ASSURANCES have been given that a proposed minewater treatment plant will not blight a stretch of the nearby North-East coastline.

The Coal Authority plans to create the £2.5m facility in Dawdon, Seaham, to pump and treat contaminated water from nearby disused mine workings in east Durham.

Fears grew following the closure of the last working collieries on the Durham coast, in 1993, that if unchecked, rising contaminated water in old mine shafts could threaten water supplies.

A short-term solution saw the opening of a minewater treatment plant at the former Horden Colliery site, further down the coast, in 2004.

It was designed as a temporary measure to protect undergound water supplies while a more permanent solution was formulated.

Following joint studies with the Environment Agency, in conjunction with local councils and other interested groups, Dawdon and Horden were identified as the two most suitable sites for permanent treatment facilities.

The authority said the two-site option would, "minimise the risk of an underground collapse isolating one treatment location".

A passive treatment system, featuring settlement ponds and reed beds, was considered the best long-term facility at Horden, with the present treatment plant transferred to the vicinity of the former Dawdon Colliery site.

Authority officials outlined proposals for the £2.5m plant at Dawdon to members of Seaham Town Council.

The site earmarked, next to the Robinson Timberkit plant, on the Fox Cover Industrial Estate, would discharge treated minewater about 1.4km - almost a mile - off the coast.

Town council leader Edward Mason expressed concerns that "two lines of contamination" would be pumped into the waters of what is now called the Durham Heritage Coast.

He said there were local fears it could affect sea-water quality.

But the authority's senior project manager, Stuart Rolley, said: "We take the contamination out.

"It might be a slightly different chemical composition to the sea. It will be slightly saltier.

"There would only be any impact inches from where it's being discharged."

But he said the authority would be happy to undertake a study to monitor the effects on marine life.

The authority is expected to submit a formal planning application to Durham County Council in coming weeks.