United States
Department of
Agriculture
Forest Service
Technology &
Development
Program
7100 Engineering
August 2003
0371-2801-MTDC
Investigative Methods
for Controlling
Groundwater Flow
to Underground Mine Workings
Phyllis Hargrave and John Metesh, Montana Bureau of
Mines and Geology
Ken McBride, Bitterroot National Forest
Steve Oravetz, Northern Region
USDA Forest Service
Technology and Development Program
Missoula, MT
7E72G71—Acid Mine Drainage Study • August 2003
The Forest Service, United States Department of Agriculture (USDA), has developed this information for
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Contents
Introduction ______________________________ 1
Groundwater Flow to Underground
Mine Workings __________________________ 2
Mitigation Methods _______________________ 3
Methods for Investigating Groundwater
Source Areas ____________________________ 4
Hydrological and Geohydrological Methods _______
Water Balance _______________________________
Age Dating of Springs _________________________
Tracer Tests _________________________________
Water Quality ________________________________
Drilling _____________________________________
Soils and Vegetation Methods ___________________
Remote Sensing, Photo Interpretation,
and Field Mapping __________________________
Field Investigations for Soil and Vegetative Mapping _
Geoscientific Methods _________________________
Literature Review _____________________________
Aerial Photography in Relation to Fracture
and Structural Studies _______________________
Field Mapping _______________________________
Geophysics _________________________________
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Discharge and Recharge Areas _________________
Water Samples _____________________________
Charter Oak Mine Site ________________________
Introduction ________________________________
History ____________________________________
Geology ___________________________________
Environmental Conditions _____________________
Underground Workings _______________________
Mine Discharges ____________________________
Surface Water ______________________________
Aerial Photography __________________________
Characterization and Mapping of Riparian Areas
and Wetlands _____________________________
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Summary _______________________________ 28
Elkhorn Mine ________________________________ 27
Charter Oak Mine ____________________________ 27
References ______________________________ 28
Hydrology __________________________________
Soil and Wetlands Interpretation ________________
Aerial Photointerpretation _____________________
Elkhorn Mine ________________________________
Charter Oak Mine ____________________________
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Appendix A—Elkhorn Mine Riparian and
Case Studies _____________________________ 10
Elkhorn Mine and Mining District _______________ 10
Introduction ________________________________ 10
History _____________________________________ 11
Geology ____________________________________ 11
Environmental Conditions _____________________ 12
Underground Workings _______________________ 13
Mine Discharges ____________________________ 13
Surface Water ______________________________ 15
Regional Structure (Aerial Photographs) __________ 16
Characterization and Mapping of Riparian Areas
and Wetlands _____________________________ 16
Office Procedures ___________________________ 17
Field Investigations __________________________ 18
Mapping Results ____________________________ 18
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Wetlands Characterization and Mapping ____________ 31
Methods ____________________________________ 31
Discharge and Recharge Areas _________________ 35
Water Samples _____________________________ 37
Appendix B—Elkhorn Mine Riparian Area
and Wetlands Map Unit Descriptions _____________
Map Unit 1F _________________________________
Map Unit 2F _________________________________
Map Unit 1H _________________________________
Map Unit 2H _________________________________
Map Unit 1FH _______________________________
Map Unit 3U _________________________________
Map Unit W _________________________________
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