INDIA 2018

Best of Germany 2014 - Mining Equipment and Mining Technology

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VDMA 32 VDMA MINING SUPPLEMENT • 2018 The control room at the mill or a processing plant has always been a technology center for most mines, especially when it comes to instrumentation and control. More recently, the use of distributed controls gave way to programmable logic controllers (PLCs), which allowed a higher degree of automation. Now sen- sors embedded throughout the plant are giving engineers the ability to recognize trends in data and make decisions based on different criteria. Despite their high levels of sophistication, plants and mills still rely heavily on gravity-based systems where the ore is convert- ed to slurry and separated by size. This process requires two import- ant inputs: water and energy. Both can be expensive commodi- ties in remote parts of the world. Any process improvements that reduce water and power consumption would be welcomed by mining companies. Tailings treatment is another challenge for the mining sector. In addition to the water needed to transport tailings, there are con- cerns related to environmental risk and storage space constraints. Safe tailings disposal has become a major consideration for the mining industry. The ANDRITZ GROUP, headquartered in Austria, has the broad- est portfolio of separation technologies and it also specializes in high-capacity technologies for tailings, including the world's larg- est decanters and filter presses. The technology has now become even smarter with the Metris addIQ automation solution for fully automatic operations. Metris addIQ combines all of ANDRITZ's extensive experience in operation, troubleshooting and startup into one tailored automation solution. Its nucleus is a modular, PLC-based control system that allows operators to maximize machine performance regardless of whether they are using ANDRITZ filter presses or other makes. Efficient Tailings Treatment A South American gold mine was looking for a single filter press ca- pable of covering the plant's entire demand for tailings treatment. The goal was to fulfill every environmental regulation as effectively and economically as possible. The mining company selected an AN- DRITZ overhead filter press A4 F 2500 in combination with Metris addIQ automation. The plant produces around 1,500 metric tons per day (mt/d) of tailings containing cyanide, at an ambient temperature of ap- proximately 1°C-15°C. The solids in the pulp average 51%, but the solids content needs to reach more than 80% for the cake to be stored safely. Every day the plant initiates 36 filter press cycles lasting around 30 minutes each at feed pressure of 6 bar and max- imum pressure of 15 bar. To ensure that production forecasts could be met reliably and better cake moisture achieved, ANDRITZ sold an extraordinarily large overhead filter press that features 2,500-mm x 2,500-mm plates to- gether with a Metris addIQ package for fully automated operations. Safe tailings disposal has become an intrinsic cost factor in the mining industry, and the filter press is one way of reducing oper- ating expenses when producing dry stacked tailings. Not only does it have the longest lifespan, it is suitable for very rough climate conditions, offering excellent durability and reliability. In combina- tion with the addIQ automation system, it also requires extremely low maintenance. The fast filter cake discharge system has yielded some of the highest tailings throughputs, and operators can also adjust the speed for different applications and cake properties. Clogged filter cloths can be a major source of downtime in less advanced systems, and that's why the heavy-duty press features a filter cloth washing device. The use of the Metris addIQ system has resulted in measurable improvements in throughput, safety, reliability and costs. The hy- draulic closing pressure control, for example, enhances operating safety because the pressure is maintained at a safe, constant level. Metris addIQ automatically measures and controls the hydraulic and feed pressure. For faster filter cake discharge, the speed of the plate shifter can be adjusted. The drip plates are moved by means of hydraulic cylinders, also controlled by Metris addIQ. This ensures that the drip trays are in the open position for cake discharge and in the closed position during filtration. A key benefit here is that the filtrate is kept sepa- rate from any containers or the conveyor system. The next step toward achieving a fully autonomous filter press for 24/7 operations without operator supervision is an optical mon- itoring system for filter cake discharge. The filter cloth washing device enhances operating convenience because filter cloths are subsequently cleaned after the fully automatic filter cake discharge. The filter press feed is continuously controlled by pressure-feed- ing and load cells to obtain the optimum filling level, while the best possible dewatering is achieved by means of an optimized mem- brane squeezing system. In the final process steps, fully automatic conveying systems ensure efficient filter cake discharge and the Intelligent Processing The proliferation of technology leads to automated processes and new grinding techniques This ANDRITZ large overhead filter press with 2,500- x 2,500-mm plates integrates a Metris addIQ package for fully automated operations.

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