
• Knowledge base
• Legal obligations
• Closure risks
• Post mining land uses
• Closure objectives and completion criteria, and
• Community consultation.
The development of the plan will bring together knowledge from a range of experts considering:
• Geochemistry
• Geotechnical
• Mine planning and schedule, including final landform designs
• Ecology
• Rehabilitation
• Visual effects, and
• Stakeholder requirements.
ES 20. Project Implementation
The Project implementation critical path timeline, from receipt of consent and financing, is two
months for mobilisation and site establishment, four months pioneering work to establish at RAS
haul roads, ELF and first mine benches, then sixteen months of bulk-stripping of 39.5Mt through
to commencement of processing.
In October 2024 the BOGP was designated as a ‘Fast-track Project’ under Schedule 2 of the NZ
Government's Fast-track Approvals Bill (FAB). The Bill is anticipated to be enacted by year-end.
An Assessment of Environmental Effects (AEE) is currently in progress, as per the current
requirements under the Resource Management Act. The designation of the BOGP as a fast-track
project does not change the specifics or level of detail being prepared. It is anticipated the
application will be lodged for the required consenting documentation into the FAB by the end of
February 2025.
79
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Whilst the draft FAB legislation allows for decisions within a shorter timeframe, the pathway is
yet to be utilised, and timeframes are still relatively unknown. As a result, the company expects
up to six months for approval.
ES 21. Risks and Opportunities
Opportunities are presented by:
• Adding resources to the production schedule through RAS downdip (Inferred extension).
• Adding production schedule ounces through further gold price escalation.
• Ongoing exploration to increase resource and reserve base.
• Improved understanding of geological domains leading to conversion of further resource to
reserves.
• Conversion of inferred resources to indicated at CIT and generation of viable mine plan.
• Existing opportunities within Central Otago to meet short-term accommodation needs thus
avoiding the need for or the reducing the size of the construction camp.
As part of the PFS, a specific risk assessment has been undertaken across all disciplines covered
in this report. From this work, 108 risks were identified, then assessed and ranked, to allow
further targeted investigations. These risks were grouped as either High, Significant, Moderate or
Low.
The risks were further categorised as to what stage of the project they related to, these groups
being:
• Design,
• Consent,
• Construction, and
• Operations.
And the responsible departments of:
• Project Engineering,
• Implementation Manager,
• Operational Readiness Manager,
• Environment Manager, and
• Corporate.
Generally, the main grouping of risks related to:
• The Fast-track Approval Bill is yet to be passed into law so the final form of the Act may
need further consideration,
• The project start-up timeframe,
o Ability to mobilise the main mining fleet in a timely manner; and
o Ability to connect the high voltage supply to the site.
• The ramp up of pre-strip volume requirements in the pre-strip (critical to first positive
cashflows); and
• Ability to secure financing.
80
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
ES22. Funding
The Board reasonably believes funding will be available for development of the Project based on
the following PFS highlights, together with the following attributes of the Company and its
Board’s experience:
• The PFS shows strong economics associated with Project development, including a very
strong return on capital and robust cashflows, even at a base case gold price of
US$1,900/oz. This provides a strong platform to source debt and equity funding.
• The Board of Santana has a strong track record in raising funds through debt and equity
markets.
• The Project has a 9-year mine life generating significant free cash flow relative to the
development capital required.
• The PFS illustrates an NPV that is significantly value-accretive to current shareholder
value.
• The Company has a tight capital structure and owns 100% of the Project, making
potential financing arrangements uncomplicated.
• The Board has extensive experience in mine development and production in the
resources industry which is attractive to potential financiers seeking certainty of project
delivery.
• At high gold prices, global debt and equity finance availability for gold projects remains
robust with several recent examples of funding being made available for ASX listed gold
development projects.
There is, however, no certainty that the Company will be able to source funding as and when
required. Typical project development financing would involve a combination of debt and equity.
It is possible that such funding may only be available on terms that may be dilutive to or otherwise
affect the value of the Company’s existing shareholders.
81
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
JORC Code, 2012 Edition – Table 1
Section 1: Sampling Techniques and Data
Criteria JORC Code explanation Commentary
Sampling techniques
Nature and quality of sampling (e.g. cut channels, random
chips, or specific specialised industry standard measurement
tools appropriate to the minerals under investigation, such as
down hole gamma sondes, or handheld XRF instruments, etc).
These examples should not be taken as limiting the broad
meaning of sampling.
Include reference to measures taken to ensure sample
representivity and the appropriate calibration of any
measurement tools or systems used.
Aspects of the determination of mineralisation that are Material
to the Public Report.
In cases where ‘industry standard’ work has been done this
would be relatively simple (e.g. ‘reverse circulation drilling was
used to obtain 1 m samples from which 3 kg was pulverised to
produce a 30 g charge for fire assay’). In other cases more
explanation may be required, such as where there is coarse gold
that has inherent sampling problems. Unusual commodities or
mineralisation types (e.g. submarine nodules) may warrant
disclosure of detailed information.
This Mineral Resource Estimate (MRE) is estimated from drilling samples collected by reverse
circulation and diamond drilling. ‘Blasthole’, surface trench and underground channel samples
were used as an aid for geological interpretation and domaining but not for grade estimation.
Diamond drill (DD) core samples for laboratory assay are typically 1 metre samples of diamond
saw cut ½ diameter core. In the rare cases where the core was friable or unconsolidated, the
sample was collected from one side of the core using a scoop. Where distinct mineralisation
boundaries are logged, sample lengths are adjusted to the respective geological contact. RC
samples were sub-sampled at 1.0 m intervals using either a riffle splitter or a cone splitter
mounted below the cyclone. The splitter produced 2 x 12.5% splits and 1 x 75% split. The two
12.5% splits were used as primary sample and field duplicate (if submitted) with the 75% split
used for logging and then stored at the MGL core yard.
Samples are crushed at the receiving laboratory to minus 2mm (85% passing) and split using a
rotary splitter to provide 1kg for pulverising in a ring mill to -75um. Pulps are fire assayed (FAA)
using a 50g charge with AAS finish. Prior to 2019 only 200g of the crushed material was
pulverised. 877 samples were assayed this way.
Certified standards, blanks and field replicates are inserted with the original batches at a
frequency of ~5% each for QAQC purposes.
All pulps and crush reject (CREJ) are returned from the laboratory to MGL for storage on site. Of
these returned samples, a further ~5% are re-submitted as QC check samples which involve pulp
FAA re-assays by the original and an umpire laboratory and CREJ re-assayed by 500-gram (+ & -
75mu) screen fire assay (SFA), 1kg BLEG (LeachWELL) and 2*500-gram Photon analysis (PHA)
for gold.
Where multiple assays exist for a single sample interval, larger samples are ranked in the
database: PHA > BLEG > SFA > FAA.
All returned pulps are analysed for a suite of 31 elements by portable XRF (pXRF).
The sampling, sub-sampling and assaying methods are appropriate to the geology and
82
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
mineralization being reported.
Drilling techniques
Drill type (e.g. core, reverse circulation, open-hole hammer,
rotary air blast, auger, Bangka, sonic, etc) and details (e.g.
core diameter, triple or standard tube, depth of diamond tails,
face-sampling bit or other type, whether core is oriented and if
so, by what method, etc).
Diamond (DD) and reverse circulation (RC) drilling has been used to inform the MREs being
reported here. All diamond coring was PQ3 size triple tube for holes MDD001 to MDD016. The
DD coring in since MDD016 has all been HQ3 size triple tube. Where PQ3 core size (83mm
diameter) is commenced this is maintained throughout the DD hole until drilling conditions
dictate reduction in size to HQ3 core (61mm diameter). DD pre-collars are drilled open hole
through un-mineralised TZ3 schist to within about 15 m of the mineralisation hangingwall at
which point diamond coring commences.
RC drilling was only carried out where the mineralisation target was less than about 150m
downhole and used a face sample bit with sample collected in a cyclone mounted over a riffle
or cone splitter producing 2 x 12.5% splits and 1 x 75% split. The two 12.5% splits were used as
primary sample and field duplicate (if submitted) with the 75% split used for logging and then
stored at the MGL core yard.
Drillholes are oriented to intersect known mineralised features in a nominally perpendicular
orientation as much as is practicable. A small number of holes are oriented in other directions to resolve
areas of ambiguous geological interpretation.
All drill core is oriented to assist with interpretation of mineralisation and structure using a Trucore
orientation tool.
Drill sample recovery
Method of recording and assessing core and chip sample
recoveries and results assessed.
Measures taken to maximise sample recovery and ensure
representative nature of the samples.
Whether a relationship exists between sample recovery and
grade and whether sample bias may have occurred due to
preferential loss/gain of fine/coarse material.
DD core sample recoveries are recorded by the drillers at the time of drilling by measuring the
actual distance of the drill run against the actual core recovered. The measurements are checked
by the site geologist. DD core recovery averages 94.2% within the gold estimation domains.
