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Please detail the proposed methods of placement of coal mine waste, in accordance with <br />BGI's recommendations. <br />NC: Placement and Compaction of coal mine waste is described on the proposed Page 9 of <br />Volume IX. A comparison with the recommendations for placement of coal waste found in <br />Section 6.0 of the BGI TR-56 report reveals that not all of the recommendations have been <br />incorporated. Specifically, the details for benching new coal mine waste into material <br />previously placed should be described. <br />3. Please modify the Placement and Compaction section to incorporate all of the <br />recommendations included in the BGI TR-56 report. <br />NC: The third paragraph on Page 9 of Volume IX states that Compaction tests will be taken <br />at a frequency and location of not less than one per every other layer. A review of the <br />dimensions of CMWDA2 indicates that a single two-foot layer may have a surface area of <br />600 feet by 1200 feet (a volume of approximately 50,000 cubic yards). The proposed <br />compaction test frequency is therefore apparently just one test per 100,000 cubic yards. <br />According to Volume IX Page 1, the mine's current production of coal mine waste averages <br />330,000 cubic yards per year. Three to four compaction tests per year for a pile this size is <br />not sufficient to guarantee that compaction is consistently achieved. <br />4. Please clarify and/or modify the proposed compaction test frequency, to ensure a <br />sufficient level of confidence in the uniform compaction of coal mine waste. <br />Analysis of Monitoring Data <br />OC: BGI's stability evaluation report recommends that monitoring of CMWDA2 with <br />piezometers and inclinometers be continued. Utilization of the monitoring data collected was <br />not discussed in the report. <br />In the upcoming Technical Revision, please describe, as a minimum: <br />• How the monitoring data collected will be used <br />• Measurements (of pore pressure or inclination) that might indicate any potential <br />instability in the CMWDA2 configuration <br />• Proposed mitigation of any potential or actual stability issues <br />• How often and by what means data will be reported to the Division <br />NC: The Stability Analysis portion of the proposed Volume IX text (pages 13 and 14) <br />describes, in general terms, the collection, evaluation, and reporting of monitoring data that <br />will occur on a quarterly basis. <br />5. No further action is required.