The Enchi Gold Project PEA considers a conventional heap leach processing route for oxide and saprolite mineralization from three deposits, supported only by conceptual design due to an absence of direct test work.
Report context
The technical report and preliminary economic assessment (PEA) for the Enchi Gold Project was prepared by WSP Canada Inc. for Pinecrest Resources Ltd. The report date is not stated in the supplied evidence. The process facility has been designed to process oxide or saprolite mineralization from the Boin, Nyamebekyere, and Sewum deposits.
Processing route
Overview and basis
Due to the lack of test work for direct heap leach amenability, only a conceptual design has been studied for the purpose of the PEA. The process route selected is a conventional heap leaching facility. The design is similar to existing and operating heap leach mines processing similar material under comparable conditions. The heap leach pads and recovery plant will operate year-round while crushing, agglomeration and stacking will be shut down during wet weather periods.
Crushing and agglomeration
During regular operations (300 d/a), run-of-mine (ROM) material will be delivered by haul trucks from the open pits to a pile adjacent to the primary crusher. A loader will feed a hopper and an apron feeder will draw the material to a twin shaft mineral sizer at a feed rate of approximately 550 t/h. The average crushing plant availability will be 75% during regular operations. The primary crusher product will have an average particle size P80 of 100 to 150 mm and will be transferred by conveyor to the secondary crusher feed screen. The screen feed conveyor will be equipped with a belt scale and magnet to remove any tramp metal. The screen will have a deck aperture of 40 mm. The secondary crusher will reduce the average particle size to a final P80 of 25 mm, suitable for agglomeration with cement as a binding agent, water for wetting the product to 10% moisture, lime for pH control and sodium cyanide solution.
Stacking and leaching
The agglomerate will be transported and stacked onto the heap leach pads through a series of moveable conveyors. A dilute process solution containing cyanide will be applied in counter-current two stage application to the pads through a drip or wobbler irrigation system.
Gold recovery
The resultant pregnant leach solution (PLS) will flow through the collection system and be stored in the PLS pond. The PLS will be pumped to an adsorption-desorption-recovery (ADR) plant for gold recovery. The gold will be adsorbed onto activated carbon granules, then periodically stripped from the carbon using a Zadra type desorption process. The gold will then be plated onto steel wool cathodes in an electrowinning cell, removed by pressure washing, filtered, dried and then smelted to produce doré bullion.
Key reported parameters
| Parameter | Value | Basis |
|---|---|---|
| Design throughput rate | 3 Mt/a (10,000 t/d) | Conceptual design |
| Overall gold recovery | 75% | Conceptual design |
| Annual gold production (doré) | Approximately 65,000 troy oz/year | Conceptual design |
| Primary crusher feed rate | Approximately 550 t/h | Conceptual design |
| Primary crusher product P80 | 100 to 150 mm | Conceptual design |
| Secondary crusher product P80 | 25 mm | Conceptual design |
| Screen deck aperture | 40 mm | Conceptual design |
| Agglomeration moisture target | 10% | Conceptual design |
| Crushing plant availability | 75% (300 d/a) | Conceptual design |
| Operating days for crushing, agglomeration, stacking | 300 d/a | Conceptual design |
| Heap leach pads and recovery plant operation | Year-round | Conceptual design |
Project website: https://newcoregold.com/enchi-project/enchi-overview/
Technical qualifications
The report explicitly states that due to the lack of test work for direct heap leach amenability, only a conceptual design has been studied for the purpose of the PEA. The design is based on similarity to existing and operating heap leach mines processing similar material under comparable conditions, rather than on project-specific test work results.
Source: Technical Report and Preliminary Economic Assessment on the Enchi Gold Project, WSP Canada Inc., No 141-20688-00_RPT-01_R1, Pinecrest Resources Ltd., Section 17 Recovery Methods.
