Chinese mine officials arrested

Thousands have died in a series of deadly accidents

Police in China say four mining officials have been detained following an explosion at a coal mine in northern China on Thursday which killed at least 33 people.

A police spokesman said those held included the owner of the Podi mine in Shanxi province, Hou Junping.

Investigations are continuing into the cause of the blast.

Another two such blasts were reported over the weekend in Shanxi province, with eight people killed.

China's coal industry is the world's largest, but also one of its deadliest, with 5,300 deaths reported last year alone in mining accidents.

State media said on Sunday that the Chinese cabinet had approved spending of $64m on improving safety.

Twelve miners were rescued from the privately run Podi coal mine in Jiaocheng county after the blast late on Thursday, the official news agency Xinhua said.

The other explosion occurred on Wednesday at a mine in Yuxian county, about 50 km south-west of the local capital, Taiyuan.

Poor ventilation

Initial investigations point to a blockage in a ventilation system caused after a new shaft was built too close to a former one.

The China Daily newspaper said two workers in Yuxian had been rescued after the blast and 26 had escaped from the small mine.

The Yuxian mine was due to close because of "small production and flawed safety standards", the China Daily said.

A Xinhua report quoted an official as saying the mine had been shut since June and the workers on site were making repairs.

Lack of safety

But the agency quoted a survivor as saying the workers had been mining coal when the blast happened.

In September, at least 23 people were killed in a similar blast in Shanxi.

Most miners comes from poor rural areas with high unemployment, and are willing to jeopardise their lives to earn a living.

The main causes of mining accidents include lack of training, poor engineering and a lack of basic safety features such as adequate ventilation to disperse coal gas produced while mining.