At least 13 miners were killed when an explosion ripped through a mine in southwestern China, just weeks after safety inspectors warned of high levels of gas in the shaft, state press said Friday.
The blast occurred in the Gaoqiao coal mine in Chongqing municipality early Thursday evening, Xinhua news agency said.
An investigation into the precise cause of the explosion is underway, it added.
According to the report, local safety inspectors at the end of last year warned mine bosses of high levels of gas concentrations in the shaft.
China is the world's largest coal producer and consumer, and its mines have been rife with accidents as energy demand has rocketed along with the boom in the nation's economy.
Accidents in the nation's mines took nearly 3,800 lives in 2007, down about 20 percent from the year before and following a series of efforts to improve safety in the industry.
But independent labour groups say the real death toll is much higher than official figures as local mine bosses and regional leaders cover up accidents to avoid fines and costly shut downs.
