Updated Integrated Development Plan Highlights (effective date January 1, 2024):
K92 Mining Inc. (TSX: KNT) (OTCQX: KNTNF) is pleased to announce the results of its Updated Integrated Development Plan for its Kainantu Gold Mine Project in Papua New Guinea. The Updated IDP comprises two scenarios: 1) Kainantu Stage 3 Expansion Definitive Feasibility Study Case; and 2) Kainantu Stage 4 Expansion Preliminary Economic Assessment Case. The results of the Updated IDP will be set forth in an independent technical report prepared in accordance with National Instrument 43-101 – Standards for Disclosure of Mineral Projects within forty-five days from now.
The Updated IDP supersedes the January 1, 2022 effective date Integrated Development Plan and has delivered a significant improvement in economics in both the DFS Case and the PEA Case, and particularly the PEA Case, driven by the following key changes:
The Updated IDP, which includes the Kainantu Stage 3 Expansion DFS Case and the alternative Kainantu Stage 4 Expansion PEA Case, was independently prepared by Entech Pty Ltd of Perth, Australia; ATC Williams Pty Ltd of Brisbane, Australia; WSP Canada Inc. of Ontario, Canada; Metallurgical Management Services Pty Ltd of Perth, Australia, EMM Consulting Pty Ltd of Queensland, Australia, H & S Consultants Pty. Ltd of Sydney, Australia, and; GR Engineering Services Limited of Brisbane, Australia, with some cost information provided by K92.
The PEA is preliminary in nature and includes Inferred Mineral Resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as Mineral Reserves, and there is no certainty that the PEA will be realized. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. Mineral Reserves are defined by the Definitive Feasibility Study and are not predicated on the Preliminary Economic Assessment in any way.
John Lewins, K92 Chief Executive Officer and Director, stated, “The Updated Integrated Development Plan is a major milestone for K92, marking a significant improvement to mine economics by incorporating a larger updated Mineral Resource estimate, a new off-take agreement with Trafigura, more robust engineering designs and information from our ongoing construction activities, along with margin expansion from improved commodity prices.
This has resulted in the DFS Case NPV5% increasing from US$586 million at $1,600/oz in the 2022 IDP to, in the Updated IDP, US$680 million at $1,900/oz, or US$1.2 billion at near-spot prices of $2,600/oz. The PEA Case saw its NPV5% rise from US$1.3 billion at $1,600/oz in the 2022 IDP to, in the Updated IDP, US$2.3 billion at $1,900/oz or US$3.5 billion at near-spot prices of $2,600/oz gold.
Importantly, the realization of strong cash flow and the economic benefits of the Updated IDP are expected near-term. In less than nine months, the commissioning of the Stage 3 Plant Expansion is planned to begin, marking the start of K92’s transformation into a Tier 1 Mid-Tier Producer. Concurrent with advancing the Stage 3 and 4 Expansions, we remain very active in improving upon the outcomes of the study, particularly through exploration. There are currently 11 drill rigs on site of which 6 are operating underground and 5 on the surface, focused on upgrading and expanding resources both near-mine and across our highly prospective gold-copper district.
Later this month, we are excited to host a large group of analysts and investors on-site to showcase our progress to date in multiple areas and also the mining-friendly jurisdiction of Papua New Guinea.”
1 – Kainantu Updated IDP – Definitive Feasibility Study Case
The DFS evaluates an expansion of mining and processing to a run-rate throughput of 1.2 mtpa, representing a 100% increase from the Stage 2A Expansion run-rate of 600,000 tpa. This expansion is referred to as the Stage 3 Expansion and involves on-site treatment of ore by a new standalone 1.2 mtpa process plant, utilizing single stage crushing, SAG and ball milling, along with gravity and flotation recovery.
The DFS and Mineral Reserve statement is derived from the global Kora and Judd Mineral Resource Estimate (September 12, 2023 effective date), net of post-resource mining depletion from September 12, 2023 to December 31, 2023, and does not incorporate post-resource-estimate drilling results.
Table 1.1: DFS Highlights
US Dollars unless otherwise stated | Updated IDP | |
Life of Mine (starting January 2024) |
Stage 3 Run-Rate(1) (2027-2029) |
|
Production | ||
Mine life (years) | 7 years | |
Total mill feed (000s tonnes) | 6,176 | 3,600 |
Average mill throughput (000s tonnes per annum) | 882 | 1,200 |
Total Metal Production | ||
AuEq (000s ounces) | 1,561 | 910 |
Gold (000s ounces) | 1,223 | 666 |
Copper (million lbs) | 126 | 92 |
Silver (000s ounces) | 2,910 | 1,986 |
Peak Annual Production | ||
Year | 2027 | |
AuEq (000s ounces per annum) | 319 | |
Average Annual Metal Production | ||
AuEq (000s ounces per annum) | 223 | 303 |
Gold (000s ounces per annum) | 175 | 222 |
Copper (mlbs per annum) | 18 | 31 |
Silver (000s ounces per annum) | 416 | 662 |
Average Grade | ||
AuEq grade (g/t) | 8.5 g/t | |
Gold grade (g/t) | 6.7 g/t | |
Copper grade (%) | 1.0% | |
Silver grade (g/t) | 19 g/t | |
Average Recovery | ||
Gold recovery (%) | 93% | |
Copper recovery (%) | 94% | |
Silver recovery (%) | 78% | |
