Laserfiche WebLink
Demonstration of Compliance Climax Molybdenum Company <br /> With Regulation 41 Permit M-1977-493 <br /> Beginning in the 1990s several reclamation and environmental protection projects were <br /> undertaken in the Eagle River Watershed, as described in Section T-5.2.2 of the EPP. A brief <br /> chronological summary of these projects is as follows: <br /> ■ 1 Dam was upgraded and reconfigured in a project that was initiated in 1989 and <br /> completed in 1992. Briefly, this project entailed construction of a large-diameter toe <br /> drain collection and discharge system, flattening of the slope of the dam from <br /> approximately 2H:1V to approximately 4H:1V, and armoring the face of the dam with <br /> rock cover material. <br /> o The 1 Dam toe drain system collects seepage from 1 Dam and routes it to <br /> Warren's Pump Station (within the Robinson Lake footprint) for delivery to the <br /> Climax water treatment system in the Tenmile Creek basin. <br /> ■ In 1993, a project was initiated to convert the Oxide Tailing Impoundment (4 Dam), <br /> now referred to as Eagle Park Reservoir,to a fresh water impoundment to allow Climax <br /> to sell the storage facility. The conversion of this impoundment required draining of <br /> impacted water, removal of tailing material and contaminated sediments, and <br /> prevention of Robinson Lake seepage from entering the impoundment. This project <br /> was completed in 1997. Impacted media (water, tailing, sediment, and soils) were <br /> removed to the Tenmile TSF and 2 Dam during the course of this project. Eagle Park <br /> Reservoir was released from DRMS financial warranty and was sold to a private <br /> consortium of downstream users in 1998. <br /> ■ The construction of the Robinson Seepage Pump System occurred in 1997 in <br /> conjunction with the conversion of Eagle Park Reservoir to a clean water reservoir. <br /> The initial construction focused on the installation of a concrete cut-off wall below the <br /> Robinson Dam outlet area that is keyed into bedrock on the bottom and sides. The <br /> system was improved in 2001, by extending the height of the wall and creating a <br /> collection pond on the upstream side of the cutoff wall to provide detention storage <br /> and emergency storage capacity in the system. <br /> ■ Warren's Pump System, including Tim's Pond and Warren's Pump Station, was also <br /> constructed in 1997, to reduce the flow of 1 Dam seepage into Robinson Lake. Prior <br /> to its construction, 1 Dam seepage would flow into Robinson Lake. Tim's Pond <br /> consists of a cut-off wall and collection pond designed to capture and contain 1 Dam <br /> seepage, which is then piped to Warren's Pump Station. Warren's Pump Station <br /> serves to pump waters collected below 1 Dam back to the water treatment system in <br /> the Tenmile Creek basin via the 2 Dam Pipeline. <br /> ■ Additional reclamation work was performed on the Robinson TSF beginning in 2004. <br /> Portions of 1 Dam were covered with topsoil and revegetated successfully from 2004 <br /> to 2009. The majority of the remainder of the TSF was capped with rock material to <br /> reduce infiltration of surface water into the tailing material and reduce available oxygen <br /> necessary for acid production. The vegetation also consumes water that would <br /> otherwise infiltrate into the tailing material and become impacted. Revegetation work <br /> began in 1997 and is ongoing. As part of a reclamation project in 2005, the East Side <br /> Channel and a spillway for the TSF through 2 Dam were constructed and now convey <br /> December 2016 12 <br />