The death toll from a collapse at a coal mine in northern China rose to four on Thursday, state media reported, as the search for dozens still missing resumed after a massive landslide hindered progress overnight.

More than 50 people were trapped when a 180-metre-high slope gave way at the open-pit mine in the Inner Mongolia region’s Alxa Left Banner area at around 1pm (5am GMT) on Wednesday, according to state broadcaster CCTV.

Hundreds of rescue workers were dispatched to the remote site, but another landslide later that day temporarily halted efforts to save those trapped beneath the rubble.

Rescuers have since resumed their work, CCTV reported around midday Thursday, adding that at least four people had been killed in the incident, with six injured and 49 still unaccounted for.

Footage from the broadcaster showed rescue workers in orange overalls and yellow helmets dwarfed by a mountain of rust-coloured rubble, and excavators working to clear some of the debris.

“I had just started work when I saw slag falling down the slope. The situation got worse and worse,” a rescued worker named Ma Jianping told CCTV.

“We tried to organise an evacuation, but it was too late — the slope came down,” he said from a hospital bed in the neighbouring Ningxia region, a catheter protruding from his throat.

The injured were all currently in stable condition, CCTV reported a doctor at the hospital as saying.

State media initially reported that the collapse had affected a “wide area” of the mine operated by the Xinjing Coal Mining Company.

It was not clear what caused the collapse, and calls to the company by AFP went unanswered on Thursday.

CCTV on Thursday said police were investigating the collapse, with “the relevant personnel currently under control”. The report did not share further details.

A video posted on social media by a coal truck driver on Wednesday showed rocks cascading down a slope, kicking up clouds of dust that engulfed several vehicles.

“The whole slope has collapsed… How many people must be dead from that?” a male voice can be heard saying in the background.

“If I’d lined up over there today, I’d have died in there, too.”

Chinese President Xi Jinping has instructed authorities to “do everything possible to search for and rescue the missing people”, state media reported Wednesday.

Dangerous work

Located in China’s arid north, Alxa League — which includes the Alxa Left Banner — is a sparsely populated region whose economy runs largely on mining and other extractive industries.

Mine safety in China has improved in recent decades, as has media coverage of major incidents, many of which were once overlooked.

Accidents still occur frequently, however, in an industry where safety protocols are often lax, especially at the most rudimentary sites.

Around 40 people were working underground when a gold mine in the northwestern Xinjiang region collapsed in December.

In 2021, 20 miners were rescued from a flooded coal mine in northern Shanxi province, while two others died.