Modern Mining April 2015

MINING News

Wassa has a carbon-in-leach processing plant with a rated capacity of 2,7 Mt/a (photo: GSR).

Wassa gold mine in Ghana to go underground 4,26 g/t for 745 000 ounces of gold.

ing plant with a rated capacity of 2,7 Mt/a. Golden Star has been mining the Wassa open pits since commissioning the plant in 2005. Mining is currently at theWassa open pit, which is within 500 m of the plant. In November 2014, SRK Consulting (UK) was awarded the contract to prepare a Feasibility Study to determine the eco- nomic viability of an underground mine beneath the Wassa open pit. Open-pit mining is expected to con- tinue in the Wassa open pit area at a total material mined rate of approximately 1,2 Mt per month until 2021 when the strip ratio is expected to start to decrease. On average, GSR anticipates that the open pit will produce approximately 2,0 Mt/a of ore feed, with the balance of the total plant capacity of 2,7 Mt/a being supplied by Wassa Underground. Access development to the under- ground stoping areas will be via a twin decline system from the north-east wall of the current Wassa open pit. The twin decline system will enable efficient ven- tilation during the early stages of the

Golden Star Resources (GSR), which has offices in Toronto and Accra, has announced the results of its Feasibility Study (FS) on the development of an underground mining operation (Wassa Underground) at its currently operating Wassa open-pit mine in Ghana. The FS estimates the Wassa mine (underground and open pit) will produce an average of 163 000 ounces of gold per annum over its production life with average cash operat- ing costs of US$780 per ounce. The FS indicates an IRR of 83 % for the Wassa mine at a US$1 200 per ounce gold price and an NPV, assuming a 5 % discount rate, of US$176 million. Pre-production incremental capital expenditure for Wassa Underground is estimated at US$39million with first production from the under- ground project expected in early 2016 and estimated to continue into 2024. The total proven and probable mineral reserves for Wassa as of December 31, 2014 are 24,1 Mt at 2,04 g/t for 1,6 million ounces of gold. The Wassa Underground mineral reserves are estimated at 5,4 Mt at

“We are excited to announce this posi- tive Feasibility Study on the combined existing Wassa open-pit operation and the Wassa Underground extension,” com- ments Sam Coetzer, President and CEO of GSR. “The strong rate of return on invest- ment suggested by the study validates the Preliminary Economic Assessment of Wassa Underground we published in 2014 and is a confirmation of the decisions made for the expenditures on drilling and the studies of the last few years. “The Wassa Underground project has been underway since December 2014 when we purchased certain underground mining equipment and received the exploration decline permit. The Wassa Underground deposit remains open down plunge and has great potential to grow and the company plans to extend develop- ment. The Wassa mine will help transform Golden Star into a lower cost gold pro- ducer going forward.” The mine is in the Western Region of Ghana. It has a carbon-in-leach process-

6  MODERN MINING  April 2015