Shares of Zijin Mining Group Co. fell 1.4 percent to 5.64 yuan (0.83 U.S. dollar) at Wednesday's opening on the Shanghai bourse after the company said late Tuesday that it was asked to limit production at a gold mine in the area where its copper mine polluted a river in east China's Fujian Province.

The local government of Shanghang County, where Zijin is headquartered, made the decision to limit the company's output to a level that can ensure the safety of environment, according to the company's statement filed to the Shanghai Stock Exchange.

The decision is expected to cut the company's gold output by 1 tonne this year, said the statement. Statistics show Zijin produced 75.37 tonnes of gold in 2009, up 31.05 percent from the previous year.

Between 4 p.m. July 3 and 2:30 p.m. July 4, about 9,100 cubic meters of waste water spewed from a blown-out sewage tank at a copper plant owned by Zijin into the Tingjiang River in Fujian Province, killing thousands of fish.

Trading of the company's stock was suspended for two days in Hong Kong and Shanghai pending the sensitive announcement.

The shares fell 0.4 percent to 5.72 yuan at previous trading on July 23.