Twelve officials have been prosecuted for alleged dereliction of duty over two mining accidents that killed 31 people in southwest China's Guizhou province last year, local work safety authorities said Friday.

Seven officials were prosecuted for the gas explosion at the Jinying Coal Mine in Panxian county on March 12, 2011. Nineteen miners were killed while 15 others were injured. The mine was operating illegally at the time and had substandard ventilation, the official probe concluded.

The head of the county government was forced to resign, while nine people found directly responsible for the accident were also indicted, officials with the Guizhou provincial work safety administration said.

In another case, five officials were prosecuted for flooding at the Fuhong Coal Mine in the city of Guiyang on May 29, which left 12 miners dead and one other missing. The mine's managers failed to halt operations in spite of early safety warnings, the work safety officials said, citing the result of a probe.

The boss of the mine, along with five others who were found directly responsible, have been indicted, the officials said.