Xinhua reported that a rock outburst early on Friday morning trapped 20 miners at the Junde coal mine in the northeast Heilongjiang province.

Contact was established with 16 of the miners, who were rescued about 10pm Friday. Rescuers are trying to make contact with the four remaining miners.

The accident comes after a gas blast at a mine in the southeast of the country last Tuesday.

While 21 people were killed, four remain missing after the explosion at the Machang coal mine, Shuicheng county.

The explosion is the third in the area in the past five months. Another 13 miners died in an explosion in Panxian county on January 18 and a coal gas burst just two months earlier killed 23 miners at the Xiangshui mine.

In the aftermath of this most recent explosion, authorities announced that 18 local government officials had been reprimanded.

Xinhua reported that a statement from the Liupanshui Municipal government said a number of heads of local provinces and safety bureaus had been stood down, sanctions were issued and eight local officials directly responsible for the accidents had been detained.

The statement also revealed that the municipal government would suspend the three mines and increase safety monitoring across all the mines in the province.

According to recent economic figures from the Chinese National Bureau of Statistics, the country’s 2012 coal mine death toll was down 33.75% from 2011.

Government efforts to reduce hazardous mines have resulted in the closure of more than 9000 small coal mines since 2006.

In September, Chinese authorities pledged to shut down 20,000 illegal and unsafe mines by 2015 following a string of deadly gas explosions and collapses.