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Rock Flow uses a Rock Feeder under each drawpoint, using a reciprocating hydraulic push-beam system to provide a continuous flow of ore on to a Rock Mover—a chain conveyor that takes output from a series of adjacent drawpoints. Caterpillar already had one such unit on trial at Codelco's Salvador mine in 2007, with a second, more extensive system scheduled for installation at the company's Andina operation in 2013. Major Rock Flow benefits include fully automated, continuous high-performance operation supervised from a surface control room, the company says, as well as ease of maintenance and system redeployment. In addition, ventilation requirements are lower because of the replacement of diesel LHD engines with electric drives, while the system needs significantly fewer people working underground. Changing Mining Concepts with R&D; At the beginning of this year, Aker Wirth GmbH released some updated information on its MTM 6 mobile tunnel miner, developed in cooperation with Rio Tinto (See Best of Germany 2011, p.55). Designed to achieve advances of up to 10 m a day, the machine is now scheduled to be put through full-scale trials at Rio Tinto's Northparkes copper mine in Australia during 2013, the company said. Carried on a crawler and walking mechanism, the MTM 6 excavates rock with six hydraulic arms fitted with disc cutters, with the muck being handled by a loading apron and a chain conveyor. Using undercutting technology, it can handle hard rock with a compressive strength of up to 300 MPa, and although it is 75 m long, it has a turning radius of just 30 m, according to Aker Wirth. The company is also supplying a smaller version of the machine, a four-arm MTM 4, to Codelco for use in development in preparation for the underground production phase at Chuquicamata. Just 40 m long with a 12 m turning radius, the MTM 4 should be able to achieve up to 12 m 2013 • VDMA MINING SUPPLEMENT VDMA Aker Wirth's MTM 6 mobile tunnel miner will be trialled this year. advance a day, more than double existing drill-and-blast rates, Aker Wirth believes, adding that tunnelling costs should be at least 30% lower than for drill and blast, depending on the conditions. The MTM 4 is scheduled to begin trial development at Chuquicamata in mid-2014. Aker Wirth provided an update on progress on its conceptual seabed-mining system, developed in cooperation with the German Federal Institute for Geosciences and Natural Resources (BGR) between 2009 and 2012. Designed for mining manganese nodules from water depths of up to 6,000 m, the system consists of two nodule collectors, a transport system for conveying the material, and a specially-designed production vessel. During 2012, the company and its partners undertook a profitability analysis for the complete system, concluding that deep-sea mining is very lucrative, even given current prices of raw materials and anticipated price developments. VDMA 15