West African Resources Building Sanbrado Mine in Burkina Faso
Average annual production over the first five years of Sanbrado mine life is estimated at 217,000 oz per year (oz/y) of gold. Life-of-mine production is estimated at an average of 153,000 oz/y over the current projected 10-year mine life. Preproduction capital costs are estimated at $186 million. Probable gold reserves currently stand at 1.7 million oz in 21.6 million metric tons (mt) at a grade of 2.4 grams (g)/mt.
West African Resources Managing Director Richard Hyde said, “The optimized feasibility study confirms that Sanbrado is a high-margin gold project, producing 217,000 oz/y of at all-in sustaining costs of $563/oz over the first five years of mine life. “Recent deep high-grade intercepts demonstrate the potential to extend reserves and increase annual production post-year six with additional infill and extensional drilling.” Sanbrado’s underground high-grade gold mineralization is associated with quartz vein and veinlet arrays, silica, sulphide- and carbonate-albite, and tourmaline- biotite alteration. Gold is visible and is mainly associated with minor pyrite, chalcopyrite, and arsenopyrite disseminations and stringers.
The currently defined economic mineralization is sub-vertical, with a strike length of up to 120 m and widths of up to 50 m over two discrete lenses. It remains open at depth. The underground mine will be developed using conventional two-boom jumbos capable of face advance and installation of ground support. Access will be by decline, starting from a box-cut and portal to the immediate south-west of the M1 South open pit.
Underground mining will be by longhole open stoping, progressing upwards from the base of each lift. Stope filling uses a combination of cemented aggregate fill, cemented rock fill, and development waste rock, depending on whether or not fill needs to be exposed to mine adjacent stopes. The deposit has been divided into four lifts, each of four or five levels. Within these lifts, stoping progresses upward from the base of the lift. The final level in each lift is mined as a pillar recovery beneath the lift above, or the open pit in the case of lift 1. The crown between the underground mine and the open pit will be mined after the completion other stopes.
A level interval of 25 m was chosen to fit with the geotechnical conditions and variable geometry of the orebody, as well as to ensure maximum recovery of what is a valuable resource. West African Resources is 90% owner and operator of the Sanbrado project. The government of Burkina Faso has a 10% free-carried interest.