Ball mill at Bogoso.

Denver, Colorado-based Golden Star Resources expects to increase its production from West Africa from 200,000 ounces of gold last year to 300,000 ounces this year and 500,000 ounces in 2007, mainly thanks to its Sulphide Expansion Project at the Bogoso/Prestea mine in Ghana. Construction and development activities for this expansion are expected to be completed towards the end of the third quarter of this year at a cost of US$125 million. The company had originally targeted to complete construction in the fourth quarter.

Current production of 1.5 million tonnes a year from the existing oxide plant will be increased to a projected total capacity of about 5 million tonnes a year from the combined oxide and sulphide plants. The new sulphide plant will utilise the Biox bio-oxidation process that is marketed by a subsidiary of Gold Fields, currently being used in eleven gold processing plants that are operating or under development worldwide. Upon completion, the Bogoso/Prestea sulphide plant will be the largest operating Biox plant in the world.

At the end of June the Fuller Traylor gyratory crusher, associated conveyors, crushed ore stockpile and reclaim system were substantially complete and dry commissioning commenced at Bogoso/Prestea. The CIL tanks were close to ready for dry commissioning and the first blower to supply air to the Biox tanks had arrived in Ghana. Two other blowers were expected to arrive in Ghana in early July, with three blowers to be delivered progressively after that.

Also by the end of June the civils work for the flotation circuit was complete and steel erection was scheduled to start in the first week in July. The Biox tanks, neutralisation tanks and associated thickeners had been erected, and of the 62 km of stainless steel welding required, approximately 72% was complete. Some 40 m3 of material containing active Biox bacteria had been delivered to site and as the activity levels of the bacteria reach satisfactory levels the process of filling the Biox tanks with inoculated sulphide material, which is expected to take three months, was to commence. Electrical and piping construction was underway, as was work on the elution circuit, gold room, laboratory, and tailings storage facility.

Pre-stripping of the sulphide pits to create a stockpile of transition and sulphide ore for the Biox plant was underway at the end of June 2006 and some 800,000 tonnes of ore is expected to be in the stockpile by the end of September this year.