Twenty-nine people were confirmed dead and 19 injured in a coalmine gas explosion in Northwest China's Gansu Province, rescuers said Tuesday.

The explosion occurred at 12:16 pm yesterday at the Weijiadi mine belonging to Jingyuan Coal Industry Corporation in the city of Baiyin.

A ventilation system was being checked when the blast occurred, said Wang Jun, general manager of the company.

Workers above ground only realized an accident had occurred when a sudden blackout of gas monitoring and communication systems occurred at 1:36 pm. They immediately started emergency procedures, Wang said.

The 29 fatalities occurred at one level, where six miners were injured including one seriously. Thirty-six miners, including 13 injured, were rescued from other levels. All the injured are being treated at local hospitals.

State-run Jingyuan Corp has an annual output of 8 million tons of coal. It ranks 59th in the nation's top 100 coal producers according to Chinacoal Website, recording a turnover of 1.2 billion yuan (US$154 million) in 2005.

In May, one of its mines was the site of a carbon monoxide poisoning accident that caused nine deaths.

Winter is a dangerous season for miners. Last week, at least 40 miners died or remain missing in the Xinjiang Uygur Autonomous Region, Jilin, Hebei and Guizhou Provinces, according to the website of the State Administration of Coal Mine Safety.

"There is a much higher coal demand in the winter, which increases production," an official from the administration warned in a recent work meeting.

"Besides, inspection of production safety has slackened due to a comparatively stable environment in the first three quarters of the year."

They called for stricter accident investigation and penalties.