The fire was extinguished but "after preliminary verification, 16 people have no vital signs", the Panzhou City government said in a notice posted on its website.

"It was preliminarily determined that the conveyor belt caught fire," the notice said.

The Panzhou City mine is about 3,600 kilometres (2,250 miles) southwest of the capital, Beijing.

While safety in the mining sector in China has improved in recent decades, accidents still frequently plague the industry, often due to lax enforcement of safety protocols, especially at the most rudimentary sites.

In February, a coal mine collapse in the northern Inner Mongolia region left dozens of people and vehicles buried under a mountain of debris.

Authorities did not disclose the final death toll for months, only revealing in June that 53 people had been killed.