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Water Storage Reservoir — Design Drawings. Pipeline trenching operations were conducted using a track -hoe with <br />the maximum working area assumed to be 40 feet wide. Approximately 7 acres were disturbed in construction of <br />the original water line, with another 7.1 acres disturbed by the pipeline. Pipeline construction involved removing <br />and temporarily windrowing soil materials along the edge of the pipeline corridor; trenching and temporary <br />placement of the excavated material on the opposite side of the trench; bedding, placement, connection, and testing <br />of the pipeline; controlled backfilling and compaction of the excavated material over the pipeline; and replacement, <br />grading, and reseeding of the soil material over pipeline disturbance areas. Access manholes were established <br />along the pipeline route for inspection and maintenance purposes. Soil materials were <br />replaced following completion of pipeline installation. Reseeding of the disturbed areas will be completed during <br />the first appropriate planting period following soil material replacement. <br />18LT Mine Water Transfer Pipeline (TR09-70 <br />The 18 -Left Mine Water Transfer Pipeline (18LT Pipeline) will originate from a permitted mine dewatering <br />borehole at the 18 -Left Shaft location, and extend approximately 8,200 feet to the southeast, connecting to the <br />existing Fish Creek Mine Water Transfer Pipeline just to the east of the Fish Creek Water Treatment Facility. The <br />18LT Pipeline will be a 12 -inch HDPE pipeline with thermally welded joints, buried below the frontline at a depth <br />of approximately 5 feet. The pipeline will be installed under Routt County Road 27 by boring the pipeline under <br />the road, and a crossing of Fish Creek will be either trenched through, or bored under the creek. Manholes, <br />consisting of 8 -foot diameter x 10 -foot high CMP culverts, fitted with locking lids and access ladders, will be <br />installed at either end of the pipeline for access to pipeline valving. <br />Pipeline construction will involve placement of sediment control materials (straw wattles or silt fence) downslope <br />of the disturbance at any location where the pipeline corridor is within 50 feet of a Stream Buffer Zone or non- <br />qualifying ephemeral drainage; removal and windrowing of available soil material to one side of the 40 foot <br />pipeline construction corridor; excavation of the pipeline trench, with temporary placement of the excavated <br />material on the opposite side of the trench; placement, connection, and bedding of the pipe; backfilling and <br />compaction of the excavated material around the pipe; re -spreading of the soil material; and re -seeding using the <br />standard rangeland seed mixture. Because the soil materials will be replaced immediately after pipeline placement, <br />as construction advances, stabilization measures are not necessary. Where the pipeline crosses under Routt County <br />Road 27, boring or jacking pits will be excavated and the pipeline will be bored or jacked under the road. The Fish <br />Creek crossing has been located to take advantage of a deeply incised stream channel, minimizing potential impacts <br />to the narrow riparian fringe which exists along this section of the creek. To the extent feasible, the trenched <br />crossing will be completed during the winter low -flow period. A temporary upstream flow barrier will be <br />established in the channel, and normal streamflows will be transferred around the work area by pumping from the <br />resulting pool above this upstream barrier to well below the crossing work area. If the Fish Creek pipeline crossing <br />is completed by boring the pipeline under the creek, the surface protective measures, as outlined above, will not be <br />necessary. <br />Specific protective measures (BMP's) will be used at the crossing location including placement of stream buffer <br />zone markers, silt fence or anchored straw bales at least 50 feet downstream to catch any sediment; placement of <br />sediment control materials (straw wattles or silt fence) around the entire side and near stream perimeters of the <br />boring/jacking pits; restrictions on storage or transfers of petroleum products within the buffer zone, and <br />reclamation of the affected areas immediately following completion of pipeline installation. Soil materials will be <br />replaced following completion of pipeline installation, and reseeding of the disturbed areas will be completed <br />during the first appropriate planting period following soil material replacement. <br />19RT Mine Dewatering Borehole and Pipeline (TR10-73) <br />In order to dewater the sealed mine workings in the completed Northern Mining District (NMD), TC plans to complete <br />a nominal 17 -inch diameter dewatering borehole to a depth of approximately 1,700 feet. A downhole pump, capable of <br />pumping up to 550 gpm, will transfer water from a sump in the sealed NMD mine workings to the surface, where a <br />buried 6,200 -foot 12.5 -inch diameter pipeline will carry the water to the 6MN Mine Water Storage Reservoir. The <br />proposed dewatering borehole has been located to intercept the 19 -Right (19RT) mine entries, at the low point on the <br />synclinal axis in the NMD. The selected borehole location is also near several existing ranch roads, for access. TC <br />proposes to complete the 19RT Dewatering Borehole during the summer when the ground is dry. Given the <br />MR16-299 2.05-50.9 06/16/16 <br />