Pumping knowledge prevents environmental overspill at former mine
20 Oct 2018
The UK’s disused former coal mines still have a contribution to make to the nation’s energy supply but this requires careful management of the water within them.
The potential of disused mines to produce clean energy has been much in the news this year, since the award of £6.5million for the UK’s first large-scale geothermal scheme in the old Caerau colliery near Bridgend, South Wales.
If successful this would involve pumping water that has been naturally heated by the earth to nearly 21? from 230 metres below ground. The aim is to eventually produce cheaper heating for 1,000 homes.
The Environment Agency’s annual report on water companies’ environmental performance in July served as a reminder that the management of disused mines is still a significant issue for the UK environmental and water industries.
One of the key issues affecting the management of disused mines throughout the country is maintenance, with regards to water levels and the removal of excess.
In deep
Although a certain amount of water is allowed in disused mines to fill voids and reduce the risk of an old tunnel collapsing, the Environment Agency and DEFRA constantly monitor levels carefully to avoid the build-up of any surplus, which can contain pollutants such as iron and zinc. These and other minerals could contaminate water supplies and surrounding land.
Newburn Power Rental, suppliers of temporary and permanent power generation solutions, worked with a water company at one such mine.
Monitoring staff at the site has become aware that the generator was tripping out occasionally and, as a result, water levels had risen to an unacceptable level – potentially leading to an environmental risk to surrounding land and water supplies.
Submersible pumps were needed to remove excess water and transfer it to a holding lagoon, with Newburn contracted to provide the 250kVA generator and fuel supply.
This wasn’t a complex solution, but the problem averted had the potential to cause major environmental damage
Mark Henstock, managing director, Newburn Power Rentals
An engineer from Newburn visited the site and discovered that the problem was not with the generator but with the configuration of the submersible pumps.
Several had been connected to a single distribution board in a way that caused them to start simultaneously. This created a huge demand in a single hit, causing the trip-out.
Quick fix
Newburn’s engineer proposed a simple solution - for the pumps to be re-set sequentially to spread start-up demand.
Mark Henstock, managing director at Newburn, commented:
“Our recommendation for solving this problem was accepted and implemented. It proved to be 100 percent successful, reducing the excess water in time to prevent any contamination.
“This wasn’t an elaborate or complex solution, but the problem averted had the potential to cause major environmental damage.”
