A gas explosion at a coal mine in southwest China has trapped 50 miners underground, state media said Wednesday, in the latest disaster to hit the country's troubled mining industry.

Around 120 miners were working underground at the Xiaojiawan mine in the city of Panzhihua in Sichuan province when the blast occurred in the afternoon, the official Xinhua news agency said.

Rescue workers had already pulled 70 people out of the mine by late evening, but another 50 remained trapped with rescue efforts still underway, it said.

The mine's owner was given as the Zhengjin Industry and Trade Co.

China's mines are known for being among the world's most deadly due to lax regulation, corruption and inefficiency, and accidents are common as safety is often neglected by bosses seeking quick profits.

Rapid economic growth has caused China's demand for energy, including coal, to surge. The world's second-biggest economy is the top global consumer of coal.

In April, nine miners were killed and 16 injured in a blast at a colliery in northern China's Inner Mongolia region.