Golden Star Achieves Commercial Production at Wassa Underground

The Wassa portal for the main decline is 5.8 m high x 5.2 m wide. (Photo: Golden Star Resources)
Golden Star Resources reported in early January that it has achieved commercial production at the “Wassa Underground” gold mine it has developed below its Wassa open pit in southwest Ghana. Construction of the underground mine began in mid-2015 and is now essentially complete, on time and on budget.

Wassa Underground production will continue to ramp up during 2017 as mining operations begin to access the B Shoot, which is a higher-grade area of the orebody. Golden Star plans to begin longitudinal stoping of the B Shoot in the first quarter of 2017, with larger, transverse stopes expected to be accessed in the third quarter of the year.

Since Golden Star blasted the first Wassa Underground stope in July 2016, the company has been developing the mine and stope ore in the F Shoot. The underground production is supplementing ongoing open-pit production as feed to the 2.7-million-metric-tons-per-year (mt/y) Wassa processing plant.

The Wassa mine is forecast to produce an average of 163,000 ounces per year (oz/y) of gold over a mine life to 2024. The project feasibility study estimates life-of-mine cash operating costs for combined open-pit and underground operations at $780/oz, while all-in sustaining costs are estimated at $938/oz.

The underground mine will produce about 700,000 mt/y of ore once it is fully ramped up, while the open pit will produce about 2 million mt/y. Preproduction capital expenditure to develop the underground mine came in at $39 million.

Access to underground stoping areas is via a twin-decline system from the northeast wall of the Wassa open pit. The main decline is 5.8 m high x 5.2 m wide and was developed using standard trackless mechanized mining equipment.

At year-end 2015, Wassa had proven and probable mineral reserves of 1.5 million oz at an average grade of 2.27 g/mt gold and measured and indicated mineral resources inclusive of reserves of 3.6 million oz at an average grade of 2.02 g/mt gold.

Golden Star President and CEO Sam Coetzer said, “Achieving commercial production at Wassa Underground marks the successful completion of a 17-month construction period. It is an important milestone in our transformation into a highgrade, non-refractory gold producer.”

As featured in Womp 2017 Vol 02 -