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subsidence. Subsidence and rockfall due to mining in Panel 6 in the SW Mining District <br />required that the operator re -design the mitigative measures proposed originally under <br />PR -02 to protect the use of County Road No. 27 in Sections 33, TSN, R86W and Section <br />25, TSN, R87W. Technical Revision No. 19 (TR -19) approved construction of a <br />trench/berm system approximately 4200 feet in length adjacent to County Road No. 27 to <br />stop any rockfall prior to reaching the county road. Exhibit 7a, Stability Investigation of <br />the Twentymile Sandstone Cliff, and Exhibit 7f, Rockfall Hazard Assessment and <br />Selection of Hazard Control or Mitigation Measures, outline details with regard to the <br />cliff, County Road No. 27 and required mitigation measures. As a result of undermining <br />the cliff along County Road No. 27 in Panels 7, 8 and 9 of the Southwest Mining District, <br />substantial rockfall did occur. The trench/berm system along the road, in addition to <br />slight road relocation, proved to be an effective and necessary measure to protect the <br />safety of the public users of this road as numerous boulders were trapped in the <br />trench/berm system. <br />Permit Revision No. 3 (PR -03) allowed undermining a significant portion of Routt <br />County Road No. 33 in portions of Sections 14, 22, 23, 27, and 28, TSN, R86W. The <br />Division published a notice on October 7, 1993 in the Steamboat Pilot providing the <br />opportunity for a public hearing concerning the undermining of approximately four (4) <br />miles of Routt County Road No. 33. These four miles of road lie within the area affected <br />by longwall panels 9R, 8R, 7R (PR -03), 6R and 5R (PR04). There was no public <br />response or concern voiced about undermining of the road. The applicant received all <br />necessary approvals from Routt County to undermine County Road No. 33. Special Use <br />Permit No. 92-233 issued by Routt County approved the undermining and subsidence of <br />County Road No. 33 as long as the conditions addressing appropriate road warning <br />signage, monitoring, and repairs are met by Twentymile Coal Company. Based on the <br />above information, the Division finds Twentymile Coal Company in compliance with <br />Rule (2.07.6(2)(d)(iv)) for the undermining of Routt County Road No. 33. <br />Approval of Permit Revision No. 4 (PR -04) on April 20, 1998, allowed for continued <br />mining in the Eastern Mining District of longwall panels 6R through 2R. Only panels 6R <br />and 5R had an impact to Routt County Road No. 33. Experience gained during <br />subsidence of panels 9R through 7R demonstrated that traffic on County Road No. 33 <br />was not been interrupted as a result of the subsidence of the road. Subsidence of <br />Longwall panels 6R and 5R did not interrupt traffic on Routt County Road No. 33. <br />Approval of Permit Revision No. 5 (PR -05) on May 28, 2000, allowed longwall panel <br />12R to undermine a Twentymile sandstone outcrop in Section 14, TSN, R86W. Prior to <br />approval, Twentymile Coal Company committed to scaling loose rock on the slope prior <br />to undermining, and the use, as necessary, of concrete barriers along the north side of <br />Routt County Road No. 33, and chain link meshing draped over the face of the outcrop, <br />to ensure that rockfall would not reach the road. Subsidence of the longwall panel did <br />not interrupt traffic on Routt County Road No. 33. <br />Affected areas approved in Permit Revision No. 6 (PR -06) on May 21, 2004, were more <br />than one-quarter mile from public roads. <br />Foidel Creek Mine 25 February 25, 2016 <br />