2014-06-12_REPORT - C1996083

• Permit No: C1996083
• IBM Index Class Name: Report
• Doc Date: 6/12/2014
• Doc Name: May 2014 VWP Monitoring Results
• From: J.E. Stover & Associates, Inc
• To: DRMS
• Permit Index Doc Type: Waste Pile/Fill Report
• Email Name: MLT
• Email Name: SLB
• Email Name: SB1
• Media Type: D
• Archive: No

The re- calculated data produced the following pore water pressure summary information.
Table 2. Summary of Functional VWP Pore Pressures
VWP ID #
Initial Pore
Pressure
(psi)
4/21/14 Pore
Pressure
(psi)
5/21/14 Pore
Pressure
(psi)
Difference
Since
Installation
(psi)
Difference
Since Last
Reading
(psi)
VWP -05
6.8
1.9
1.9
-4.9
0
VWP -06
11.3
14.6
14.8
+3.5
+0.2
VWP -08
8.2 12.2*
8.7
1 8.9
+0.7
1 +0.2
VWP -09
2.8 (1.5 *)
2.9
2.8
0
-0.1
VWP -10
-1.9 0.6*
-1.8
-1.9
0
+0.1
* indicates previously reported initial value
The physical locations of the piezometers are shown on the attached Instrumentation
Site Plan, Drawing 1. We revised the graph showing all piezometer data from their initial
readings to current reading (5- 21 -14) to reflect the changes and this graph is presented
as Figure 1. We also have prepared a new graph showing active piezometers only as
Figure 2. As mentioned above the historic graph which shows damaged and active
piezometers will not be revised but will be presented in future reports in its current form
for reference. Updated graphs will be produced for the currently functional piezometers
only (refer to Figure 2).
The corrected initial pore water pressures were lower by 4 psi in VWP -08 and 2.5 psi in
VWP -10, and higher by 1.3 psi in VWP -09. The negative value at VWP -10 indicates that
the soil is in an "unsaturated" state. The results generally indicate an enhanced shear
strength of the Gob where the pore water pressure was reduced and decrease shear
strength where the pore water pressure increased. Since the pore water pressure data
was lowered at two locations and raised at one location, the net result would be expected
to be an overall increase in Gob pile stability.
If you have any questions regarding this letter or the instrumentation monitoring at
CWDA No. 2, please don't hesitate to contact me at (970) 497 -8827 or
w, nandorffbuckhornaeo. com.
Respectfully Submitted,
BUCKHORN GEOTECH, INC.
Wayne Pandorf, P.E.
Enclosures: VWP Location Plan
Figure 1 - Historic Piezometer Data Graph
Figure 2 - Currently Active Piezometer Data Graph
May 2014 VWP report-5-27-14 PN #13- 231 -001
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