Debottlenecking to increase throughput and expansion to 2.6Mtpa to enhance operating margins in Southern Goldfields
HIGHLIGHTS
-
The HXP Scoping Study evaluates the expansion of the existing 1.6Mtpa Higginsville processing plant to 2.6Mtpa - reducing the operating cost per tonne of a large facility that can be further expanded as resource opportunities grow
- The HXP increases steady state gold production at Higginsville from 87kozpa to between 122kozpa and 160kozpa (at the historic
1 August 2024 Ore Reserve grade of 1.9g/t1) -
The HXP is expected to reduce current processing costs from ~36$/t to ~33$/t and the Southern Goldfields mid-point AISC by
~A$142 /oz -
The HXP Scoping Study is financially compelling:
-
Modest mid-point capital requirements of
~A$92M - largely funded fromA$85M sale of Lakewood -
Mid-point IRR of 37% - with a mid-point payback of 2.1 years @
A$3,200 /ounce gold price -
Brings forward
A$135M -$279M of cash flow - @A$3,200 /ounce gold price
-
Modest mid-point capital requirements of
-
The HXP Scoping Study outcomes are based on 2024 reserves only – and does not incorporate any debottlenecking improvements of the existing 1.6Mtpa Higginsville processing plant, cost benefits from conversion to hybrid energy and ongoing resource/reserve conversion or exploration success at Beta Hunt, Two Boys or regional open pit targets
-
Debottlenecking the existing plant is in progress – to lift throughput from current production rate of 1.6Mtpa
- Detailed engineering study to commence - to improve the order of accuracy of the 2.6Mtpa expansion case to support a financial investment decision in FY26
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Cautionary Statement
The HXP Scoping Study is based on an order of magnitude technical and economic assessment and is insufficient to support estimation of new Ore Reserves or to provide assurance of an economic development case at this stage, or to provide certainty that the conclusion of the HXP Scoping Study will be realised.
The HXP Scoping Study referred to in this ASX release has been undertaken to evaluate the potential expansion of the Higginsville Processing Plant.
The HXP Scoping Study has been prepared on a 100% basis and is a preliminary technical and economic study of the potential viability of the expanded Higginsville facility. It is based on technical and economic assessments that are sufficient to support estimation of Ore Reserves reported (as at
The Company believes that it has a reasonable basis for providing these forward-looking statements and the forecast financial information based on material assumptions outlined in this release.
While the Company considers all the material assumptions used in the HXP Scoping Study to be based on reasonable grounds, there is no certainty that they will prove to be correct or that the range of outcomes indicated by the HXP Scoping Study will be achieved.
One of the key assumptions is that the funding for the expansion of the Higginsville Processing Plant will be available when required. To achieve the outcomes indicated in the HXP Scoping Study, funding of
The Company has at
In addition, on
Given the uncertainties involved, investors should not make any investment decisions based solely on the results of the HXP Scoping Study.
Westgold Managing Director and CEO
"Westgold's strategy is to drive our cost base lower and increase free cash generation by expanding and improving outputs at our largest mines and processing plants across our portfolio.
The HXP Scoping Study closely aligns with this strategy and showcases the value that modest capital investment can deliver by expanding this existing 1.6Mtpa processing plant to circa 2.6Mtpa. The increased processing capacity lowers Higginsville's operating cost and can increase steady state gold production from 87kozpa to between 122kozpa and 160kozpa (at the historic
An expanded, lower cost 2.6Mtpa Higginsville mill will also enable greater resource development opportunities across the Southern Goldfields portfolio. Exploration and resource conversion within the Beta Hunt and Two Boys underground mines is advancing rapidly with open pit opportunities around Higginsville currently being tested.
Debottlenecking of the existing Higginsville mill has commenced with the next phase of the Higginsville detailed engineering study to commence immediately, with a view to making a financial investment decision on the HXP during FY26."
______________________________________ |
Westgold's Southern Goldfields Assets – An Overview
Westgold's Southern Goldfields portfolio includes the large Beta Hunt underground at Kambalda, the smaller Two Boys underground at Higginsville, a 1.6Mtpa processing plant and associated processing infrastructure, and 244 live mining tenements (as of
The Higginsville Processing Plant is a conventional carbon-in-leach (CIL) processing plant built by GR Engineering Services and commissioned in 2008. The original plant design capacity was 1.0 Mtpa, with subsequent upgrades and modifications, taking the capacity to 1.6 Mtpa.
