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COLORADO <br />Division of Reclamation, <br />Mining and Safety <br />Department of Natural Resources <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />November 12, 2015 <br />From: Clayton Wein <br />To: Leigh Simmons <br />Subject: West Elk Subsidence Reports: spring of 2012 through the spring of 2015 <br />As requested I have reviewed the semi-annual subsidence monitoring reports for the West Elk Mine <br />from the spring of 2012 to the current report for the spring of 2015. <br />The monitoring reports are in compliance with the following rules: <br />Rule 2.05.6(6)(b)(ii) —The mining in the SOD and Dry Fork mining areas prediction of the worst <br />possible subsidence consequences determined that no material damage or diminution of <br />reasonably foreseeable use could result in the event of mine subsidence within the permit and <br />adjacent areas. The subsidence monitoring of the longwall panels E1, E2 and E3 before, during <br />and after mining supports the prediction. <br />Rule 2.05.6(6)(c)(i)(A) —The West Elk Mine installed and surveyed monuments prior to <br />undermining. Since the fall of 2007, the frequency of the visual inspections has been conducted <br />semiannually. <br />Rule 2.05.6(6)(c)(i)(B) —The monuments are located to detect vertical subsidence and <br />horizontal displacement. <br />Rule 2.05.6(6)(c)(i)(C) — Each structure's orientation, location, and elevation were monitored. <br />Rule 2.05.6(6)(c)(i)(D) — Monitoring of monuments and structures were preformed quarterly, <br />commencing one month prior to the initiation of mining beneath any established monument or <br />structure. <br />Rule 2.05.6(6)(c)(i)(E)—The results of monitoring are submitted to the Division semiannually. <br />Rule 2.05.6(6)(c)(i)(F) — Subsidence monitoring is conducted with sufficient post mining <br />monitoring to verify subsidence predictions. Discussions of the traverses in the field surveys <br />include observations of new and previously identified subsidence features. The report describes <br />the changes to the previously existing features that occurred since the previous visual <br />inspections. <br />1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 http://mining.state.co.us <br />John W. Hickenlooper, Governor I Mike King, Executive Director I Virginia Brannon, Director <br />