At least ten people have died in a coal mining accident in the city of Pingdingshan in central China.

Six people remain missing, the local emergency management agency said on Saturday, adding that it will continue rescue efforts and launch city-wide safety checks at operating mines.

Few details have emerged about the accident so far, but China’s Xinhua news agency said that 425 workers were underground when it happened. The emergency management agency said it will make concrete plans to help determine the cause of the accident, but no time frame was given.

A widespread safety campaign could disrupt operations in the coal-rich city and put a strain on production and supply. Coal prices jumped more than 5% in November after China’s cabinet vowed safety checks across the country would be ramped up amid rising fatal disasters at its mines.

At least 100 people died in coal mining accidents alone last year, with most of these deaths occurring in Shanxi, the country’s top coal-producing region.

A major coal mine collapse in the northern Inner Mongolia region in February last year killed at least 53 workers, although few details about the accident have emerged since initial reports broke. The mine is owned by the Xinjing Coal Company.

In August 11 people were killed in an explosion in a coal mine shaft in the Shaanxi region. Just three months ago, at the end of September, 16 were killed in a fire at a coal mine in the Guizhou region. Production at the mine was suspended for one day after the indecent. 

In November, a fire in the offices of a coal company killed at least 26, with 38 reportedly injured. Chinese police detained several people for questioning shortly after the fire broke out, state broadcaster CCTV reported at the time, although no updates have been given since.