G Mining Ventures Delivers Robust Feasibility Study For High-Grade Oko West Gold Project in Guyana
April 28, 2025
G Mining Ventures Delivers Robust Feasibility Study For High-Grade Oko West Gold Project in Guyana
- After-tax NPV5% of $2.2 billion, IRR of 27% and payback of 2.9 years at $2,500/oz base case gold price (long-term consensus)
- After-tax NPV5% of $3.2 billion, IRR of 35% and payback of 2.1 years at $3,000/oz gold price Average annual gold production of 350,000 ounces at an AISC of $1,123/oz for 12.3 years
• Initial capital cost of $972 million and sustaining capital of $650 million over the life of mine •
- Early works construction progressing well after receipt of Interim Environmental Permit
- Final Environmental Permit expected in Q2-25, targeting construction decision in H2-25
- An average of 1,270 direct permanent jobs to be created from the Oko West Project
BROSSARD, QC, April 28, 2025 – G Mining Ventures Corp. (“GMIN” or the “Corporation”) (TSX: GMIN, OTCQX: GMINF) is pleased to announce the results of its Feasibility Study (the “FS” or the “Study”) for the development of its wholly-owned Oko West Gold Project (“Oko West” or the “Project”), located in Region 7, Guyana. Unless otherwise stated, all dollar amounts in this news release are expressed in U.S. dollars. The FS confirms robust economics for a low-cost, large-scale, conventional open pit (“OP”) and underground (“UG”) mining and milling operation, with industry-leading operating costs and high rate of return. The Study outlines total gold production of 4.3 million gold ounces (“Au oz”) over 12.3 years, resulting in an average annual gold production profile of 350,000 ounces with an All-In-Sustaining Cost (“AISC”) per ounce of $1,123. The Project after-tax net present value (“NPV”) (5% discount rate) is $2.2 billion with an after-tax internal rate of return (“IRR”) of 27% at a gold price of $2,500 per ounce.
Final environmental permits are expected in Q2-25, with a targeted construction decision in H2-25. The Project is ideally sequenced to leverage the strong macroeconomic conditions including a strong gold price, lower inflation, and Guyana’s rapidly developing economy.
“The Oko West Feasibility Study marks a major milestone in realizing the value of what we consider one of the world’s most exciting undeveloped gold projects. It confirms a long-life, high-margin operation with strong economics, supported by a proven resource and solid infrastructure,” commented Louis-Pierre Gignac, President & Chief Executive Officer. “With Tocantinzinho nearing nameplate capacity and generating meaningful free cash flow, GMIN is well positioned to advance Oko West using the same experienced team and disciplined execution that delivered our first mine ahead of schedule and on budget. We remain committed to responsible development and look forward to deepening our partnership with the Government of Guyana and local communities as we advance Oko West as our second cornerstone asset.”
