Mexican mining firm complains about spill probe

Mexico City • A mining conglomerate charged Thursday that it is being subjected to "punitive" legal actions by Mexican officials because one of its mines spilled acid-laced copper sulfate and heavy metals into two rivers.

Environmental authorities have ordered a full inspection of Grupo Mexico's Buenavista copper mine near the U.S. border and threatened possible fines of up to $3 million. Prosecutors, meanwhile, have filed a criminal complaint over the spill, which caused water supplies to be shut off for tens of thousands of people in northern Sonora state.

Late Wednesday, the Mexican Senate passed a nonbinding resolution calling for the government to cancel the mine's operating concession, a move that could affect the $1 billion-a-year mining company that provides 9,000 jobs in the area. The mine produces about 200,000 tons of copper annually.

Grupo Mexico said in a full-page ad that such actions were unfair and uncalled for, "given the unforeseeable nature of the incident and the company's prompt and complete response."

Officials have said the company lied about what caused the Aug. 7 spill and the measures it supposedly took to control its effects. The company blamed heavy rains for the overflow of containment ponds, but officials have said lax supervision at the mine and construction defects appeared to have caused the accident.

The spill sent about 10 million gallons (40,000 cubic meters) of copper sulfate and heavy metals into the rivers and on to a reservoir behind a dam that supplies water to the capital of Sonora.

National water commission head David Korenfeld said the dam would have to raise intake levels for years to avoid stirring up possibly contaminated sediment.