Higginsville is currently fed by the Beta Hunt and Two Boys underground mines. Open pit mining at Higginsville has recently recommenced at
Higginsville Expansion Plan (HXP) – Summary
The HXP Scoping Study reviewed multiple plant expansion scenarios ranging from 2.6Mtpa to 4.0Mtpa.
The HXP expansion, as defined in this release, refers to Westgold's preferred option - a 1.0Mtpa3 increase in processing capacity of the existing Higginsville plant from 1.6Mtpa to 2.6Mtpa, that can be further expanded, once regional mine outputs can sustainably exceed 2.6Mtpa.
This HXP expansion is achieved via the replacement of the existing four stage crushing circuit with primary crushing, a 5.5MW SAG mill, and a pebble crusher tied into the existing ball mill. Other downstream modifications including a pre-leach thickener and an additional leach tank is incorporated to allow for increased volumetric flow while maintaining circuit residence time and recovery.
This expansion balances capital efficiency, financial returns, operating risk, and implementation time.
The HXP is also intentionally designed to provide optionality over another expansion in the future, once resource conversion increases the output of our existing Southern Goldfields mines and exploration delivers new targets.
Note that all HXP Scoping Study figures represented below are mid-point values.
Key outputs of the HXP Scoping Study include (see Tables 1-3 for further details, including appropriate ranges):
-
Modest capital outlay of approximately
A$92M – and delivers a 1.0Mtpa expansion of the existing plant to 2.6Mtpa. -
Increases steady state annual gold production by approximately 55kozpa - from 87kozpa to 141kozpa
-
Reduces operating costs in the Southern Goldfields
from ~36$/t to ~33$/t - and the Southern Goldfields mid-point AISC by
~$142 /oz -
Brings forward approximately
A$207M in free cash flow at aA$3,200 /oz gold price -A$808M at spot gold ofA$5,213 /oz4 on11 April 2025 . -
Delivers an internal rate of return of 37% - and a 2.1-year payback
- Establishes a 2.6Mtpa processing facility - that can be further expanded as mine outputs grow.
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4
|
Table 1 – Summary of HXP Study Inputs and Results @
Key Study Inputs |
Units |
Base Case 1.6 Mtpa Existing |
2.6 Mtpa Expansion |
|
Plant Capacity |
Mtpa |
1.6 |
2.6 |
|
Total Ore Processed |
Mt |
20.358 |
20.358 |
|
|
y |
12.7 |
8.7 |
|
Gold Produced |
koz |
1,103 |
1,103 |
|
Key Study Results |
Mid |
Min - Max |
||
|
$M |
N/A |
92 |
60 – 124 |
Processing Opex |
$/t |
36 |
33 |
22 – 48 |
Δ Processing Opex |
$/t |
0 |
(3) |
(2) – (4) |
Max Δ Cumulative Pre-Tax Cash Flow |
$M |
0 |
207 |
135 – 279 |
LOM Cumulative Pre-Tax Cash Flow |
$M |
486 |
550 |
358 – 743 |
NPV(8%) |
$M |
298 |
350 |
228 – 473 |
AISC |
$M |
2,760 |
2,618 |
1,702 – 3,534 |
Δ AISC |
$/oz |
0 |
(142) |
(92) – (192) |
Payback Period |
y |
N/A |
2.1 |
1.4 – 2.8 |
IRR |
% |
N/A |
37 |
24 – 50 |
Key Study Outcomes and Assumptions
The HXP Scoping Study assumes a conservative two-year period to reach an expanded steady state (circa 2.6Mtpa) from the final investment decision (FID). All cases assume processing the entire current Southern Goldfields Ore Reserve of 20.4Mt at 1.9g/t6 for 1.2Moz at its current average grade, without specific timing or sequencing assumptions for individual ore bodies within the Southern Goldfields.