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Table 1: Oko West Feasibility Study Highlights
| Description | Units | FS | PEA | Δ (%) | |||
|---|---|---|---|---|---|---|---|
| Production Data | |||||||
| OP Mill Feed Tonnage | Mt Mt | 62 | 61 15 | +2% (5%) | |||
| UG Mill Feed Tonnage | 14 | ||||||
| Total Mineralized Material Mined | Mt | 77 | 75 | +2% | |||
| Total Waste Mined (OP and UG) | Mt | 429 | 367 | +17% | |||
| Total Tonnage Mined (OP and UG) | Mt | 506 | 443 | +14% | |||
| Strip Ratio | waste: ore | 6.8 | 6.0 | +14% | |||
| Average Milling Throughput | Mtpa tpd | 6.2 | 6.0 16,110 | +3% | |||
| Average Milling Throughput | 16,911 | ||||||
| Gold Head Grade | g/t | 1.89 | 2.00 | (6%) | |||
| OP Head Grade | g/t g/t | 1.57 | 1.72 3.19 | (9%) +2% | |||
| UG Head Grade | 3.26 | ||||||
| Contained Gold | koz | 4,642 | 4,848 | (4%) | |||
| Average Recovery | % | 93.5% | 92.8% | +1% | |||
| Total Gold Production | koz years oz | 4,340 | 4,500 12.7 353,000 | (4%) (3%) (1%) | |||
| Mine Life | 12.3 | ||||||
| Average Annual Gold Production | 350,000 | ||||||
| Operating Costs (Average LOM) | |||||||
| Total Site Costs | USD/oz USD/oz | $798 | $728 $126 | +10% +27% | |||
| Government Royalties (6.4%)* | $160 | ||||||
| Total Operating Cost* | USD/oz | $958 | $853 | +12% | |||
| All-In Sustaining Costs* | USD/oz | $1,123 | $986 | +14% | |||
| Capital Costs | |||||||
| Total Upfront Capital Cost | USD M | $972 | $936 | +4% | |||
| Initial UG Capital Costs (Sustaining Capital) | USD M USD M | $68 | $124 $413 | (45%) +41% | |||
| OP and UG Sustaining Capital | $582 | ||||||
| Life of Mine Sustaining Capital | USD M USD M | $650 | $537 $37 | +21% +5% | |||
| Closure Costs | $39 | ||||||
| Total Capital Costs | USD M | $1,661 | $1,510 | +10% | |||
| Financial Evaluation | |||||||
| Gold Price Assumption | USD/oz USD M % Years | $2,500 | $1,950 $1,367 21% 3.8 | ||||
| After-Tax NPV 5% | $2,163 | ||||||
| After-Tax IRR | 27% | ||||||
| Payback | 2.9 |
*Note: Assumes $2,500 per ounce base case gold price for calculating Government Royalty ($160 per ounce), which impacts Total Operating Costs and AISC in FS evaluation. PEA assumed a $1,950 base case gold price for the calculation ($126 per ounce).
Government Royalty rate has not changed.
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Figure 1: Average Annual Gold Production and Operating Costs
700 $1,400
| 433 | ||||||||||||
| 312 | 317 | 303 | 325 | 354 | 353 | 352 | 368 | 380 | 386 | 334 | ||
| 93 |
600 $1,200
500 $1,000
400 $800
300 $600
200 $400
100 $200
- - Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Gold Recovered Total Cash Cost AISC
Table 2: Sensitivity Analysis
| Downside | Base | Upside | |||||
|---|---|---|---|---|---|---|---|
| Scenario | Case | Case | Case | ||||
| Gold Price USD/oz After Tax NPV 5% USD M Payback Years | $2,000 $1,155 4.4 Years | $2,500 | $3,000 $3,169 2.1 Years | ||||
| $2,163 | |||||||
| 2.9 Years | |||||||
| After-Tax IRR % | 18% | 27% | 35% | ||||
| Average Annual EBITDA USD M Average Annual Free Cash Flow USD M | $375 $265 | $538 | $702 $511 | ||||
| $388 | |||||||
| LOM EBITDA USD M LOM Free Cash Flow USD M | $4,606 $3,253 | $6,622 | $8,638 $6,281 | ||||
| $4,767 |
Note: Average annual figures represent the 12.3-year operating period.
