2018-03-13_REVISION - C1982056 - Laserfiche WebLink

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Peab LI d" Twentymile Coal, LLC RECE�vE,d MAR 13 2p1� Ms. Tabetha Lynch, Environmental Protection Specialist.o{ Reclamation+ Division of Reclamation, Mining, and Safety Divisonnin9 &Safety 1313 Sherman Street, Room 215 Denver, Colorado 80203 (303) 866-3567 X 8147 29515 Routt County Road 27 Oak Creek, CO 80467 970.879.3800 March 8, 2018 RE: Twentymile Coal, LLC - Foidel Creek Mine (Permit No. C-82-056), Technical Revision (TR18-89) Stoker Coal Handling Modifications Dear Ms. Lynch: Twentymile Coal, LLC (TC) requests CDRMS approval of a Technical Revision to our existing approved Permit for construction, operation, and reclamation of major modifications to our existing Stoker Coal Handling System. We have been working with one of our major stoker coal customers to address concerns about excessive coal fines at the point of use, including an evaluation of all points in the loading, haulage, and unloading sequence where fines may be generated, and potential measures to reduce fines generation. One option considered and evaluated (MR17-305) was screening the coal at the source so that the initial material is of a larger and more uniform size. This test and subsequent evaluations indicate that this approach may be the most effective means of addressing the concerns. In order to implement this solution, TC proposes to modify the existing Stoker Coal Handling System to include a screening stage prior to loading the coal for off-site transport. The proposed modifications will involve; 1) Installing and modifying an existing building to serve as a Screening/Loading Building; 2) Removing the existing discharge conveyor and loading chute from the Stoker Coal Stockpile and connecting a conveyor extension from the Stoker Coal Stockpile to a the upper floor of a new Screening/Loadout Building; 3) Adding an out -of -spec coal transfer conveyor from the Screening/Loadout Building to the existing Overland Conveyor to route the screen over -size and under- size back to the coal product stream; 4) Constructing a 15 x 20 foot extension on the west end of the current Washplant Building where the non -spec coal transfer conveyor will discharge to the existing overland conveyor; 5) Relocating an existing sub -station west of the current Washplant; and 6) Realigning a segment of Haulroad B-2 to route stoker coal haulage traffic under the new Screening/Loadout Building and divert other traffic around the Building. All of the proposed modifications will occur within the existing disturbance area, so there will be no new disturbance, and drainage from the affected areas will be handled by the existing drainage and sediment control network. TC proposes to use a coal crushing/screening building moved from the Williams Fork Mine, and modify it with the addition of double -deck screen and a truck -loading system. The stoker coal transfer conveyor extension will be an inclined conveyor, approximately 200 -feet long and with a maximum conveyor width of 48 -inches. The conveyor will be fully -enclosed within the tubular conveyor gallery. The Screening/Loading Building will be supported by concrete piers, with a reinforced concrete slab floor/loading ramp, and will be approximately 69 -feet high and 30 x 30 feet. The out -of -spec coal transfer conveyor will be an elevated conveyor, approximately 112 -feet long and with a maximum conveyor width of 42 -inches. Dependent on the results of site foundation evaluations, a reinforced -earth or concrete retaining/barricade wall may be constructed between the Screening/Loading Building and the current road berm adjacent to the Foidel Creek buffer zone. TC currently has a stream buffer zone variance for this area, which remains applicable for the proposed installation. With the exception of the