Gold miner Harmony Gold is using mine-impacted land and tailings to pilot biocrop procreation in the form of giant king grass and sugar beet. Read on page 16 of this edition of Mining Weekly of the R47-million project being directed at simultaneously returning the land to an agricultural state. Combining renewables with bioenergy and land rehabilitation, the project’s biocrops will be used as feedstock to generate natural gas as a fossil fuels substitute at the Harmony 1 metallurgical plant. Electrical and polyfuel methods of heating the water needed in the elution process will be converted to biogas heating. The first phase is expected to deliver 71 000 GJ and then rise to 187 000 GJ in 36 months. Skills development and job creation for communities will be fostered along the way.

The Raglan mine, a Glencore group nickel complex in the Nunavik region of northern Quebec, in Canada, has installed a 3 MW wind turbine and energy storage facility, which will be grown fourfold if all goes to plan. The mine site is smack bang in sub-Arctic permafrost, where there is plenty of wind. The aim is to cut the use of expensive diesel at its fully diesel-powered operations, where energy accounts for up to 23% of operating costs. The focus of the first phase is to test the three storage technologies in Arctic conditions, ahead of the roll-out of a larger wind farm at the mine site.

Rising energy prices and supply constraints are also encouraging mining companies operating in Africa to find new energy solutions that are affordable, consistent and secure. The first hydropower plant that Randgold Resources is building in the Democratic Republic of Congo, for example, has been such a success that more plants are on the way. Randgold’s first plant generates power at $0.10/kWh and capital payback in a trade-off against diesel is 20 months. Remote mining companies have to bear not only the high cost of diesel, but also the high cost of transporting that diesel to site. Against that background, renewable-energy integration is on the way, with comprehensive photovoltaic hybrids also playing a part in hot areas. Mixed solutions can help extend the life of generators and decrease operational and maintenance costs. They also lower noise and carbon dioxide emissions. Owing to the frequent availability of solar, wind and hydropower on the continent, mines in Africa are often well positioned for renewable solutions, which increasingly are being considered during the initial planning phases of new mining projects and standalone brownfield expansions.