2010-06-04_PERMIT FILE - C1982056A (9)

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Pipeline construction will involve placement of sediment control materials (straw wattles or silt fence) downslope of the disturbance at any location where the pipeline corridor is within 50 feet of a Stream Buffer Zone or non- qualifying ephemeral drainage; removal and windrowing of available soil material (total soil material volume for the pipeline project is estimated at 12,150 cy) to one side of the 40 foot pipeline construction corridor; excavation • of the pipeline trench using a track -hoe, with temporary placement of the excavated material on the opposite side of the trench; placement, connection, and bedding of the pipe; backfilling and compaction of the excavated material around the pipe; re- spreading of the soil material; and re- seeding using the standard rangeland seed mixture. Where the pipeline is installed by boring, boring pits will be excavated within the pipeline construction corridor for the boring equipment and pipe handling. Because the soil materials will be replaced immediately after pipeline placement, as construction advances, stabilization measures are not necessary. Where the pipeline crosses under Routt County Road 27, boring or jacking pits will be excavated on the edges of the road right -of -way, and the pipeline will be bored or jacked under the road. The Fish Creek crossing has been located to take advantage of a deeply incised stream channel, minimizing potential impacts to the narrow riparian fringe which exists along this section of the creek. Because pipeline installation activities will occur within Stream Buffer Zones, TCC is requesting a variance from the Stream Buffer Zone requirements, consistent with the applicable provisions of Rule 4.05.18. To the extent feasible, the trenched crossing will be completed during the winter low -flow period. A temporary upstream flow barrier will be established in the channel, and normal streamflows will be transferred around the work area by pumping from the resulting pool above this upstream barrier to well below the crossing work area. Pumping capacity will be approximately 10 cfs (greater than maximum measured historic flows for the construction timeframe) to assure that there is no diminution of flow, and back -up pumping capacity will be provided in the crossing construction area to address any leakage or underflow. Details of the Fish Creek pipeline crossing are presented in Exhibit 49R, 18LT Ventilation Shaft Installation — Design Drawings. If the Fish Creek pipeline crossing is completed by boring the pipeline under the creek, the surface protective measures, as outlined above, will not be necessary. Protective measures (BMP's) at the crossing location will include placement of stream buffer zone markers at any point where the pipeline corridor is within 50 feet of the stream buffer zone prior to any activity; placement of silt • fence or anchored straw bales at least 50 feet downstream to catch any sediment released prior to initiation of work; placement of sediment control materials (straw wattles or silt fence) around the entire side and near stream perimeters of the pipeline excavation and stockpile disturbance areas on both sides of the stream; restrictions on storage or transfers of petroleum products within the buffer zone, and reclamation of the affected areas immediately following completion of pipeline installation. These measures should be effective in assuring compliance with applicable provisions of Rule 4.05.18 (1)(a) through (c). Construction and sediment control details are shown by the design drawings in Exhibit 49R. Manholes, consisting of 8 -foot diameter x 10 -foot high CMP culverts, fitted with locking lids and access ladders, will be installed at either end of the pipeline for access to pipeline valving. Following commissioning, the shaft pad site, access road, and pipeline corridor will be cleaned -up and surface areas graded and stabilized by seeding with the temporary seed mixture. When these facilities are no longer needed to support ongoing or future mining and related operations, reclamation will involve removal of surface structures and facilities, demolition of concrete foundations and pads, disposal of concrete debris in the shafts, replacement of cuttings from the temporary cuttings pits in the shafts, grading of disturbance areas to blend with the surrounding terrain, soil material replacement, and reseeding with the appropriate permanent revegetation seed mixture (Pastureland Mixture for Shaft site and road, and Rangeland Mixture for Pipeline corridor). Boreholes will be plugged and sealed in accordance with applicable State Engineer requirements, and pipelines will be cut -off below grade, capped, and buried in- place. Temporary and Permanent Shaft Heater Installation (MR08 -227, MR09 -234) It was necessary to install temporary shaft heaters during winter 2007/2008 to address severe icing conditions within the shaft that had the potential to interfere with operation of the 6MN Emergency Escape Hoist. TCC initially installed two portable skid- mounted propane air heaters (15' long, 7' wide, and 7.5' high) on the existing • 6MN Shaft Pad (located adjacent to and immediately west of the Escape Shaft Hoist -House (see MR07 -218) approximately 50' from the shaft opening), and connected them to a portable propane tank, the existing electrical lines, and to the shaft opening with pre- fabricated vent tubing. TR09 -70 2.05-45.19 01/26/10