The incident occurred Friday at a Fenghuangtai Coal Industry Co. mine in Qinyuan county.

China's imports of copper rose 9.3% from a year earlier.

Exports of the group of 17 minerals from the world's largest producer stood at 3,637.10 tonnes last month.

A recovery in steel margins in China eased concerns over weak demand for the metal.

China is exposed to international iron ore prices as it must import nearly 80% of its annual consumption.

Bullion rose even after Federal Reserve officials pledged the central bank would continue an aggressive fight to cool soaring inflation.

A group of companies is investigating why a commodities storage site is holding only one-third of the copper concentrate they were financing.

Almost a third of China’s steel mills could go into bankruptcy in a squeeze that’s likely to last five years, said the chairman of Hebei Jingye Steel Group.