Uncertainty over government support for the coal industry is understood to be behind a decision to put plans for a new deep coal mine in the south of Scotland on hold for five years.

Scottish Coal, part of the Scottish Resources Group, looked into the possibility of building a new mine near Canonbie in Dumfriesshire, which is said to have reserves of 400 million tons of coal, enough to run Longannet power station for 80 years.

Sharp increases in the price of imported coal and clean-coal technology at power stations have made mining Britain's extensive reserves more attractive. UK Coal, which bought most of British Coal's assets in the 1990s, is looking at reopening Haworth colliery in Nottinghamshire.

The SNP government has been vocal in its support of the coal industry. A year ago, Alex Salmond said that clean-coal technology had a dynamic future for the industry.

Scotland has about 10% of Europe's coal reserves but without a long-term government commitment, companies are wary of investing tens of millions of pounds.

Scottish Coal said: “It is not about financial commitment, but general support. Spending tens of millions of pounds for a new mine and then finding a new government did not have the same support for the coal industry would create huge issues. The Canonbie study suggested there were plenty of reserves but progress is unlikely within the next five years.”

Plans to reopen one of Scotland's four mothballed deep mines also faced hurdles, according to Scottish Coal. Longannet in Fife, the last pit in Scotland, was closed in 2002 after it flooded. “Dealing with Longannet's flooding would cost at least £50m before it was able to be mined and even then there is no certainty it would be viable,” Scottish Coal said.

A spokesman for UK Coal said it had no plans to look at any of Scotland's mothballed pits. “We recently spent a lot of money trying to re-start a mothballed pit in England before having to abandon it,” he said. “Deep mined coal is becoming viable, which is why we are looking at Haworth, but Scotland's pits have problems which make it harder to see the justification.”

Chris Butler, a global resources specialist at Martin Currie, an investment management firm, said it was difficult to see new mines being cost effective, but that reopening mothballed pits was a possibility. “I cannot see a new deep mine being sunk in Scotland, but if coal prices remain high, mothballed pits come into the equation.”

Meanwhile it has emerged that power supplies were under threat during the recent strike at Grangemouth refinery.

Scottish Coal came within a day of being forced to stop production at all of its sites because of dwindling fuel supplies. A last minute delivery prevented the crisis.

“We have a 24-hour a day operation which requires a lot of fuel,” said the spokesman. “ It was close and and was only prevented from becoming critical by switching the supplies we had around our sites but if it had gone on for another day, we would have had to halt production.”

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