THE future of Scotland's deep mining industry was thrown in doubt and 300 miners faced ruin last night when Monktonhall Colliery appeared on the brink of losing its five-year battle for survival.

The company which owns the troubled Midlothian pit announced it was withdrawing financial support. Its closure would leave Longannet Colliery, in Clackmannanshire, as Scotland's last remaining deep mine.

Monktonhall Colliery Ltd was officially wound-up at the Court of Session when a statement of affairs revealed the company was almost #20m in the red. Its directors claimed it could no longer pay its debts and a provisional liquidator was appointed.

The pit will be kept open on a care and maintenance basis for at least another week while a new buyer is sought. Union leaders emerged from an afternoon meeting in combative mood claiming the mine was still viable.

However Waverley Mining Finance, which bought out the miners' stake in the pit in 1995 when it faced closure, said it would take up to two years and #18m just to clear the mine of water before production could restart.

Union officials last night questioned the way Waverley Mining had handled the running of the pit. They claim that they warned management 18 months ago of the dangers of flooding in seam PC8, a problem which subsequently led to severe flooding of the pit and the withdrawal of funds from Waverley Mining

Miners invested #10,000 of their redundancy cash when the mine was privatised in 1992.

Officials from the STUC were in urgent talks yesterday with the NUM and Midlothian Council. They were seeking a meeting with liquidator John Laurie, of Coopers and Lybrand, to discuss the possibility of a buy-out. Today miners, senior politicians and local councillors will meet in Dalkeith to outline their reasons why the pit should be kept open.

Last night, NUM vice-president in Scotland Peter Neilson said the union had met with the coal authority, who, he said, had made it clear they were now running Monktonhall.

The coal authority, he said, planned to advertise the mine in The Times tomorrow in a bid to attract interested parties.

Midlothian MP Eric Clarke described yesterday's news as devastating. He added: ''The closure of the colliery would present a major blow to the Lothians' economy with a knock-on effect on rail and transport workers plus others employed by companies supplying Monktonhall.''

Mr David Hamilton, convener of the council's strategic services committee, said Monktonhall contributes #6m-a-year to the local economy. He added: ''There are considerable coal reserves at Monktonhall and I am optimistic that there are opportunities for a buyer from outside Scotland to take advantage of Scottish markets through Monktonhall's existing contracts.''

Chief executive Mr William McLucas, added: ''I feel bloody terrible. We have nursed this thing for three years, poured money into it to get to the point where it was breaking even and looking fantastic for the future. To have this final kick in the teeth is pretty depressing stuff.''