Costs | ||
Mining cost (US$/t ore mined) | $68.05 | $57.73 |
Processing cost (US$/t processed) | $19.44 | $18.12 |
G&A cost (US$/t processed) | $37.11 | $33.38 |
Paste plant cost ($/t processed) | $10.31 | $13.32 |
TSF cost ($/t processed) | $0.64 | $0.48 |
Transport and Insurance cost ($/t processed) | $9.85 | $10.93 |
Total operating cost per tonne processed (US$/t) | $145.40 | $134.56 |
Royalties ($/t processed) | $10.90 | $10.93 |
Sustaining capital per tonne processed (US$/t) | $54.59 | $34.47 |
Total cost per tonne processed (US$/t) | $210.88 | $179.96 |
Growth capital expenditure ($m) | $194 | |
Sustaining capital expenditure ($m) | $337 | |
Total capital expenditure with closure costs ($m) | $541 | |
Cash cost per ounce AuEq ($/oz)(2) | $694 | $646 |
All-in sustaining cost per ounce AuEq ($/oz)(3) | $920 | $789 |
Cash cost per ounce gold ($/oz)(2) | $380 | $204 |
All-in sustaining cost per ounce gold ($/oz)(3) | $665 | $397 |
Base Case Economic Analysis at US$1,900/oz Gold, US$4.50/lb Copper and US$25.00/oz Silver | ||
After-tax NPV0% | $869 million | |
After-tax NPV5%(4) | $680 million | |
Economic Analysis at $2,500/oz Gold, US$4.50/lb Copper and US$25.00/oz Silver | ||
After-tax NPV0% | $1,359 million | |
After-tax NPV5%(4) | $1,091 million | |
1.2 – Kainantu Mineral Reserve Statement
The Mineral Reserve estimate outlined in the DFS was prepared by Daniel Donald FAusIMM MSME of Entech, in accordance with the classification criteria set out in the 2014 CIM Definition Standards for Mineral Resources and Mineral Reserves prepared by the CIM Standing Committee on Reserve Definitions. Daniel Donald is an independent consultant of the Company and is a Qualified Persons as defined by NI 43-101. The total Mineral Reserve for the Kainantu Project is shown in Table 1.2. The Mineral Reserve estimate is based on the Global Kora and Judd Mineral Resource estimate (September 12, 2023 effective date – refer to Table 1.3), net of post-resource mining depletion from September 12, 2023 to December 31, 2023, of 183,768 tonnes at 8.1 g/t Au, 0.9 % Cu and 15 g/t Ag.
Table 1.2 – Kainantu Mineral Reserve Statement (Effective Date January 1, 2024)
Kora and Judd Deposit Reserve Summary (January/2024) | |||||||||
Tonnes | Gold | Silver | Copper | Gold Equivalent | |||||
mt | g/t | moz | g/t | moz | % | kt | g/t | moz | |
Kora Deposit | |||||||||
Proven | 2.95 | 7.4 | 0.70 | 19 | 1.9 | 1.1 | 31 | 9.4 | 0.89 |
Probable | 2.52 | 5.7 | 0.46 | 19 | 1.6 | 1.0 | 26 | 7.6 | 0.61 |
Proven & Probable | 5.47 | 6.6 | 1.16 | 19 | 3.4 | 1.1 | 57 | 8.6 | 1.50 |
Judd Deposit | |||||||||
Proven | 0.24 | 8.3 | 0.06 | 17 | 0.1 | 0.6 | 1 | 9.4 | 0.07 |
Probable | 0.47 | 6.5 | 0.10 | 13 | 0.2 | 0.5 | 2 | 7.5 | 0.11 |
Proven & Probable | 0.71 | 7.1 | 0.16 | 14 | 0.3 | 0.5 | 4 | 8.1 | 0.18 |
Consolidated | |||||||||
Total Proven | 3.19 | 7.5 | 0.77 | 19 | 2.0 | 1.0 | 33 | 9.4 | 0.96 |
Total Probable | 2.99 | 5.8 | 0.56 | 18 | 1.8 | 1.0 | 28 | 7.6 | 0.73 |
Total Proven & Probable | 6.18 | 6.7 | 1.32 | 19 | 3.7 | 1.0 | 61 | 8.5 | 1.69 |
1.3 – Kainantu Mineral Resource Estimate
The Company’s current Mineral Resource estimate for Kora and Judd (effective date of September 12, 2023) was completed by H & S Consultants Pty. Ltd. (Table 1.3). The Irumafimpa deposit was not incorporated into the Updated IDP and will be reviewed at a later date.
Table 1.3 – Global Kora and Judd Mineral Resource Estimate, (3.0 g/t AuEq cut-off)
Kora Deposit Resource Summary (September 12/2023) |
|||||||||
Tonnes | Gold | Silver | Copper | Gold Equivalent | |||||
mt | g/t | moz | g/t | moz | % | kt | g/t | moz | |
Kora Deposit | |||||||||
Measured | 3.7 | 8.7 | 1.0 | 21 | 2.5 | 1.2 | 45 | 11.0 | 1.3 |
Indicated | 3.1 | 7.0 | 0.7 | 22 | 2.2 | 1.3 | 41 | 9.4 | 1.0 |
Measured & Indicated | 6.9 | 7.9 | 1.8 | 21 | 4.7 | 1.3 | 86 | 10.2 | 2.3 |
Inferred | 14.3 | 5.6 | 2.6 | 29 | 13.2 | 1.6 | 231 | 8.6 | 3.9 |
Judd Deposit Resource Summary (September 12/2023) | |||||||||
Tonnes | Gold | Silver | Copper | Gold Equivalent | |||||
mt | g/t | moz | g/t | moz | % | kt | g/t | moz | |
Judd Deposit | |||||||||
Measured | 0.4 | 9.1 | 0.12 | 19 | 0.2 | 0.8 | 3 | 10.6 | 0.14 |
Indicated | 0.8 | 6.4 | 0.17 | 16 | 0.4 | 0.7 | 6 | 7.8 | 0.21 |
Measured & Indicated | 1.2 | 7.2 | 0.29 | 17 | 0.7 | 0.8 | 9 | 8.7 | 0.35 |
Inferred | 2.3 | 6.3 | 0.45 | 16 | 1.1 | 0.8 | 17 | 7.7 | 0.56 |
Consolidated | |||||||||
Total Measured | 4.1 | 8.8 | 1.2 | 20 | 2.7 | 1.2 | 48 | 10.9 | 1.5 |
Total Indicated | 4.0 | 6.9 | 0.9 | 21 | 2.6 | 1.2 | 47 | 9.1 | 1.2 |
Total Measured & Indicated | 8.1 | 7.8 | 2.0 | 20 | 5.3 | 1.2 | 96 | 10.0 | 2.6 |
Total Inferred | 16.5 | 5.7 | 3.0 | 27 | 14.3 | 1.5 | 248 | 8.5 | 4.5 |
1.4 – DFS Mining Operations
K92 engaged Entech to undertake the DFS for the Kainantu Project, which involved:
The Stage 3 Expansion mine plan considered in the DFS is designed as an incline access operation with a series of ore passes for efficient material movement between sublevels and the twin incline for material transport to surface. The DFS mine plan initially employs a long hole open stoping mining method utilizing Avoca and Modified Avoca mining methods, which are currently employed at the mine. Upon construction of the pastefill plant, the mining method transitions to long hole open stoping with pastefill in Q3 2025.