When poor core recoveries are recorded the site geologist and driller endeavour to immediately
rectify any problems to maintain maximum core recoveries. DD core logging to date indicate
~97% recoveries.
RC sample recovery is visually estimated and averages 96.5%. All RC samples logged as wet
were omitted from use in this MRE. Of the RC samples used in these MREs, 94.7% were logged
as dry and 4.9% logged as moist.
Sample grades were plotted against drilling recovery by drilling method and no relationship was
83
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
established.
Wet RC samples do show higher grades than dry RC samples. This may be due to wet RC samples
coming from higher grade zones or sampling bias due to the loss of fines in wet samples.
Whatever the cause, this bias was the reason that wet RC samples were omitted from use in this
MRE.
Logging
Whether core and chip samples have been geologically and
geotechnically logged to a level of detail to support
appropriate Mineral Resource estimation, mining studies and
metallurgical studies.
Whether logging is qualitative or quantitative in nature. Core
(or costean, channel, etc) photography.
The total length and percentage of the relevant intersections
logged.
All DD holes have been logged for their entire length below upper open hole drilling (nominally 0-
450 metres below collar). Data is recorded directly into AcQuire database with sufficient detail
that supports Mineral Resource estimations (MRE).
Logging is mostly qualitative but there are estimations of quartz and sulphide content and
quantitative records of geological / structural unit, oxidation state and water table boundaries.
Oriented DD core allows alpha / beta measurements to determine structural element detail (dip
/ dip direction) to supplement routine recording of lithologies / alteration / mineralisation /
structure / oxidation / colour and other features for MRE reporting, geotechnical and
metallurgical studies.
All RC chips were sieved and logged for lithology, colour, oxidation, weathering, vein percentage
and sulphide minerals.
All core is photographed wet and dry before cutting. Sieved RC chips are also photographed.
100% of all relevant (within the gold grade domains) intersections were logged. The logging is of
sufficient quality and detail for resource estimation.
Sub-sampling
techniques and
sample preparation
If core, whether cut or sawn and whether quarter, half or all
core taken.
If non-core, whether riffled, tube sampled, rotary split, etc and
whether sampled wet or dry.
For all sample types, the nature, quality and appropriateness
of the sample preparation technique.
Quality control procedures adopted for all sub-sampling
stages to maximise representivity of samples.
Measures taken to ensure that the sampling is representative
DD core drill samples are sawn in ½ along the length of the core on cut lines marked by geologists’
perpendicular to structure / foliation or to bisect vein mineralisation for representative samples
whilst preserving the orientation line. One half is dispatched to the laboratory for assay and the
other half retained in core trays at MGL’s core storage facility. Intervals required for QAQC
checks are nominated by geologists and the crushed sample being split by the laboratory with
the two replicated samples then assayed.
QA procedures used to maximise the representivity of sub-samples include the use of a riffle
splitter on the RC rig and cutting DD core perpendicular to the regional foliation. QC procedures
to assess the representivity of sub-sampling include field duplicates, pulp duplicates, standards,
and blanks at a frequency of ~5%. In addition approximately 5% of the mineralised samples are
84
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
of the in situ material collected, including for instance results
for field duplicate/second-half sampling.
Whether sample sizes are appropriate to the grain size of the
material being sampled.
periodically re-submitted to the primary laboratory and umpire laboratory for re-assay by fire
assay (50g), screen fire assay (200g), BLEG (LeachWELL, 1000g) and photon assay (500g). The
larger re-assay methods provide a check on sub-sampling at the laboratory.
The mass proportion of every 10th sample passing 75um is reported by the laboratory and
monitored to ensure sample preparation quality.
Calculations based on Pitard (1993) show that sub-sample masses are appropriate to gold
particle size and grade, if the size and shape of the gold particles are reduced in the ring mill in a
similar way to the gangue particles.
Quality of assay data
and laboratory tests
The nature, quality and appropriateness of the assaying and
laboratory procedures used and whether the technique is
considered partial or total.
For geophysical tools, spectrometers, handheld XRF
instruments, etc, the parameters used in determining the
analysis including instrument make and model, reading
times, calibrations factors applied and their derivation, etc.
Nature of quality control procedures adopted (e.g. standards,
blanks, duplicates, external laboratory checks) and whether
acceptable levels of accuracy (i.e. lack of bias) and precision
have been established.
FA, BLEG, SFA and PHA are all total gold assays and are appropriate to the RSSZ mineralization.
DD core and RC chip samples for gold assays undergo sample preparation by SGS laboratory
Westport. Sample preparation involves drying and crushing of the entire sample to 2 mm
followed by milling of a 1000g sub-sample to 75um. The sample is then sent to SGS laboratory
Waihi where a 50 g sub-sample is assayed by fire assay with an AAS finish (SGS method FAA505
DDL 0.01ppm Au or FAD505 DDL 1ppm Au & FAD52V DDL 500ppm Au). Other SGS laboratories
at Macraes and Townsville and the ALS laboratory in Townsville, are used from time to time and
follow the same processes. Prior to 2019 the 75um sub-sample was only 200g. For laboratory
QAQC, samples (certified standards, blanks and field replicates) are inserted into each
laboratory batch at a frequency of ~5% respectively. A selection of 5% of retained lab pulps
across a range of grades are sent for re-assay and to an umpire laboratory for cross-lab check
assays.
Portable XRF (pXRF) instrumentation is used onsite (Olympus Innov-X Delta Professional Series
model DPO-4000 equipped with a 4 W 40kV X-Ray tube) primarily to identify arsenical samples
(arsenic correlates well with gold grade in these orogenic deposits). The pXRF analyses a 31-
element suite (Ag, As, Bi, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, K, Mn, Mo, Nb, Ni, P, Pb, Rb, S, Sb, Se,
Sn, Sr, Th, Ti, V, W, Y, Zn, Zr) utilising 3 beam Soil mode, each beam set for 30 secs (90 secs total).
pXRF QAQC checks involve regular calibration (every 20 samples) and QAQC analyses of SiO2
blank, NIST standards (NIST 2710a & NIST 2711a), & OREAS standards. pXRF QAQC checks
involve regular calibration (every 20 samples) and QAQC analyses of SiO2 blank, NIST standards
(NIST 2710a & NIST 2711a), & OREAS standards.
85
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
No geophysical tools have been used in this MRE.
Verification of
sampling and
assaying
The verification of significant intersections by either
independent or alternative company personnel.
The use of twinned holes.
Documentation of primary data, data entry procedures, data
verification, data storage (physical and electronic)
protocols.
Discuss any adjustment to assay data.
Significant gold assays and pXRF arsenic analyses are checked by alternative senior company
personnel. Original lab assays are initially reported and where replicate assays and other QAQC
work require re-assay or screen fire assays, the larger sample results are adopted. To date results
are accurate and fit well with the mineralisation model.
Twinned data is available where DD core holes have been sited adjacent to previous RC drillholes
and where DD redrills have occurred.
pXRF multi-element analyses are directly downloaded from the pXRF analyser as csv electronic
files. These and laboratory assay csv files are imported into the database, appended and merged
with previous data.
Since October 2022 all logging has been directly entered into the Acquire database using tablets.
All collar surveys, downhole surveys and assay results are provided digitally and directly
imported into the database. On import into the database validation checks are made for: interval
overlaps, gaps, duplicate holes, duplicate samples and out of range values. The AcQuire
database is stored on a cloud server and is regularly backed up, updated and verified by an
independent qualified person.
The only adjustment made to the data on import to the database is to convert below detection
results to negative the detection limit. Samples with multiple Au results are ranked by assay
method (SFA > FA > other) and on export only the highest ranked method is exported. Prior to
import into Minesight software for resource estimation the data is further validated as above plus
checks on the highest and lowest values. Negative below detection results are converted to half
the detection limit on import into Minesight.
Location of data
points
Accuracy and quality of surveys used to locate drill holes
(collar and down-hole surveys), trenches, mine workings and
other locations used in
Mineral Resource estimation. Specification of the grid
All drillhole collar locations are accurate (+/- 50mm) xyz coordinates when captured by an
experienced surveyor using RTK-GPS equipment.
All drill holes reference the NZGD2000 NZTM map projection and collar RLs the NZVD2016 vertical
datum.
86
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
system used.
Quality and adequacy of topographic control.
DD down hole surveys are recorded continuously with a Precision Mining and Drilling “North-
seeking” Gyro downhole survey tool. RC holes are surveyed at 12m intervals using a Reflex multi-
shot camera in a non-magnetic stainless steel rod behind the hammer.
There are very minor historical adits and shafts at RAS. No surveys of these voids exist, although
at least one adit is still accessible. Historical production records total 630.5 tons of ore crushed.
Such small volumes are not material to this MRE.
Topographic control is provided by LiDAR topographic surveys in 2018 and 2021 covering the
entire project area. These are very accurate and suitable for resource estimation.
Data spacing and
distribution
Data spacing for reporting of Exploration Results.
