|In two years, the Gevra mine will transition to 100% production by surface miners.|
Indian mine operator Sainik Mining and Allied Services Ltd., a contractor for Coal India Ltd., operates a total of 21 Wirtgen surface miners, 10 of which are 2200 SMs operating in the 530-km2 Gevra mine in the province of Chhattisgarh.
The vertical coal seams in the Gevra mine require a selective mining method. Additionally, 90% of the cut coal ought to have a maximum particle size of 100 mm. This is why, since 1999, the mine operators have gradually switched mining activities from drilling and blasting to Wirtgen surface mining. Presently, 80% of the coal is already being mined using this technique, another 20% still via conventional methods. The mine operators are planning, however, to shift to 100% surface miners within the next two years. In Gevra, surface mining has proven to be clean, safe and more environmentally friendly as well.
In the mine, windrowing turned out to be the optimal mining method. Thanks to this technique, it is economical and easier to keep tabs on product quality. With windrowing, the cut coal is placed directly behind the machine, between the crawlers, without the use of a loading conveyor. The coal is later loaded by a front loader. As a result, each 2200 SM — with a 3.8-m cutting width and a 300-mm cutting depth — can mine roughly 15,000 metric tons per hour (mtph) of coal. The annual capacity of the coal mine is an enormous 80 million mt, 90% of which is being used as thermal coal for power generation.
The service contract especially tailored to the Gevra mine by Wirtgen’s local subsidiary guarantees that two experienced Wirtgen engineers are available there at all times during operation. They provide support for all necessary maintenance activities relating to the surface mining fleet, including machine repairs, preventive maintenance measures, inspection of certain machine parts, training of machine operators, etc. The Wirtgen experts also make sure that all spare parts needed are kept in stock.