Compressed air is used in a variety of critical mining applications, such as heap leaching and wastewater treatment, and to power compressed air-driven equipment. Because mines are often located in remote regions and in harsh, dirty environments, reliable equipment, access to spare parts and local service support are all top priorities for mine operators.
For one coal extracting mine in South Wales, add energy efficiency to the list of top priorities. The Unity Mine in Neath Valley reopened in 2008 and is now increasing its production up to one million metric tons of coal per year to supply fuel to major industrial companies, including nearby power plants. The volume increase of imported coal coupled with global price increases and demand, driven mainly by booming economies in China and India, has created a market where previously uneconomic domestic coal mining sites are commercially viable again.
The Unity Mine is a drift mine, which follows the coal seam from the surface and is accessed by driving sloping tunnels through the ground. Because drift mines start at the surface, they do not need to use vertical mine shaft winding systems to travel deep underground. To extract the coal, the mine uses pillar and stall methods that employ a continuous miner unit and secure the work with roof bolting, as opposed to arched roadways. This method requires air-driven equipment fed by a continuous and reliable supply of compressed air.
Originally, the mine utilized small, rented diesel-driven compressors, but there was growing concern with their mechanical reliability and their dependency on supplied diesel fuel, in addition to increasing rental and fuel costs. With energy efficiency, reliability and ongoing service and support in mind, the company switched from rented, diesel-driven compressors to two, Atlas Copco GA 110-160 oil-lubricated, air-cooled full feature variable speed drive screw compressors. The new compressors are projected to save nearly $22,000 annually in energy costs alone, not including additional projected savings in equipment rental costs.
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