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Table 3: Sensitivity Analysis cont'd
| After Tax | Average Annual | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Gold Price | NPV 5% | IRR | Payback | EBITDA | FCF | ||||||
| (USD/oz) | (USD M) | (%) | (years) | (USD M) | (USD M) | ||||||
| $1,400 $1,600 $1,800 | ($86) $337 $748 | 4% 9% 14% | 9.9 7.6 5.7 | $178 $243 $309 | $117 $166 $215 | ||||||
| $2,000 | $1,155 | 18% | 4.4 | $375 | $265 | ||||||
| $2,200 $2,400 | $1,558 $1,961 | 22% 25% | 3.7 3.1 | $440 $506 | $314 $363 | ||||||
| $2,500 | $2,163 | 27% | 2.9 | $538 | $388 | ||||||
| $2,600 $2,800 | $2,364 $2,767 | 29% 32% | 2.7 2.3 | $571 $637 | $412 $461 | ||||||
| $3,000 | $3,169 | 35% | 2.1 | $702 | $511 | ||||||
| $3,200 $3,400 $3,600 $3,800 $4,000 | $3,571 $3,974 $4,376 $4,778 $5,181 | 38% 40% 43% 45% 48% | 1.9 1.7 1.6 1.5 1.4 | $768 $833 $899 $965 $1,030 | $560 $609 $658 $708 $757 |
Note: Average annual figures represent the 12.3-year operating period.
FS Summary
The Corporation retained G Mining Services Inc. (“GMS”) as lead consultants, along with other engineering consultants, to complete the Study and prepare a technical report in compliance with National Instrument 43-101 Standards of Disclosure for Mineral Projects (“NI 43-101”).
The Study is derived using the Corporation’s mineral resource estimate effective as at September 15, 2024 (the “MRE”). The effective date of the FS is April 28, 2025, and a NI 43-101 compliant technical report will be filed on the Corporation’s website and under its SEDAR+ profile within 45 days of this news release.
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Property Description, Location and Access
Guyana is a mining friendly country with active gold and bauxite mines. Oko West is an advanced-stage gold development project, which straddles the Cuyuni-Mazaruni Mining Districts (administrative Region 7) in north central Guyana, South America. The Project is located approximately 120 kilometres (“km”) southwest of Georgetown, the capital city of Guyana and approximately 50 km west of Bartica, the capital city of Region 7 (Figure 2). Bartica is a small town with approximately 17,000 people and is known as the gateway to the country’s interior and its gold mining regions.
The Project can be accessed via numerous methods: helicopter direct from Ogle airport to the site, fixedwing plane from Ogle airport to Bartica airstrip, by car and then speedboat, or by four-wheel drive vehicle. An air strip on site will be built to service the Project. From the town of Itaballi at the confluence of the Cuyuni and Mazaruni rivers, one can use the Puruni or the Aremu laterite roads, using four-wheel drive vehicles. Bartica is accessible by a 20-minute direct flight from the Ogle airport in Georgetown or by road and boat from Parika on the Essequibo River. There are regular boat services between Bartica and Parika. The climate is equatorial and humid. The Project operated throughout the year without any interruptions related to the weather. The total surface area of the property is 71 km2.
Figure 2: Project Location Map
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Updated Mineral Resource Estimate
Indicated mineral resources total 80.3 million tonnes (“Mt”) at an average gold grade of 2.10 grams per tonne (“g/t Au”) for 5.4 million contained ounces of gold (“Moz Au”). Gold contained in the indicated category represents 93% of the global resource. Inferred resources total 5.1 Mt at an average gold grade of 2.36 g/t Au, for 0.4 Moz Au.
The MRE considers 544 diamond drill holes (including 39 wedged holes), 366 reverse circulation holes, and 59 trenches completed between December 2020 and September 2024. A total of 45,700m has been drilled since the PEA for conversion of inferred mineral resources.
Approximately 90% of the inferred resources have been converted into indicated resources within the pit and about 70% of the underground inferred mineral resources. The remaining underground material will be drilled from underground. This high conversion rate increases confidence in the resource estimation.