The HXP Scoping Study excludes depletion since the date of the Ore Reserve statement (
The HXP Scoping Study assumes the mine-mill system is constrained by mill capacity, resulting in 100% mill utilisation over the life of mine. In addition, it assumes a flat mining cost of
The conservative gold price assumption of
Table 2 – HXP Key inputs and assumptions
Description |
Unit |
Value |
Gold price (AUD) |
A$/oz |
3,200 |
Ore reserve / Ore Milled |
Mt |
20.4 |
Head grade |
g/t |
1.90[6] |
Recovery |
% |
89.1 |
Mining cost |
$/t milled |
85 |
Site general & administrative expenses |
$M |
12 |
Discount rate |
% |
8.0 |
Development capital in year -17 |
$M |
30 |
Development capital in year -2 6 |
$M |
62 |
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6 To be updated in the next phase of the detailed engineering study, along with the 2025 Reserve and Resource update |
7 Based on midpoint project capex of |
The financial summary is shown below:
Table 3 – HXP Financial Results Ranges at AUD$3,200/oz and spot gold price
Financials Results |
|||||
Gold Price (AUD) |
A$/oz |
3,200 |
5,2138 |
||
Project Valuation of 2.6Mtpa Expansion |
|
Mid |
Min - Max |
Mid |
Min - Max |
Cumulative free cash flow pre-tax |
$M |
550 |
358 – 743 |
2,604 |
1,693 – 3,515 |
Free cash flow brought forward9 |
$M |
207 |
135 – 279 |
808 |
525 – 1091 |
NPV(8%) |
$M |
350 |
228 – 473 |
1,746 |
1,135 – 2,357 |
AISC margin |
$/oz |
582 |
378 – 786 |
2,444 |
1,589 – 3,299 |
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8
|
9 Max Δ Cumulative |
Sensitivity Analysis
The project NPV is most sensitive to changes in gold price and operating cost as shown in Table 4, whilst being more resilient and less sensitive to changes in the discount rate and capital cost.
Table 4 – Higginsville Scoping Study sensitivities
|
NPV Sensitivity |
Gold price (± 10%) |
± |
Operating Cost (± 10%) |
± |
Discount Rate (± 1%) |
- |
Capital Cost (± 10%) |
± |
Capital Costs
Capital cost estimates are derived from several sources, including quotes, contractor estimating database and recently tendered pricing. Estimated capital considered direct costs for mechanical equipment, bulk commodities, additional on-site infrastructure requirements and transport.
Indirect costs for construction, EPCM, third party consultants and provisioned for taxes, duties, contingency and escalation were also included in the estimate. The basis for capital cost estimation included process flow diagrams, conceptual layout sketches and mechanical equipment lists. The capital cost estimate excludes potential projects external to the processing plant such as power systems, bulk earthworks/civils, TSF, mining infrastructure or water upgrades.
The capital cost estimate is factored based on the cost of the mechanical equipment, and benchmarked against recent studies and projects, to meet the required accuracy criteria of +35% for the HXP Scoping Study.
Further opportunities to optimise and refine the capital cost estimate will be taken during the detailed study of the expansion.
Table 5 – HXP Scoping Study capital cost estimates
Expansion Capital Cost |
Mid |
Min - Max |
|
Crushing |
$M |
12 |
8 – 16 |
Grinding |
$M |
27 |
18 – 36 |
Leaching, Adsorption & Gold Room |
$M |
9 |
6 – 12 |
Other Infrastructure |
$M |
6 |
4 – 8 |
Indirect costs |
$M |
38 |
25 – 51 |
Total Capex |
A$M |
92 |
60 – 124 |
Operating Cost
The operating cost estimate for the expansion have been developed to a HXP Scoping Study level accuracy of ±35%. The processing operating cost estimates include:
- labour costs for onsite management and technical activities directly associated with the processing plant
- labour costs for operation and maintenance of the processing plant and supporting infrastructure
- costs associated with the direct operation of the processing plant, including power, all reagents, consumables and maintenance materials
- operating costs for on-site assay laboratory requirements.
The operating cost estimates were determined from first principles using inputs from a variety of sources, including but not limited to:
- base staffing schedule and an assessment of incremental labour requirements
- grinding energy requirement assessments
- power consumption derived from load lists and from unit power costs
- current maintenance requirements and maintenance materials calculated as a percentage of the total direct costs
- reagent consumption and supply costs from current plant data and consultant databases
- previous studies, and current plant production and cost data.
Mining costs were estimated on a fixed
Table 6 – HXP Scoping Study operating cost estimates
Processing Plant Operating Costs |
Base Case |
2.6Mtpa Expansion |
||
Current |
Mid |
Min - Max |
||
Plant Total |
$M/y |
58 |
87 |
57 - 118 |
Plant total unit cost |
$/t |
36 |
33 |
22 - 48 |
Looking Forward
The results of the HXP Scoping Study are compelling and consistent with Westgold's strategy to expand its larger and more productive mines and mills to reduce costs and increase free cash flow. As such, the Company will now commence a more detailed study on the HXP 2.6Mtpa case.
