The blaze appears to have started in a building containing offices and dormitories in Luliang city of Shanxi province.

The fire broke out on Thursday morning at the Yongju Coal Industry Joint Building in the country’s top coal-producing hub of Shanxi province.

The blaze appeared to have started in the four-storey building with offices and dormitories in Luliang city, and not where coal was being mined. The cause of the fire is still under investigation.

Rescuers evacuated 63 people from the premises, 51 of whom were hospitalised, and brought the fire under control by the afternoon.

Video footage posted on the social media site Weibo showed bright flames and thick black smoke billowing from the building, while dozens of people stood in the parking lot watching.

The building shown in the video matched images of the coal company’s headquarters posted on its website.

Emergency response personnel could be seen in the footage racing to put on protective gear outside a fire truck parked at the building’s entrance.

China’s coal producers are under scrutiny for a series of accidents in mines in recent months, which has weighed on production as mines stop work for safety inspections.

In August, 11 people were killed in an explosion at a coal mine also in Shanxi province.

A deadly mine collapse in Inner Mongolia in February that left more than 50 miners trapped, forced production to be halted for an official investigation, causing direct economic losses of more than 204 million yuan ($27.99m), according to local media.