Six miners were confirmed dead Sunday after Saturday's sudden gas leak at a deep coal mine in southwest China's Sichuan Province, local authorities said.

Rescue efforts ended Sunday after all the bodies of the six trapped miners were found, said a spokesman with the government in Shifang City, where the coal mine is located.

The gas leak occurred at 9 a.m. Saturday down a pit about 3,500 meters deep. Fifteen workers were cleaning the mine's shaft at the time.

Nine people were lifted to ground unharmed.

Authorities are investigating the deadly incident at the mine run by Hongda Red Star Mining Co., Ltd.

In a separate case, seven miners are still trapped in a coal mine pit after a sudden gas leak early Sunday morning in northwest China's Xinjiang Uygur Autonomous Region.