(Reuters) - Up to 100 Sardinian miners armed with hundreds of kilograms of explosives have barricaded themselves nearly 400 metres underground in Italy's only coal mine to put pressure on the Rome government to protect its survival.

The miners from a 460-strong workforce seized 350 kilos of company explosives and locked themselves inside the Carbosulcis mine west of Cagliari overnight on Monday, one of them said, ahead of a government meeting this week to discuss the pit's future.

"We are worried that the mine may close. We are afraid for our jobs," said Sandro Mereu, 54, a miner who has worked there for 28 years.

"We are prepared to stay here until we hear a response from the government that secures the future of the mine. We will stay here indefinitely," Mereu told Reuters by telephone.

The miners want the mine to be diversified into a combined mining and carbon capture site to protect its future. Carbon capture is the storing of polluting emissions underground to mitigate global warming.

Carbosulcis was estimated to have 600 million metric tonnes of coal reserves in 2006 but has struggled to stay productive. It was previously occupied in 1984, 1993 and 1995, when protesting workers stayed in a tunnel for 100 days.

(Reporting By Naomi O'Leary; editing by Barry Moody)