2016-12-23_REVISION - C1982056 (3)

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NOTICE OF PROPOSED DECISION The Colorado Division of Reclamation, Mining and Safety proposes to approve Technical Revision Application No. 86 (TR-86) for the Foidel Creek Mine (Permit No. C-1982-056), submitted by Twentymile Coal, LLC. Twentymile Coal, LLC. (TC) is seeking to revise their current approved permit for construction, operation and reclamation of a new thickener underflow borehole, a pipeline, and associated ancillary equipment and facilities in the Southwest Mining District (SWMD). The borehole installation will be located near the west entrance to the main Foidel Creek Mine site. Borehole location SWMD- 1 is located on the west side of Routt County Road (RCR) 27 between the west entrance and the Fish Creek Borehole road. The lands affected by the proposed revision are located in Sections 25 and 36 of T5N, R87W and Sections 31 and 32 of T5N, R86W; and surface owners for this area include 20 Mile Sheep, LLC., Sage Creek Land and Reserves, LLC. (an affiliate of TC), and Twentymile Coal, LLC. TC is requesting to increase their approved disturbed area by 1.6 acres. The borehole will extend from the surface into the sealed SWMD mine workings a maximum of approximately 850 feet. Installation of the borehole will involve placement of construction erosion controls (silt fence and/or straw wattles), removal and stockpiling of soil materials and the limited vegetation from the existing pad area and road margins, minor fill placement (if necessary) and grading to establish a level drill pad, placement of gravel surfacing at the access point, excavation of a temporary cuttings pit on the drill pad, and drilling and casing of the borehole. Upon completion of drilling and casing operations, the cuttings pit will be allowed to dry -out, material excavated from the pit will be replaced and graded, and the pad surface will be graveled to control erosion and sediment and provide an all-weather operating surface. The completed borehole installation will include an access road, soil material stockpiles; a leveled pad (maximum 250’ x 170’), an 18 -inch cemented surface casing ( 60 feet deep), a 12 -inch cased borehole, and a covered 8 -foot diameter CMP manhole with lightning protection. The pipeline installation will involve removal and windrowing of soil materials; trenching in most areas; placement of suitable bedding materials; placement, connection, and pressure testing of the pipeline; backfilling and compaction of suitable fill materials around and over the pipeline; backfilling and compaction of the trench; re -grading; replacement of soil materials; and re - vegetation of all disturbed areas. The pipeline disturbance will occur within the same disturbance corridor previously used for installation of the Fish Creek Water transfer pipeline and is entirely within the disturbed right-of-way of County Road 27 and the paved entrance road into the Foidel Creek Mine. The pipeline will be a double walled HDPE pipe system, with a 8 -inch carrier pipe inside a 12 -inch containment pipe, buried approximately 5 -feet deep, and extending to the south and east a maximum of approximately 7,720 feet between the selected borehole and the junction to the 1 - MN Thickener Underflow Pipeline leading from the Washplant facility to the existing 1 - MN Thickener Underflow borehole. Electronic moisture sensors in the interstice between the inner and outer pipe connected to the pump controls and shut-off valves will provide for timely leak detection and spill prevention. Access/ Inspection manholes will be established at key points along the pipeline route. It is anticipated that a maximum of six manholes will be placed within the pipeline disturbance corridor.