Laserfiche WebLink
Mr. Kent Gorham <br />April 25, 2011 <br />Page 3 <br />proposed within the permit boundary. The rooms are constructed on advance using <br />room-and-pillar mining method. Extraction of pillars occurs on retreat. Pages 2.05-2, 3, <br />3a have been modified to more clearly describe the mining methods and sequences. <br />5. What additional surface and groundwater monitoring is proposed for the mine plan <br />proposed under TR-56? <br />NECC Response: Text describing installation and sampling of additional monitoring <br />wells has been added to Section 2.05.6(3). No additional surface water monitoring is <br />planned under TR-56. <br />6. For the area of mining in the Allen seam where development-only mining will occur, <br />please submit the information required by Rule 4.20.1(3). This information may be <br />present in various portions of the text and Exhibit 24 in the revised materials but should <br />be consolidated. Specifically, the location and the methods to be taken in the various <br />mining areas under TR-56 to prevent subsidence or minimize subsidence and related <br />damage are required. <br />NECC Response: The detail plan of the underground workings is included in Figure 19 <br />(page 2.05-92). Pillars have been sized such that subsidence is not anticipated in areas of <br />development-only workings. Permit text and Exhibit 24 have been consolidated. <br />7. Please submit the names and addresses of all owners of property and residents above the <br />underground workings and the adjacent area (within 500 feet of the permit boundary). <br />[Rule 4.20.2] <br />NECC Response: The names and addresses of all owners of property above the <br />underground works and those within 500 feet of the permit boundary are included on <br />pages 2.03-6a. <br />8. Exhibit 24 Subsidence Control, Monitoring, and Mitigation Plan includes a subsidence <br />prediction along with subsidence control and monitoring plans for structures to be <br />undermined and/or subsided. The subsidence analysis and control plan uses various <br />terms to indicate mining predictions and buffer zones with regard to angles of offset. <br />Given that state-of-the-art subsidence predictions commonly include terms like angle of <br />draw, angle of influence, angle of break, and vertical angle offset, please consider <br />reviewing the analysis and control plans and indicating each of these angles by figures or <br />cross sections so that it is clear which term is being referred to. The Division suggests <br />using consistent terms for all control plans, similar to that used in the subsidence <br />prediction. <br />NECC Response: Exhibit 24 has been revised to include definitions and figures to clarify <br />the terms being referred to in the plan. <br />9. Please define edge offset. The analysis provided indicates that edge offset was estimated <br />using SDPS guidelines based on panel width and depth of workings. <br />Agapito Associates, Inc.