Long hole open stoping has been successfully executed at both the Kora and Judd deposits, with the first long hole stope mined in Q1 2020 at Kora, and Q4 2021 at Judd. The Avoca mining method involves backfilling from the overcut sublevel while the long hole stope is advanced from the undercut sublevel to limit the strike length of the open stope. By limiting the strike length of the open stope, the method is designed to provide sufficient stability to the stope walls and backs, increasing the ultimate strike length extracted. The application of cemented pastefill provides improved geotechnical conditions for less dilution and higher mining recovery factors, greater operating flexibility through the ability to mine above and below pastefill and a reduction in surface tailings storage requirement.
Stopes were identified for the mine plan contained in the DFS based on the Datamine Mineable Shape Optimizer (MSO) program at a cut-off grade of 3.5 g/t AuEq. Stope shapes with uneconomic development access requirements were excluded. Dilution was estimated based on a 0.5 m dilution skin for both the footwall and hanging wall using the MSO program for a minimum stope width of 3.0 m. Additional dilution factor of 5% was added for stopes utilizing Avoca and Modified Avoca and 2.5% for stopes with pastefill. Where a stope is within 5.0 m proximity of the HW or FW of the fault gouge, an additional 1.0 m of dilution was added at a grade averaging 1.42g/t AuEQ. The overall dilution averaged 27.8%. Mining recovery factors of 90% and 95% were applied for long hole open stoping with Avoca and long hole open stoping with pastefill, respectively. The life of mine average head grade is 6.7 g/t Au, 1.0 % Cu and 19 g/t Ag or 8.5 g/t AuEq.
The DFS Case operates at the Stage 2A Expansion 600,000 tpa throughput rate until mid-2025, where the operation commences ramp up to the Stage 3 Expansion run-rate of 1.2 mtpa in late Q2 2025. Mining is predominately from the Kora Central Zone within the Kora deposit and the Judd deposit. See Table 1.6 for a material movement summary as part of the simplified economic model.
Figure 1.1 – DFS Life of Mine Plan – Lateral, Vertical Development and Stope Shapes at 3.5 g/t AuEq cut-off grade (looking West)
1.4 – DFS Mineral Processing, Tailings and Infrastructure
K92 engaged GR Engineering Services, WSP, and ATCW to complete and update the DFS Stage 3 Expansion process plant, pastefill plant, tailing facility and integration of surface infrastructure design. The DFS involves the construction of a standalone 1.2 mtpa processing plant and supporting infrastructure. The new plant is adjacent to the existing process plant, which is undergoing a Stage 2A Plant Expansion with an upgraded design throughput of 600,000 tpa (previously 500,000 tpa). The existing plant will be placed on care and maintenance in Q4 2025 upon the commissioning and ramp-up of the Stage 3 Expansion Process Plant commencing in late Q2 2025.
Run-of-mine material is trucked ~6 km from the 800 Portal to the Kainantu process plant, where it is either stockpiled or direct tipped into the crusher. The 1.2 mtpa processing plant design flowsheet incorporates a conventional single stage jaw crusher (200 tph) reporting to a crushed ore overflow surge bin and dead stockpile which provides 12 hours of stockpile capacity. The primary crushed ore supplies a SAB milling circuit (150 tph) that includes an open circuit SAG mill and closed circuit ball mill. The ball mill product reports to hydrocyclones, with cyclone overflow reporting to the flotation circuit and the cyclone underflow stream being split between the gravity circuit, flash flotation circuit and ball mill for grinding.
The gravity circuit involves one batch centrifugal concentrator followed by two stages of gravity separation using shaking tables to upgrade the gravity concentrate, which is then calcined and smelted to produce gold doré. The flotation circuit includes flash flotation and conventional sulphide flotation, followed by thickening and filtering to produce a gold-copper-silver concentrate. The circuit is based on simple conventional technology with the flowsheet largely similar but optimized from the existing Kainantu processing plant. The key difference between the existing plant and the proposed Stage 3 Expansion process plant is the implementation of a one stage crushing circuit (vs two stage crushing) and two stages of milling with a SAG and ball mill (vs one stage of ball milling).
