Modern Mining June 2018

POWER SUPPLY AND ENERGY EFFICIENCY

engines, with a total capacity of 4,5 MW. The plant has performed extremely well, deliver- ing a 99,8 % power output availability since commissioning. Outlining the rationale for the solar farm project, Roos says that tight control of energy costs is essential for a low-cost producer such as Otjikoto, given that electricity generation has typically accounted for approximately 12 % of the mine’s overall operating costs and

the Otjozondjupa Region of Namibia, approxi- mately 300 km north of Windhoek and just off the national highway linking the towns of Otjiwarongo and Otavi. Officially opened in mid-2015 (although it achieved its first gold pour in late 2014), it has been one of the most successful gold mine start-ups seen in Africa in recent years. In 2017 it produced a record 191 530 ounces at a remarkably low cash oper- ating cost of US$468/oz. It forms the backbone

The Otjikoto Solar Farm is one of the biggest instal- lations of its type in Africa (photo: B2Gold).

Some of the guests who attended the inauguration with the solar farm in the background.

of Namibia’s gold-mining industry, the only other gold operation in the country being the much smaller Navachab mine. Otjikoto is what is known as an ‘island energy producer’ – meaning that it is off the Namibian national grid. Although not in a particularly remote area, it is powered by a ther- mal plant which was installed during the development phase of the mine when it became evident that rely- ing on a grid connection would have delayed the start-up of operations. The plant has a generating capacity of 23,5 MW – which is almost twice the mine’s average demand – pro- vided through four Cat MaK 12CM32 medium-speed HFO generators, capa- ble of generating a combined 19 MW, and three Cat 3516 high-speed diesel

June 2018  MODERN MINING  27