Whether the data spacing and distribution is sufficient to
establish the degree of geological and grade continuity
appropriate for the Mineral Resource and Ore Reserve
estimation procedure(s) and classifications applied.
Whether sample compositing has been applied.
Drill collar locations in steep terrain are dictated to some degree by best access along contour
tracks and gradients that allow safe working access. Drillhole designs take into account this
variation to achieve evenly spaced intercepts at the hangingwall of the mineralisation.
Drillhole intersection spacing on the hangingwall of the mineralisation at RAS is typically 30 m
(EW) by 30 m (NS) but varies from 20 m (EW) by 20 m (NS) in closely spaced areas to 120 m (EW)
by 100 m (NS) in widely spaced (inferred) areas. At SRX and SRE drillhole intersection spacing
varies from 20 m (EW) by 20 m (NS) to 100 m (EW) by 100 m (NS). These spacings are considered
appropriate for determination of geological and grade continuity at the mineral resource
categories reported.
Some of the RC drilling was sampled as 4m composites and if the composite result exceeded a
threshold later re-sampled. There are no composited samples within the gold grade estimation
domains and so no composited samples were used in this MRE.
Sampling and assaying are in one metre intervals or truncated to logged features.
Orientation of
data in relation to
geological
structure
Whether the orientation of sampling achieves unbiased
sampling of possible structures and the extent to which this is
known, considering the deposit type.
If the relationship between the drilling orientation and the
orientation of key mineralised structures is considered to
have introduced a sampling bias, this should be assessed and
Drillholes are oriented to intersect known mineralised features in a nominally perpendicular
orientation as much as is practicable. True widths are estimated perpendicular to mineralisation
boundaries where these limits are known. As the deposits are tabular and lie at low angles, there
is not anticipated to be any introduced bias for resource estimates.
87
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
reported if material.
Sample security
The measures taken to ensure sample security.
Company personnel manage the chain of custody from sampling site to laboratory.
DD drill core samples are transported daily from DD rig by the drilling contractor in numbered
core boxes to the Company secure storage facility for logging and sample preparation. After core
cutting, the core for assay is bagged, securely tied, and weighed before being placed in polyweave
bags which are securely tied. Retained core is stored on racks in secure locked containers. RC
samples are also place in polyweave bags and secured with zip ties.
Polyweave bags with the calico bagged samples for assay are placed in plastic cage pallets,
sealed with a wire-tied cover, photographed, and transported to local freight distributer for
delivery to the laboratory. On arrival at the laboratory photographs taken of the consignment are
checked against despatch condition to ensure no tampering has occurred.
Audits or reviews
The results of any audits or reviews of sampling techniques
and data.
An independent Competent Person (CP) conducted a site audit in January 2021 and December
2022 of all sampling techniques and data management. No major issues were identified, and
recommendations have been followed.
In February 2023 Snowdon Optiro completed a desktop review of the assay methods and QC
sample results and in its report concluded that the sampling and assaying methods are in line
with standard industry procedures and that that the assay data in the supplied database is
suitable to be used as the basis for a Mineral Resource.
88
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Section 2: Reporting of Exploration Results
Criteria JORC Code explanation Commentary
Mineral tenement
and land tenure
status
• Type, reference name/number, location and ownership
including agreements or material issues with third parties
such as joint ventures, partnerships, overriding royalties,
native title interests, historical sites, wilderness or national
park and environmental settings.
• The security of the tenure held at the time of reporting along
with any known impediments to obtaining a licence to
operate in the area.
Exploration is being currently conducted within Mineral Exploration Permit (MEP) 60311 (252km²)
registered to Matakanui Gold Ltd (MGL) issued on 13
th
April 2018 for 5 years. In 2023 the term
of this permit was extended for a further 5 years until 12 April 2028.
There are no material issues with third parties.
MGL was granted Minerals Prospecting Permit (MPP) 60882 (40km²) to the north of MEP60311 on
30 Nov 2023 for a term of 2 years.
The tenure of the Permits is secure and there are no known impediments to obtaining a licence
to operate.
As gold is a Crown mineral, a royalty is payable to the Crown as either the higher of an ad
valorem royalty of 2% of the net sales revenue or an accounting profits royalty of 10%.
The Project is subject to a 1.5% Net Smelter Royalty (NSR) on all production from MEP 60311
(and successor permits) payable to an incorporated, private company (Rise and Shine
Holdings Limited) which is owned by the prior shareholders of MGL (NSRW Agreement) before
acquisition of 100% of MGL shares by Santana Minerals Limited.
Access arrangements are in place with landowners that provide for current exploration and
other activities, and any future decision to mine. As such, compensation is payable, including
payments of up to $1.5M on a decision to mine, plus total royalties starting at 1% on the net
value of gold produced, increasing to 1.5% and ultimately 2% dependent on location and total
gold produced over the life of the mine. The royalties are also subject to pre-payment of up to
$3M upon commencement of mining operations.
Exploration done by
other parties
• Acknowledgment and appraisal of exploration by other
parties.
Early exploration in the late 1800’s and early 1900’s included small pits, adits and cross-cuts
and alluvial mining.
Exploration has included soil and rock chip sampling by numerous companies since 1983 with
drilling starting in 1986. Exploration in the 1990’s commenced with a search for Macraes style
gold deposits along the RSSZ. Drilling included 13 RC holes by Homestake NZ Exploration Ltd
in 1986, 20 RC holes by BHP Gold Mines NZ Ltd in 1988 (10 of these holes were in the Bendigo
Reefs area which is not part of the MRE area), 5 RC holes by Macraes Mining Company Ltd in
89
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
1991, 22 shallow (probably blasthole) holes by Aurum Reef Resources (NZ) Ltd in 1996, 30 RC
holes by CanAlaska Ventures Ltd from 2005-2007, 35 RC holes by MGL in 2018 and a further
18 RC holes by MGL in 2019 prior to SML acquiring MGL.
Geology
• Deposit type, geological setting and style of mineralisation.
The RSSZ is a low-angle late-metamorphic shear-zone, presently known to be up to 120m
thick. It is sub-parallel to the metamorphic foliation and dips gently to the north- east. It occurs
within psammitic, pelitic and meta-volcanic schists.
The hangingwall of the RSSZ is truncated by the post metamorphic and post mineralisation
Thomsons Gorge Fault (TGF). The TGF is a regional low-angle fault that separates upper barren
chlorite (TZ3) schist from underlying mineralised biotite (TZ4) schists.
Gold mineralisation occurs in the RSSZ as 4 known deposits with Mineral Resource Estimates
(MRE) – Come-in-Time (CIT), Rise and Shine (RAS), Srex (SRX) and Srex-East (SRE). The gold
and associated pyrite/arsenopyrite mineralisation at all deposits occur as stockworks of
brecciated / laminar quartz veinlets within the highly- sheared and silicified schist. The
stockworks are centred on highly silicified shear zones and breccia (SBX) which control
mineralisation with TGF parallel, moderately east dipping and very steeply east dipping
structures all influencing gold distribution.
The gold mineralisation in the oxide, transition and fresh zones is characterised by coarse free
gold.
Drill hole Information
• A summary of all information material to the understanding
of the exploration results including a tabulation of the
following information for all Material drill holes:
o easting and northing of the drill hole collar
o elevation or RL (Reduced Level – elevation above sea
level in metres) of the drill hole collar
o dip and azimuth of the hole
o down hole length and interception depth
o hole length.
• If the exclusion of this information is justified on the basis
that the information is not Material and this exclusion does
Not applicable as no exploration results are being reported.
90
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
not detract from the understanding of the report, the
Competent Person should clearly explain why this is the
case.
Data aggregation
methods
• In reporting Exploration Results, weighting averaging
techniques, maximum and/or minimum grade truncations
(eg cutting of high grades) and cut-off grades are usually
Material and should be stated.
• Where aggregate intercepts incorporate short lengths of high
grade results and longer lengths of low grade results, the
procedure used for such aggregation should be stated and
some typical examples of such aggregations should be
shown in detail.
• The assumptions used for any reporting of metal equivalent
values should be clearly stated.
Not applicable as no exploration results are being reported.
Relationship between
mineralisation widths
and intercept lengths
• These relationships are particularly important in the
reporting of Exploration Results.
• If the geometry of the mineralisation with respect to the drill
hole angle is known, its nature should be reported.
• If it is not known and only the down hole lengths are
reported, there should be a clear statement to this effect (eg
‘down hole length, true width not known’).
Not applicable as no exploration results are being reported.
Diagrams
• Appropriate maps and sections (with scales) and tabulations
of intercepts should be included for any significant discovery
being reported These should include, but not be limited to a
plan view of drill hole collar locations and appropriate
sectional views.
Not applicable as no exploration results are being reported.
91
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
Balanced reporting
• Where comprehensive reporting of all Exploration Results is
not practicable, representative reporting of both low and high
grades and/or widths should be practiced to avoid
misleading reporting of Exploration Results.
Not applicable as no exploration results are being reported.
