A battle to stop a major pollution incident after floodwater threatened to flow into the Carnon River and the Fal Estuary from an abandoned mine has been successful.
The quick action of Cornwall Fire and Rescue service in using specialist high volume pumps to remove millions of litres of contaminated water from former Wheal Jane mine has been praised as helping prevent pollution in one of the most environmentally sensitive estuaries in Cornwall.
The Fal estuary is a designated marine Special Area of Conservation with sensitive coral maerl and eel grass beds. The estuary also contains a number of designated shellfish beds for oysters and mussels.
Over seven days last week, teams of four fire fighters from Cornwall have been operating two high volume pumps around the clock at the former Wheal Jane mine – pumping more than 60 million litres of contaminated water – the equivalent of 25 Olympic sized swimming pools - from the mine shafts to the treatment plant at the rate of 6,000 litres a minute. This has involved sinking the pumps to a depth of 58 metres down two separate mineshafts. Cornwall is the first fire and rescue service in the country to successfully use a high volume pump at this depth.
Wheal Jane mine, near Baldhu, was closed in 1991 when mining activity stopped. Following an incident in 1992 when contaminated water from the flooded mine spilled into the Carnon River and the Fal Estuary, a specialist plant was set up by the Environment Agency to treat the mine water before discharging it into the estuary. The plant is now operated by Veolia Water Solutions & Technologies on behalf of the Coal Authority. DEFRA fund the Wheal Jane operations.
The company typically removes 180 litres of water per second from the mine before discharging it back into the river system. Arrangements are in place to increase this to 440 litres per second to cope with peak flows. This is normally enough to keep water levels stable. However the recent floods meant that, although all the pumps were operating at full capacity, the water levels were continuing to rise, creating a risk that contaminated water from the mine could spill out from the mine workings into the Carnon river. Cornwall Fire and Rescue Service was initially contacted by Veolia and the Coal Authority on Wednesday, November 28 to see if its high volume pump could be used to help reduce the levels of contaminated water in the mineshafts. Following agreement from the Council. The pump was successfully lowered into shaft two later that evening.
Although the use of this pump increased the rate of removal, slowing down the rate of rise of water in the shaft, the overall water levels continued to rise. Working closely with the National Resilience Assurance Team (NRAT), Cornwall Fire and Rescue requested a second high volume pump from the National Co-ordination Centre. This was sunk into the main shaft to provide additional capacity. Due to the very restricted access, this pump had to have its outer casing and float chamber removed and an additional 60 metres of hose added before it could be sunk into the main shaft.
Both pumps have now been removed from the mine shafts at Wheal Jane. The Cornwall Fire and Rescue service high volume pump was cleaned on the site to remove any contamination from the acidic water and has now been returned to normal use.
Cornwall’s chief fire officer Des Tidbury said: “The Wheal Jane incident has proved to be a very demanding exercise over a prolonged period of time. As usual our firefighters have proved, yet again, that they can deal with anything that is thrown at them.
“I’m also glad to report that our high volume pumps have proved to be very effective pieces of equipment”.