Rescuers said on Sunday there was little hope that 11 missing miners survived a gas leak in a central Chinese coalmine that already claimed 26 lives.

With sorrow etched on her face, a young relative of a miner killed in a gas leak grieves near the coalmine, in Yuzhou, Henan, on Sunday. [Photo/China Daily via Agencies]

"Based on experience, the remaining 11 miners could be buried in coal dust, so the chances of survival are slim," Du Bo, deputy chief at the rescue operation headquarters, was quoted by Xinhua as saying.

The accident occurred at about 6:00 am on Saturday in a pit owned by Pingyu Coal & Electric Co Ltd in Yuzhou, Henan province.

A total of 276 miners were working underground when the accident happened but 239 managed to escape.

The confirmed death toll rose to 26 by 8:00 am on Sunday, but the condition of 11 missing miners remains unknown, according to the headquarters.

Ventilation and electricity were resumed to the pit on Sunday afternoon.

The rescue operation is being hindered by as much as 2,500 tons of coal dust released during the accident as well as high levels of gas, the rescue headquarters said.

"We have already located the trapped miners, but we must clear the dust from the shaft first, which could take several days," said Du.

Pingyu Coal & Electric Co Ltd was jointly established by four investors, including Zhong Ping Energy Chemical Group and China Power Investment Corp, which are State-owned.

The same mine suffered a gas leak on Aug 1, 2008, which claimed the lives of 23 miners.

"After the accident in 2008, the mine took measures to prevent gas leaks," said Du, who is also an engineer with the mine's parent company.

Miners were drilling underground on Saturday to release high-density gas, as part of procedures to prevent gas leaks.

Liu Wenbin, assistant chief engineer of the mine who was underground when the accident happened, said everything went well at first. But the ventilation system in the pit had been "abnormal" at 5:00 am, he said. "I then asked workers to leave the shaft immediately."

Officials said most of the 26 victims were Henan residents.

Luo Lin, head of the State Administration of Work Safety, and Zhao Tiechui, head of the State Administration of Coal Mine Safety, rushed to the site on Saturday to supervise the rescue operation.

Luo criticized officials at the mine and urged them to learn from the accident. "Fortunately, there was no gas explosion in the accident, otherwise no one could have escaped."

The rescue operation attracted the attention of Chilean President Sebastian Pinera, who offered to help using his country's experience at the San Jose mine in northern Chile where 33 miners were rescued last week after being trapped for two months.

"If we can be of any help, they (the Chinese) know that they can count on us," Pinera said during a visit to London.