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

Home Browse Search

that when the pipeline is no longer needed to support mining and related operations, it will be plugged below grade and abandoned in- place. Reclamation of the wells, when no longer needed, will involve plugging and sealing the • well consistent with approved sealing practices, consistent with applicable State Engineer requirements. TORT 1 lonitoring Borehole Installation and Pum house Modifications R09 -238 In order to accurately monitor water levels in the EMD sump area, TCC plans to drill and case a monitoring borehole at the IORT location. The new TORT Monitoring Borehole will be drilled on the existing IORT facilities pad, and will involve no new surface disturbance. The borehole will be collared with an 8 -inch ID surface casing, extending to a depth of approximately 40 feet. The borehole will then be drilled as a 6.25 -inch borehole to a depth of approximately 1,365 feet, and cased with 3 -inch ID cemented in -place casing. The casing will extend approximately 4 feet above the ground surface, and be fitted with a locking cap to prevent unauthorized access. The 10 -RT Monitoring Borehole will be used for regular monitoring of mine water levels in the EMD. When no longer needed to monitor water levels, the IORT Monitoring Borehole will be plugged and sealed in compliance with State Engineer requirements, the casing will be cut -off below grade, and the associated disturbance will be reclaimed along with the rest of the l ORT facilities area. The addition of the second l ORT Dewatering Borehole resulted in the need for changes to the pumping and control systems for the l ORT dewatering installation. To accommodate pumping and control equipment for the two l ORT Dewatering Boreholes, the existing IORT Pumphouse and foundation pad will be demolished, and replaced with a larger Pumphouse and foundation pad with support piers. Specifically, the existing 16 x 14 foot wood -frame building and 14 x 24 foot concrete pad will be replaced by a 25 x 43 foot concrete pad with 12 — 1 -foot diameter concrete piers extending to a depth of approximately 12 feet, and a 25 x 30 foot pre - fabricated steel building. The Pumphouse expansion will occur on the existing 10 -Right facilities pad and will involve no new surface disturbance. Other associated work will include placement of the existing electrical transformer on the northeast corner of the new pad, and completion of the necessary plumbing and electrical hook -ups. When the pumping • installation is no longer needed to support ongoing or future operations, the l ORT Pumphouse, foundation pad, and associated equipment will be removed for salvage or demolished, and the associated disturbance area reclaimed along with the rest of the l ORT facilities area. 1ORT/FCM -2 Transfer Pi eline and 1ORT /6MN Transfer Pipeline R07 -224 MR08 -230 A water line was installed from the TORT dewatering facility to FCM -2 to route water back into the mine for underground operations. The location of this water line is shown on Figure Water Discharge Return Line, East Mine District. Approximately 6,740 fet of 8Iinch pipe L was buried at 5 to 6 feet below grade from the TORT dewatering facility to FCM -2. This pipe will be left in place when no longer needed to support ongoing mining and related operations. As part of the 6MN Facilities project, TCC established a new pipeline running approximately 6,040 feet from the I 0RT/FCM -2 Transfer Pipeline to the 6MN Mine Water Storage Reservoir and Million - Gallon Tank. The pipeline is constructed of 10 -inch HDPE pipe, buried to a depth of approximately six feet, with one sub -grade crossing (bored under) of Fish Creek. Details of the Fish Creek pipeline crossing are presented in Exhibit 490, 6MN Mine Water Storage Reservoir — Design Drawings. Pipeline trenching operations were conducted using a track -hoe with the maximum working area assumed to be 40 feet wide. Approximately 7 acres were disturbed in construction of the original water line, with another 7.1 acres disturbed by the pipeline. Pipeline construction involved removing and temporarily windrowing soil materials along the edge of the pipeline corridor; trenching and tempo rary placement of the excavated material on the opposite side of the trench; bedding, placement, connection, and testing of the pipeline; controlled backfilling and compaction of the excavated material over the pipeline; and replacement, grading, and reseeding of the soil material over pipeline disturbance areas. Access manholes were established along the pipeline route for inspection and maintenance purposes. Soil materials were replaced following • completion of pipeline installation. Reseeding of the disturbed areas will be completed during the first appropriate planting period following soil material replacement. TR09 -70 2.05 -50.6 11/16/09