2016-05-04_REVISION - C1982056 (12)

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subsidence evaluation and predictions for both Foidel and Fish Creek. TC has previously undermined these creeks before successfully and expects them to react in a similar fashion Lieske headgate and USGS water monitoring site 700 These two structures were monitored to detect damage or improper function. If mining impaired the function of these structures, Twentymile Coal Company committed to re -align or re -level the structure, as necessary, prior to seasonal use. Routt County Road No. 27 1. Twentymile Coal Company proposed to subside portions of Routt County Road No. 27 with Western Mining District Longwall panels 13L, 14L, 15L, 16L, and 17L in Township 5 North, Range 87 West, Sections 23 and 26. Routt County Special Use Permit PP2009-008 specifies signage, monitoring, and mitigation measures required by the County for subsidence impacts to the county road. In accordance with Rule 2.05.6(6), the applicant has proposed a subsidence mitigation plan for the segment of Routt County Road 27 that crosses panels 13L, 14L, 15L, 16L, and 17L. The applicant has committed to monitoring and making needed repairs in accordance with its agreement with the county. Gertie #1 and Livestock #2 Springs The applicant has predicted that in a worst-case scenario, mining in the Western Mining District may cause the potentiometric surface of the Twentymile Sandstone to drop to a level that causes two natural springs, the Gertie #1 and the Livestock #2, to dry up. In accordance with Rule 2.05.6(6), the applicant has proposed a subsidence mitigation plan for the springs in the form of a commitment to install impoundments at the spring locations in the event mining reduces flows in the springs. 2. The applicant has proposed a subsidence control plan in accordance with Rule 2.05.6(6) and has committed to adopt all measures in order to reduce the likelihood of subsidence, to prevent material damage, and to mitigate the effects. A detailed description of the monitoring program for each structure within the Western Mining District begins on page 2.05-182 of the permit application. Exhibit 25Z provides additional review of the proposed subsidence anticipated with the Western Mining District. The results of the monitoring program will be submitted to the Division semi-annually. Exhibit 34 of the permit outlines the requirements for the subsidence report. The Division proposes to approve the plan (4.20.1(2) and 4.20.3(1)). XVI. Concurrent Surface and Underground Mining No specific approvals are granted to the applicant under this section. Page 39 of 52