Other substantive
exploration data
• Other exploration data, if meaningful and material, should be
reported including (but not limited to): geological
observations; geophysical survey results; geochemical
survey results; bulk samples – size and method of treatment;
metallurgical test results; bulk density, groundwater,
geotechnical and rock characteristics; potential deleterious
or contaminating substances.
Not applicable as no exploration results are being reported.
Further work
• The nature and scale of planned further work (eg tests for
lateral extensions or depth extensions or large-scale step-
out drilling).
• Diagrams clearly highlighting the areas of possible
extensions, including the main geological interpretations and
future drilling areas, provided this information is not
commercially sensitive.
DD infill drilling of existing inferred resources is continues along with minor programmes
designed to resolve local geological interpretation uncertainties.
A review of field mapping, soil sampling and geophysical surveys is in progress to determine
new targets for drilling in the project area.
Concurrent to the planned drilling outlined above, additional metallurgical test work,
environmental, geotechnical and hydrological investigations are on-going to support the
studies into a gold mining and processing operation.
Section 3 Estimation and Reporting of Mineral Resources
(Criteria listed in section 1, and where relevant in section 2, also apply to this section.)
Criteria JORC Code explanation Commentary
Database integrity
• Measures taken to ensure that data has not been
corrupted by, for example, transcription or keying
errors, between its initial collection and its use for
Mineral Resource estimation purposes.
Collar location surveys, downhole surveys and assay data are imported into the database from
digital files provided by external providers. Geological logging, sample information and QAQC
sample insertion data are entered directly using picklists into spreadsheets on mobile devices
in the field. All source data is archived for later audits.
92
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
• Data validation procedures used.
All data is validated on import into the database with checks made for interval overlaps, gaps,
duplicate holes, duplicate samples and out of range values. The database structure uses key
fields to ensure there are no duplicate drillholes or samples.
Site visits
• Comment on any site visits undertaken by the
Competent Person and the outcome of those visits.
• If no site visits have been undertaken indicate why
this is the case.
Mr Allwood has visited the site on 7 occasions between January 2021 and May 2024, inspecting
RC and DD drilling, logging, sampling, QC insertion practices and site geology. No major issues
were identified. Some minor recommendations were made and these have since been
implemented.
Geological
interpretation
• Confidence in (or conversely, the uncertainty of ) the
geological interpretation of the mineral deposit.
• Nature of the data used and of any assumptions
made.
• The effect, if any, of alternative interpretations on
Mineral Resource estimation.
• The use of geology in guiding and controlling Mineral
Resource estimation.
• The factors affecting continuity both of grade and
geology.
There is good confidence in the large scale interpretation of the geology. The TGF is easily
recognized in core and has a simple tabular geometry. Structural measurements of vein and
fault orientations from oriented core allow good confidence in the geometry of mineralisation
controlling faults. The drill spacing makes recognizing small scale (<10 m) variations in
geometry, especially the internal grade geometries within the estimation domains difficult.
The RAS gold grade domains were created using Leapfrog software (v 2023.1.0) which created
a 50% probability iso-surface wireframe using a radial basis function (rbf) interpolation of an
0.2 g/t Au indicator of 2 m composites. The rbf used a ‘structural trend’ comprising an an-
isotropy of 3:3:1 oriented parallel to the manually interpreted TGF and parallel to a manually
interpreted very steeply east dipping, north striking zone identified in the west of the deposit.
The TGF footwall and steep zone were manually interpreted from logged lithology and oriented
structural data (specifically quartz veins). The gold domains were also restricted to below the
footwall of the TGF. Some below indicator grade samples are included within the gold grade
domains and some above indicator grade samples are excluded from the gold grade domains
because the rbf estimates the probability of points in space being above or below the indicator
grade.
Manual grade orientation domains were used to split the RAS Leapfrog gold grade wireframe
into an east dipping (roughly parallel to the TGF) domain and a steeply dipping domain. 94.5%
of the samples are within the east dipping domain.
The Srex (SRX) and Srex East (SRE) gold grade domains were interpreted on east-west sections
at a nominal grade threshold of 0.25 g/t Au. The TGF and quartz vein orientations were used to
guide the domain interpretations. A nominal interpretation grade was used because histograms
93
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
and cumulative probability plots of the un-domained SRX data showed no natural lower cutoff
that could be used to define mineralization. The Au domain grade nominal criteria (0.2 g/t Au)
was selected because it is sufficiently below the likely resource reporting cut-off grade
(previously 0.25 g/t) that the resource would largely be constrained by block grade estimation
rather than interpretations based on sample support. Most of the contained metal (67%) at SRX
and SRE occurs in the SRX main domain which is parallel to, and immediately below the TGF. The
SRX and SRE gold domains had a minimum width of 2 m downhole and in places included
material not meeting the domain criteria to ensure geological and geometric continuity.
While individual high grade samples occur throughout the deposit, the best gold grades
generally occur immediately below the TGF in the east dipping domain. Further below the TGF
gold grades are generally best in the core of the domains and weaken towards the margins.
The geometry of the main zone immediately below the TGF is well defined, alternative
interpretations of the gold mineralization geometry deeper (more than about 40 m) below the
TGF and in the RAS steep domain are possible. The resource categorization reflects this with
areas where alternative interpretations are likely classified as inferred, regardless of grade
estimation quality measures.
Oxidation domains were interpreted from logged oxidation.
Dimensions
• The extent and variability of the Mineral Resource
expressed as length (along strike or otherwise), plan
width, and depth below surface to the upper and
lower limits of the Mineral Resource.
At RAS the east dipping domain has been defined by drilling 1,850m down plunge (-25° towards
025°) and is 300 m to 380 m wide. In plan, this equates to approximately 1,750 m NNE and 300
m to 380 m ESE. Mineralisation extends vertically in multiple zones over about 180 m. The
thickest part of the east dipping domain is continuously mineralized over 50 m vertically below
the TGF. Other zones range in thickness from 20 m to 2 m. The deepest part of the east dipping
domain is at 180 RL or about 650 m below surface. The core of the east dipping domain is very
continuous
At SRX the main gold domain extends approximately 700 m along strike (NW), 150 m to 450 m
down dip and is typically 4 m to 12 m thick. The other SRX domains are less extensive, having
strike lengths of 100 m to 250 m, extending 50 m to 100 m down dip and being typically 2 m to 6
m thick. The mineralization at SRX is quite continuous, but there are rare un-mineralised holes
within the domains.
94
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
Similarly, at SRE the gold domain extends approximately 100 m along strike (NW), 400 m down
dip and is typically 2 m to 14 m thick. The mineralization at SRE is quite continuous, but there
are rare un-mineralised holes within the domains.
Estimation and
modelling
techniques
• The nature and appropriateness of the estimation
technique(s) applied and key assumptions, including
treatment of extreme grade values, domaining,
interpolation parameters and maximum distance of
extrapolation from data points. If a computer
assisted estimation method was chosen include a
description of computer software and parameters
used.
• The availability of check estimates, previous
estimates and/or mine production records and
whether the Mineral Resource estimate takes
appropriate account of such data.
• The assumptions made regarding recovery of by-
products.
• Estimation of deleterious elements or other non-
grade variables of economic significance (eg sulphur
for acid mine drainage characterisation).
• In the case of block model interpolation, the block
size in relation to the average sample spacing and
the search employed.
• Any assumptions behind modelling of selective
mining units.
This MRE was made by interpolating gold assays composited to 2.0m by ordinary kriging into a
sub-blocked model using Minesight v 16.1.0 software. Geostatistical analysis was carried out
using Leapfrog Edge v 2023.1.0 software.
Outlier grade limits were determined from log histograms and cumulative probability plots were
used to restrict the spatial influence of extremely high grades by domain. At RAS the outlier
grades were 40 g/t Au in the east dipping domain and 20 g/t Au in the steep domain. In the SRX
main domain the CV was reduced to 1.3 after the application of the top cut (10 g/t Au).
The same variogram model was used in all RAS domains. The variogram model was determined
from experimental variograms of composites below the outlier limit grade (40 g/t Au) in the east
dipping domain. There are insufficient data in the steep domain to create robust experimental
variograms, therefore the east dipping domain variogram model was appropriately rotated to
reflect the geometry of the steep domain. The variogram model had a relative nugget effect of
52% and two sills. The major axis was parallel to the intersection of the steep zone and the east
dipping zone (19/357), the semi-major axis 16/093 and the minor axis 65/220. The total ranges
were 125 m for the major axis, 55 m for the semi-major axis and 35 m in the minor axis direction.
At RAS blocks were interpolated by ordinary kriging of the top cut composites using a minimum
of 4 and a maximum of 15 composites from within a 150m by 150m by 50m ellipsoid oriented
parallel to the variogram model. A maximum of 7 composites were used per quadrant from a
minimum of two quadrants. Gold domain boundaries were treated as hard boundaries. Parent
blocks were 12.5 m (E) by 12.5 m (N) by 5m (vertical), sub-blocked to 2.5 m by 2.5 m by 0. 5m.
