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 a.m. 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 under ground. The report said the explosion was caused by a gas buildup. It shattered windows within 20 yards 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 northeast of the provincial capital, Harbin. It is run by one of Chinas 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. A blast at the Tunlan coal mine in northern Chinas Shanxi province killed 77 people in February in Chinas worst industrial accident in a year.