|Free gold visible in a Yaramoko core sample.|
Roxgold Inc. received the exploitation permit for its Yaramoko gold project in Burkina Faso in late January and was expecting to begin initial site work shortly thereafter. The exploitation permit was finalized through endorsement of a Mining Decree by the president of Burkina Faso and other governmental authorities. The decree formally grants Roxgold the rights to develop and operate the Yaramoko project.
The Yaramoko project is located in the Houndé greenstone region of Burkina Faso, approximately 200 km southwest of the capital city of Ouagadougou. The property is directly south of and contiguous to Semafo’s Mana gold mine property.
Roxgold released the results of the Yaramoko feasibility study in April 2014. Probable mineral reserves stand at just under 2 million metric tons (mt), grading 11.8 g/mt gold and containing 759,000 oz of gold. The feasibility study envisions an underground mining operation producing an average of 99,500 oz/y of gold over an initial mine life of 7.4 years.
Pre-production capital costs are estimated at $106.5 million. Average all-in sustaining costs are estimated at $590/oz.
The upper levels of the Yaramoko mine will be accessed through two spiral declines. At the 5072 level, approximately 240 m below surface, the double decline access ends, and a single decline progresses from this level to the 4884 level, 430 m below surface. Twenty-four levels of lateral development designed to openup multiple working faces and allow operating flexibility are incorporated into the mine plan.
Mining will be based on long-hole retreat mining on close-spaced sublevels, with cemented rock backfill used to eliminate nonrecoverable pillars, maximizing mining recovery to 96%. The feasibility study assumes initial contractor mining, with engineering and grade control provided by Roxgold. Owner mining is assumed after approximately five years of operation.
The mine plan is based on a 4.9-g/mt gold cutoff at a minimum mining width of 1.6 m. A 750-mt/d extraction rate is planned. The typical stope has a 25-m strike length, a vertical height of 34 m, and full-vein width. The average vein width before dilution is 4 m.
The processing facility will be sized for 750-mt/d throughput. The flowsheet includes single-stage jaw crushing, SAG milling, gravity recovery, leaching and adsorption circuits, gold recovery, and thickening. Average recoveries are assumed to be 96.9% based on three rounds of metallurgical test work. Material milled is estimated to be of moderate hardness with a Bond Ball Work Index of 18 kWh/mt.
The plant will be amenable to expansion at minimum additional investment in the event that extraction under the current mine plan is higher than forecast or additional sources of ore feed are developed.