The block model parent blocks are approximately 25% of the typical drill spacing. The parent
block size was selected as a compromise between honouring the domain geometry / volume and
minimizing block grade estimation error.
At SRX and SRE the variogram model was determined from experimental variograms of normal
score transformed composites from the SRX main domain. The variogram model was back-
transformed prior to use. The back-transformed variogram model had a relative nugget effect of
68% with one sill. The major axis (00/130) and the semi-major axis (25/040) have similar ranges
and together define a plane parallel to the TGF. The minor axis was 65/220. The total ranges were
95
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
• Any assumptions about correlation between
variables.
• Description of how the geological interpretation was
used to control the resource estimates.
• Discussion of basis for using or not using grade
cutting or capping.
• The process of validation, the checking process
used, the comparison of model data to drill hole
data, and use of reconciliation data if available.
30 m for the major axis, 25 m for the semi-major axis and 4 m in the minor axis direction. The
orientation of the variogram model and search ellipsoid was varied to be parallel to other
domains as appropriate. At SRX and SRE blocks were interpolated by ordinary kriging of the top
cut composites in two passes. The first pass used a minimum of 10 and a maximum of 20
composites from within a 40 m by 40 m by 6 m ellipsoid oriented parallel to the variogram model.
A maximum of 7 composites were used per quadrant from a minimum of two quadrants with a
maximum of 4 composites from each drillhole. The second pass was the same as the first pass
except that it used a minimum of 4 and a maximum of 15 composites, no quadrant restriction
and a 150 m by 120 m by 20 m ellipsoid. Gold domain boundaries were treated as hard
boundaries. Parent blocks were 12.5 m (E) by 12.5 m (N) by 4 m (vertical), sub-blocked to 2.5 m
by 2.5 m by 0.5 m. The block model parent blocks are approximately 25% of the typical drill
spacing. The parent block size was selected as a compromise between honouring the domain
geometry / volume and minimizing block grade estimation error.
Check estimates were completed on the RAS MRE as follows: using top cuts at the outlier grade
limits; outlier restriction at 12.5 m instead of 25 m; and no top cut.
In addition, volume – variance analysis using an affine correction was completed to assess
which variants best represented the theoretical grade – tonnage curve.
Previous estimates of the gold MRE at RAS have been made in 2019, 2021, July 2022 and
February 2023 and February 2024. At SRX and SRE previous estimates of the gold MRE were
made in November 2021.
There has been no production from the BOGP to allow reconciliation of the model.
No by-products are assumed.
pXRF Arsenic grades have been estimated in the block models for use in characterizing waste.
The block model parent blocks are approximately 25% of the typical drill spacing. The parent
block size was selected as a compromise between honouring the domain geometry / volume
and minimizing block grade estimation error.
Open pit mining is assumed with a likely smallest mining unit (SMU) of about 5m by 5m by 5m.
Underground mining is also possible, albeit at a higher cut-off grade (around 1.5 g/t Au).
No assumption is made of correlation between variables.
96
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
The MRE is geologically controlled by the use of domains interpreted with reference to the
geological model.
At RAS the influence of outlier grade composites was restricted to 25 m. At SRX and SRE top
cuts were applied to the composites prior to grade interpolation as described above.
The block model was validated against drilling grades visually in section and in plan, by the use
of swath plots, and by comparison of the block model volumes to domain wireframe volumes.
No reconciliation data is available as mining has not commenced.
Moisture
• Whether the tonnages are estimated on a dry basis
or with natural moisture, and the method of
determination of the moisture content.
Tonnages are estimated on a dry basis. Assays are reported as weight proportion of oven
(110°C) dried samples. Bulk densities were determined from air dried core by immersion.
Cut-off
parameters
• The basis of the adopted cut-off grade(s) or quality
parameters applied.
The reporting cut-offs (0.25 g/t) for ‘open pittable’ resources and 1.5 g/t for underground
resources are based on metallurgical recovery indicated by gravity / CIL test work, processing,
mining and G & A costs from comparable projects and revenue from a gold price of
USD$1,830/oz escalated by 30% to allow for the reasonable prospects test. Reporting using
the lower 0.25g/t cut-off grade than the 0.5g/t used in the RAS July 2024 MRE is due to the
robust economics reported in this PFS, additional metallurgical testing and increase gold price.
Other than reporting at a lower cut-off grade there are no other changes from the RAS July 2024
MRE.
Mining factors or
assumptions
• Assumptions made regarding possible mining
methods, minimum mining dimensions and internal
(or, if applicable, external) mining dilution. It is
always necessary as part of the process of
determining reasonable prospects for eventual
economic extraction to consider potential mining
methods, but the assumptions made regarding
mining methods and parameters when estimating
Mineral Resources may not always be rigorous.
No allowance has been made for mining dilution or mining recovery except that domains were
interpreted with a minimum width of 2 m.
97
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
Where this is the case, this should be reported with
an explanation of the basis of the mining
assumptions made.
Metallurgical
factors or
assumptions
• The basis for assumptions or predictions regarding
metallurgical amenability. It is always necessary as
part of the process of determining reasonable
prospects for eventual economic extraction to
consider potential metallurgical methods, but the
assumptions regarding metallurgical treatment
processes and parameters made when reporting
Mineral Resources may not always be rigorous.
Where this is the case, this should be reported with
an explanation of the basis of the metallurgical
assumptions made.
Metallurgical test work investigating a gravity – CIL process has resulted in combined
recoveries ranging from 86.0% to 97.8% and averaging over 90%. Further work is underway to
determine full processing parameters and economics.
Environmental
factors or
assumptions
• Assumptions made regarding possible waste and
process residue disposal options. It is always
necessary as part of the process of determining
reasonable prospects for eventual economic
extraction to consider the potential environmental
impacts of the mining and processing operation.
While at this stage the determination of potential
environmental impacts, particularly for a greenfields
project, may not always be well advanced, the status
of early consideration of these potential
environmental impacts should be reported. Where
these aspects have not been considered this should
It is assumed that all permits necessary for commercial gold production will be obtained.
Baseline studies are well advanced including:
• surface water flow and quality
• aquatic ecology
• ecology including geckos, skinks, bats, birds, pests and flora
• geochemistry
• hydrology
• socio-economic
Other studies have commenced as mine studies advance including noise, traffic, lighting and
visual.
98
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
be reported with an explanation of the environmental
assumptions made.
Bulk density
• Whether assumed or determined. If assumed, the
basis for the assumptions. If determined, the
method used, whether wet or dry, the frequency of
the measurements, the nature, size and
representativeness of the samples.
• The bulk density for bulk material must have been
measured by methods that adequately account for
void spaces (vugs, porosity, etc), moisture and
differences between rock and alteration zones within
the deposit.
• Discuss assumptions for bulk density estimates
used in the evaluation process of the different
materials.
Bulk density was interpolated by inverse distance squared weighting into the fresh and partial
oxidation domains from 2,202 bulk density measurements. There was insufficient data in the
oxide domain to allow interpolation.
Bulk density was assigned to un-interpolated blocks by oxidation domain based on the median
values of the bulk density samples in each oxidation domain.
No difference was found in the median value of bulk density data between mineralised and un-
mineralised samples.
Bulk density was measured by core immersion. The core was not routinely coated, allowing
water to penetrate voids, however the rocks have very low porosity due to metamorphism. 100
samples of fresh (unweathered) core were tested by the routine method and by wax coating to
check for the effect of the water ingress on the bulk density measurements. There was no
difference in the average value or the CV of the two methods. Therefore, MGL continues to use
un-coated core for density determinations.
Classification
• The basis for the classification of the Mineral
Resources into varying confidence categories.
• Whether appropriate account has been taken of all
relevant factors (ie relative confidence in
tonnage/grade estimations, reliability of input data,
confidence in continuity of geology and metal
values, quality, quantity and distribution of the data).
• Whether the result appropriately reflects the
Competent Person’s view of the deposit.
Input data quality, confidence in the geological interpretations, average distance to composites
used, distance to the nearest composite used and the kriging slope of regression (a function of
grade continuity and data (drilling) configuration), and for SRX and SRE, interpolation pass
number were all considered when classifying the model. In general, indicated resources are
reported from continuous zones of un-ambiguous geological interpretation and in block grades
where the nearest composite was less than 25 m away, the average composite distance was
less than 40 m, kriging slope of regression was greater than 0.6 and at SRX and SRE
interpolated in pass 1.
Resource categorization is based on confidence in the estimation of gold grades only.
The resource classification appropriately reflects the Competent Person’s view of the deposit.
99
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
Audits or reviews
• The results of any audits or reviews of Mineral
Resource estimates
An earlier iteration of the RAS MRE was reviewed by AMC Consultants who concluded that the
MRE is an adequate representation of average grade and grade trends but with a degree of local
variability not able to be accurately represented in the model.
