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Thursday, 03 October 2013 05:05

Compressors switch at re-opened Welsh coal mine

AtlasUnity MineCompressorUnity Mine has improved efficiency and reduced energy consumption at its Cwmgrwach operation in the Neath Valley, Wales by replacing the existing diesel driven compressors with new electrically-powered units from Atlas Copco.

The mine re-opened in 2008 as it became commercially viable again. This was due to increasing volumes of imported coal coming in to the UK and global price increases driven by demand particularly in China and India.

Unity Mine is now ramping up production to deliver up to one million tonnes of coal per year to supply fuel for major industrial companies, including the nearby coal-fired Aberthaw Power Station. Current geological estimates are that there are reserves of 90 million tonnes of coal that will be extracted from the mine complex over the next 25 years.

The Cwmgrwach operation is a drift mine, meaning that miners can walk in rather than being transported, via a vertical mine shaft winding system, as used in other deep mining sites. At the mine, the coal seams are accessed by driving sloping tunnels through the ground.

After the mine’s re-opening, the company’s management focus was on the reliability and efficiency of production equipment, according to Duncan Kilbride, director of projects & procurement at Unity Mine

“The initial plan of the mine’s workings were based on the pillar and stall extraction methods that employ a continuous miner unit and secure the work with roof bolting, as opposed to arched roadways," said Kilbride.

"These all require air-driven equipment fed by a reliable continuous supply of compressed air. We also operate pumps on a permanent basis to remove water,” he added.

Air for these operations was supplied originally from a number of small, rented diesel-driven compressors but there was growing concern with their mechanical reliability and the risks of any break in the regular supply of diesel fuel. This issue, coupled with increasing rental and fuel costs, ensured the case for replacement with more energy and cost-efficient compressors.

“We invited tenders for the system and Atlas Copco came up trumps as a one-stop shop solution for the compressors, filtration units, controller and compressor house installation,” said Kilbride.

Two oil-lubricated, air-cooled, full-feature GA110 variable speed drive screw compressors were installed together with a companion fixed-speed version machine.

These, say Atlas Copco, could provide energy savings of around £13,000 per year as well as substantial savings in equipment rental costs.

The Atlas Copco compressor units provide base load and back up peak 7bar air to the drilling and roof bolting equipment, and the water pumps.

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