The Site contains areas affected by mining, including three principal areas that were directly affected by mining along with other areas, primarily downstream, where hazardous substances have come to be located. The three principal areas include the 1950s Mine and Mill Area, the 19th Century Operations Area and a Main Tailings Impoundment. The Action memo recommends response actions to address threats from the main tailings impoundment.
The 1950's Mine and Mill Area comprises 15 acres and is located northwest of the intersection of Ore Knob Road and Little Peak Creek Road, just north of Highway 88. This area contains derelict ore bins, concrete mill foundations, a transformer building, other ruins, a small sawmill currently in operation, two acres with about 10,000 cubic yards of tailings - now mostly covered with stumps, and a two acre former pond where process water was stored. Little Peak Creek starts just upstream of the former pond, flows through the former pond, and discharges into Peak Creek 2.5 miles downstream.
The 19th Century Operations Area and the Main Tailings Impoundment are located across Little Peak Creek Road, at the end of Ore Knob Mine Road. The 19th Century Operations Area includes a series of barren and nearly barren stretches of land (totaling about 5 acres) near the top of Ore Knob that contain waste rock dumps from at least 11 mine shafts as well as locations where ore was roasted to drive off sulfur and smelted to recover copper.
EPA resumed site activities on 12/2/2008. During this reporting period, EPA excavated approximately 400 cubic yards of sediment and completed the excavation of sludge from the sediment pond. Excavated material was hauled and placed atop the tailings dam. In order to prevent sludge from entering the tailings dam inlet pipe, a barrier of sawdust and topsoil was constructed around the sludge pile. Saw dust was added to the excavated sludge to stabilize the material.
Surveyors completed the topographic survey of the site on 12/2/2008. A preliminary contour map was provided on 12/3/2008 to aid in the final design of the diversion channel and dam re-sloping. Site activities were suspended on 12/4/08 due to precipitation. Work resumed on Friday, December 5th and included the removal of small trees in the area of the proposed diversion channel. Minimal tree removal was conducted to remove small trees and snags to provide a line of sight for the proposed diversion channel and to prepare the area for removal of larger trees. Tree stumps were left in place to prevent erosion.
A representative from the United States Bureau of Reclamation visited the site on 12/2/2008 to collect additional soil and bedrock data to facilitate completion of dam stability calculations. The ERRS crew excavated a test pit to identify the depth to bedrock (approximatey 5 feet) below topsoil.
Final design of the diversion channel and slope re-facing is currently being completed. Excavation of the diversion channel will be scheduled when the final design is approved.
A representative from the United States Bureau of Reclamation will visit the site on 12/11/08 to assess the proposed diversion channel location and collect the remaining data required to complete the final design.
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