Discussion of
relative accuracy/
confidence
• Where appropriate a statement of the relative
accuracy and confidence level in the Mineral
Resource estimate using an approach or procedure
deemed appropriate by the Competent Person. For
example, the application of statistical or
geostatistical procedures to quantify the relative
accuracy of the resource within stated confidence
limits, or, if such an approach is not deemed
appropriate, a qualitative discussion of the factors
that could affect the relative accuracy and
confidence of the estimate.
• The statement should specify whether it relates to
global or local estimates, and, if local, state the
relevant tonnages, which should be relevant to
technical and economic evaluation. Documentation
should include assumptions made and the
procedures used.
• These statements of relative accuracy and
confidence of the estimate should be compared with
production data, where available.
The relative accuracy and confidence in the MRE is reflected in the resource classification. No
quantitative assessment of errors has been made.
The RAS MRE is a global estimate intended to give the best global grade – tonnage relationship,
suitable for use in long term planning but not for local (block scale) estimates.
No production data are available for reconciliation as mining has not commenced.
100
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Section Four: Estimation and Reporting of Ore Reserves
(Criteria listed in section 1, and where relevant in section 2, also apply to this section.)
Criteria JORC Code explanation Commentary
Mineral Resource
estimate for
conversion to Ore
Reserves
• Description of the Mineral Resource estimate used as a
basis for the conversion to an Ore Reserve.
• Clear statement as to whether the Mineral Resources are
reported additional to, or inclusive of, the Ore Reserves.
• The Ore Reserve estimate is prepared from the following Mineral Resources reported by
Santana Minerals:
Deposit Mining method Category
Cutoff
(Au g/t)
tonnes
(Mt)
Au
(g/t)
koz
RAS
open pit
Indicated
0.25
19.6 2.3 1,452
Inferred 9.9 2.0 634
Total 29.5 2.2 2,086
underground
Indicated
1.5
0 1.9 0
Inferred 2.1 2.2 145
Total 2.1 2.2 145
RAS Total
Indicated
19.6 2.3 1,452
Inferred 12 2.0 779
Total 31.6 2.2 2,231
SRX open pit
Indicated
0.25
2.6 0.7 59
Inferred 2.4 0.9 73
Total 5.0 0.8 132
SRE open pit
Indicated
0.25
0.4 0.7 10
Inferred 0.1 0.9 3
Total 0.5 0.8 13
CIT open pit Inferred 0.25 3.2 0.8 80
Total combined
Indicated
22.6 2.1 1,521
Inferred 17.7 1.6 935
Total 40.3 1.9 2,456
• The Mineral Resources are reported inclusive of Ore Reserves
• The block models used were
o 20240625 RAS PFS Model ext.bmf (Extended model bmf file to cover enlarged model
101
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
extents.)
o 20240830 SHRE model.bmf (SRX Block model)
Site visits
• Comment on any site visits undertaken by the Competent
Person and the outcome of those visits.
• If no site visits have been undertaken indicate why this is
the case.
• The Ore Reserve estimate was completed by Rodney Redden who is the project study
manager and has been to site multiple times since February 2024
Study status
• The type and level of study undertaken to enable Mineral
Resources to be converted to Ore Reserves.
• The Code requires that a study to at least Pre-Feasibility
Study level has been undertaken to convert Mineral
Resources to Ore Reserves. Such studies will have been
carried out and will have determined a mine plan that is
technically achievable and economically viable, and that
material Modifying Factors have been considered.
• The Reserves are supported by the completion of a pre-feasibility study undertaken by
Santana Minerals – PFS (this study).
Cut-off
parameters
• The basis of the cut-off grade(s) or quality parameters
applied.
• Estimated site operating costs, royalty payments, processing recoveries and an underlying
gold price assumption were used to calculate the cut-off grades
• For the underground estimate a dilution % was also factored.
• Cut-off grades applied to select material for inclusion in the ore reserves were:
o RAS Open pit: 0.3 g/t
o SRX Open pit: 0.35 g/t
o RAS Underground 1.70 g/t
Mining factors or
assumptions
• The method and assumptions used as reported in the Pre-
Feasibility or Feasibility Study to convert the Mineral
Resource to an Ore Reserve (i.e. either by application of
appropriate factors by optimisation or by preliminary or
detailed design).
• The resource block models as received were re-blocked for open pit mining assessment to
simulate the assessed minimum mining unit (12.5m x 12.5m x 2.5m). Which only required the
existing block size to be increased in the z direction from 2m to 2.5m.
• The Lerch Grossman algorithm (LG) was used to create sets of possible open pit mining shells
for both RAS and SRX. This process was performed on all Indicated resources as well as a high
grade – high confidence core wireframe at RAS. The high confidence core scenarios were
particularly used for guiding the initial mining stages (stages 1 and 2)
102
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
• The choice, nature and appropriateness of the selected
mining method(s) and other mining parameters including
associated design issues such as pre-strip, access, etc.
• The assumptions made regarding geotechnical
parameters (eg pit slopes, stope sizes, etc), grade control
and pre-production drilling.
• The major assumptions made and Mineral Resource model
used for pit and stope optimisation (if appropriate).
• The mining dilution factors used.
• The mining recovery factors used.
• Any minimum mining widths used.
• The manner in which Inferred Mineral Resources are
utilised in mining studies and the sensitivity of the outcome
to their inclusion.
• The infrastructure requirements of the selected mining
methods.
• For underground analysis, an insitu cut-off grade was used to target mineralization for mining.
Both an automated (MSO) process followed by a more thorough manual targeting process
were utilised.
• The open pit mining base assumption is that all material will be dug off in 2.5m high flitches
(this is in line with optimized practices at the nearby Macraes mine which has a very similar
ore geometry). The pre-strip at RAS is significant as it outcrops under the RAS ridge. The
selected fleet sizing is based on 150 tonne haul trucks loaded by 300 tonne excavators.
• The Underground method selected is longitudinal open stoping with paste backfill. The
scoping study examined a number of different mining methods with open stoping with paste
backfill an obvious preferred option.
• The grade of the underground mineralization supports the increased costs of backfilling
compared with the resource loss without using backfill
• Paste backfilling has significant benefits over other filling methods due to
o Quick filling time; and
o Ability to tight fill to support the stope backs
• The geotechnical parameters recommended and applied for RAS open pit are:
Wall
Aspect
(1)
(°)
Unit
IRA
(2)
(°)
BFA
(3)
(°)
Berm
Width (m)
Bench
Height (m)
Controlled By
Southwest
350 to
065
All 30 50 9 15
Foliation/foliation shears
dipping towards northeast
West
065 to
160
TZ3 35 50 11 15
Planar sliding along the
obliquely dipping TGF
(4)
TZ4 45 60 6.5 15
Planar failure along faults
and shears identified
behind the pit wall
Northeast
160 to
235
All 45 60 6.5 15
East
235 to
350
TZ3 40 60 9 15
Planar sliding along the
obliquely dipping TGF
(4)
TZ4 47 70 7.5 15
Planar failure along faults
and shears identified
behind the pit wall
(1) Slope aspect measured as the direction the wall dips towards.
103
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
(2) Inter-ramp angle.
(3) Batter face angle.
(4) Opportunity to steepen IRA based on future 3D stability analyses and/or mapping data of the TGF.
• The geotechnical parameters recommended and applied for SRX open pit are:
Wall Aspect (°) IRA (°) BFA (°)
Berm Width
(m)
Bench Height
(m)
Controlled by
Southwest 350 to 065 30 50 9 15
Foliation/foliation
shears dipping
towards northeast
West,
Northeast,
and East
065 to 350 45 60 6.5 15
Probable Planar
failure along faults
and shears identified
behind the pit wall
• The geotechnical parameters recommended and applied for RAS underground are:
Depth
(mbgl)
Stope Height
(1)
(m)
Maximum Stope
Length
(2)
(m)
Maximum Stope
Width
(3)
(m)
Notes and Limiting Wall
Mechanism
250
20 25
15
(4)
Assumes heavy support of
the backs is practical
and economic
Potential for footwall planar
slide
25 20
400
20 20
25 15
(1) Vertical height.
(2) Along strike.
(3) Across Strike
(4) Stope width is expected to be controlled by the ability to support the backs.
• Grade control drilling in the open pits will be done in conjunction with the blastholes. No
separate grade control drilling program is planned. Ore-zone drilling will be based on 7.5m
high packages and drilling is on a 4.0m x 4.7m pattern
• Underground grade control will be performed by a diamond drill from the lower ore-drives
once they are in place to define the orebody hangingwall
104
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
• The re-blocked open pit model is a recoverable model with dilution and ore-loss accounted
for in this process. No further dilution or ore-loss is then factored
• For Underground, the applied dilution and recoveries are:
o Development dilution was calculated at 18%;
o Primary stope dilution of 8% and secondary stope dilution of 12% was used;
o Recovery of blasted material calculated at 95%; and
o Recovery of the final pillars was factored 60%.
