2010-05-03_REPORT - C1980007 ‎(9)‎

• Permit No: C1980007
• IBM Index Class Name: REPORT
• Doc Date: 5/3/2010
• Doc Name: 2009 Subsidence Report
• From: Wright Water Engineers, Inc
• To: DRMS
• Permit Index Doc Type: Subsidence Report
• Email Name: TAK
• Media Type: D
• Archive: No

Fall 2009 Subsidence and Geologic Field Observations
Box Canyon, Apache Rocks, and South of Divide Mining Areas
• E-seam longwall mining began in the South of Divide mining area in December 2008. The
spring and fall 2009 field visits represented the first opportunities to make seasonal post-mining
observations in this area. While subsidence cracks were observed at some of the MDW drill
pads (particularly those closest to the longwall face), there appeared to be an equal number of
observed cracks in MDW pads above the unmined portion of E-seam Longwall Panel 1
(Longwall Panel E1). Observational evidence suggests that these latter cracks are the result of
differential settlement of portions of the pad where the greatest amount of fill was placed. These
differential settlement cracks were most prominent during the spring 2009 field visit and visibly
diminished during the fall 2009 field visit (likely the result of additional adjustment and sealing).
•
•
831-032.791 Wright Water Engineers, Inc. Page 4
April 2010