KUNMING - Seven officials will be prosecuted and 15 others will receive administrative punishments for a deadly colliery blast in Southwest China in April and their attempts to cover up the accident, the local mining safety watchdog said Thursday.

Those to be indicted include the mine bosses, two mining officials of a township government and two mine safety supervisors in the city of Xuanwei, Yunnan province, the provincial coal mine safety supervision administration announced in a statement.

Twelve miners were killed and three others were injured in explosions at Yangmeishan Coal Mine in Xuanwei's Haidai township on April 15. An investigation found that after the accident mine bosses and township government officials hid corpses, forged safety records, tampered with witnesses, destroyed evidence and arranged secret deals in an effort to silence the victims' families.

"They tried to hide the scale of the accident. What they did was extremely bad and had very negative social impacts," the statement said.

It said the mine was shut down, its license revoked and owners fined 6.3 million yuan (about $1 million).

The administration, however, did not reveal the charges against the officials and the identities of the 15 others who received various administrative punishments.

China's mines are among the deadliest in the world. The latest available data from the central government showed that 1,973 miners were killed in coal mine accidents in 2011. The death toll for that year, however, was 19 percent lower than that of 2010.