Modern Mining June 2018

feature POWER SUPPLY AND ENERGY EFFICIENCY The process plant of the Otjikoto gold mine. It has a consistent demand of 12,5 MW, 24 hours a day. “We’re particu- larly proud of the fact that a total of 105 000 man hours was worked without a single LTI incident and that the Namibian con- tent of the project was maximised, both in terms of procurement and construction.”

the state-of-the-art capabilities of the Cat ® Microgrid technology.” He adds that the technology is relatively new on the market and, at the time B2Gold was evaluating proposals, had not yet been used in a commercial application, the only installa- tion being at Caterpillar’s Proving Ground near Tucson in Arizona. “We were able to visit this and see for ourselves the system in operation. As far as I’m aware, we’re the first company in the world to deploy it in a mining application.” The engineering, procure and construction (EPC) contract to deliver the solar farm was awarded to Barloworld Namibia in June last year. Shortly after B2Gold received the neces- sary environmental approval from Namibia’s Ministry of Environment & Tourism, debushing and ground levelling of the 22 ha site started. The first shipment of solar panels arrived on site at the end of October and the first PV module was installed on 1 November. Construction of the solar farm was completed by late February 2018 and in early March the powerline export- ing energy to the HFO plant was energised successfully. On 14 May the MMC and its asso- ciated SCADA system, the ‘brain’ of the system, was commissioned. Comments Roos: “The project was com- pleted on schedule and within its budget of N$115 million or US$8,5 million. We’re partic- ularly proud of the fact that a total of 105 000 man hours was worked without a single LTI incident and that the Namibian content of the project was maximised, both in terms of procurement and construction.” He adds that many members of the construction team were trainees sourced from the Namibian Institute of Mining & Technology (NIMT). The completed solar farm comprises 62 400,

35 % of total processing costs. “Going the solar route will allow us to achieve a very significant reduction in our consumption of HFO – which is steadily increasing in price – with the saving amounting to approximately 3 million litres a year,” he states. “Moreover, it fits in well with B2Gold’s com- mitment to environmental stewardship. It will, of course, reduce the mine’s carbon footprint and the likelihood is that it will remain as an income-generating asset long after the mine has closed, benefitting both local communities and the wider Namibian economy.” The Otjikoto solar project was approved by B2Gold Corporate in October 2016 after intensive feasibility studies. Subsequent to the approval being received, a rigorous ven- dor evaluation process was initiated with the assistance of B2Gold Namibia’s appointed engineer, GS Feinsinger & Associates, a consulting engineering practice based in Windhoek, with several major players in the solar energy industry being invited to sub- mit proposals. Ultimately, the contract was awarded to Barloworld Namibia, in partner- ship with Barloworld Power in South Africa, the Caterpillar dealer in Southern Africa, and Caterpillar Microgrid Solutions in the US. “Barloworld and Caterpillar offered us the most advanced solution based on their Cat ® Microgrid Solutions technology,” says Roos. “This offered a total and seamless inte- gration between our existing HFO plant and the proposed solar farm, with the integration being managed by Caterpillar’s Microgrid Master Controller (MMC). Also influenc- ing our decision was the fact that our HFO plant is a Caterpillar installation. None of the other potential vendors were able to match

28  MODERN MINING  June 2018