PERMFILE130419

• Permit No: C1980007A
• IBM Index Class Name: Permit File
• Doc Date: 4/8/2005
• Section_Exhibit Name: Exhibit 60C Subsidence Evaluation 2004 Geological Hazard Field Observations for the WFLA
• Media Type: D
• Archive: Yes

Exhibit 60C
Subsidence Evaluation and 2004 Geologic Hazard Field Observations
Wesi Flatiron Lease Area
• 7.1.1 Maximum Vertical Displacement (Subsidence)
The following range of vertical displacements (subsidence values) is projected for the West
Flatiron Lease area. The projected range of maximum vertical displacements, for the West
Flatiron Lease azea and adjacent Box Canyon mining area is shown in Table 1.
Longwall Panel 18A:
• Maximum vertical displacement above the chain (gate road) pillars (SAP) is estimated to range
from 1.7 to 3.8 feet.
• Maximum vertical displacement {subsidence, Sm) is projected to range from 6.0 to 9.6 feet'
Lonewall Panels 18 and 19:
• Maximum vertical displacement above the chain (gate road) pillars (SAP) is estimated to range
• from 2.2 to 6.5 feet.
• Maximum vertical displacement (subsidence, Sm=at) is projected to range from 4.8 to 9.6,i
feet.
Lon wall Panels 20 and 21:
• Maximum vertical displacement above the chain (gate road) pillars (SAP) is estimated to range
from 2.9 to 6.5 feet
• Maximum vertical displacement (subsidence Sm=at) above the longwall panel centers is
projected to range from 4.8 to 9~ eet.
•
831-032.650 Wright Water Engineers, Inc. Page 13
November 2004