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Bowie No. 2 Mine <br />TR-61 2nd Adequacy Review <br />18 June 2009 <br />Page 2 of 3 <br />Inclinometers <br />Page 14 of the Volume IX text in the application states, in essence, that quarterly <br />inspection reports will provide a summary of instrumentation monitoring on <br />CMWDA2, including a discussion of the inclinometer data. The Operator commits to <br />having a geotechnical engineering firm continue instrumentation monitoring on a <br />quarterly basis. Installation of any additional inclinometers is proposed to be at the <br />discretion of the geotechnical engineering firm. <br />While specific details of inclinometer location have not been provided, the Operator <br />has committed to the utilization of a geotechnical firm for monitoring of'the <br />inclinometer and for determining the necessity of additional inclinometers. In <br />accordance with the recommendations of the BGI TR-56 report, please revise the <br />monitoring frequency to be a minimum of once per quarter. <br />Page 14 has been updated accordingly- no further action is required. <br />Construction <br />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 <br />found in Section 6.0 of the BGI TR-56 report reveals that not all of the <br />recommendations have been incorporated. Specifically, the details for benching new <br />coal mine waste into material previously placed should be described. <br />Please modify the Placement and Compaction section to incorporate all of the <br />recommendations included in the BGI TR-56 report. <br />Page 9 has been modified accordingly - no further action is reguirec1. <br />The third paragraph on Page 9 of Volume IX states that Compaction tests will be <br />taken at a frequency and location of not less than one per every other layer. A review <br />of the dimensions of CMWDA2 indicates that a single two-foot layer may have a <br />surface area of 600 feet by 1200 feet (a volume of approximately 50,000 cubic yards). <br />The proposed compaction test frequency is therefore apparently just one test per <br />100,000 cubic yards. According to Volume IX Page 1, the mine's current production <br />of coal mine waste averages 330,000 cubic yards per year. Three to four compaction <br />tests per year for a pile this size is not sufficient to guarantee that compaction is <br />consistently achieved. <br />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 />Page 9 has been modified accordingly - no further action is require 1.