"The definite number is not available," Xinhua said late on Monday.
About 116 men remain missing following Sunday's blast at Shaanxi province's Chenjiashan Coal Mine, which occurred as nearly 300 miners were on duty.
A mine official, Song Zhigang, told Xinhua that even though a ventilation system had been repaired, the hundreds of rescuers involved were still having difficulty getting to the area where the explosion took place.
It was impossible for those still missing to have survived because there was no air in the underground area where they were trapped, the China Daily quoted an unidentified mine official as saying.
"They have no chance of surviving at all, not even a 1% chance," said Yan Mangxue, Communist Party secretary for Yaoyu village, home to 14 of the trapped miners.
Yan was citing information given to all local government and mining officials during a meeting on Sunday night.
"Imagine a gas poisoning inside your home, you would die in no more than half an hour. Inside a mine, with no air ventilation, it's much faster. In five minutes you would lose your life," Yan said.
China's coal mines, which provide the main fuel for the world's seventh-biggest economy, have a dismal safety record that has been underscored by a series of major accidents this
At least two others occurred in the past few days. Seven miners were killed in a fire on Thursday at a mine in eastern Jiangxi province, the official Xinhua news agency said.
The rescue operation continues
as relatives await news
One man was killed and four injured on Saturday in a mine gas blast in Xuanwei in southwestern Yunnan province, it said.
A blast at the Chenjiashan mine in 2001 killed 38 workers.
Rescuers advanced several hundred metres into the mine, but were blocked by heavy smoke, state media said.
Sunday's blast could be the worst since a September 2000 explosion in the southern province of Guizhou killed 162 people.
The top priorities were to repair ventilation equipment damaged in the explosion, and to guarantee the safety of rescuers, Xinhua quoted Zhao Tiechui, deputy head of the State Production Safety Bureau, as saying.
A mine blast in September 2000
killed 162 people
Of the miners who escaped, 45 were injured and in hospital, Xinhua said. Some had suffered carbon monoxide poisoning.
Chinese President Hu Jintao urged officials to "take substantial steps and spare no efforts" to save those trapped.
About 2000 rescue workers have rushed to the mine, 740km southwest of Beijing, along with the Communist Party's provincial boss and the acting provincial governor.
The Chenjiashan mine, administered by the Tongchuan mining administration, can produce 2.3 million tonnes of coal a year.
The blast occurred two days after the Shaanxi government ordered tougher mine inspections and closure of any mine with insufficient or substandard ventilation.
The provincial government has ordered all mines in Shaanxi with high gas concentrations to halt operations until safety examinations have been carried out, Xinhua said.
Official figures show 4153 coal mine deaths in the first nine months of this year, down 630, or more than 13%, from the same period last year.
A coal mine blast in central Henan province this month killed 33. That followed an October explosion in Henan that killed 148.
Sixteen officials in the northern province of Hebei are being prosecuted for covering up a coal mine explosion on 3 June that killed 14 and injured 23, the China Daily said.