2013-09-27_REPORT - C1980007 ‎(4)‎

• Permit No: C1980007
• IBM Index Class Name: REPORT
• Doc Date: 9/27/2013
• Doc Name: Spring 2013 Subsidence Monitoring Report
• From: Wright Water Engineers, Inc
• To: DRMS
• Permit Index Doc Type: Subsidence Report
• Email Name: JRS
• Email Name: DIH
• Media Type: D
• Archive: No

Spring 2013 Subsidence and Geologic Field Observations
South of Divide and Dry Fork Mining Areas (E -Seam)
Figure 2. Northwestward view during spring 2013 site visit of several small subsidence cracks on
the MDW E4 -09 well pad. Note the existence of several cracks along the loose material used as
a containment berm at the left side of the image.
4.3.2 Location 2
An approximately 600 -foot long road connects MDW pad E4 -9 and with the MDW E4 -10 pad.
Approximately 300 feet east of the MDW E4 -10 pad, a 6 -foot long subsidence crack was observed
along the right wheel track. The maximum crack width and depth were observed to be 0.5 and 6
inches, respectively. Eleven sub - parallel cracks with similar maximum width and depth
dimensions were observed across the MDW E4 -10 pad (Figure 3). The general direction on these
sub - parallel cracks was N70 °E. The number and extent of subsidence cracking are likely the result
of the pad's location immediately above the active longwall mining face (as of the time of our
spring 2013 field visit) and its lateral proximity (less than 300 feet) to the tailgate entries for E-
seam Longwall Panel E4 (see Maps 1 and 2). The E -seam overburden depth at this location is
approximately 980 feet.
831 - 032.795 Wright Water Engineers, Inc. Page 12
September 2013
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Figure 2. Northwestward view during spring 2013 site visit of several small subsidence cracks on
the MDW E4 -09 well pad. Note the existence of several cracks along the loose material used as
a containment berm at the left side of the image.
4.3.2 Location 2
An approximately 600 -foot long road connects MDW pad E4 -9 and with the MDW E4 -10 pad.
Approximately 300 feet east of the MDW E4 -10 pad, a 6 -foot long subsidence crack was observed
along the right wheel track. The maximum crack width and depth were observed to be 0.5 and 6
inches, respectively. Eleven sub - parallel cracks with similar maximum width and depth
dimensions were observed across the MDW E4 -10 pad (Figure 3). The general direction on these
sub - parallel cracks was N70 °E. The number and extent of subsidence cracking are likely the result
of the pad's location immediately above the active longwall mining face (as of the time of our
spring 2013 field visit) and its lateral proximity (less than 300 feet) to the tailgate entries for E-
seam Longwall Panel E4 (see Maps 1 and 2). The E -seam overburden depth at this location is
approximately 980 feet.
831 - 032.795 Wright Water Engineers, Inc. Page 12
September 2013