Modern Mining June 2016

WEST AFRICA

GSR goes underground in Ghana Golden Star Resources (GSR), listed on the TSX, NYSE AMEX and the Ghana Stock Exchange (GSE), reports it is progressing well with the development of two high-grade, low cost underground mines at its Wassa and Prestea properties in western Ghana. Wassa Underground is the more advanced project and is due to deliver its first gold production within the next few weeks while Prestea Underground should be in production by mid-2017. The estimated pre-production capex for the two projects is US$39 million for Wassa and US$63 million for Prestea.

L ocated approximately 35 km north- east of the town of Tarkwa within the southern portion of the Ashanti greenstone belt, Wassa – acquired by GSR in 2002 – is currently an open-pit operation with the ore being treated in a CIL plant with a nameplate capacity of 2,7 Mt/a. In late 2014, GSR initiated a Feasibil- ity Study (FS) to determine the viability of an underground mine operating in conjunction with the open pit. The results were announced in March last year and confirmed the econom- ic case for the project. The FS covers both the open-pit and under- ground operations and essentially constitutes a mine plan through to 2024. It estimates the

combined gold production from both opera- tions over this period will average 163 000 ounces a year with the IRR (at a gold price of US$1 200 per ounce) estimated at 83 % and the NPV (assuming a 5 % discount rate) at US$176 million. The FS puts the payback period at 3,25 years. The underground mine – which will exploit an underground mineral reserve of 5,4 Mt at 4,26 g/t for 745 000 ounces of gold – is accessed by a twin decline system (currently at an advanced stage of development) from the north-east wall of the current Wassa open pit. The system will enable efficient ventilation during the early stages of the underground life and removes the requirement for a raisebore

A Cat 50-t truck at Wassa. The mining fleet deployed on the project includes Cat LHDs and haul trucks and Sandvik jumbos and drill rigs.

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30  MODERN MINING  June 2016