2020-04-13_REVISION - M1993035 - Laserfiche WebLink

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REQUEST FOR TECHNICAL REVISION Mine ID# M-1993-035 Mine Name: Swan River Resource Location: Summit County appropriate valley shape, Iandforms, and achieve appropriate elevations for groundwater interactions. Large heavy equipment will be used to contour the valley bottom and excavate a new channel alignment. Onsite material will be stockpiled and processed (sorted/screened/crushed) to produce specific materials (fine mineral soils,gravel and cobbles) used for restoration features. Processed materials will then be hauled back and placed to form new restoration features.A majority of the surface grading and new channel excavation work will be completed with groundwater and stream flows directed around active earthwork areas. However, localized drainage and minor flows are anticipated within the new channel work and will be discharged through Best Management Practices (BMPs). Once the new channel is completed, flows will be introduced and the existing channel abandoned and backfilled. The new channel alignment will require installation of a new bridge crossing for Rock Island Road. This road crossing currently consists of an at-grade crossing upstream of a culvert location. As an interim measure,the existing culverts will be relocated to a new location and invert in Rock Island Road to allow for the site to continue to drain while grades for the new channel are being established. Large scale revegetation efforts will focus on developing a suitable growth medium to cap dredge spoils and the contoured land surface in order to establish native riparian,wetland, and upland vegetation communities. Reclamation Goals and Objectives Summit County has embarked on a detailed and progressive approach to management and restoration of the overall, Swan Valley, the County Open Space Property and specifically for the Swan River Resource.The County has coordinated with many agencies including the Town, Colorado Parks and Wildlife (CPW), US Forest Service (USFS) White River National Forest, Colorado Water Conservation Board (CWCB), Blue River Watershed Group (BRWG),Trout Unlimited (TU), and other local interested individuals. The proposed reclamation restoration plan has been developed based utilizing this coordination. In addition,the current proposed restoration reclamation approach has undergone numerous iterations to develop the most appropriate restoration project that meets project goals and objectives within limitations of M-1993-035.This process has developed an overall valley restoration plan that incorporates numerous reaches and phases as dredge spoils are managed with significant stakeholder consideration. Reclamation of the Swan River is being broken into four phases (Reaches A—D). Reach B coincides with the current Swan River Resource permit boundary. Please refer to attached project location map for additional detail on the restoration reaches. The attached Reach B restoration reclamation design represents the second phase of the future restoration at the Williams Placer. Downstream restoration on Reach A was completed in 2016,with a subsequent acreage reduction to the permit area approved by DRMS in 2019. From the planning efforts to date,the mine operators have developed generalized concept principles and guidelines for restoration activities of the entire valley and specifically the Swan River Resource.The primary project goal is to restore the channel and adjacent areas within the permit boundary, returning them to a natural and functional state. Generalized goals for the project included the following: • Create a natural, stable channel based on existing and anticipated flows and sediment loads; • Eliminate stream flow losses through the dredge spoils and maintain natural perennial stream flows; • Establish instream aquatic habitat including pools, riffles,glides, spawning and rearing areas and 2 of 7