The Wassa mine and oxide ore mill are located in the Wassa East District, in
the Western Region of Ghana. Golden Star Wassa Ltd. (GSWL) owns the
rights to mine the Wassa, Benso and Hwini-Butre concessions. Chifeng Jilong Gold Mining Co., Ltd., owns a 90% interest in GSWL, with the
Government of Ghana owning the remaining 10%.
The Wassa open-pit operations commenced in 2005 and the Wassa underground
mine achieved commercial production in January 2017. In early 2018, Wassa
transitioned into an underground-focused operation.
Gold mineralization at Wassa is structurally controlled and related to vein
densities and sulphide contents. The mineralization is subdivided into
several domains that each represent discontinuous segments of the main
mineralized system, and the domains include the F Shoot, B Shoot, 242, South
East, Starter, 419, Mid East and Dead Man’s Hill. Current
primary underground mining targets are the F Shoot and the B Shoot.
The underground mine design utilizes a twin decline access from the base of
the open pit, with the capacity to support a production rate of 5,000 tonnes
per day. The mining method is sublevel open-stoping using unconsolidated
waste backfill, with conversion to cemented paste backfill occurring in
2020. Mining is undertaken using trackless, diesel powered equipment
including twin boom jumbos for development and long-hole drills for
production drilling, and mined material is trucked to surface through a
combination of 17 tonne loaders and 40 tonne trucks. Ore is treated in a
carbon-in-leach (CIL) mill with a capacity of 7,400 tonnes per day.