Table 4: Mineral Resource Estimate
| Category | Tonnes (Mt) | Gold Grade (g/t Au) | Contained Gold (koz) | |
|---|---|---|---|---|
| Open Pit Resource | ||||
| Indicated | 73.0 | 2.00 | 4,689 | |
| Inferred | 1.5 | 1.06 | 52 | |
| Underground Resource | ||||
| Indicated | 7.2 | 3.09 | 718 | |
| Inferred | 3.6 | 2.93 | 337 | |
| Total Resource | ||||
| Indicated | 80.3 | 2.10 | 5,407 | |
| Inferred | 5.1 | 2.36 | 390 | |
| These Mineral Resources are not Mineral Reserves as they have not demonstrated economic viability. All figures are rounded to reflect the relative accuracy of the estimates. The Mineral Resources described above have been prepared in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum (“CIM”) Standards (2014) and follow Best Practices outlined by the CIM (2019). The qualified person for the estimate is Christian Beaulieu, P. Geo. (OGQ#1072), Consulting geologist for GMS. The estimate has an effective date of September 15, 2024. The lower cut-offs used to report open pit Mineral Resources, constrained by an open pit optimization shell, are 0.30 g/t Au in saprolite and alluvium/colluvium, 0.34 g/t Au in transition, and 0.38 g/t Au in rock. Underground Mineral Resources are reported inside potentially mineable volume and include below cut-off material (stope optimization cut-off grade of 1.35 g/t Au). The cut-off grades are based on a gold price of US$1,950 per troy ounce and show , 94.5%, 93.3% and 93.9% processing recoveries for saprolite and alluvium/colluvium, transition and rock, respectively. |
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Initial Mineral Reserve Estimate
The Project mine plan is based on Probable Mineral Reserves of 76.6 Mt at an average gold grade of 1.89 g/t Au for 4.64 Moz Au.
Table 5: Mineral Reserve Estimate
| Category | Tonnes | Gold Grade | Contained Gold (koz) | |||
|---|---|---|---|---|---|---|
| (Mt) | (g/t Au) | |||||
| Open Pit Reserves | ||||||
| Probable | 62.4 | 1.57 | 3,156 | |||
| Underground Reserves | ||||||
| Probable | 14.2 | 3.26 | 1,486 | |||
| Total Reserves | ||||||
| Probable | 76.6 | 1.89 | 4,642 | |||
| The Mineral Reserves were estimated using the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) Estimation of Mineral Resources & Mineral Reserves Best Practice Guidelines (Nov 29th, 2019) and CIM Definition Standards for Mineral Resources and Reserves, (May 10th, 2014). The mine design and Mineral Reserve estimate have been completed to a level appropriate for feasibility studies. As such, the Mineral Reserves are based on the Measured and Indicated Mineral Resources and do not include any Inferred Mineral Resources. The Inferred Mineral Resources contained within the mine design are classified as waste. Mineral Reserves are estimated using a long-term gold price of 1,800 $/oz USD. The qualified person for the estimate is Alexandre Burelle, P. Eng. (OIQ#5019855), Mine planning and financial analysis consultant. The estimate has an effective date of April 2, 2025. Mineral Reserves for Open Pit are estimated at a cut-off grade of 0.41, 0.37, and 0.33 g/t Au for Rock, Transition, and Saprolite respectively. The Open Pit Strip Ratio is 6.83:1 and Dilution factor is 14 %. Mineral Reserves for Underground Mine are estimated at a cut-off grade of 1.70 g/t Au. The underground mine dilution factor is 10% including 4% for the backfill. For the underground a minimum mining width of 5 m was used. The numbers may not sum due to rounding; rounding followed the recommendations in NI 43-101. The mine design and Mineral Reserve estimate have been completed to a level appropriate for feasibility studies. The Mineral Reserve estimate stated herein is consistent with the CIM definitions and is suitable for public reporting. |
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Production Profile
The FS outlined an average annual gold production profile of 350,000 oz Au over the 12.3-year mine life. Total gold production is 4.34 Moz Au with an average gold grade milled of 1.89 g/t Au, and an average metallurgical recovery of 93.5%.
