A senior Chinese official has accused the country's coal mine operators of covering up at least 12 accidents in the first three months of this year.
The safety record of Chinese mines is extremely poor
They "have sabotaged the (accident) scenes, destroyed incriminating evidence and removed the bodies," said safety official Li Yizhong.
China's mines are among the most dangerous in the world.
About 5,000 deaths are reported every year, but independent groups put the annual death toll at about 20,000.
This week alone, at least 64 people have been killed in Chinese mines.
In the most recent accident, early on Thursday morning, 11 miners were killed and six are still missing after a blast in northern Hebei province.
Mr Li, the head of the State Administration of Work Safety, said mine owners and managers had purposely destroyed incriminating evidence of accidents at their plants.
"Those responsible have covered up the accidents and refused to report them," said Mr Li, in a speech posted on the administration's website and also reported by state media.
China's government has been trying for years to improve safety in the coal industry.
Last year Beijing pledged to close all small mines, which often have the worst safety record.
But coal provides more than two-thirds of China's electricity, and demand is huge, hampering progress at improving safety standards.