ABB said in early December it had successfully completed testing and no-load commissioning of an ACS 6000 drive installed on a shaft hoist at Ma JiaLiang coal mine in Shanxi Province, China.
The Switzerland-based company said the ACS 6000 drive is designed to allow for continued hoist operation at half-speed and under full load, if required by the process. With this technical accomplishment, ABB claims to be the first supplier worldwide to design and realize this kind of function in a hoist system. This capability, according to the company, will greatly reduce maintenance time and increase the reliability and availability of mine production.
The Ma JiaLiang coal mine has a planned annual production capacity of 12 million metric tons (mt) of coal and maximum capacity of 15 million mt. When put in operation, the main shaft will boast the highest production rate of its type in China.
ABB provided two hoist systems for the main shaft, with each hoist pulley having a diameter of 5.7 m, a payload of 45 mt, and a motor power of 7,000 kW. It uses MV AC-DC-AC direct torque control technology and reportedly is the largest hoist system ever installed in China.
ABB, in June 2011, started installation and no-load commissioning of the mine’s No. 2 main shaft hoist, including the mechanicals, motor and control system as well as the ACS 6000 MV drive and brake control system. The half-speed under full-load function is designed to maintain the safety of the hoist system with continued production in case of failure of the hoist’s drive system.
ABB said half-speed with full-load redundancy has been available for systems using DC drives and AC-AC direct conversion frequency drives, but this specific function has never been realized before for hoist systems based on AC-DC-AC frequency conversion drives.
Stephen Zhu, manager of ABB’s mining and minerals business in China, said, “ABB designed an ACS 6000 MV drive system using two independent sets of active rectifier units and inverter units for the Ma JiaLiang project. Under normal conditions, the two operate together, providing power to the motor. If one fails, a switch cabinet will connect the redundancy operation mode and start the operational set. This is a significant achievement which can greatly reduce shutdown time, providing our customers continuous production with improved reliability.”
ABB also announced in late November that it won a $24-million order to supply a complete ore hoisting solution for Xstrata Zinc’s George Fisher mine (GFM) located near Mount Isa in northwest Queensland, Australia. The ground-mounted friction hoist will carry ore from a depth of 1,135 m and help increase GFM’s annual production rate. The order was booked during the third quarter of 2011.
The hoist installation is part of a A$274-million (US$246-million) expansion of GFM intended to increase the production rate by almost 30% from 2013.
The GFM expansion will increase the annual production rate from 3.5 million mt/y to 4.5 million mt/y and involves the development of a second hoisting shaft and associated infrastructure to service the northern area of the mine using large-diameter raise boring technology. It also includes installation of an underground crushing and ore handling facility and upgrades to power and air ventilation services. An existing shaft servicing the northern end of the mine will be lined and extended by 420 m.
Xstrata Zinc’s resources in and near Mount Isa, including GFM, comprise the world’s largest zinc resource base, with an estimated 600 million mt of ore and 36 million mt of contained zinc metal.
ABB will design, supply and commission all of the electrical and mechanical equipment for a new ground-mounted mine ore hoist system. At speeds of 16 m/sec, the hoist will raise 600 mt/h of ore. ABB’s ACS 6000 medium voltage drive system will power a 9,000-kW synchronous motor to run the hoist. The hoist design, said ABB, will minimize impact on the surrounding power network.
ABB will also design and supply the bottom dump ore skips with inspection platforms, the rope deflection sheaves and a skip dumping system. ABB’s System 800xA AC800M industrial controller will manage and control the entire mine hoisting system, from the loading conveyors to the surface ore dump station.
Delivery is scheduled to be completed in the second half of 2013.