Figure 3: Gold Production Profile
3.00
2.40 500 2.50 2.14 2.04 2.03 2.03 1.96 1.96 1.95 1.80 1.78 400 2.00 1.54 1.49 1.50 300 1.50
200 1.00
380 386 354 353 352 317 325 312 303
100 0.50
- - Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Gold Recovered Grade Milled
During the initial three years of commercial production, the processing feed will solely be supplied by the open pit. Starting in the fourth year of production, underground mining begins to contribute to processing feed, and the UG operation is expected to achieve targeted production rates of 4,500 tonnes per day (“tpd”) by the sixth year. Over the LOM, UG ore represents 32% of total gold recovered.
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Figure 4: Gold Production Profile by Feed Source
600 3.00
2.40 500 2.50 2.14 2.03 2.03 2.04 1.96 1.96 1.95 1.80 1.78 400 2.00 1.54 1.49 1.50 164 -
- 153
300 1.50 6 56 122 164
200 1.00
312 317 297 269 269 232 233
100 204 216 190 0.50
178 165
- - Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13
Open Pit Gold Recovered Underground Gold Recovered Grade Milled
LOM open pit average annual gold production totals 238,000 oz Au with an average grade of 1.57g/t Au, while LOM underground average annual gold production totals 112,000 oz Au with an average grade of 3.26 g/t Au.
Table 6: Gold Production by Mill Feed Type
| Open Pit | Underground | Total OP + UG | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Material | Grade | Contained | Material | Grade | Contained | Contained | Gold | |||||||||
| Milled | Milled | Gold | Milled | Milled | Gold | Gold | Recovery | Recovered | ||||||||
| Year | (kt) | (g/t) | (koz) | (kt) | (g/t) | (koz) | (koz) | (%) | (koz) | |||||||
| Year 1 | 6,741 | 1.54 | 335 | - | - | - | 335 | 93% | 312 | |||||||
| Year 2 | 7,000 | 1.49 | 336 | - | - | - | 336 | 94% | 317 | |||||||
| Year 3 | 6,616 | 1.48 | 316 | 71 | 2.85 | 7 | 322 | 94% | 303 | |||||||
| Year 4 | 5,327 | 1.67 | 286 | 673 | 2.79 | 60 | 347 | 94% | 325 | |||||||
| Year 5 | 4,748 | 1.62 | 247 | 1,269 | 3.23 | 132 | 379 | 94% | 354 | |||||||
| Year 6 | 4,213 | 1.40 | 189 | 1,787 | 3.29 | 189 | 378 | 93% | 353 | |||||||
| Year 7 | 4,289 | 1.47 | 202 | 1,711 | 3.16 | 174 | 376 | 93% | 352 | |||||||
| Year 8 | 4,316 | 1.56 | 217 | 1,723 | 3.20 | 177 | 394 | 93% | 368 | |||||||
| Year 9 | 4,519 | 1.58 | 230 | 1,711 | 3.22 | 177 | 407 | 93% | 380 | |||||||
| Year 10 | 4,309 | 2.06 | 286 | 1,691 | 3.26 | 177 | 463 | 94% | 433 | |||||||
| Year 11 | 4,405 | 1.75 | 248 | 1,595 | 3.21 | 165 | 413 | 93% | 386 | |||||||
| Year 12 | 3,887 | 1.41 | 176 | 1,570 | 3.62 | 183 | 358 | 93% | 334 | |||||||
| Year 13 | 1,360 | 1.22 | 53 | 380 | 3.77 | 46 | 100 | 93% | 93 | |||||||
| Total | 61,730 | 1.57 | 3,121 | 14,181 | 3.26 | 1,486 | 4,607 | 94% | 4,310 |
Note: Excludes mill feed during pre-production period.
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Mining
The Project is planned as a mining operation that integrates both conventional open pit mining and mechanized long hole open stoping for the underground mine. Combined, a total of 76.6 Mt of ore will be mined at an average diluted gold grade of 1.89 g/t Au.
