His 47-year-old sibling, a father of three, was working in the Liushenyu shaft in northern China's Shanxi province on Friday when a catastrophic gas explosion ripped through the mine, killing at least 82 people.

A total of 247 workers were underground at the time, according to state media.

Emergency rescuers were racing on Sunday to find two people still missing, state media reported, but it was unclear if the man's brother was one of them -- or indeed if more people were missing than had been reported.

Phone calls to the man's brother "wouldn't go through" since the explosion, he told AFP, asking not to be named, adding that his parents are still unaware that their older son is missing.

"I don't dare tell them," he said.

The man and a few other family members milled around the checkpoint on Sunday that prevented them from continuing up the road to the mine, hoping for information about their loved ones.

Police kept a watchful eye nearby, ordering AFP reporters at the checkpoint to avoid talking to the families and to leave the area.

The man said his brother, whose youngest child is just five, had been working at the mine for three to four years, earning around 7,000 to 10,000 yuan ($1,030 to $1,470) a month.

"I really hope nothing has happened to him," the younger brother said.

"They say two people are missing, but who knows if that's accurate? We honestly don't know," he added.

He said he had "no idea how the accident actually happened" and hoped only that his brother is safe.

- 'Worst' management -

As family members paced back and forth near the checkpoint, ambulances and police cars were allowed through.

Some relatives wiped tears from their faces, AFP reporters saw.

Rugged and mountainous Shanxi, one of China's poorer provinces, is the centre of the country's coal mining industry.

While mine safety in China has improved in recent decades, accidents still occur in an industry where safety protocols are often lax and regulations vague.

Chinese authorities have launched an investigation into the blast, saying initial findings showed the Tongzhou Group operating the mine had committed "serious illegal violations".

"Those found responsible will be severely punished in accordance with laws and regulations," officials told a news conference on Saturday.

Miners working at the Liushenyu shaft accused their employer of a lack of care, with two telling AFP they had not been paid in months.

"From what I've seen, the management (at this company) is the worst," said a 58-year-old miner from Shandong, who has worked in several coal mines over the last three decades.

The miner, who wished to remain anonymous for fear of repercussions, said workers at the mine paid for safety helmets out of their own pockets.

They told AFP they had been working a morning shift on Friday and were not in the mine during the gas explosion.

"If we had been (working) a few hours later, it would have been us," the 58-year-old told AFP.

"I feel really heartbroken."

AFP has contacted Tongzhou Group for comment.

- 'Worried sick' -

One middle-aged woman sitting under a tree near the checkpoint waited for information about her husband, a coal miner who also remained unaccounted for.

"Worrying about it won't do any good," she told AFP, not wanting to give her name.

"We're already worried sick, but being anxious doesn't change anything," she said.

Her husband of more than 20 years, who was unreachable since the explosion, rarely talked about his job, she told AFP.

"You should go ahead and do your work first," she said, brushing AFP reporters away.

"I'm really not in the mood to talk about this."