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Y <br />A AGAPITO ASSOCIATES, INC. <br />715 HORIZON DR., STE 340 GOLDEN OFFICE <br />GRAND JUNCTION, CO 81506 303.271.3750 <br />USA <br />VOICE 970.242.4220 <br />www.agapito.com <br />April 29, 2011 RFCIr-rNIEE) 723-01 T1 <br />Mr. Kent Gorham MAY 022011 <br />Colorado Division of Reclamation, Mining and Safety <br />1313 Sherman Street, Room 215 Mir. n3 z-VI-1 Sa`ov <br />Denver, CO 80203 <br />Re: New Elk Mine (Permit No. C-1981-012) <br />Technical Revision No. 56 (TR-56) <br />Incidental Boundary Change/Allen-Apache Mining <br />Completeness Response <br />Dear Mr. Gorham: <br />This letter and supporting documents are submitted in response to a modification to the adequacy <br />response dated April 24, 2011. As a follow-up to a meeting with the Colorado Department of Wildlife <br />concerning the TR56 submittal, the mine plan has been slightly modified. <br />At this time, secondary recovery of pillars is not included in the mine plan for TR-56. Permit <br />pages 2.05-2, -3, and -3a have been modified to accurately reflect the mine plan. Pages 2.05-90f, -90g, - <br />91, -92, -93, and -94 have been modified to reflect the change in subsidence discussion. Map 3-2011 <br />Mine Plan and Figure 19 on page 2.05-92 were updated to show only room-and-pillar (development) <br />mining. Please replace these adequacy response items from April 24, 2011 with those included here. <br />The adequacy letter dated March 24, 2011, included requests for definitions and clarifications in <br />the subsidence analysis. With the modification from retreat mining to development-only mining, the <br />references to subsidence prediction are no longer relevant. Adequacy responses to those items have been <br />modified as follows. <br />DRMS: Exhibit 24 Subsidence Control, Monitoring, and Mitigation Plan includes a subsidence <br />prediction along with subsidence control and monitoring plans for structures to be undermined <br />and/or subsided. The subsidence analysis and control plan uses various terms to indicate mining <br />predictions and buffer zones with regard to angles of offset. Given that state-of-the-art <br />subsidence predictions commonly include terms like angle of draw, angle of influence, angle of <br />break, and vertical angle offset, please consider reviewing the analysis and control plans and <br />indicating each of these angles by figures or cross sections so that it is clear which term is being <br />referred to. The Division suggests using consistent terms for all control plans, similar to that used <br />in the subsidence prediction. <br />NECC Response: Exhibit 24 has been revised to include definitions where new terms are <br />introduced. No subsidence is planned, therefore many of the definitions are no longer needed. <br />4. DRMS: Please define edge offset. The analysis provided indicates that edge offset was <br />estimated using SDPS guidelines based on panel width and depth of workings. <br />& Civil Engineers & Geologists <br />Mining <br />GEOENGINEERING • MINING ENGINEERING • CIVIL ENGINEERING