2008-10-03_PERMIT FILE - C1982056A (4)

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Where the pipeline crosses under Fish Creek, jacking pits will be excavated adjacent to the creek, while maintaining a minimum 5-foot buffer between the near edge of the pits and the crest of the stream bank, and the pipeline will be bored or jacked under the creek. 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; a~mpletion of the work during low-flows; 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 jacking pit disturbance areas; restrictions on storage or transfers of petroleum products within the buffer zone, and reclamation of the affected areas immediately following completion of pipeline installation. Construction and sediment control details are shown by the design drawings in Exhibit 490. With constructio~i of the 6MN Mine Water Storage Reservoir, the temporarily direct connection from the 10-Right Mine Dewaterin~; Pipeline to the 6MN Million-Gallon Tank will be replaced with an inlet line from the 10-Right Mine Dewatering; Pipeline to the 6MN Reservoir, and a pumped outlet line from the Reservoir to the 6MN Million- Gallon Tank. The 6MN Storage Reservoir will be used to provide back-up storage for TCC's 10-Right Mine Dewatering Well (also previously identified as the EMD Dewatering Facility), allowing the well to pump continuously at full capacity, providing buffer storage for pump maintenance or failure, and limiting the distance over which the mine water must be transferred. The 6MN Storage Reservoir will be designed as a closed reservoir, with no discharge, and provision for adequate operating free-board to allow for storage of runoff from a small upslope drainage area. The 6MN Mine Water Storage Reservoir will be constructed south of the current 6MN Shaft pad and northwe:~t of the NW Mains Ventilation installation. The reservoir embankment will be an earthen dam constructed of suitable fill material excavated from the reservoir basin and placed and compacted consistent with engineering design specifications and construction recommendations. The engineering designs will be based on site geotechnical investigations, which included drilling of six, 4-inch hollow-stem auger test holes; examination and testing of soil sarnples; placement of 1.5-inch slotted PVC pipe in two of the auger holes to measure water levels (piezometers); and excavation of seven shallow (6-11 feet in depth) test pits. The location of the 6MN Mine Water Storage Reservoir geotechnical investigations is shown on Map 24 (sheet 2 of 3), Surface Facilities and Freshwater Systems, and by the attached drawing, which will be inserted in Exhibit 490, 6MN Mine Water Storage Reservoir -Design Drawings No. 7 North Escape Shaft (Section 20, TSN, R86V~ A 1,066 foot escape borehole shaft was constructed into the No. 7 entry of North Mains to allow emergency evacuation of personnel from the development sections of the 9-Right and 10-Right gateroads. The construction of the shaft utilized raise drilling techniques. It is anticipated that the escape shaft will be utilized for approximately ten years. The site is shown on, Figure 23, General Location of Escape Shaft. The drilling of th.e shaft resulted in minimal surface disturbance. A drill pad approximately 200 x 200 feet was constructed at the resulting site in 1,450 CY of cut and fill. Available topsoil was salvaged and stockpiled for future reclamation of the site immediately northeast of the drilled pad. Approximately 18 inches of topsoil derived from Cochetopa Loam is available for salvaging (222 CY). Casing and other drilling supplies were stockpiled on the borehole pad. After topsoil removal, two mud pits 10 x 10 x 7.5 feet were dug adjacent to the drillhole. Drilling fluids and cuttings were discharged :into the adjacent pits, allowing settling in one pit, with water decanting into the adjacent pit. Drilling muds were used during the course of drilling the surface collar and pilot hole. The surface collar was approximately 5.0 feet in diameter, and the pilot hole was 11 inches in diameter. The collar was comprised of two components; a surface concrete pad and a liner or casing that extends to bedrock. A concrete centering base is a.t the bottom of the liner. The concrete pad was poured around the liner and was approximately 14x 10 x 2 feet, however, the liner extends • through the pad, reducing the amount of concrete needed to construct the pad. Approximately 8.9 CY of concrete was required to construct the pad. TR07-62 2.05 - 45.6g ~~'~ F~~ ~ LI ~~~~ 02/04/08