Tuesday six miners were killed and six were injured in an accident at the Hongxing coal mine in Changji city, according to official state news outlet Xinhua.

The injured workers have been rushed to hospital but the cause of the accident remains unknown.

Meanwhile, rescuers were gathering efforts to get seven trapped miners out of the Nuanquan coal mine in Luliang, Shanxi Province, after its 10m-long roof collapsed on Monday morning.

While six of the 13 workers were pulled to safety, the remaining seven were stuck underground for 42 hours.

They finally saw the light today and were sent to hospital for medical observation.

The incidents added to Monday’s gas blast tragedy that killed four and injured five more miners in the Honghe coal mine, in the Chongqing municipality in China’s southwest.

Xinhua reports three of the 12 miners were safely lifted from the worksite, while the five injured survivors were rushed to a nearby hospital.

No information has yet been released about the conditions of the surviving miners, the legality of the mine or the immediate cause of the explosion.

A probe into the accident is underway.