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Discussion of individual VWP's <br />VWP -05: Installed on August 3, 2005, VWP is installed near the toe of the CDWA #2 <br />pile adjacent to the access road /bench. This VWP has showed continual decline in pore <br />pressure from an initial value of 6.8 psi to the latest reading of 2.5 psi in this report. This <br />is consistent with anticipated dewatering and a lowering of pore pressure over time. The <br />site around VWP -05 has been graded to its current slope for some time and has not seen <br />the temporary storage as experienced in the other VWP locations as described below. <br />VWP -06: Installed on June 5, 2009, VWP had an initial pressure of 11.3 psi. We <br />recorded a spike of 16.2 psi in our March 14, 2013 monitoring report which is consistent <br />with the additional storage of coal waste near the VWP -06 site at that time. Since that <br />time, VWP -06 has shown a steady decline in pore pressures to its most recent reading of <br />15.0 psi. This indicates that the upper Pile #2 slope near VWP -06 is experiencing <br />anticipated dewatering. Pore pressures are expected to increase slightly as additional coal <br />waste is added to the slope near the VWP -06 site, but again, we are looking for a <br />downward trend in pressures as the pile dewaters and reaches equilibrium. <br />VWP -08: Also installed on June 5, 2009, VWP -08 had an initial pressure reading of 12.2 <br />psi and a peak of 15.0 as reported on December 21, 2009. That peak, as with VWP -06, <br />was coincident with the addition of coal waste near the VWP -08 site. Since that peak, <br />VWP -08 has shown steady decline in pressure to the latest reading of 13.4 psi in this <br />report. <br />VWP -09: This VWP was installed on May 18, 2012 to provide an additional analysis point <br />near the toe of CDWA #2. After an initial reading of 1.5 psi, VWP -09 has remained <br />generally stable with the latest reading at 1.7 psi. These readings are indicative of a <br />generally stable slope with consistent pore pressure indicating mostly complete <br />dewatering. The area around VWP -09 is generally in its final grading state and over time <br />the pore pressures are expected to remain constant or slightly decrease as the area near <br />VWP -09 reaches its equilibrium state. <br />VWP -10: Also installed on May 18, 2012, VWP -10 had an initial reading of 0.6 psi and a <br />current reading of 0.7 psi. Like VWP -09, the area surrounding VWP -10 is not expected to <br />receive any additional gob and is awaiting final reclamation. Pore pressures are expected <br />to stabilize following that reclamation at or near their current readings. <br />Pore pressures at the active VWP locations are anticipated to continue to decrease as <br />drainage occurs. Upward spikes in pore pressure occur in locations where gob is either <br />temporarily stored prior to spreading and compacting or where the pile has received <br />additional coal waste as it is built upward. In our analysis we look at those spikes and <br />monitor the trend in reading after the spikes. In all cases, the VWP's have recorded <br />declining pore pressures following those spikes. Triaxial testing, performed in 2008 and <br />again in 2013 on gob samples, indicates a range of pore pressures at shear failure from <br />37.8 to 38.9 psi with an average of approximately 38.0 psi. Therefore, a pore pressure in <br />excess of 35.0 psi at any VWP location would be a concern and would require immediate <br />attention. To date, the highest recorded pore pressure has been 20.9 psi at VWP -07 (no <br />longer active) on December 21, 2009. Among active VWP's the highest pressure has <br />2013- REVISED 40 Quarter Monitoring Report PN #05- 126 -GEO <br />Page 3 of 6 <br />