• The minimum cut-back applied to the open pits is 40m
• The minimum stoping height assumed is the ore development drive height of 4.5m, which is
not required
• Inferred mineralization was not targeted for pit optimisations or designs, nor was it used as a
guide for underground stoping designs.
• Inferred that is mined in the schedule is only as a consequence of falling inside the pit design,
stopes or development.
o RAS Open pit scheduled material is 94.4% Indicated
o SRX open pit scheduled material is 99.0% Indicated
o RAS UG scheduled is 96.2% Indicated
• No Inferred resources are included in the ore reserves and their exclusion from the overall
scheduled mill feed has a negligible effect.
• The total site infrastructure requirements are discussed in “infrastructure” below.
• The open pit mining specifically will require an explosive emulsion plant and magazines, fleet
workshop, refuelling facility, mobile fleet workshop and washdown facilities, supported by
mining offices and a crib-room/pre-start area.
• The Underground requires a paste backfill plant installed on surface. A dedicated portal area
is established for twin decline ramps that provide the primary ventilation circuit, secondary
egress, main haulageway and for paste/services. The 11kv site system is extended to the
105
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
portal and then underground, eventually reduced to 11kv. The primary fan is on surface at the
portal exhaust.
Metallurgical
factors or
assumptions
• The metallurgical process proposed and the
appropriateness of that process to the style of
mineralisation.
• Whether the metallurgical process is well-tested
technology or novel in nature.
• The nature, amount and representativeness of
metallurgical test work undertaken, the nature of the
metallurgical domaining applied and the corresponding
metallurgical recovery factors applied.
• Any assumptions or allowances made for deleterious
elements.
• The existence of any bulk sample or pilot scale test work
and the degree to which such samples are considered
representative of the orebody as a whole.
• For minerals that are defined by a specification, has the ore
reserve estimation been based on the appropriate
mineralogy to meet the specifications?
• The final selected flowsheet is appropriate to the style on mineralization and involves:
o a single stage crush (121mm);
o single stage SAG mill (p80 106 micron), with the addition of a ball mill when the
throughput rate is to be expanded;
o Cyclone classification;
o Gravity gold concentration;
o CIL leach and adsorption gold extraction of the gravity tails;
o Elution;
o Cyanide destruction;
o Arsenic removal;
o Tails thickening and tails pumping to a wet TSF facility
• The technology is well tested. There is no novel technology involved.
• The process flowsheet is supported by multiple rounds of metallurgical testwork.
o Stages 1-4 of testwork was completed from 2018-2022
o The most recent (stage 5 testwork) of which undertaken in 2024 has used a master
composite for both RAS and SRX of 100kg each plus variability samples (10) for RAS and 8
for (SRX)
The stage 5 (PFS) testwork programme had the following objectives:
• Composite master sample selection to represent the expected Life of Mine (LOM) ore blend
for the RAS deposit.
• Variability sample selection for RAS to provide spatial variability data
• Determination of comminution characteristics for the master composite and variability
samples.
• Gravity recovery and intensive leaching of gravity concentrate on all samples.
• Flotation sighter testing on master composite.
• Cyanide leach grind optimisation, reagent optimisation and CIL testing on master composite.
106
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
• Cyanidation response based on optimised flowsheet for the variability samples.
As the testwork program proceeded the following steps were included:
• Cyanide destruction testwork on master composite.
• Arsenic removal on master composite.
• Diagnostic leaching of optimised CIL of master composite.
• Thickening testwork.
The SRX deposit was subsequently added to the testwork program, with initial testwork based on
the RAS optimised program.
• The RAS master and variability testwork is complete. The variability samples supported the
aster composite recoveries at 106 micron grind of 65.2% gravity and a 93.9% overall recovery.
• The SRX master composite work is also complete and through the process route optimized for
RAS it returned 22.9% gravity and a 68.3% overall recovery
• No allowances have been made for deleterious elements
• No bulk sample has been taken
Environmental
• The status of studies of potential environmental impacts of
the mining and processing operation. Details of waste rock
characterisation and the consideration of potential sites,
status of design options considered and, where applicable,
the status of approvals for process residue storage and
waste dumps should be reported.
• A comprehensive set of baseline studies have been commissioned to understand the existing
environment across the project area and surrounding landscape. As the project description
has developed the assessment of effects on the environment has also progressed along with
associated considerations of opportunities to address potential negative effects as far as
practical.
• Environment related studies include ecology, waterways and wetlands, ground and surface
water, geochemistry, noise, air quality, heritage, closure, visual effects, recreation and traffic.
• Project waste rock characterization is well advanced. Studies indicate that the rocks
associated with the project (TZ3, TZ4, and RSSZ) will not generate acid rock drainage
with >350 samples tested by industry accepted acid base accounting (ABA) techniques (e.g.,
AMIRA, 2002). This is a function of the high acid neutralisation capacity (ANC) of the rocks
associated with carbonate minerals (e.g., dolomite) and a low sulfide mineral content (e.g.,
arsenopyrite, pyrite) that can generate lesser acidity. The overall ABA assessment indicates
that the rocks are classified as non-acid forming (NAF). Data for waste rock indicates that the
TZ4 and RSSZ lithologies contain ~97.7% of arsenic and 37.2% of sulfur yet represent only
107
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
18% of the waste rock that will be disturbed. Hence, appropriate management of waste rock
to reduce sulfide mineral oxidation and the release of arsenic is a critical step to minimise any
potential deleterious effects of mining, i.e., manage 18% of the waste rock well to mitigate
97.7% of the arsenic risk in the Engineered Landform ELF) that will contain the waste rock.
Nitrogenous compounds such as nitrate are also expected to be elevated in seepage from
blasted rock due to the use of ANFO, an ammonium-nitrate fuel oil explosive. This is not an
uncommon problem in the mining industry.
• The management of MIW will involve several engineering controls to minimise the effects on
the downstream environment. These engineering controls have been accounted for in the
mine plan, including:
o Materials management and the construction of an Engineered Landform (ELF) to
minimise contaminant loads from the waste rock; and
o Water management and treatment as necessary.
• The main waste rock stack (Shepherds ELF) has been designed to enclose TZ4 and RSSZ
materials in its core away from water and air ingress
• The ELF will require a building consent from the local council. This would be subsequent to
the FAB major consent decision
• The TSF will require both a resource consent and building consent.
• Waste rock stack approval. This would be subsequent to the FAB major consent decision
Infrastructure
• The existence of appropriate infrastructure: availability of
land for plant development, power, water, transportation
(particularly for bulk commodities), labour,
accommodation; or the ease with which the infrastructure
can be provided, or accessed.
• Planned infrastructure includes:
o An initial 1.5Mtpa processing facility expanding to 2.1Mtpa eventually
o A Tailings Storage Facility (TSF)
o A ROM pad
o An Engineered Landform (ELF) to take the non processed materials
o A 24MVa 66kv high voltage transformer and power supply from the local power grid
o An all weather two lane road from the nearby state highway connection
o A 100l/sec borefield and pipeline to site
o Administration, mining and processing offices
o A warehouse
108
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
o Mobile fleet workshops for Open pit and Underground
o Refuelling and plant washdown facilities
o Metallurgical laboratory
o An 80-person construction workforce camp
• The company has agreements in place with the two main landowners that the project
straddles to purchase or lease the required land for the project and all infrastructure.
Costs
• The derivation of, or assumptions made, regarding
projected capital costs in the study.
• The methodology used to estimate operating costs.
• Allowances made for the content of deleterious elements.
• The source of exchange rates used in the study.
• Derivation of transportation charges.
• The basis for forecasting or source of treatment and
refining charges, penalties for failure to meet specification,
etc.
• The allowances made for royalties payable, both
Government and private.
• Operating costs have been estimated by:
Applying productivity, availability and utilisation to the mining and processing
physicals (including derived activities) to calculate required quantities for
equipment, personnel, consumables and power.
• Input costs for equipment, personnel, consumables and power have been sourced from
current administration costs, nearby operating sites, rates submitted by contractors and
suppliers, updated budget pricing for consumables and advice from consultants.
• Capital costs have been estimated by:
o Engineering cost estimate by MACA Interquip Mintrex for processing plant and tailings
pipeline, completed in October 2024.
o TSF estimate by Engineering Geology Limited, October 2024
o Power costs estimate by ERGO consulting, October 2024
o Water servicing to site by Pattle Delamore Partners, October 2024
o Road upgrades by Stantec NZ Ltd, October 2024
o Other infrastructure by Performance Ltd
o Mobile fleet purchase cost estimates from TerraCAT, Cable-price, Sandvik, Normet and
Volvo
• Capitalised operating costs for pre-production operations include:
o Open pit mining costs
o Site G&A costs
• After Commercial Production, capital costs include:
109
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
o Sustaining capital projects
o TSF raises
o Underground mine development – capital development only
o Ecological offsets and water treatment facilities
o Closure
• No allowance has been made for deleterious elements.
• Exchange rates are derived from current exchange rates.
