Copper Mining  Elmhurst College
Ore Crushing Water Reclamation/Tailings Copper Smelter  Chemistry Department
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Water Reclamation and Tailings
Asarco Mining Operations in Arizona
Mission Mine, Tucson
Text edited by Rob Vugteveen, Director, Asarco Mineral Discovery Center


Water Reclamation and Tailings

The concentrated ore, now called copper concentrate, is dewatered and dried to about 10% moisture content. It is shipped by truck to the Asarco smelter in Hayden, Arizona. (The El Paso smelter is on stand-by status). Water is recovered from the tailings in another thickener. The thickened tailings flow by gravity in large pipes to tailings ponds, where the solid material settles out and additional water is recovered and pumped back to the mill. About 80% of the water used at the mine is recycled and re-used. The rest is lost to evaporation and used to keep haul roads damp to minimize dust.

After a tailings dam is decommissioned, the tailings are capped with dirt and treated with manure for grazing cows or amended with biosolids (sludge) from a local waste water treatment plant. This provides organic material and nutrients to create a sustainable soil for native grasses and shrubs.