The director of China Coal Industry Development Research Centre, Guo Yuntao, said that investments in China's coal mines need to be reined in, the country's power shortages and coal shortages notwithstanding, state media reported. The warning may spur more macro-control measures to cool a sector in which investors and coal mine operators are spending billions to expand production, as they look to profit from growing coal prices, which have increased more than 50% in the past two years.