ABSTRACT
During the 1980s, a sulfuric acid solution was pumped into the Agua Zarca aquifer in order that a mining venture could leach and recover copper from an ore body located in a graben surrounded on four sides by local and regional faults. This operation impacted approximately 25 million gallons of groundwater, with pHs as low as 2.2 and dissolved copper concentrations as high as 385 milligrams per liter (mg/L). A Remedial Investigation and Feasibility Study (RI/FS) was conducted to characterize the contamination and evaluate remedial technologies which would restore groundwater to the specified applicable or relevant and appropriate requirements (ARARs). The overall extent of acidic groundwater was identified during the RI and subsequent treatability testing, using site groundwater, provided critical information for the FS remedial alternatives evaluation. A groundwater model was also developed to assist in selecting optimum pumping scenarios. This paper describes an approach for evaluating remedial technologies at sites that are impacted by acidic groundwater.