Tailings management upgrades would be part of the Stage 3 Expansion, through the construction of a pastefill plant to provide improved underground support and reduce surface tailings deposition needs. Thickened tailings at the process plant are designed to be dewatered in filter presses and trucked to the underground pastefill plant, with the final pastefill product pumped to stope voids as fill. Remaining thickened tailings report to the tailings impoundment on the surface. To support the increased processing capacity, implementation of the pastefill plant and increased underground mining activity, the standby diesel generator capacity is expanded.
Papua New Guinea Power Limited have completed engineering information which has been used in the DFS and involves an upgrade of the local electrical grid to facilitate improved availability and distribution of clean hydroelectricity to the mine. This is expected to considerably reduce the mine’s Scope 1 and Scope 2 greenhouse gas emission intensity per ounce produced – the amount of diesel fuel consumed for backup generators. K92 has already engaged with PNG Power to commence this project and the Company expects it to have a notable improvement on our greenhouse gas emission intensity over the next 6 to 12 months. In June 2023, the Company announces its 2030 greenhouse reduction target, as part of its ongoing overall sustainability commitments to reduce Scope 1 and Scope 2 emissions by 25% on a business-as-usual basis by 2030 (a 25% reduction against forecast Scope 1 and 2 GHG emissions by 2030 assuming no mitigation measures are implemented to reduce carbon emissions). Further information on the GHG target and the overall approach to sustainability is available in the Company’s 2022 and 2023 Sustainability Reports.
The tailings storage facility design was completed by ATC Williams. With the application of pastefill significantly reducing the amount of tailings reporting to surface, the current storage facility approved has sufficient capacity (constructed as staged development) for the DFS mine plan. The TSF is constructed as a downstream type, utilizing Australian and International guidelines and standards.
Figure 1.2 – DFS 1.2 mtpa Process Plant Flowsheet
1.6 – DFS Capital and Operating Costs
The initial capital cost estimate in the DFS includes contingency ranging from 7% to 15% depending on the capital item, with the major items outlined in Table 1.4. Operating costs are presented in Table 1.5.
Table 1.4: DFS – Capital Cost Estimates
US Dollars unless otherwise stated | |
Process Plant | $90.3m |
Paste Plant | $42.5m |
River Crossing | $14.4m |
Power Station | $10.3m |
Electrical Infrastructure | $6.9m |
OHPL | $1.9m |
Maintenance Facilities | $3.0m |
Warehouse | $0.9m |
Owner’s Team, Approvals, Indirects | $20.1m |
Camp Upgrade | $4.2m |
Growth Capital | $194.4m |
Total Life of Mine Sustaining Capital | $337.1m |
Totals may differ due to rounding
Table 1.5: DFS – Operating Cost Estimates (Life of Mine Average)
US Dollars unless otherwise stated | |
Mining Cost ($/t) | $68.05 |
Processing Cost ($/t) | $19.44 |
General & Administrative Cost ($/t) | $37.11 |
Paste Plant Cost ($/t processed) | $10.31 |
TSF ($/t processed) | $0.64 |
Transport and Insurance ($/t processed) | $9.85 |
Royalties ($/t processed) | $10.90 |
Total Cost Per Tonne Processed ($/t) | $156.30 |
Sustaining Capital per Tonne of Processed ($/t) | $54.59 |
Total Cost Per Tonne Processed ($/t) | $210.88 |
Totals may differ due to rounding
1.7 DFS – Economic Analysis
Entech prepared a conceptual cashflow and discounted cashflow derived from the life-of-mine schedule. Tax calculations for the after-tax cashflow and discounted cashflow were prepared by K92. A summary of the cashflow analyses is shown in Table 1.6 and a sensitivity analysis to gold price is shown in Table 1.7.
Table 1.6: DFS – Simplified Financial Model at US$1,900/oz Au, US$4.50/lb Cu, US$25.00/oz Ag
Year | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 |
Mill Throughput (ktpa) | 473 | 800 | 1,001 | 1,200 | 1,200 | 1,200 | 302 |
Gold Grade (g/t) | 7.59 | 6.54 | 6.43 | 6.86 | 5.26 | 6.48 | 11.66 |
Copper Grade (%) | 0.60% | 0.55% | 0.62% | 1.11% | 1.48% | 1.10% | 1.07% |
Silver Grade (g/t) | 11.48 | 12.04 | 14.37 | 22.44 | 25.07 | 18.50 | 24.39 |
AuEq Grade (g/t) | 8.72 | 7.59 | 7.63 | 8.95 | 8.00 | 8.52 | 13.72 |
Gold Produced (000s oz) | 107 | 154 | 190 | 245 | 190 | 231 | 106 |
Silver Produced (000s oz) | 136 | 241 | 361 | 675 | 754 | 557 | 185 |
Copper Produced (m lbs) | 5.9 | 9.1 | 12.7 | 27.5 | 37.1 | 27.4 | 6.8 |
AuEq Produced (000s oz) | 122 | 179 | 225 | 319 | 287 | 303 | 125 |
Net Revenue (US$m)(1) | $212 | $310 | $405 | $575 | $507 | $547 | $225 |
Total OPEX (US$m)(1) | $96 | $130 | $159 | $179 | $172 | $172 | $57 |
Growth Capital (US$m) | $107 | $87 | – | – | – | – | – |
Sustaining Capital (US$m) | $82 | $72 | $47 | $56 | $38 | $30 | $13 |
After-tax CF (US$m) | ($98) | ($14) | $147 | $247 | $219 | $252 | $116 |
Cumulative After-tax CF (US$m) | ($98) | ($112) | $36 | $283 | $502 | $754 | $869 |
Figure 1.3 – DFS Material Movement Schedule
Figure 1.4 – DFS Production and All-in Sustaining Cost (Co-Product) Schedule
Figure 1.5 – DFS Cash Flow Projects at US$1,900/oz Au (top chart) and US$2,500/oz Au (bottom chart)
Table 1.7: DFS – After-Tax NPV5% Sensitivity to Gold Price
Gold Price | After-Tax NPV5% (US$M) |
$1,600 | $475 |
$1,900 | $680 |
$2,200 | $886 |
$2,500 | $1,091 |
$2,800 | $1,296 |
$3,100 | $1,501 |
2 – Kainantu Updated IDP – Preliminary Economic Assessment Case
2.1 – PEA Overview
The alternative PEA Case conceptualizes a multi-expansion plan to an ultimate plant run-rate of 1.8 mtpa, representing a 200% increase from the upgraded Stage 2A Expansion run-rate of 600,000 tpa design throughput (previously 500,000 tpa). The PEA Case involves the construction of a standalone 1.2 mtpa process plant adjacent to the 600,000 tpa Stage 2A Expansion process plant. In mid-2025, the Stage 2A Expansion process plant is idled as the 1.2 mtpa Stage 3 process plant ramps up, with commissioning of the Stage 3 Expansion process plant commencing in late Q2 2025. Upon achieving the Stage 3 run-rate throughput in 2027, the Stage 2A Expansion plant is recommissioned in H2 2027, ramping up to run-rate throughput of 600,000 tpa by year end, for a combined processing run-rate of 1.8 mtpa at the beginning of 2028.
