The death toll from a rock blast in a Chinese coal mine has risen to 10 after two seriously injured workers who were rescued from the shaft died from their wounds, state media reported Tuesday.

The accident happened in the central province of Henan last week, instantly killing eight miners and trapping another 53, most of whom were only pulled out 40 hours after the blast in a rescue mission broadcast live on state TV.

Three of those pulled out were in a critical state, and two subsequently died, a mine official was quoted as saying by the official Xinhua news agency.

The miners had been trapped by a rock burst -- a violent explosion caused by huge pressure -- moments after a minor 2.9 magnitude earthquake struck the city of Sanmenxia, according to Xinhua.

It was not immediately clear if the earthquake directly caused the accident at the colliery, which is part of the Henan Yima Coal Mine Group, a giant state-owned mining company.

Officials at the group refused to comment when contacted by AFP.

While mining accidents are common in China, it is unusual for so many people to be successfully brought to the surface alive.

The operation is the most successful such effort in the country since April 2010, when 115 miners were rescued after eight days of being trapped underground at a mine in northern China.

But the incident was the latest to hit the hazardous mining industry in China, and came days after a gas explosion at a state-owned coal mine in neighbouring Hunan province left 29 miners dead.

Earlier in October, blasts at mines in the southwestern city of Chongqing and the northern province of Shaanxi killed 13 and 11 miners respectively.

In 2010, 2,433 people died in coal mining accidents in China, according to official statistics -- a rate of more than six workers per day. Campaigners suggest the true figure is likely to be far higher.