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William A. Bear <br />Page 3 of 5 <br />July 7, 2014 <br />New Items: <br />44. a. Laboratory data for Consolidated - Undrained triaxial shear testing is presented in <br />Appendix A of the HBET analysis. As explained in HBET Section 3.0, samples of <br />blended material from Gob Pile #3 were collected and tested. HBET does not <br />describe what this "blended material" is, and it does not appear that the Volume XI <br />text describes the practice of blending wet coal mine waste with available coverfill <br />to achieve a desirable moisture content for placement. Please revise the Placement <br />and Compaction section in Volume XI to address the blending process. <br />b. Item resolved; HBET's 11- Jun -2014 analysis utilized a (p of 30 degrees for the native <br />soil. <br />45. a. Subsection 4.3 of the HBET analysis discusses the location of the natural <br />piezometric surface based on elevations observed in the piezometers installed in <br />2006. HBET does not state which of the piezometers were monitored by Buckhorn <br />in June 2013. Please clarify the status (functioning or destroyed) of each of the <br />original seven standpipe piezometers. This clarification could be accomplished <br />in either the Volume XI text or in the HBET analysis. <br />b. In the 11- Jun -2014 analysis, HBET evaluated the sensitivity of stability at Gob Pile <br />#3 to fluctuations in the groundwater table. This is not what was intended by the <br />Division's original question, which likely could have been worded better. (The Rules <br />require that any seeps or springs encountered beneath a refuse pile be captured by <br />an underdrain in order to prevent groundwater from coming into contact with the <br />refuse.) <br />A rough depiction of the estimated groundwater surface (red lines), based on data in <br />the Mar -2007 Buckhorn report, is shown below. We intended to inquire about the <br />relationship of the inferred water table to the floor of the excavation that was <br />created prior to placement of the coal mine waste. Will that nearer proximity <br />create any potential impacts on the stability of the pile? [The elevations shown in <br />HBET's analyses are not tied to the elevations used in the permit maps, so we are <br />unable to correlate the cross sections with the groundwater surface.] <br />