To support the higher throughput rate, the underground mining fleet is significantly increased to support expanded mining operations operating multiple mining fronts concurrently: Kora Upper, Lower and Central Zones within the Kora deposit, and the Judd deposit. Site infrastructure is also expanded, including power, camp facilities and the pastefill plant. Several capital items, such as the pastefill system, are configured during the construction of Stage 3 to be amenable to the larger ultimate Stage 4 Expansion run-rate.
The PEA uses the conclusions of the Company’s Mineral Resource estimate for Kora and Judd (effective date of September 12, 2023) and does not incorporate post resource drilling results. The effective date of the PEA life of mine plan is January 1, 2024; therefore, Kora is net of post-resource mining depletion from September 12, 2023 to December 31, 2023 of 183,768 tonnes at 8.1 g/t Au, 0.9 % Cu and 15 g/t Ag.
The PEA is preliminary in nature and includes Inferred Mineral Resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as Mineral Reserves, and there is no certainty that the PEA will be realized. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability.
Table 2.1: PEA Highlights
US Dollars unless otherwise stated | Life of Mine (starting January 2024) |
Stage 4 Run-Rate(1) (2028 – 2034) |
Production | ||
Mine life (years) | 14 years | |
Total mill feed (000s tonnes) | 20,396 | 12,600 |
Average mill throughput (000s tonnes per annum) | 1,457 | 1,800 |
Total Metal Production | ||
AuEq (000s ounces) | 4,977 | 2,895 |
Gold (000s ounces) | 3,620 | 2,011 |
Copper (mlbs) | 508 | 332 |
Silver (000s ounces) | 11,799 | 7,399 |
Peak Annual Production | ||
Year | 2034 | |
AuEq (000s ounces per annum) | 485 | |
Average Annual Metal Production | ||
AuEq (000s ounces per annum) | 356 | 414 |
Gold (000s ounces per annum) | 259 | 287 |
Copper (mlbs per annum) | 36 | 47 |
Silver (000s ounces per annum) | 843 | 1,057 |
Average Grade | ||
AuEq grade (g/t) | 8.2 g/t | |
Gold grade (g/t) | 6.0 g/t | |
Copper grade (%) | 1.2% | |
Silver grade (g/t) | 23 g/t | |
Average Recovery | ||
Gold recovery (%) | 93% | |
Copper recovery (%) | 94% | |
Silver recovery (%) | 78% | |
Costs | ||
Mining cost ($/t ore mined) | $62.60 | $58.58 |
Processing cost ($/t processed) | $18.19 | $17.65 |
General & Administrative cost ($/t processed) | $25.45 | $23.33 |
Paste plant cost ($/t processed) | $9.16 | $9.89 |
TSF cost ($/t processed) | $0.48 | $0.42 |
Transport and Insurance cost ($/t processed) | $10.24 | $10.44 |
Total operating cost per tonne processed (US$/t) | $126.12 | $120.59 |
Royalties ($/t processed) | $10.75 | $10.10 |
Sustaining capital per tonne of processed (US$/t) | $44.15 | $35.57 |
Total cost per tonne of processed (US$/t) | $181.02 | $166.06 |
Growth capital expenditure ($m) | $201 | |
Sustaining capital expenditure ($m) | $900 | |
Total capital expenditure with closure costs ($m) | $1,122 | |
Cash cost per ounce AuEq ($/oz)(2) | $633 | $644 |
All-in sustaining cost per ounce AuEq ($/oz)(3) | $822 | $805 |
Cash cost per ounce gold ($/oz)(2) | $174 | $108 |
All-in sustaining cost per ounce gold ($/oz)(3) | $432 | $338 |
Base Case Economic Analysis at US$1,900/oz Gold, US$4.50/lb Copper and US$25.00/oz Silver | ||
After-tax NPV0% | $3.5 billion | |
After-tax NPV5%(4) | $2.3 billion | |
Economic Analysis at $2,500/oz Gold, US$4.50/lb Copper and US$25.00/oz Silver | ||
After-tax NPV0% | $5.0 billion | |
After-tax NPV5%(4) | $3.3 billion | |
2.2 – PEA Mining Operations
The Company engaged Entech to undertake the PEA Case for the Kainantu Project, which involved:
The mine plan considered in the PEA is designed as an incline access operation with a series of ore passes for efficient material movement between sublevels and the twin incline for material transport to surface. Initially, the mine plan employs a long hole open stoping mining method utilizing Avoca and modified Avoca, with waste rockfill. This mining method has been successfully employed at the mine since Q1 2020 at Kora and Q4 2021 at Judd. The mining method will then transition to long hole open stoping with pastefill in Q2 2025, upon the construction of the pastefill plant. Cemented pastefill provides improved geotechnical conditions for less dilution, higher mining recovery factors, and greater operating flexibility through the ability to mine above and below pastefill, plus a reduction in surface tailings.
