JINAN, May 19 (Xinhua) -- China will close its only offshore coal mine, which has been in operation for more than 30 years, in October, as the government toughens its efforts to phase out excess production capacity.

The Beizao Coal Mine, owned by the Shandong Energy Longkou Mining Group in eastern Shandong Province, is located about five kilometers from the coast of Longkou City. Its mine shaft reaches 350 meters underwater.

Li Gongjian, the mine's manager, on Friday confirmed the closure, adding that it is part of a national move to phase out sub-standard production capacity. Sea mining is not efficient as it has a cost three times higher than mining on land.

He said the sea mine, which covers an area of 18 square km, has produced up to 8 million tonnes of raw coal.

The sea mine, with proven reserves of 1.29 billion tonnes of coal, made China the fifth country to boast offshore exploitation technology.

Li said the mine opened at a time when the country was energy thirsty, and the group's coal deposits on land were not sufficient to cope with growing market demand.

The mine shaft was not easy to reach. Miners had to take an elevator down 180 meters and a 20-minute tramcar ride to reach the mine face.

The mine's closure will force 1,580 workers to become laid-off. The company has offered them other positions.

Li said that although the mine will be closed, the company will keep and document the offshore mining technology and experience, as sea mining requires sophisticated safety systems, such as technology to prevent flooding.