State media said Saturday that the three had slim chances of survival because they were believed to be located at the center of the explosion that shook the Xiaojiawan coal mine Wednesday afternoon in coal-rich Panzhihua city in the southwestern province of Sichuan.
Police detained the mine owners, and the Sichuan government launched a province-wide safety check on all coal mines and pledged to shut down those with safety hazards.
There were 154 miners working at the mine when the explosion occurred, and 108 survivors have been pulled to the surface.
It is China's deadliest mine accident since November 2009 when 108 people were killed in an explosion in a mine in Heilongjiang province.
The official Xinhua News Agency said the rescue work was dangerous because of high temperatures in the mine and dense carbon monoxide that meant only mask-wearing paramedics were able to enter the shaft.
Xinhua quoted one miner, Xu Changyong, as saying he heard the explosion and then ash started coming out of his air compressor before he scrambled out of the mine.
Of the miners who made it to the surface, 50 are suffering from carbon monoxide poisoning and seven are in critical condition, Xinhua said.
The mine is owned by Zhengjin Industry and Trade Co. Ltd. and the owners were in police
Coal mine accidents are common in China, where work safety rules are often ignored. Last year, 1,973 miners were killed in coal mine accidents in the country, but that was down 19 percent from the previous year as authorities continue to beef up safety measures.
The State Administration of Work Safety said last week that it planned to close more than 600 small coal mines—considered more dangerous than larger mines—this year to further reduce fatalities.