Stopes were identified for the PEA mine plan based on the MSO program at a cut-off grade of 4.0 g/t AuEq. Stope shapes with uneconomic development access requirements were excluded from the assessment. Dilution was estimated based on a 0.5 m dilution skin for both the footwall and hanging wall using the MSO program for a minimum stope width of 3.0 m. Additional dilution factor of 5% was added for long hole stoping utilizing Avoca and Modified Avoca and 2.5% for long hole open stoping with pastefill. Where a stope is within 5m proximity of the HW or FW of the fault gouge, an additional 1.0 m of dilution was added at a grade averaging 1.42 g/t AuEq. The overall dilution averaged 28.5%. Mining recovery factors of 90% and 95% were applied for long hole open stoping with Avoca and long hole open stoping with pastefill, respectively. The life of mine average head grade is 6.0 g/t Au, 1.2% Cu and 23 g/t Ag or 8.2 g/t AuEq.
The mine plan operates at the Stage 2A Expansion 600,000-tpa throughput until mid-2025, with the operation commencing ramp up to the Stage 3 Expansion run-rate of 1.2 mtpa in late Q2 2025, sequentially ramping-up to the Stage 4 Expansion run-rate of 1.8 mtpa at the beginning of 2028. To support the Stage 4 mining rate, multiple mining fronts are mined concurrently: Kora Central, Kora Upper and Kora Lower within the Kora deposit, and the Judd deposit. See Table 2.6 for a material movement summary as part of the simplified economic model.
Figure 2.1 – PEA Life of Mine Plan – Lateral, Vertical Development and Stope Shapes at 4.0 g/t AuEq cut-off grade (looking West)
2.4 – PEA Mineral Processing, Tailings and Infrastructure
K92 engaged GR Engineering Services, WSP, and ATCW to complete an update to the PEA Stage 4 Expansion process plant, pastefill plant, tailing facility and integration of surface infrastructure design. The PEA conceptualizes constructing a new standalone processing plant for the Stage 3 Expansion adjacent to the existing Stage 2A Expansion process plant. The existing Stage 2A Expansion process plant operates until mid-2025, where it is idled as the Stage 3 Expansion ramps-up (starting in late Q2 2025). The process plants are fed from run-of-mine (ROM) material that is trucked ~6km from the 800 Portal to the Kainantu process plant, where it is either stockpiled or direct tipped into the crusher.
The Stage 3 Expansion process plant design flowsheet incorporates a conventional comminution circuit, utilizing a single stage of jaw crushing (200 tph) reporting to a crushed ore overflow surge bin, followed by a SAB milling circuit (150 tph) with an open circuit SAG mill and close circuit ball mill. The ball mill product reports to cyclone classification, where the cyclone overflow reports to the flotation circuit and the cyclone underflow stream being split between the gravity circuit, flash flotation circuit and ball mill for grinding. The gravity circuit involves one batch centrifugal concentrator followed by two stages of gravity separation using shaking tables. The upgraded gravity concentrate is then calcined and smelted to produce gold doré. The flotation circuit consists of flash flotation and conventional sulphide flotation, followed by thickening and filtering to produce a gold-copper-silver concentrate.
Processing performance estimates were based on a combination of test work and operating results. Over the period, January 2018 to August 2024, six stages of processing plant upgrades allowed increased throughput and improved recovery performance. The plant has operated in its current configuration (Stage 2A expansion) since June 2023. Metal recovery factors for the PEA were based on an analysis of processing results from June 2023 until August 2024, plus a consideration of economic factors associated with metals offtake agreements and concentrate transport costs.
The PEA incorporates tailings management upgrades, with underground pastefill commencing in Q3 2025 upon the completion of construction of the pastefill plant. The delivery of pastefill involves pumping thickened tailings from the process plant, then dewatered in filter presses and trucked to the underground pastefill plant. This is followed by pumping the final pastefill product into stope voids. Remaining tailings are pumped to the tailings impoundment as thickened tailings. The significant increase to processing capacity, mining rates and underground infrastructure requires additions to the standby diesel generating capacity on site. The PEA also involves an upgrade to the local electrical grid to facilitate improved availability and distribution of clean hydroelectricity to the mine. This upgrade is expected to materially reduce overall Scope 1 and Scope 2 greenhouse gas emission intensity per ounce produced. In June 2023, the Company announced its 2030 greenhouse reduction target, as part of its ongoing overall sustainability commitments to reduce Scope 1 and Scope 2 emissions by 25% on a business-as-usual basis by 2030 (a 25% reduction against forecast Scope 1 and 2 GHG emissions by 2030 assuming no mitigation measures are implemented to reduce carbon emissions). Additional information on the GHG target and the overall approach to sustainability is available in the Company’s 2022 and 2023 Sustainability Reports.
The implementation of pastefill significantly reduces the amount of tailings reporting to the TSF. The existing TSF has sufficient tailings capacity until 2029, after which tailings then report to the new TSF. The development of the new tailings facility is situated less than 2 km from the existing TSF with a number of suitable sites identified. The new tailings facility design has significant capacity beyond the material movements in the PEA. The existing and proposed new TSF is by downstream construction methods, suitable for the climate and geotechnical environment of mine site with Australian and international guidelines and Standards being met or exceeded. The TSF design work was completed by ATC Williams.
