The purpose of this letter is to provide additional information concerning possible modifications to the Barrel (Preferred) Alternative. In short, Rosemont has determined that although the Barrel Alternative allows sufficient space to accommodate the proposed heap leach pads, the operational sequencing required under this alternative does not allow Rosemont sufficient time to complete the leaching process and fully recover the copper from the oxide ore materials. In addition, Rosemont has reevaluated the underdrain systems for the waste rock and tailings storage areas, and has concluded that the regulatory uncertainty and confusion created by the underdrain system exceeds that system’s geotechnical and environmental benefits. Consequently, Rosemont is proposing to eliminate these features from the Barrel Alternative.
Rosemont Copper Company. 2012h. Rosemont Copper Project; Proposed Modifications to Barrel Alternative. Letter from Katherine Ann Arnold, Vice President, Environmental and Regulatory Affairs, Rosemont Copper Company, to Jim Upchurch, Forest Supervisor, Coronado National Forest. Document No. 052/12-15.3.1. Tucson, AZ: Rosemont Copper Company. July 10.