The company embarked on a US$63 million development of Prestea Underground a few years back as part of its plan to shift production away from low-grade openpit mining and technically-tricky refractory ore processing to high-grade underground mining alongside a more reliable gold recovery process.

 

 

Its Wassa underground mine, also in Ghana, produced first ore last year and later hit the commercial milestone. Now Prestea Underground has done likewise, 15 years after it was last in commercial production, CEO Sam Coetzer said.

 

"Achieving commercial production at Prestea Underground is an important milestone in Golden Star's transformation into a high grade, margin-focused gold producer," he said.

 

The mine reached the landmark several months later than initially planned due to development issues but, now construction is complete, it can ramp up to its target of 90,000 ounces of gold a year at an all-in sustaining cost of $615 per ounce. 

 

The mine is set to boost the overall grade of operations in Ghana due to its high-grade reserve base of 490,000oz at 13.9g/t.

 

The joint openpit and underground Prestea operations are due to produce 93,000-113,000oz at a cash operating cost of $740-880/oz but, from next year, the underground mine will fend for itself with ounces from the openpit mine being drawn down in the first half of 2018.

 

Overall, Golden Star's full year production is expected to come in at 230,000-250,000oz at an AISC of $850-950/oz.