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CWDA No. 2 <br />#01349-0001 Huddlmon-Bevy <br />04/13/16 J <br />As indicated in the referenced Stability Evaluation report, the stability of CWDA No. 2 is <br />sensitive to increases in pore pressures in VWP-08. An increase in the pore pressure of 7 psi in <br />VWP-08 would result in a reduction of the Factor of Safety to below 1.5. <br />The current pore pressure reflects a piezometric surface elevation of approximately 6098 feet <br />which is much less than the critical elevation of 6113 feet. As a result, HBET does not believe <br />that the measured pore pressures in VWP-08 are any indication of instability in CWDA No. 2. <br />VWP-09 <br />VWP-09 was installed on May 18, 2012 near the toe of CWDA No. 2. The pore pressures <br />recorded at VWP-09 have been fairly steady since installation. This suggests that dewatering of <br />the gob in this area is likely nearly complete. It is anticipated that the pore pressures at VWP-09 <br />will remain fairly steady over time. <br />VWP- 7 0 <br />VWP-10 was installed on May 18, 2014 near the toe of CWDA No. 2. The pore pressures <br />recorded at VWP-10 have been fairly steady since installation. This suggests that dewatering of <br />the gob in this area is likely nearly complete. It is anticipated that the pore pressures at VW -10 <br />will remain fairly steady over time. <br />Site Visit Observations <br />HBET visited the site on April 12, 2016. At the time of our visit, wet coal mine waste from the <br />fall of 2015 was being moved around on top of CWDA No. 2 in order to dry the material in <br />preparation of placement and compaction. HBET did not observe any material from the wash <br />plant being moved to CWDA No. 2. In general, CWDA No. 2 appeared to be in good condition <br />and no evidence of instability or other adverse conditions were observed. <br />General <br />In general, based upon the results of the recent VWP and inclinometer monitoring data, and upon <br />our observations at the site, HBET does not believe that there is any reduction in the stability of <br />CWDA No. 2. Continued quarterly monitoring of piezometers and inclinometers is <br />recommended. <br />We are pleased to be of service to your project. Please contact us if you have any questions or <br />comments regarding the contents of this report. <br />Respectfully Submitted: <br />Huddleston -Berry Engineering and Testing, LLC <br />Michael A. Berry, P.E. <br />Vice President of Engineering <br />X:\2008 ALL PROJECTS\01349 -Bowie Resources, LLC\01349-0001 Bowie Mine\200 - Geo\Gob 2\lnstrumentation Monitoring\2016\01349-0001 GP2 1stQ 2016 L041316.doc 3 <br />