The death toll in Wednesday's mine blast in Sichuan province climbed to 45 on Sunday, as one more body was retrieved in the morning.

"More than 2,000 search-and-rescue personnel are looking for the last two miners trapped in the pit," said Mu Fei, deputy chief of the Panzhihua city government information office.

A rescuer takes a nap in a stretcher on Friday at the Xiaojiawan Coal Mine in Panzhihua, Sichuan province. Lu Jia / for China Daily

A total of 154 miners were in the Xiaojiawan Coal Mine in Panzhihua when the gas explosion took place around 5 pm on Wednesday. Of the 108 survivors, 54 are receiving treatment in four hospitals in the city.

"It's the largest gas explosion in the country since 2009. The death toll accounts of one-quarter of the country's total in gas accidents in the first eight months of this year," said Wu Yin, deputy chief of the National Energy Administration.

Wu is a member of the State Council investigation group probing the explosion. The group is made up of leading officials from the State Administration of Work Safety, State Administration of Coal Mine Safety, National Energy Administration, Ministry of Supervision, the All-China Federation of Trade Unions and the Sichuan provincial government.

Group members have said malpractice and poor management caused the accident.

"The mine owner allowed miners to drill at a site not permitted by regulations. And there was no gas sensor where the workers drilled — which would have automatically cut the power — so work continued despite the excessive amount of gas," said Fu Jianhua, director of the State Administration of Coal Mine Safety.

The Xiaojiawan mine, which has little modern equipment, was unusually narrow and was supposed to have no more than 75 miners. But when the explosion took place, 154 miners were underground.

"After the incident, the mine could not provide a map showing the layout of the pit. When its technicians were asked to draw the map of the mazelike pit for rescuers, they kept changing it (because they did not know the layout)," said group leader Yang Dongliang, head of the State Administration of Work Safety.

The mine owner resorted to deception when reporting the accident, saying there were fewer miners at the site.

The confusion with the map and the misleading report hindered rescue operations, said Yang, who said he was puzzled how a mine with so many problems could have all the required operating certificates.

Nationally, 5 million miners work at annual production of 3.5 billion tons of coal, said Yang.

Yang said he was astonished by the poor living and working conditions generally found at coal mines.

According to Liu Jie, deputy governor of Sichuan, the mine passed a safety check in the province one month before the explosion.

"For personal gain, some government officials help businessmen at the expense of public interest," the deputy governor said angrily.

Liu promised that any officials involved in fraud at the mine would face severe punishment.

Yang Shuwen, an official with the Supreme People's Procuratorate, said that during the accident investigation, procuratorial agencies will probe whether government workers had been derelict in duty, showed favoritism, or otherwise undermined the law, making them accountable to the victims' families.

In an emergency meeting on work safety in Sichuan held on Friday evening, Liu said Sichuan had decided to close all small coal mines with an annual output below 60,000 tons.

Meanwhile, another gas explosion killed two miners and stranded 13 others underground at Gaokeng Coal Mine in Pingxiang, Jiangxi province, on Sunday, China News Services quoted sources with local publicity authorities.

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