Figure 2.2 – PEA 1.8 mtpa Process Plant Flowsheet
2.5 – PEA Capital and Operating Costs
The growth capital cost estimate includes a contingency ranging from 7% to 15% and the major items are outlined in Table 2.4. Operating costs are presented in Table 2.5.
Table 2.4: PEA – Capital Cost Estimates
US Dollars unless otherwise stated | |
Process Plant | $90.3m |
Paste Plant | $45.0m |
River Crossing | $14.4m |
Power Station | $12.3m |
Electrical Infrastructure | $6.9m |
OHPL | $1.9m |
Maintenance Facilities | $3.0m |
Warehouse | $0.9m |
Owner’s Team, Approvals, Indirects | $20.1m |
Camp Upgrade | $6.2m |
Growth Capital | $200.9m |
Total Life of Mine Sustaining Capital | $900.5m |
Totals may differ due to rounding
Table 2.5: PEA – Operating Cost Estimates (Life of Mine Average)
US Dollars unless otherwise stated | |
Mining Cost ($/t ore mined) | $62.60 |
Processing Cost ($/t processed) | $18.19 |
General & Administrative Cost ($/t processed) | $25.45 |
Paste Plant Cost ($/t processed) | $9.16 |
TSF ($/t processed) | $0.48 |
Transport and Insurance ($/t processed) | $10.24 |
Royalties ($/t processed) | $10.75 |
Total Cost Per Tonne Processed ($/t) | $136.87 |
Sustaining Capital per Tonne of Processed ($/t) | $44.15 |
Total Cost Per Tonne Processed ($/t) | $181.02 |
Totals may differ due to rounding
2.6 PEA – Economic Analysis
Entech prepared a conceptual cashflow and discounted cashflow derived from the life-of-mine schedule. Tax calculations for the after-tax cashflow and discounted cashflow were prepared by K92. A summary is shown in Table 2.6 and a sensitivity analysis to gold price is shown in Table 2.7.
Table 2.6: PEA – Simplified Financial Model at US$1,900/oz Au, US$4.50/lb Cu, US$25.00/oz Ag
Year | 2024 | 2025 | 2026 | 2027 | 2028 | 2029 | 2030 | 2031 | 2032 | 2033 | 2034 | 2035 | 2036 | 2037 |
Mill Throughput (ktpa) | 469 | 802 | 1,059 | 1,440 | 1,800 | 1,800 | 1,800 | 1,800 | 1,800 | 1,800 | 1,800 | 1,742 | 1,566 | 718 |
Gold Grade (g/t) | 7.45 | 6.34 | 6.12 | 6.55 | 5.98 | 4.58 | 3.59 | 4.77 | 6.59 | 4.73 | 7.29 | 6.03 | 7.53 | 10.08 |
Copper Grade (%) | 0.75 | 0.73 | 0.69 | 0.86 | 1.21 | 1.35 | 1.57 | 1.45 | 1.11 | 1.25 | 0.93 | 1.36 | 1.45 | 1.30 |
Silver Grade (g/t) | 13.93 | 13.91 | 12.89 | 16.04 | 19.76 | 24.87 | 27.90 | 26.54 | 21.20 | 22.31 | 21.35 | 27.65 | 32.09 | 31.48 |
AuEq Grade (g/t) | 8.86 | 7.71 | 7.41 | 8.16 | 8.21 | 7.10 | 6.50 | 7.48 | 8.66 | 7.06 | 9.09 | 8.59 | 10.30 | 12.60 |
Gold Produced (000s oz) | 104 | 150 | 191 | 279 | 321 | 246 | 194 | 256 | 352 | 253 | 390 | 313 | 354 | 218 |
Silver Produced (000s oz) | 164 | 280 | 342 | 579 | 892 | 1,123 | 1,259 | 1,198 | 957 | 1,007 | 964 | 1,208 | 1,260 | 567 |
Copper Produced (m lbs) | 7 | 12 | 15 | 25 | 45 | 51 | 59 | 55 | 41 | 47 | 35 | 49 | 47 | 20 |
AuEq Produced (000s oz) | 123 | 182 | 231 | 347 | 440 | 380 | 350 | 401 | 462 | 377 | 485 | 445 | 482 | 272 |
Net Revenue (US$m)(1) | $214 | $317 | $417 | $628 | $789 | $675 | $610 | $712 | $836 | $674 | $877 | $800 | $868 | $490 |
Total OPEX (US$m)(1) | $100 | $131 | $168 | $198 | $235 | $233 | $234 | $234 | $237 | $236 | $238 | $231 | $225 | $91 |
Growth Capital (US$m) | $109 | $91 | – | – | – | – | – | – | – | – | – | – | – | – |
Sustaining Capital (US$m) | $76 | $99 | $69 | $83 | $68 | $75 | $70 | $64 | $58 | $50 | $60 | $59 | $53 | $16 |
After-tax Net CF (US$m) | ($96) | ($40) | $130 | $249 | $350 | $264 | $222 | $298 | $388 | $281 | $409 | $359 | $420 | $273 |
Cumulative After-tax Net CF (US$m) | ($96) | ($136) | ($6) | $244 | $594 | $858 | $1,080 | $1,378 | $1,766 | $2,047 | $2,456 | $2,815 | $3,235 | $3,508 |
Figure 2.3 – PEA Material Movement Schedule
Figure 2.4 – PEA Production and All-in Sustaining Cost (Co-Product) Schedule
Figure 2.5 – PEA Cash Flow Projects at US$1,900/oz Au (top chart) and US$2,500/oz Au (bottom chart)
Table 2.7: PEA – After-Tax NPV5% Sensitivity to Gold Price
Gold Price | After-Tax NPV5% (US$M) |
$1,600 | $1,791 |
$1,900 | $2,295 |
$2,200 | $2,798 |
$2,500 | $3,302 |
$2,800 | $3,806 |
$3,100 | $4,309 |
Diamond Drill and Face Sampling Methodology, Data Verification and QA / QC
Diamond drill holes are first logged to determine the sampling intervals, which range from a minimum of 0.1 m to generally 1.0 m. The drill core is sawn half core cut along a reference line, with the remainder of the core returned to the core tray. Core samples are then placed in numbered calico and plastic bags, with a numbered sample ticket for dispatch to the assay laboratory. Samples are separately assayed for gold, copper and silver. K92’s procedure includes the insertion standards, blanks and duplicates. Gold assays are by the fire assay method. Copper and silver assays are by three-acid-digestion method (nitric, perchloric & hydrochloric mix).
