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W.A. Bear, Bowie Resources, LLC <br />4th Qtr 2013 CMWB Review <br />06- Mar -2014 <br />Page 2 of 2 <br />DRMS 02/12: The second paragraph of the VWP section discusses pore pressure measurements taken <br />during the subject quarter. The fourth sentence states, "Readings at these piezometers have generally <br />decreased since they were installed." This general statement is not supported by the graph presented in <br />the report, and specific data regarding pore pressures would be more informative. Please give the <br />actual pore pressure measured from each VWP, and address the results (and history) individually. <br />DRMS 03/06: A new Table 2, Summary of Active VWP Pore Pressures, was provided, together <br />with a discussion of the individual VWPs. For VWP -05, the text says this VWP has showed <br />"continual decline in pore pressure from an initial value of 6.8 psi to the latest reading of 2.5 <br />psi." The graph appears to indicate that a pore pressures declined to —3 psi by Mar -2006, and <br />have remained relatively constant since then. The Division makes a similar observation for <br />VWP -08: pore pressures appear to have declined to their current level by Mar -2010, with little <br />change since then. Please revise the wording of the VWP -05 and VWP -08 paragraphs to <br />accurately represent the histories as presented on the graph. <br />DRMS 02/12: The final sentence of the second VWP paragraph says that all measured pore pressures <br />are "well below" the pore pressures at failure for similar confining pressures for the CU triaxial shear <br />tests that have been conducted. Please enhance this general statement by identifying the threshold at <br />which the pore pressure for each VWP installation might generate concern for the stability of the pile. <br />DRMS 03/06: A paragraph was added to identify a threshold (35 psi) at which the pore pressure <br />would cause concern. The new text indicates that additional triaxial testing of coal mine waste <br />was performed in 2013. In the Division's adequacy review of TR -84, we are requesting that any <br />new laboratory test data be incorporated into the permit. <br />We have no further comments on the Revised 4th Quarter Coal Mine Waste Bank Instrumentation <br />Monitoring report as submitted. If you have any questions or need additional information, please contact <br />me. <br />Sincerely, <br />Susan L. Burgmaier <br />Environmental Protection Specialist <br />cc: Jim Stover, J.E. Stover & Associates <br />Marcia Talvitie, DRMS <br />