Clifton Town Manager Ray Pini is reported as saying "someone opened the wrong valve" that allowed thousands of gallons of a sulfuric acid solution to flow from the Morenci copper mine [right, my photo, May 2008] into the dry bed of Chase Creek. Freeport McMoRan crews were building earthen dams yesterday to stop the slow moving ooze from making it to the San Francisco river. The Eastern Arizona Courier has a photo of Freeport crews building one of the dams.
The Arizona Daily Star reports this morning that 168,000 gallons of the solution were involved and some got within 120 feet of the river before it was halted.
The acid solution is used as part of the solvent extraction/electrowinning plant to extract copper from low grade ore.