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Joe Dudash <br />June 11, 2009 <br />3. Please modify the Placement and Compaction section to incorporate all of the <br />recommendations included in the BGI TR-56 report <br />BRL: The Placement and Compaction section of Volume IX has been updated to reflect BGI's <br />recommendations. Please see revised page 9. <br />NC: The third paragraph on Page 9 of Volume IX states that Compaction tests will be taken at a <br />frequency and location of not less than one per every other layer. A review of the dimensions of <br />CMWDA2 indicates that a single two-foot layer may have a surface area of 600 feet by 1200 <br />feet (a volume of approximately 50,000 cubic yards). The proposed compaction test frequency <br />is therefore apparently just one test per 100,000 cubic yards. According to Volume IX Page 1, <br />the mine's current production of coal mine waste averages 330,000 cubic yards per year. Three <br />to four compaction tests per year for a pile this size is not sufficient to guarantee that <br />compaction is consistently achieved. <br />4.P/ease 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 />BRL: When coal mine waste is being placed in the pile, geotechnical testing is performed on <br />average, weekly. Please see revised page 9. <br />Analysis of Monitoring Data <br />OC: BGI's stability evaluation report recommends that monitoring of CMWDA2 with piezometers <br />and inclinometers be continued. Utilization of the monitoring data collected was not discussed in <br />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 instability <br />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. DRMS: No further action is required. <br />General Comments (New) <br />6. DRMS: The Volume IX text refers to various coal mine waste ("Gob") piles, numbered 1 <br />through 4, and the west expansion area of Gob Pile #2. The various Gob piles are not identified <br />on the Maps (Figures) for Volume IX. <br />Please identify the various coal mine waste piles on the figures in Volume IX