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