Omai Gold Mines Corp. announced positive results from its first Preliminary Economic Assessment for the Wenot Project, one of the two gold deposits located on its 100%-owned Omai Property, in Guyana. The PEA supports an initial open pit mining scenario for production averaging 142,000 ounces of gold per year over a 13-year mine life, with peak year production of 184,000 ounces.

Total Wenot production is estimated at 1,840,000 ounces of payable gold. A spot gold price sensitivity of $2,200/oz supports an after-tax Net Present Value5% of $777 million, a 24.7% Internal Rate of Return (?IRR?), and a payback period of 3.5 years. The PEA is based only on the Wenot Open Pit Deposit and excludes the adjacent Gilt Creek Deposit.

Management believes that the Gilt Creek Deposit, which would require underground mining, is sufficiently attractive to be integrated into a larger mine plan, however, to accelerate and simplify this current PEA, it was excluded. On February 8, 2024, the Company announced an updated Mineral Resource Estimate (?MRE?) for the Omai Property in Guyana. It details a total Indicated MRE of 1.985 million ounces of gold averaging 2.15 g/t Au and an Inferred MRE of 2.279 million ounces averaging 2.26 g/t Au.

The PEA is based on the Wenot Deposit, with an Indicated MRE of 834,000 ounces averaging 1.48 g/t Au and an Inferred MRE of 1,614,000 ounces averaging 1.99 g/t Au. The pit design used in the PEA does not include 58,600 oz of Indicated Mineral Resources and 456,900 oz of Inferred Mineral Resources, which represents approximately 21% of the total Wenot MRE ounces. These excluded MRE ounces are either hosted within multiple, narrow veins or are isolated zones at depth that result in a high strip ratio.

However, it is expected that at least a portion of this currently excluded Mineral Resource could be incorporated in future economic scenarios upon further drilling. The Project area consists of subdued topography. The area, topography, and climate are amenable to the conventional open pit mining operations proposed for the Project, similar to historical operations.

No underground mining is planned at this stage although the potential for development of underground mining of the Gilt Creek Deposit will be evaluated in the future. The Wenot mining operations will encompass a single large open pit with 55o hard rock inter ramp slopes and 30o saprolite slopes that will be mined with conventional mining equipment in two pushback phases. In order to improve mining selectivity and reduce dilution, two different bench heights and sets of mining equipment will be used.

Mineralization will be mined using a 5 m high bench height with 150 mm diameter blast hole drills, and a fleet consisting of 5 m3 bucket excavators and 35 t rigid body haul trucks. Waste rock and saprolite will be mined on 10 m high benches using 200 mm diameter blast hole drills, 22 m3 bucket hydraulic excavators, and 177 t haul trucks. Major pieces of mining equipment will be purchased via a lease financing agreement.

Various support equipment will be required, such as dozers, graders, water trucks, and light vehicles for maintenance, personnel transport and mine supervision. The surficial saprolite cover, which is anticipated to be free digging and will not require blasting, is up to 60m thick forming the upper part of the 440 m deep open pit. The open pit mine will have a mineralization production rate that averages 9,000 tpd over a 13-year mine life.

A total of 322.3 Mt of waste rock is planned to be mined, with 2.6 Mt of mineralization in saprolite and 38.5 Mt of mineralization in fresh rock, for a total strip ratio of 7.8:1, at an average grade of 1.51 g/t Au containing 1.99 Moz Au. Total material mined will peak at 110,000 tpd. Mineralization may be delivered either to the primary crusher or placed into a nearby stockpile.

Waste rock is either taken to a waste storage facility or used in tailings dam embankment construction. An average of 9,000 tpd of gold mineralized material will be treated in the Omai process plant. The process plant will consist of a semi-autogenous grinding mill in closed circuit with a pebble crusher and ball mill in a closed circuit with cyclones.

Primary crushing will consist of a gyratory crusher for hard run-of-mine ("ROM") feed. A gravity circuit, which precedes leaching will recover coarse gold from the cyclone underflow, while the cyclone overflow is thickened and treated in a multi-tank carbon-in-leach ("CIL") or carbon-in-pulp ("CIP") circuit. Gold will be stripped from the loaded carbon, concentrated by electrowinning and recovered as gold bars in a gold room.

The Omai Gold process plant will be designed to be a compact facility with attached grinding media and reagent reception. The process plant facilities will include a laboratory, a mill maintenance workshop, and safety, personal services and management offices. The anticipated metallurgical performance for processing the Omai Mineral Resources has a dual base of verification: (i) A comprehensive test program by Lakefield Research that was completed in 1990 on drill core representing seven mineralized zones, and (ii) The processing of 80 million tonnes of mineralized material over 12 years by Omai Gold Mines Limited from the Fennel and Wenot pits as well as alluvial zones.

During operations from 1993 to 2005, the hard rock ROM feed was crushed in a gyratory crusher and ground by a combination of SAG and ball mills. Soft mineralized material was blended by a backhoe into the crushed hard rock feed. A combination of gravity-based methods including spiral, Nelson centrifuge and tabling was employed to recover free gold.

Gold leaching was conventional with a mild concentration of process reagents, air-sparged leaching followed by CIP gold recovery, stripping from the carbon, electrowinning and electric furnace refining. The historical gold recovery ranged from 92% to 94%. Metallurgical testing at Lakefield included grinding tests indicating that the Bond Work Index was very high for the hard-rock composites at 19 to 25 KWh/t. As anticipated, the Work Index was very low (6 KWh/t) for saprolite.

Gravity concentration was examined for diorite and saprolite composites and a substantial proportion of gold (30%) was recovered. A series of standard, 48-hour leach tests were performed on each composite, with the effect of pre-grinding of the samples to up to 90% passing -200 mesh. The results indicated a high gold extraction, from 92% to 97% on the hard rock samples, with only a small effect due to grind size.

Carbon-in-pulp (CIP) testing, representing the recovery of the extracted gold liberated as a process reagent-complex in leaching, was also tested. The recovery of gold to carbon was high for all composites. Flocculation and thickening tests indicated that reasonable performance could be anticipated in pre-leach thickening which is a key parameter when processing soft, saprolitic feeds.