Seventy-one miners were in the shaft when the blast occurred on Thursday afternoon at Nanlou township near the city of Yangquan in Shanxi province, a county official said.

The accident comes less than two weeks after 166 people were killed in a coal mine in neighbouring Shaanxi province in the country's worst mining disaster in 44 years.

``It is a problem of mine management and a lack of safety awareness,'' said An Yuanjie, propaganda director for the State Administration of Coal Mine Safety.

``Over-production exceeding mine capacity, especially in the small mines where there is already a lack of safety facilities, as well as inadequate investment in safety infrastructure, these are all the reasons that are causing these coal mine disasters.

``As the national administration of work safety we need to strengthen our efforts to supervise these mines,'' she said. Experts blame most accidents in China's mines not just on poor safety but the government's failure to enforce regulations.

While the government said it closed down 60,000 small mines in the last decade because they were considered unsafe and inefficient, soaring demand has led to many being reopened.

As well as safety concerns, China's miners have to deal with health issues.

According to recent state media reports, about 600,000 miners suffer from pneumoconiosis, a disease of the lungs caused by inhalation of dust.

The figure is increasing by some 70,000 miners every year, Xinhua said.

China depends on coal for 70 per cent of its energy and has significantly increased production in the past year to meet the demands of rapid industrialisation.

Critics and miners say lives are being sacrificed in the quest for energy.

Officially, more than 7,000 workers are killed each year in China's coal mines, considered the world's most dangerous.

However, labour rights groups say the real figure could be around 20,000 as many accidents are unreported in an effort to keep mines open and to avoid fines.

An, at the mine safety bureau, said it was likely that small mines in the Yangquan region would be shut down for safety inspections following the latest tragedy, but it was too early to say how many would be closed or for how long.

China's mine safety record also highlights the dismal plight of workers who do not enjoy the right to form independent unions or undertake collective bargaining, critics say.

AGENCE FRANCE-PRESSE