A gas explosion at a coal mine in northern China on Friday was the result of the company involved having committed multiple serious safety violations, according to a preliminary investigation by Chinese authorities. The announcement was made around the same time the incident's death toll was revised down from 90 to 82, with officials apologising for having conducted an incorrect headcount amid the initial confusion.The blast, at the Liushenyu coal mine in Shanxi was the country's biggest mining disaster in 17 years, after 108 people were killed in a mine blast in the north-east Heilongjiang province in 2009.More than 750 emergency personnel had been dispatched to the incident, and search efforts were still underway to find two missing people as of Saturday evening, state broadcaster CCTV reported.A total of 247 workers were underground at the time of the blast, which occurred at 7:29pm on Friday, local time, according to state news agency Xinhua.Of those, 128 people were sent to hospital for treatment, CCTV said.Medical staff attend to an injured worker after the mine explosion. (Xinhua News Agency via AP: Cao Yang)Sulphur smellMiner Wang Yong, who was injured in the blast, told CCTV he smelled sulphur right as the explosion happened."I didn't hear any sound at all, but then a cloud of smoke appeared," he said."When I smelled it, it was the smell of sulphur, like when people set off firecrackers. When the smoke came down, I shouted for people to run."He recalled seeing people choking in the smoke before he fainted."After more than an hour, I came to on my own, and then I woke up the person next to me [and got out]," he told CCTV.Chinese President Xi Jinping last night urged "all-out efforts" to treat the injured at the site of the explosion, and said any investigation into the incident must be thorough, according to Xinhua.Rescue workers prepare to descend into a coal mine in the aftermath of the explosion. (AP: Cao Yang)It was reported earlier in the evening that the government had launched an "uncompromising" investigation into the incident, as well as ordering a nationwide crackdown on illegal mining activities."Those found responsible will be severely punished in accordance with laws and regulations," the report on Xinhua said."All regions and relevant authorities are required to … launch tough crackdowns on illegal and unlawful activities" including the falsification of safety data, unclear headcounts of underground workers and illegal contracting, it added.At least one person has already been arrested in relation to the Liushenyu blast, the news agency said.Lax safety protocolsShanxi, one of China's poorer provinces, is the centre of the country's coal-mining industry.Mine safety in China has improved in recent decades, but accidents still occur in an industry where safety protocols are often lax and regulations sometimes deliberately vague.In 2023, a collapse at an open-pit coal mine in the northern Inner Mongolia region killed 53 people.China is the world's top consumer of coal and its largest greenhouse gas emitter, despite installing renewable energy capacity at record speed.AFP/ABC