This study will incorporate an updated reserve and resource statement, regional mining studies and consider the longer-term portfolio plan to ensure the design provides optionality to further expand Higginsville to circa 4Mtpa. This study is expected to take approximately 6 - 8 months to complete.
In parallel, Westgold has commenced debottlenecking and optimising the existing Higginsville Processing Plant. These activities include balancing ore blend (incorporating softer oxide open pit ore and higher grade Two Boys underground), optimising crushed ore sizing to the existing milling circuit, upgrading the tailings discharge pumps and maximising power draw by managing mill target grind size.
Westgold looks forward to providing an update on the progress of the Higginsville Expansion Plan during FY26.
This announcement is authorised for release to the ASX by the Board.
Competent/Qualified Person Statements
Mineral Resource Estimates
The information in this report that relates to Mineral Resource Estimates is compiled by Westgold technical employees and contractors under the supervision of Mr.
Ore Reserves
The information in this report that relates to Ore Reserve is based on information compiled by Mr.
General
Mineral Resources, Ore Reserve Estimates and Exploration Targets and Results are calculated in accordance with the JORC Code. Investors outside
This release contains references to estimates of Mineral Resources and Ore Reserves. The estimation of Mineral Resources is inherently uncertain and involves subjective judgments about many relevant factors. Mineral Resources that are not Ore Reserves do not have demonstrated economic viability. The accuracy of any such estimates is a function of the quantity and quality of available data, and of the assumptions made and judgments used in engineering and geological interpretation, which may prove to be unreliable and depend, to a certain extent, upon the analysis of drilling results and statistical inferences that may ultimately prove to be inaccurate. Mineral Resource estimates may require re-estimation based on, among other things: (i) fluctuations in the price of gold; (ii) results of drilling; (iii) results of metallurgical testing, process and other studies; (iv) changes to proposed mine plans; (v) the evaluation of mine plans subsequent to the date of any estimates; and (vi) the possible failure to receive required permits, approvals and licenses.
Technical Report
The NI 43-101 compliant technical report for the Company's Higginsville operations is titled 'NI 43-101 Technical Report, Higginsville Gold Operations, Eastern Goldfields,
Forward looking statements
These materials prepared by
Forward looking statements inherently involve known and unknown risks, uncertainties and other factors that may cause the Company's actual results, performance and achievements to differ materially from any future results, performance or achievements. Relevant factors may include, but are not limited to, changes in commodity prices, foreign exchange fluctuations and general economic conditions, increased costs and demand for production inputs, the speculative nature of exploration and project development, including the risks of obtaining necessary licenses and permits and diminishing quantities or grades of reserves, political and social risks, changes to the regulatory framework within which the Company operates or may in the future operate, environmental conditions including extreme weather conditions, recruitment and retention of personnel, industrial relations issues and litigation.
Forward looking statements are based on the Company and its management's good faith assumptions relating to the financial, market, regulatory and other relevant environments that will exist and affect the Company's business and operations in the future. The Company does not give any assurance that the assumptions on which forward looking statements are based will prove to be correct, or that the Company's business or operations will not be affected in any material manner by these or other factors not foreseen or foreseeable by the Company or management or beyond the Company's control.
Although the Company attempts and has attempted to identify factors that would cause actual actions, events or results to differ materially from those disclosed in forward looking statements, there may be other factors that could cause actual results, performance, achievements or events not to be as anticipated, estimated or intended, and many events are beyond the reasonable control of the Company. In addition, the Company's actual results could differ materially from those anticipated in these forward looking statements as a result of the factors outlined in the "Risk Factors" section of the Company's continuous disclosure filings available on SEDAR+ or the ASX, including, in the Company's current annual report, half year report or most recent management discussion and analysis.
Accordingly, readers are cautioned not to place undue reliance on forward looking statements. Forward looking statements in these materials speak only at the date of issue. Subject to any continuing obligations under applicable law or any relevant stock exchange listing rules, in providing this information the Company does not undertake any obligation to publicly update or revise any of the forward-looking statements or to advise of any change in events, conditions or circumstances.
Reasonable Basis for Forward-Looking Statements
This ASX release has been prepared in compliance with the JORC Code (2012) and the ASX Listing Rules. All material assumptions on which the HXP Scoping Study production target and projected financial information are based have been included in this release.
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