Face channel samples under geological control, were taken across the full face of both the exposed lode system and any waste rock, with sample intervals ranging from 0.1 m to 1 m in width depending on the geologist’s interpretation. Two samples were taken per interval at waist and knee height and the corresponding widths recorded. Samples are approximately 3.5 kg in size. Samples were separately assayed for gold, copper and silver, and the results averaged out using length weighting and channel orientation before entry into the database. K92’s procedure includes the insertion standards, blanks and duplicates for the face sampling. Gold assays are by the fire assay method. Copper and silver assays are by three-acid-digestion method (nitric, perchloric & hydrochloric mix).
K92 maintains an industry-standard analytical quality assurance and quality control (QA/QC) and data verification program to monitor laboratory performance and ensure high quality assays. Results from this program confirm reliability of the assay results. All sampling and analytical work for the mine exploration program is performed by Intertek Testing Services (PNG) LTD, an independent accredited laboratory that is located on site. External check assays for QA/QC purposes are performed at SGS Australia Pty Ltd in Townsville, Queensland, Australia.
The analytical QA/QC program is currently overseen by Andrew Kohler, PGeo, Mine Geology Manager and Mine Exploration Manager for K92. Andrew Kohler, a qualified person under the meaning of Canadian National Instrument 43-101 – Standards of Disclosure for Mineral Projects.
Qualified Person
K92 Mine Chief Geologist, Mr. Andrew Kohler, P.Geo, a Qualified Person under the meaning of NI 43-101 has reviewed and approved the technical content of this news release. The Company strictly adheres to CIM Best Practices Guidelines in conducting, documenting, and reporting the exploration activities on its projects.
Simon Tear, P.Geo of H & S Consultants Pty Ltd of Sydney, Australia is a Qualified Person as defined under NI 43-101 and has reviewed and approved the contents of this press release. Mr. Tear is an independent consultant and is responsible for the 2023 Mineral Resource estimate for Kora and Judd.
Brendan Mulvihill, MAusIMM (CP Met), RPEQ of GR Engineering Services Limited of Brisbane, Australia is a Qualified Person as defined under NI 43-101 and has reviewed and approved the contents of this press release. Mr. Mulvihill is an independent consultant and is responsible for the process plant design.
Daniel Donald, B.Eng Hons (Mining) MBA FAusIMM MSME of Entech Pty Ltd of Perth, Australia is a Qualified Person as defined under NI 43-101 and has reviewed and approved the contents of this press release. Mr. Donald is an independent mining consultant and is responsible for mine planning and cost modelling. Mr. Donald completed a site visit from May 29th to 31st 2024.
Dr. Evan Kirby, of Metallurgical Management Services Pty Ltd of Perth, Australia is a Qualified Person as defined under NI 43-101 and has reviewed and approved the contents of this press release. Dr. Kirby is an independent consultant responsible for minerals processing test work, analysis of plant operating results and estimating metals recovery factors.
Isaac Ahmed, P.Eng of WSP Canada Inc. of Ontario, Canada is a Qualified Person as defined under NI 43-101 and has reviewed and approved the contents of this press release. Mr. Ahmed is an independent consultant and is responsible for the pastefill delivery and pastefill plant design.
Ralph Holding, FIEAust, CPEng, IEPNG of ATC Williams Pty Ltd of Brisbane, Australia is a Qualified Person as defined under NI 43-101 and has reviewed and approved the contents of this press release. Mr. Holding is an independent consultant and is responsible for the tailing storage facility design.
Nicholas Currey, MAusIMM of EMM Consulting Pty Ltd of Queensland, Australia is a Qualified Person as defined under NI 43-101 and has reviewed and approved the contents of this press release. Mr. Currey is an independent consultant and is responsible for environmental studies and community impact.
About K92
K92 Mining Inc. is engaged in the production of gold, copper and silver at the Kainantu Gold Mine in the Eastern Highlands province of Papua New Guinea, as well as exploration and development of mineral deposits in the immediate vicinity of the mine. The Company declared commercial production from Kainantu in February 2018, is in a strong financial position, and is working to become a Tier 1 mid-tier producer through ongoing plant expansions. K92 is operated by a team of mining company professionals with extensive international mine-building and operational experience.
First Phosphate Corp. (CSE: PHOS) (OTCQB: FRSPF) (FSE: KD0) is pl... READ MORE
Further to its news release of December 18, 2024, Canadian Gold R... READ MORE
West Red Lake Gold Mines Ltd. (TSX-V: WRLG) (OTCQB: WRLGF) is ple... READ MORE
i-80 GOLD CORP. (TSX: IAU) (NYSE American: IAUX) announces that p... READ MORE
Orion Mine Finance announced today that OMF Fund IV SPV G LLC, a ... READ MORE