The state’s China News Service cited provincial officials as saying coal was being mined illegally at both operations.

The Taozigou mine in Sichuan province was meant to be closed for a technical upgrading period but mining continued at 22 coal faces, none of which had ventilation facilities, according to the state news website.

A spark is said to have set off an explosion due to accumulated gas in the mine, killing 28 people and injuring 18.

Reports from both China News Service and Xinhua confirmed that all mines in the region had been temporarily closed for a safety overhaul and the Taozigou mine had been closed permanently.

Before the blast at the Taozigou mine on Saturday, another mine explosion occurred on Friday evening at the Dashan mine in Guizhou province.

Thirty people were in the Dashan mine at the time of the explosion, leaving 12 dead and two injured.

An official from the local work safety administration told China News Service that the fatal blast was caused by mining being conducted past the approved coal seam.

Illegal mining in China has caused numerous accidents and caused thousands of deaths over the past decade.

According to the country's work safety administration, 1384 people died in 2012 in mining accidents – down 29.9% from 2011 – but safety remains an issue for the coal producing giant.