An explosion at a top state-owned coal mine in Henan province killed 12 miners and left three missing on Friday night. A provincial Coal Industry Bureau spokesman yesterday said 56 workers were underground at Malingshan coal mine in Dengfeng city, which was owned by Zhengzhou Coal Industry (Group), when the explosion happened. 'It happened about 6pm and 41 of the 56 miners managed to escape from the shaft,' he said. 'It was caused by a gas explosion because of the excessive concentration of poisonous gas in the shaft.' The spokesman said a deputy governor, the heads of the Henan Coal Mine Safety Bureau and officials from the provincial public security and health departments had arrived at the scene to direct the rescue efforts and investigations into the blast. Xinhua said Zhengzhou Coal had sent four rescue teams underground. As of last night, only 10 bodies had been recovered. Zhengzhou Coal was established in 1958 and began as a small-scale, local-government-controlled coal mine. With accelerating economic reforms fuelling the country's increasing hunger for energy resources, the group expanded rapidly to become a state-owned enterprise in January 1996. The company has 6.4 billion yuan worth of assets and employs 45,000 workers. With an annual production capacity of 10 million tonnes, it also exports to Japan and other Asian countries, according to its website. Last October, another fatal blast at the province's other large-scale producer Hebi Coal Industry (Group) Corp - one of the mainland's top 520 state-owned enterprises - killed 34 workers. China's collieries are considered the most dangerous in the world due to their high risk of poisonous gas leaks. With demand for raw materials escalating, the risks have risen, with 5,986 workers dying in coal mine accidents last year, the national safety administration reported last month. Investigations revealed rampant collusion by government officials, who also had invested in and managed coal mines, accepted bribes, covered up accidents and protected guilty parties.