Dukwe progress in Botswana

African Copper has received the initial capital cost estimates for an underground mine and flotation concentrator on its Dukwe Copper project in Botswana from Project Managers Read Swatman & Voight, with Senet producing all the process plant designs. A total of approximately $37 million is estimated in direct costs to construct a 350 t/h three-stage crushing circuit feeding a standard ball mill and sequential sulphide and oxide flotation circuits. Excess tailings will be filtered and dry stacked, and allowance has been made for a paste backfill plant. The mill is rated for a 3,000-t/d throughput, but all designs have been made to allow for an expansion in the future.

The underground mine design is for a twin ramp system. The linear nature of the Dukwe copper deposit is amenable to conveyor haulage from the deeper parts of the deposit. One ramp will house the conveyor system, and the sister ramp will be for men and materials. In the initial years of the mine, it is envisaged that supergene material will be hauled to surface by truck from above the 125 m level. Final underground mine design and related capital costs will be completed after the current delineation drilling programme has determined the geometry and distribution of copper in the deposit.

Detailed operating cost estimates are currently being prepared but initial estimates show crushing, grinding and flotation costs of some $10/t and general and administration costs of about $5/t. Mine operating costs will become available upon finalization of the underground mine design. African Copper is targeting initial underground production of approximately 50 Mlb/y of copper in concentrate.

Locked cycle metallurgical tests from the sulphide material have shown recoveries between 88% and 93% creating marketable concentrates containing 27% to 30% copper. The environmental, archaeological and water permitting processes have been initiated with permits expected shortly.