One miner has been killed and five others trapped by a sudden gas outburst at a deep coal mine in southwest China's Sichuan Province Saturday, local authorities said.

More than 100 rescuers arrived at the coal mine in Hongbai Township, Shifang City, after the accident occurred around 9 a.m. Saturday down a pit about 3,500 meters deep, officials said.

Operations at the pit in question had yet to start. Miners were cleaning the shaft when the accident occurred, they said.

Hongda Red Star Mining Co., Ltd. ran the mine responsible for the pit.It is not yet clear if the mine was licensed.

Authorities are probing the case.

It is the third gas leak to hit China's coal mines in a week. Twenty-seven people were killed in two prior accidents in southwest and central China.

Also, 16 miners died after being trapped in a gold mine fire in Zhaoyuan City, east China's Shandong Province since late Friday. All of the other 313 miners were rescued by Saturday noon.