• The NZ government royalty rate is 2% Ad Valorem or 10% of Net Accounting profits (whichever
is the higher)
• Other Royalties are vendor and landowner. These vary from a minimum of 1.5% to a maximum
of 3.5% Ad Valorem with the actual amount depending on:
o Location of extraction;
o Total ounces extracted from various locations; and
• Land ownership arrangements
Revenue factors
• The derivation of, or assumptions made regarding revenue
factors including head grade, metal or commodity price(s)
exchange rates, transportation and treatment charges,
penalties, net smelter returns, etc.
• The derivation of assumptions made of metal or
commodity price(s), for the principal metals, minerals and
co-products.
Metal prices assumed for economic test of the Ore Reserve estimate are:
• RAS (Open pit and Underground)
o Au Price: US$1,650/oz
o NZ$:US$ exchange: 0.64
• SRX
o Au Price: US$2,100/oz
o NZ$:US$ exchange: 0.64
Metal prices assumed for Base Case of the Pre-feasibility are:
• Au Price: US$1,900/oz
• NZ$:US$ exchange: 0.596 and A$:US$ exchange: 0.66
• Metal Price and exchange rate assumptions have been benchmarked against industry
peers (for Au)
110
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
Market
assessment
• The demand, supply and stock situation for the particular
commodity, consumption trends and factors likely to
affect supply and demand into the future.
• A customer and competitor analysis along with the
identification of likely market windows for the product.
• Price and volume forecasts and the basis for these
forecasts.
• For industrial minerals the customer specification, testing
and acceptance requirements prior to a supply contract.
• For gold doré sales, there is a well-established and transparent market.
Economic
• The inputs to the economic analysis to produce the net
present value (NPV) in the study, the source and
confidence of these economic inputs including
estimated inflation, discount rate, etc.
• NPV ranges and sensitivity to variations in the significant
assumptions and inputs.
Inputs to the financial model are:
• Capital and operating cost estimates from the Study, estimated as described above (no
escalation has been applied to costs);
• Physicals schedule of saleable;
• Gold prices assumed for Base Case of the Pre-feasibility Study (no escalation has been
applied to selling prices);
• The base case NPV applied:
o Au Price: US$1,900/oz
o NZ$:US$ exchange: 0.596
• A discount rate of 8% has been applied to calculate NPV
• The base case post tax NPV is $AUD535M
• Sensitivities in AUD have been assessed at various selling prices for Au as follows
111
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
Social
• The status of agreements with key stakeholders and
matters leading to social licence to operate.
• The company has established access agreements to the freehold land that is required for the
project to be executed as per the PFS.
• The company has been in frequent consultation with the Central Otago District Council and
the Otago Regional Council, various state regulators and hold good standing with the local
community.
• The company will continue to communicate and negotiate in good faith with all stakeholders
as part of the proposed development. It is not expected that there will be any significant
impediments to development of the project.
Other
• To the extent relevant, the impact of the following on the
project and/or on the estimation and classification of the
Ore Reserves:
• Any identified material naturally occurring risks.
• The status of material legal agreements and marketing
arrangements.
• The status of governmental agreements and approvals
critical to the viability of the project, such as mineral
tenement status, and government and statutory approvals.
• Earthquakes are the single largest material naturally occurring risk.
o The Shepherds TSF will safely contain tailings when subjected to potential future extreme
earthquakes. It will be designed to withstand a 1 in 10,000 year earthquake including
aftershocks. This includes withstanding a potential rupture on the Alpine Fault or any of
the other active faults in the region. The proposed design has the tailings contained
behind the downstream rockfill embankment, that will also be buttressed by a large
volume of rockfill placed in the Shepherds ELF. The proposed design will provide safe and
robust tailings storage solution for both operation and post closure of the site.
o The processing plant and all infrastructure has been engineered to NZ building code
(40,191)
(51,189)
(72,435)
(106,060)
(212,027)
(212,995)
40,180
51,185
77,862
105,993
211,649
212,957
(250,000) (150,000) (50,000) 50,000 150,000 250,000
Capex (+/-10%)
Operating Cost (+/-10%)
Discount Rate (+/-1%)
Recovery (+/-5%)
Grade (+/-10%)
Gold Price (+/-10%)
112
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
There must be reasonable grounds to expect that all
necessary Government approvals will be received within
the timeframes anticipated in the Pre-Feasibility or
Feasibility study. Highlight and discuss the materiality of
any unresolved matter that is dependent on a third party on
which extraction of the reserve is contingent.
standards relevant to the local region.
• The project is located within Minerals Exploration Permit (MEP) 60311. To develop the project,
the Company will need to apply for a minerals mining permit (MMP) over the immediate area
to New Zealand Petroleum and Minerals (NZPAM). This is part of the Ministry of Business,
Innovation and Employment (MBIE) and administers the Crown Minerals Act (1991) (CMA).
Section 23 of the CMA provides that the purpose of a minerals mining permit (MMP) is to
authorise the permit holder to mine for the minerals specified in the permit. “Mining” is
defined in the Act as meaning “to take, win, or extract, by whatever means, a mineral existing
in its natural state in land, or a chemical substance from [that mineral].” The Minister will
ordinarily grant a mining permit if satisfied that:
(a) the permit applicant has identified and delineated at least an indicated mineable mineral
resource or exploitable mineral deposit, and
(b) the area of the permit is appropriate, and
(c) the objective of the mining permit is to economically deplete the mineable mineral
resource or deposit to the maximum extent practicable in accordance with good industry
practice.
• The NZ Government has introduced a new legislation, Fast-track Approvals Bill (FAB). This Bill
provides a streamlined decision-making process to facilitate the delivery of infrastructure and
development projects with significant regional or national benefits. On 04/10/2024 it was
announced that the Santana Minerals Bendigo-Ophir gold mine is included within the list of
projects eligible to access the fast-track consenting framework under the proposed FAB. The
Bill is intended to be a “one stop shop” for consenting projects which would otherwise require
consents under multiple different regimes including resource consents under the RMA,
concessions under the Conservation Act 1987, wildlife permits under the Wildlife Act 1953,
archaeological authorities under the Heritage Pouhere Taonga Act 2014, and land access
provisions of the Crown Minerals Act 1991. The “one stop shop” approach marks a significant
change in project approvals in New Zealand, and it is hoped that this will significantly reduce
consenting costs, uncertainty, and timeframes.
Classification
• The basis for the classification of the Ore Reserves into
varying confidence categories.
• Material classified as Indicated Mineral Resources has been converted to Probable Ore
Reserve
113
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
• Whether the result appropriately reflects the Competent
Person’s view of the deposit.
• The proportion of Probable Ore Reserves that have been
derived from Measured Mineral Resources (if any).
• The results described in the PFS appropriately reflects the Competent Person’s view of the
deposit.
• There are no Probable Ore Reserves quoted from Measured Mineral Resources
Audits or reviews
• The results of any audits or reviews of Ore Reserve
estimates.
• No external audit or review of this Ore Reserve estimate has been undertaken.
Discussion of
relative accuracy/
confidence
• Where appropriate a statement of the relative accuracy
and confidence level in the Ore Reserve estimate using an
approach or procedure deemed appropriate by the
Competent Person. For example, the application of
statistical or geostatistical procedures to quantify the
relative accuracy of the reserve within stated confidence
limits, or, if such an approach is not deemed appropriate,
a qualitative discussion of the factors which could affect
the relative accuracy and confidence of the estimate.
• The statement should specify whether it relates to global or
local estimates, and, if local, state the relevant tonnages,
which should be relevant to technical and economic
evaluation. Documentation should include assumptions
made and the procedures used.
• Accuracy and confidence discussions should extend to
specific discussions of any applied Modifying Factors that
may have a material impact on Ore Reserve viability, or for
which there are remaining areas of uncertainty at the
current study stage.
• It is recognised that this may not be possible or appropriate
in all circumstances. These statements of relative
• The design, schedule and financial model for the BOGP has been completed to a Pre-
feasibility standard with a +/-25% level of confidence.
• A degree of uncertainty exists with the geological estimates used to estimate the Ore Reserve
which is reflected in the Mineral Resource classification.
• The Ore Reserve is best reflected as a global estimate.
• There is a degree of uncertainty regarding estimates of modifying mining factors, geotechnical
and processing parameters that are of a confidence level reflected in the level of the study.
• There is a degree of uncertainty in the prices used.
• The Competent Person is satisfied that the assumptions used to determine economic viability
of the Ore Reserve are reasonable at time of publishing.
• The Competent Person is satisfied that a suitable margin exists that the Ore Reserve estimate
would remain economically viable with any negative impacts applied to these factors or
parameters.
114
Bendigo-Ophir Gold Project Pre-Feasibility Study | Executive Summary
Criteria JORC Code explanation Commentary
accuracy and confidence of the estimate should be
compared with production data, where available.
•
Data sourced from publicly available filings. Our datasets may not be complete. Automated analysis can produce errors. If you believe any data on this page is incorrect, please contact us at hello@nzxplorer.co.nz. For informational purposes only. Not investment advice.