2016-04-15_HYDROLOGY - C1996083 ‎(7)‎

• Permit No: C1996083
• IBM Index Class Name: Hydrology
• Doc Date: 4/15/2016
• Doc Name: 1st Quarter 2016 Quarterly Pond Inspection Report
• From: J. E. Stover & Associates, Inc.
• To: DRMS
• Annual Report Year: 2016
• Report Quarter_Month: 1
• Permit Index Doc Type: Sediment Pond Inspections
• Email Name: JDM
• Email Name: DIH
• Media Type: D
• Archive: No

CWDA No. 2
#01349-0001�R�+�s
04/13/16
Discussion of Inclinometer Monitoring
The latest inclinometer readings indicate no significant movements since the last quarterly
reading. As indicated in the DOWL report, some deflection was observed at BG05-7A.
However, the movement was at the very top of the instrument and no movement was observed
farther down the hole. As a result, the observed movement is not anticipated to be indicative of
instability in CWDA #2. The movement may reflect disturbance of the ground surface near the
instrument; however, the 2nd Quarter 2016 monitoring data may provide additional information
as to the cause of the observed deflection.
Vibrating Wire Piezometers
Between 2005 and 2012, a total of ten vibrating wire piezometers were installed in CWDA No.
2. However, several of the piezometers have been damaged or have otherwise ceased to
function. Currently, five of the piezometers are functional.
Monitoring of the functioning piezometers was completed by DOWL on March 21, 2016. The
attached monitoring report prepared by DOWL includes the piezometer monitoring data and the
data is summarized in the following table.
VWP ID
Initial Pore
Pressure
(psi)
12/19/15 Pore
Pressure
(psi)
3/21/16 Pore
Pressure
(psi)
Difference Since
Installation
(psi)
Difference
Since Last
Reading (psi)
VWP-05
6.8
1.9*
1.7
-5.1
-0.2
VWP-06
11.3
15.0
16.1
+4.8
+1.1
VWP-08
8.2
10.0
10.0
+1.8
1 0.0
VWP-09
2.8
2.8
2.8
0.0
1 0.0
VWP-10
-1.9
-1.9
-1.8
+0.1
1 +0.1
*Measured on 01/08/16
Discussion of Vibrating Wire Piezometers
VWP-05 was installed on August 3, 2005 near the toe of CWDA No. 2 adjacent to the access
road/bench. The pore pressures recorded at VWP-05 have shown some seasonal fluctuations;
however, the range of pore pressure changes is fairly small. In general, HBET does not believe
that the pore pressures in VWP-05 are cause for concern regarding stability of the gob pile.
VWP-06
VWP-06 was installed on June 5, 2009 near the existing top of CWDA No. 2. The pore
pressures recorded at VWP-06 have fluctuated since installation. In general, the fluctuations
have been seasonal and reflect the level of coal mine waste placement activity on top of CWDA
No. 2. However, the total change since installation is only 4.8 psi. As a result, based upon the
available data, HBET does not believe that the measured pore pressures are an indication of any
instability in CWDA No. 2.
VWP-08
VWP-08 was installed on June 5, 2009 at a slightly lower elevation than VWP-06. The pore
pressures recorded at VWP-08 have fluctuated since installation. However, the fluctuations have
generally been within a narrow range of values. The measured pore pressures are generally
consistent with the level of coal mine waste placement activity at CWDA No. 2.
X:\2008 ALL PROJECTS\01349 -Bowie Resources, LLC\01349-0001 Bowie Mine\200 - Geo\Gob Nnstrumentation Monitoring\2016\01349-0001 GP2 1stQ 2016 L041316.doc 2