African Mining March 2020 | Page 47

CRADLE TO GRAVE  HYBRID SOLUTIONS POWER REMOTE MINES Lewis told African Mining at the recent 2020 Investing in African Mining Indaba that Aggreko recently signed a contract with Resolute Mining’s Syama gold mine in southern Mali to support the mine’s ambitions to reduce carbon emissions and improve overall efficiency for the site. “Once installed, Aggreko will operate and maintain a 40MW thermal power plant and a 10MW battery storage system, with a further 20MW of solar power planned in 2023. The hybrid solution will reduce Syama’s power costs by an estimated 40%. Once all the renewable power sources are fully installed it will also reduce carbon emissions by approximately 20%,” Lewis explained. Last year, Aggreko began the construction of one of the world’s largest renewable energy microgrids for Gold Fields’ CONVEYOR VS TRUCK In the mining, quarrying and cement industries, transporting bulk materials efficiently, and environmentally friendly, from the pit to their destination is essential. According to Dr Andreas Echelmeyer, compared to trucks, conveyor belts are often more energy-efficient and can be adjusted to the structure of the premises. They are also able to safely handle steep sloping routes, rivers or road crossings. The system provider determines the optimum conveying route, then takes over project planning and installation,” says Echelmeyer. Syama mine in southern Mali. Granny Smith gold mine in Western Australia. The 8MW solar power generation system integrates 20 000 solar panels supported by a 2MW /1MWh battery. The microgrid is projected to reduce fuel consumption by 10-13% – the equivalent of removing 2 000 cars from the road – and produce about 18GWh of clean energy per year.  well: new roads and access roads have a serious impact on the landscape. And then there's fuel consumption. The emissions caused by truck traffic are high, both with regard to toxic substances and noise and dust," says Echelmeyer. At Yadong Cement in China, Beumer’s conveyor belts were a lot more efficient that a fleet of trucks. " The belt conveying systems require almost 90% less primary energy than comparable truck transports", Echelmeyer explains, and refers to the concrete project-related comparison. “Trucks operated with diesel fuel require a specific primary energy of 11.4kwh for each ton of transported material. The belt conveying system, which was built later on required, on the contrary, only 1.44 kwh. If, as in this case, 7.5 million tons of raw material is transported annually, the use of belt conveyors means a total saving of 74 million kwh per year. This corresponds to a yearly energy consumption of more than 20 000 single-family houses. This can be noticed also from a monetary viewpoint: solely by saving diesel fuel, the operational costs of the company are reduced by more than EUR5.5-million per year.  For Echelmeyer, using conveyor belts makes a lot more sense than using trucks, which are still frequently used for transporting bulk materials over long distances. “Depending on the nature of the terrain, trucks can rapidly reach their limits; trucks require well-developed roads and fuel, for example, and the costs of construction, maintenance and possible extensions are significant. The ecological aspect needs to be considered as For remote mines in Africa, hybrid power solutions can be up to 30% cheaper than running thermal generators alone. This is according to John Lewis, managing director at Aggreko Africa. Bulk materials need to be transported efficiently from pit to stockpile. www. africanmining.co.za African Mining Publication African Mining African Mining  March 2020  45