The death toll from a coal mine blast in northeast China has risen to 87, with 21 other miners still trapped, state media reported Sunday. Rescuers have located eight of the trapped workers but it is unclear if they are alive, the China News Service reported. The toll rose from 42 dead and 66 trapped on Saturday evening. The blast occurred early Saturday at 2:30 am (1830 GMT Friday) at a mine in Heilongjiang province, according to a statement issued by the State Administration of Work Safety. A total of 528 miners were working in the pit, near Hegang City, when the blast occurred, the state administration said. President Hu Jintao and Prime Minister Wen Jiabao have issued instructions on the rescue, while Vice Premier Zhang Dejiang was dispatched to the mine to oversee the operation, state media said. The head of the mine run by the Heilongjiang Longmay Mining Holding Group and the mine's chief engineer have been removed from their posts, the China News Service said. The director of the work safety administration has been charged with leading an investigation into the blast, it added. According to the mining group's website, the mine produces 1.45 million tonnes of coal a year and in 2009 ranked 12th out of China's top 100 mining companies and seventh in terms of production volume. The blast comes after the central government has campaigned in recent years to modernise its collieries and control the leakage of gas, particularly methane, a pollutant responsible for several mine explosions. China has a dismal work safety record, with thousands of people dying every year in mines, factories and on construction sites. Its coal mines are among the most dangerous in the world, with safety standards often ignored in the quest for profits and the drive to meet surging demand for coal -- the source of about 70 percent of China's energy. 