A gas explosion tore through a coal mine in northern China on Saturday, killing 31 people and trapping 82 others nearly a third of a mile under ground, government authorities said.

A total of 528 people were working in the Xinxing mine in Heilongjiang province at the time of the 2:30 am explosion, the State Administration of Work Safety said in a statement. It said 389 escaped after the blast.

China Central Television reported that 31 were dead, 26 were rescued and the others were trapped about a third of a mile (500 meters) under ground. The report said the explosion was caused by a gas buildup.

It shattered windows within 20 yards (meters) of the mine shaft.

A man answering the phone at the mine said an unknown number of people were injured. He did not want to give his name, as is common among Chinese officials.

The mine is located near the border with Russia, about 250 miles (400 kilometers) northeast of the provincial capital, Harbin.

It is run by one of China's top 520 state-owned enterprises, according to the Web site of its owner, the Hegang branch of the Heilongjiang Longmei Holding Mining Group. It says the Hegang branch has more than 88,000 employees.

China's mines are the world's deadliest, with unregulated operations accounting for almost 80 percent of the country's 16,000 mines.

The closing of many small, dangerous mines halved the average number of miners killed to about six a day in the first half of this year, the government has said.

Most accidents are blamed on failures to follow safety rules, including a lack of required ventilation or fire control equipment.

A blast at the Tunlan coal mine in northern China's Shanxi province killed 77 people in February in China's worst industrial accident in a year.