Oko West Gold Project in Guyana is an advanced stage gold development 100% owned by G Mining Ventures.
The company announced the results of the Preliminary Economic Assessment (PEA) Study for the development of the project in September 2024.
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The PEA envisaged a low-cost, large-scale, conventional open pit and underground mining operation at the property.
It is expected to produce 353,000 ounces of gold annually for 12.7 years. Initial capital cost is estimated to be $936m, including a contingency of $100m.
Environmental Impact Assessment and Social Assessment (ESIA) is expected to be submitted by the end of 2024, while the feasibility study on the gold project is planned for the first quarter of 2025.
Early works at Oko West Gold Project may start in the first half of 2025, and it is expected to enter commercial production in H1 2028.
Oko West Gold Project Location
The Oko West Gold Project is located around 100km southwest of Georgetown, the capital city of Guyana, straddling the Cuyuni-Mazaruni Mining Districts.
The property includes one Prospecting Licence (PL) issued to Reunion Gold, G Mining Ventures’s indirect 100%-owned Guyanese subsidiary. The PL includes an area of about 10,890 acres (4,407 hectares).
History
Gold was first discovered in the region in the 19th century by artisanal miners.
The British Geological Survey carried out regional field mapping and geophysical surveys in the vicinity of the project area between 1966 and 1979.
Modern exploration began in 2016 when grab samples from Crusher Hill, a primary prospect north of Oko West, reported high gold grades.
In April 2024, G Mining Ventures and Reunion Gold announced merger to create an intermediate gold producer. G Mining Ventures became the owner of Oko West Project via this transaction.
Geology and Mineralisation
The Oko West Gold Project is located within the Guiana Shield in the northeastern portion of the Amazonian Craton.
The property sits between rocks of the Barama-Mazaruni Supergroup greenstone belt to the west and a granitoid pluton to the east (the Oko pluton).
The Barama–Mazaruni Supergroup sequence is composed of mafic volcanic flows, volcaniclastics, and siliciclastic and carbonaceous sediments.
Gold mineralisation is categorised as a structurally controlled, orogenic gold mineralisation. It is found primarily within volcanoclastic, siliciclastic, and carbonaceous sediments.
Silica and carbonate alteration was also identified within the mineralised zone. It also hosts multiple sulphides such as pyrite, chalcopyrite, sphalerite disseminated within the altered rock.
Mineral Resources Estimate
Oko West Gold Project’s Measured and Indicated Mineral Resources (M&I) total 64.6 million tonnes (Mt) at an average gold grade of 2.05 grams per tonne (g/t Au) for 4.27 million contained ounces of gold.
Inferred Resources is estimated to be 19.6Mt at an average gold grade of 2.54g/t Au for 1.6 million contained ounces of gold.
The MRE is based on data from 397 diamond drill holes, 292 reverse circulation holes, and 59 trenches completed between December 2020 and January 2024.
Mining at Oko West Gold Project
According to the PEA, mining activity at Oko West Gold will involve conventional open pit mining and mechanised long hole open stoping for the underground mine.
The main open pit will be within Block 4 of the property with two smaller sub-pits towards the northern and southern extensions.
G Mining Ventures expects to recover a total of 60.7 Mt of mineralised material from the OP at an average diluted gold grade of 1.72 g/t Au.
Open pit mining operations will be carried out in four phases over 15 years, including two years of pre-production.
Underground operations will be undertaken in the main zone and two satellite zones. These zones will be accessible via a surface mine portal through the same main decline ramp.
The project will involve using long hole open stoping mining method including transverse stoping and longitudinal stoping variations.
Around 14.5Mt of mineralised material at an average diluted gold grade of 3.19 g/t Au will be recovered via underground mining over 13 years, including a two-year development period.
During the initial three years, the process feed will be supplied by the open pit operations.
Recovery and Processing
The proposed process plant for the gold project will leverage a standard metallurgical flowsheet to treat gold bearing material and produce doré.
It will be equipped to treat 6.0Mtpy of fresh rock nominally.
The plant will comprise comminution, gravity concentration, cyanide leach and adsorption via carbon-in-leach (CIL), carbon elution and gold recovery circuits.
Comminution circuit, comprising of primary gyratory crusher, SAG and ball mill, will deliver a primary grind size material of P80 of 75μm.
Gravity concentration circuit will produce a gold-rich concentrate, which will undergo intensive leaching and electrowinning for gold recovery.
A cyanide destruction circuit will treat CIL tailings before it is disposed to a tailings storage facility.
Oko West will produce gold in doré bars, which will be exported to an international refiner. The mill will run for 13 years.
Key Infrastructure and Accessibility
Oko West Gold Project can be accessed via a new the existing Puruni road. It can also be accessed via a new, category 2,850m long airstrip. This airstrip will be used for personnel, supplies, medical emergencies and exporting gold.
The project is estimated to require 37MW of power at full operation. It is planning to install a dedicated Heavy Fuel Oil fired power plant with six 9.4MW engine generating sets, providing it with 56.4MW installed capacity and 42.3MW running capacity.
During the Feasibility Study, alternative power supplies will also be studied including the feasibility of using a liquefied natural gas (LNG) power plant.
G Mining Ventures plans to harvest water from local creeks and store it in a reservoir for use in operations.
The gold project will include mine maintenance facility, wash bay, fuel storage facility, assay laboratory, waste storage and tailings facility, among others.
Contractor Involved
The PEA report was prepared by G Mining Services (GMS). The company was supported by other engineering consultants.
