BEIJING  - A gas blast at a coal mine in China's central province of Hunan killed seven people on Sunday, state media said, the latest in a string of accidents in the country's dangerous mining industry. The explosion killed the miners on Sunday morning at the mine in Lianyuan city, though 39 others escaped, the official Xinhua news agency said, quoting the local government. The latest accident came as rescuers in another part of the same province were racing to save a dozen coal miners still missing nearly four days after their mine flooded, state media said.Rescue workers pulled four miners out of the coal mine in Leiyang city on Sunday, but 12 remained unaccounted for, state television said.Rescue of the remaining miners had been complicated since water levels were at head height in parts of the mine, it said.Water rushed into the mine on Wednesday evening, trapping 16 miners underground as 24 others managed to escape, Xinhua said.The accident was not reported to the government until the following day, delaying rescue efforts by 12 hours, it said, adding that the mine's owner, Liu Yaping, was now in police custody.The local government could not be reached for comment.Accidents in China's mines occur frequently.However, tighter safety standards appear to have been effective according to the latest official figures, which say 1,973 people died in coal mining accidents in 2011, down 19 percent on the previous year.Labour rights groups say the actual death toll is likely much higher, partly due to under-reporting of accidents as mine bosses seek to limit their economic losses and avoid punishment.China is the world's biggest consumer of coal, relying on the fossil fuel for 70 percent of its growing energy needs.