Orezone Gold Corporation is pleased to announce positive metallurgical test results from its ongoing feasibility work at its 100%-owned Bomboré Gold Project in Burkina Faso.
The Heap Leach (HL) column test results indicate that overall gold recoveries can be increased from 79% to 87% and potentially eliminate any requirement for cement agglomeration with the addition of an agitated leaching circuit (ALC) to treat 50-65% of the oxide ores. With the addition of an upfront scrubber and screen, a fine fraction (-212 microns) can be easily separated and sent directly to the ALC without grinding to yield gold recoveries of 87-92% depending on the leach residence time. The remaining coarse fraction exhibits excellent compaction and permeability results and would go directly to the HL pad to be stacked to a height of 64 m without agglomeration or interlift liners. Recoveries for the HL coarse fraction are estimated to be 82-88% based on the preliminary test work conducted by Kappes, Cassiday & Associates in Reno, Nevada.
Highlights of the Hybrid Circuit
- Significantly improved percolation and compaction yielding HL recoveries between 82-88%
- Preliminary ALC residence tests indicate at least 87% recovery with a short 12 hour leach cycle
- The agglomerator and interlift liners are removed from the HL circuit
- Lower HL reagent costs, sustaining capital and reduced labor requirements
- Low solution to ore ratio for the HL indicating a more rapid leach cycle
- Maximum HL crush size has increased from 15 mm to 37 mm without reduction in recovery
- The coarse ore potentially provides excellent overliner material to reduce leach pad costs
- The ALC circuit will include scrubber/screen, screw classifiers, leach tanks and thickener
- Reduction in working capital with approximately 50% of the gold recovered sooner in the ALC
- The ALC will lower production risks by removing the fine soft oxide material from the HL circuit that would otherwise require high cement agglomeration
- Comprised of two simple circuits that can be designed with extra capacity for expansion
The reduction in cement consumption will offset the cost of the additional power requirement for the ALC. Tailings storage of the fine fraction is envisioned to be in a separate facility for the first two years then nested within the HL pad thereafter. The ongoing test work and design modifications will continue in parallel with the 21,000 m infill drill program. The Company plans to complete a feasibility study (FS) based on the Hybrid design and apply for a mining permit by year-end. An updated resource model and mine plan will follow the FS in Q1 2015.
"This hybrid design combines two simple circuits to reduce risk, improve recoveries and allow for immediate expansion," stated Tim Miller, COO for Orezone. "Our goal is to maintain the robust returns estimated in the recent economic assessment of the project by offsetting any increased capital costs by the significantly improved recoveries and gold output."
About Orezone Gold Corporation
Orezone is a Canadian company with a gold discovery track record of +12 Moz and recent mine development experience in Burkina Faso, West Africa. The Company owns a 100% interest in Bomboré, the largest undeveloped oxide gold deposit in West Africa which is situated 85 km east of the capital city, adjacent to an international highway. The Company is continuing with various technical studies in order to be in a position to complete a full feasibility study and an application for a mining permit before year-end.
Carl Defilippi of Kappes Cassiday & Associates; and Tim Miller, COO, Pascal Marquis, SVP Exploration and Ron Little, CEO of Orezone, are Qualified Persons under National Instrument 43‐101 and have reviewed the information in this release.