Emergency workers successfully sealed a gas well that had blown out in a farm area of Southwest China's Yunnan Province after an hour-long plugging operation Tuesday.

All 775 people living nearby had been evacuated after the well blew out on Sunday night, and no casualties have been reported.

The accident occurred at 7:25 pm, while the local farmers of Luliang County were having dinner.

"Suddenly there was a big bang as if an airplane had crashed into the field, and when we rushed out of the house, we saw a 15-metre-tall white column of gas jetting out of the well," one farmer, whose name was not identified, told the Kunming-based newspaper Metropolitan Times.

The gas column consisted of methane, nitrogen and water. "Fortunately, there was no toxic sulphur, which could have caused deaths to those who breathed it in," Xu Desheng, the county's managing magistrate, told the Xinhua.

Even so, there was grave danger. "If there were one spark of fire, an explosion could have occurred and the result could be too terrible to be imagined," said the magistrate.

To prevent a possible disaster, the county government evacuated all the people who lived within 1 kilometre of the gas well on the night of the accident.

Efforts to cap the well didn't begin until about 9 am yesterday when the blowout from the well reduced, and were successfully completed at 10:10 am, according to the Metropolitan Times.

The well had been dug only 10 days before the blowout occurred.

The accident in Yunnan was preceded by a much more serious one thousands of kilometres away. On Saturday, gas exploded in a 15-year-old coal mine in Jidong County, Jixi of Northeast China's Heilongjiang Province, killing 13 miners.

The cause of the explosion is still under investigation. Immediately after the accident occurred, Premier Wen Jiabao requested that all levels of the government be especially cautious in ensuring safe production during the holiday.

"Special attention should be given to places like coal mines, and local officials should make inspections there," he noted.