African Mining September 2019 | Seite 15

GLOBAL NEWS  Turkish mining company Mikroman has set itself the target of improving product quality and increasing capacity at its three processing plants in Turkey. Mikroman has been mining and processing quartz since 1991. These goals have been achieved, and other gains made at the same time, by installing four Tomra high-capacity sensor-based sorting systems. TURKEY: SORTING DRIVES DOWN COSTS ne ws According to Nazmi Çetin, mine and plant manager at Mikroman, sorting machines deliver a wide range of commercial advantages which include a decrease in mining and haulage costs; reductions in energy and water consumption; improvements in quality and productivity; and increases in recovery. Sensor-based sorters also make it possible to significantly increase the lifetime of a mining operation. At Mikroman, quartz rocks are blasted and crushed at open-pit mines. The company runs its own mineral processing plants for crushing, washing and sorting the raw materials. In 2018 the company installed a Tomra Pro Secondary Laser sorting machine in two of its three plants, in Muğla and Aydin Provinces. The third plant, in Usak Province, invested in a Laser sorter plus a Colour sorter. According to Tomra’s area sales manager, Jens-Michael Bergmann, the Tomra Colour sorting machines employ a high-resolution camera that recognises materials based on their colour. Rocks with surficial and visible contamination are detected and sorted out, resulting in better recovery rates and higher quality than is possible with manual sorting. “The scattering effect of multiple laser beams distinguishes a rock containing quartz from its identically coloured neighbour. Under the laser beam a pure or non-contaminated quartz rock registers as a glow crystal, whereas similar-looking rocks with no quartz content remain dark, without any visible scattering,” says Bergmann. After crushing and washing (through a trommel screen), Mikroman’s sorting process consists of four key steps. In the first step, minerals are screened by size, with only stones measuring 40-100mm going through to the next stage. In the second step, the Laser machine sorts out the waste and coloured gravel from the quartz pieces at about 70 tonnes per hour (tph) capacity. In the third stage, the remaining minerals are sorted into two streams: one for coloured quartz; the other for the white and light grey quartz, and the grey and yellow quartz. Finally, these two streams are hand-sorted into product types, with some further removal of remaining gravel and waste. Diversified mining company Rio Tinto has launched the world’s first automated heavy-haul long distance rail network. The landmark AutoHaul project was deployed by Rio Tinto in partnership with Hitachi Rail STS. The 2.4km-long train is monitored remotely from an operations centre in Perth, and travels across a network of 1700km of railway tracks. Iron ore from 16 mines is delivered to ports in Dampier and Cape Lambert, with the trains already having travelled over 4.5km autonomously since they were first deployed last year. AUSTRALIA: GOLD FIELDS HOOKS ONTO HYBRID Gold Fields and global energy group EDL announced a AUD112-million investment in an energy microgrid combining wind, solar, gas and battery storage. The microgrid will be owned and operated by EDL, which will recoup its investment via a 10-year electricity supply with Goldfield’s Agnew mine. Çetin says, “Before having Tomra sorters, we were worried about quality and low capacity, but now we have achieved the desired quality standard and we have seen a decrease in waste, which means productivity has increased.” AUSTRALIA: RIO LAUNCHES A WORLD FIRST A diagram of Mikroman Mining’s processing plants. www. africanmining.co.za African Mining Publication African Mining African Mining  September 2019  13