China may have almost a fifth more coal producing capacity than it needs to meet demand by 2010, threatening the viability of some mines in the world's largest producer and consumer of the fuel, a government official said.

The nation's coal miners will be able to produce as much as 3.1 billion metric tons of the fuel by the end of the decade, Huang Yi, spokesman for China's State Administration of Coal Mine Safety, said in a phone interview from Beijing Friday. That's 19 percent more than demand, which will be capped at 2.6 billion tons, Huang said.

China burns coal to generate 78 percent of the power in the world's fastest-growing major economy. Excess capacity may drive coal prices lower and reduce producers' profitability, Bloomberg News reported.

"We shouldn't allow capacity to reach those levels because it will harm the sustainable development of China's coal mining industry," Huang said.

China is building and upgrading 1.1 billion tons of coal capacity, he said. Potential output jumped from 998 million tons in 2000 to 2.38 billion tons at the end of last year, Xinhua news agency reported yesterday, citing Zhao Tiechui, director of the safety administration.