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Potential effects of surface coal mining on the hydrology of the Greenleaf-Miller area, Ashland coal field, southeastern Montana

Water-Resources Investigations Report 82-4101

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Abstract

The Greenleaf-Miller area of the Ashland coal field contains reserves of Federal coal that have been identified for potential lease sale. A hydrologic study was conducted in the potential lease area in 1981 to describe the existing hydrologic system and to assess potential impacts of surface coal mining on local water resources. The hydrologic data collected from wells, test holes, and springs were used to identify aquifers in the alluvium (Pleistocene and Holocene age) and the Tongue River member of the Fort Union Formation (Paleocene age). Coal, clinker, and sandstone beds comprise the aquifers in the Tongue River Member. Most streams are ephemeral and flow only as a result of precipitation. The only perennial surface-water flow in the study area is along short reaches downstream from springs. A mine plan for the area is not available; thus, the location of mine cuts, direction and rate of the mine expansion, and duration of mining are unknown. The mining of the Sawyer and Knoblock coal beds in the Tonge River Member would effect ground-water flow in the area. Declines in the potentiometric surface would be caused by dewatering where the mine pits intersect the water table. Wells and springs would be removed in the mine area; however, deeper aquifers are available as replacement sources of water. The chemical quality of the ground water would change after moving through the spoils. The change would be an increase in the concentration of dissolved solids. (USGS)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Potential effects of surface coal mining on the hydrology of the Greenleaf-Miller area, Ashland coal field, southeastern Montana
Series title:
Water-Resources Investigations Report
Series number:
82-4101
Edition:
-
Year Published:
1982
Language:
ENGLISH
Publisher:
U.S. Geological Survey,
Description:
iv, 35 p. :ill., maps ;28 cm.