Four miners were killed and 50 more are missing after the accident happened late on November 3 in Sanmenxia City in Henan province.

State media reported that the rock burst - an explosion caused by the sudden release of built-up pressure - happened shortly after an earthquake.

Hundreds of Chinese miners die every year in pit accidents.

The industry is one of the most dangerous in the world, and is notorious for its lax safety standards.

Earlier this week a gas explosion at a mine in neighbouring Hunan province killed 29 people.