PERMFILE40830

• Permit No: C1980007
• IBM Index Class Name: Permit File
• Doc Date: 6/2/2006
• Section_Exhibit Name: Exhibit 18B Evaluation of Potential Groundwater Inflows Associated w/E Seam Mining
• Media Type: D
• Archive: No

Mayo and Associates, LC
1. EXECUTIVE SiJNIMARY ........................................................................................ 5
I 2. INTRODUCTION ...................................................................................................... 9
1.1 Objectives ......................................................................................................:.. 10
1.2 Sources of Information ..................................................................................... 10
3. COMPARATIVE ANALYSIS OF GROUNDWATER INFLOWS ........................ 12
2.1 Geologic Conditions ......................................................................................... 12
2.2 Styles of groundwater inflows .......................................................................... 17
2.3 Properties of sandstone bodies with and without fractures ............................... 19
4.0 DESCRIPTION OF MINE INFLOWS ....................................................:................ 22
3.1 Soldier Creek Mine (Book Cliffs, Utah) ........................................................... 22
3.2 PacifiCorp -Energy West Mines (Wasatch Plateau, Utah) ............................. 25
3.2.1 Sandstone Channel Groundwater .............................................................. 27
I 3.2.2 Sandstone in the Mine Floor ..................................................................... 31
3.2.3 Fault Zone Groundwater ....................:...................................................... 33
3.2.3.1 Pleasant Palley Fault ............................................................................ 33
I 3.2.3.2 Roans Canyon Fault ...........................:................................................. 34
3.3 Genwall -Crandall Canyon Mine (Wasatch Plateau, Utah) ............................. 37
3.3.1 Sandstone Channel and Floor Seep Groundwater .................................... 37
3.3.2 Joss Valley Fault ...................:................................................................... 38
3.4 Co-Op Mine (Wasatch Plateau, Utah) .............................................................. 40
3.4.1 Blind Canyon Seam Sandstone Channel ................................................... 40
3.4.2 Fault Zone Fracture Flow .......................................................................... 44
' 3.5 Skyline Mine (Wasatch Plateau, Utah) ............................................................. 45
3.5.1 Sandstone Channels and Floor Seeps ...................................................... 46
I 3.5.2 Fault-Related Inflow ................................................................................. 47
3.6 Bowie and Oxbow Mines (Somerset Coal Field, Colorado) ............................ 49
3.7 West Ells Mine (Somerset Coal Field, Colorado) ............................................. 49
3.7.1 Sandstone Channels ..................................................................................51
3.7.2.1 Rock Access Slope (No Name Fault #1) ............................................. 52
3.7.2.2 B East Mains Fault (BEMFault) ......................................................... 53
3.7.2.3 14 Headgate Fault (14 HG Faulr) ....................................................... 55
4.0 WEST ELK MINE E SEAM HYDROLOGIC CONDITIONS ........................... 57
4.1 Geologic Setting ................................................................................................ 57
4.2. Potential E Seam Groundwater Inflow ............................................................. 59
4.2.2 Bowie Sandstone ....................................................................................... 62
4.2.2.1 Potential consequences of fully saturated conditions .......................... 62
4.4.3.2 Possible Bowie Sandstone saturation conditions ................................ 66
4.2.4 Thickness of Bowie vs. Rollins Sandstones ............................................. 67
4.2.5 Bowie Sandstone water levels .................................................................. 67
4.2.6 Response to B Seam mining ..................................................................... 68
5.0 CONCLUSIONS AND RECOMMENDATIONS ............................................... 70
5.1 Conclusions ..................................................................................................:....70
5.2 Recommendations ...........:...:.............................................................................72
• 6.0 REFERENCES CTI'ED ......................................................................................... 73
Evaluation of Potential Groundwater Inflows 2 February 24, 2004
Associated with E Seam Mining,
West Elk Mine, Somerset, Colorado