Zijin Mining Group (601899.SH, 2899.HK) announced that it had shut down a copper smelter after discoveries that it had leaked acidic waste in Fujian, the Wall Street Journal reported. The mine is Zijin’s largest, and produces some 12,800 metric tons of copper annually. Reports estimate the plant leaked 9,100 metric tons of waste into the Ting river. It will be reopened only when inspected and cleared by local environmental officials. Shares of the company were briefly suspended on Shanghai’s stock exchange to prevent panic following the announcement on Monday, but shares were down 4.8% in pre-market trading.