Figure 5: Open-Pit and Underground Mine Development Plan
The main OP is centered on Block 4 with one smaller sub-pit positioned on a southern extension to the main pit. A total of 62.4 Mt of ore will be mined from the OP at an average diluted gold grade of 1.57 g/t Au, representing 81% of total mill feed. Approximately 0.6 Mt of this material will be milled during the preproduction period. A total of 426.2 Mt of combined waste and overburden will be extracted, resulting in a strip ratio of 6.8. The OP operation will be executed with an owner-operated mining fleet using four mining phases over a period of 15 years, which includes just over two years of pre-production. Open pit mining will utilize a fleet of 22 m³ hydraulic excavators paired with 139-tonne haul trucks as the primary production equipment.
Figure 6: Annual Open Pit Mine Production
60 3.00
50 2.50 44 44 44 44 44 43
40 2.00 2.10 30 1.50 1.66 1.62 1.60 18 1.41 1.47 1.57 1.60 1.51 1.54 1.48 1.51 1.31 1.22 20 1.00
0.94 10 0.50
-- - (Yr 3) (Yr 2) (Yr 1)
- Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Ore Tonnage Waste Tonnage Grade Mined
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The UG operation will take place in two zones: the main zone, located directly under the main open pit, and one satellite zone, both accessible from a surface mine portal through the same decline ramp. To enhance operational flexibility and meet the targeted production levels, the zones will be segmented into multiple mining horizons, enabling concurrent development and production activities across several horizons. The long hole open stoping mining method will be used, including transverse stoping and longitudinal stoping variations. The average UG production rate is expected to be 4,500 tpd of ore, with 4,000 tpd and 500 tpd from stope production and lateral development, respectively. A total of 14.2 Mt of ore is expected to be mined at an average diluted gold grade of 3.26 g/t Au, representing 19% of total mill feed. The UG mine is expected to be in production for 12 years, including a two-year development period. The initial 2 years of construction and development will use owner-operated mining supported by contract mining initially. The primary production equipment for UG mining will include a fleet of 21-tonne load-haul-dump (LHD) units and 63-tonne haul trucks.
Figure 7: Annual Underground Mine Production
5.0 5.00
3.77 3.62 4.0 4.00 3.29 3.26 3.23 3.16 3.20 3.22 3.21 2.85 2.79 3.0 3.00
2.2 2.0 1.9 1.8 1.8 1.7 2.0 2.00 1.6 1.6 1.3
0.8 1.0 1.00 0.3 0.4
-- -- Yr 1 Yr 2 Yr 3 Yr 4 Yr 5 Yr 6 Yr 7 Yr 8 Yr 9 Yr 10 Yr 11 Yr 12 Yr 13 Stope Tonnage Development Tonnage Grade Mined
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Processing and Recovery
The proposed process plant design for Oko West is based on a standard metallurgical flowsheet to treat gold bearing material and produce doré. The process plant is designed to nominally treat 6.0 million tonnes per annum (“Mtpa”) of rock and will consist of comminution, gravity concentration, cyanide leach and adsorption via CIP, carbon elution and gold recovery circuits. CIP tailings will be treated in a cyanide destruction circuit and pumped to a tailings storage facility.
The nominal milling rate will be initially set at 7.0 Mtpa to treat a blend of hard rock, saprolite and transition ores during the open pit operational period. The ramp-up period is five months, and the mill will operate for 12.3 years.
Figure 8: Process Flowsheet
Table 7: Metallurgical Recoveries
| Feed | Total | Mill | |||||
|---|---|---|---|---|---|---|---|
| Grade | Recovery | Feed | |||||
| Feed Material | (g/t Au) | (%) | (%) | ||||
| Saprolite | 1.28 | 95% | 10% | ||||
| Transition | 1.43 | 92% | 5% | ||||
| Rock – Open Pit | 1.63 | 94% | 67% | ||||
| Rock - Underground | 3.26 | 93% | 19% | ||||
| Total LOM | 1.89 | 93% | 100% |
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