Abstract: Site-Specific Coal-Reclamation Study Near Ashland, Montana

W. R. Hotchkiss

A site-specific study of reclamation potential of strippable coal deposits in southeastern Montana is being conducted on about three sections of coal-rich land between Threemile and Home Creeks, tributaries to Otter Creek near Ashland, Montana. The 60-ft-thick Knoblock coal unit and 13 lesser coal seams of the Tongue River Member of the Fort Union Formation of Tertiary age underlie the rolling topography of the semiarid Northern Great Plains physiographic province. The Knoblock unit is locally the major shallow aquifer.

Soil and vegetation data will be compiled and a series of test holes will be drilled to obtain geologic and hydrologic data. U.S. Geological Survey data collection will include geophysical logging, aquifer testing, and sampling for chemical analyses for an ongoing hydrologic monitoring program to document baseline conditions and to provide some guidance for potential reclamation problems. Baseline data will be acquired and correlations between geophysical, hydrologic, and chemical parameters evaluated.

After the initial phase, the Ashland site will be modeled to evaluate how various strip-mining plans would affect the hydrology of the area. Later model studies will seek to anticipate chemical changes as strip-mining operations proceed.

Data from Ashland study and similar data gathered from later control areas will be extrapolated to a regional model of the western coalfield. This model could be valuable as an aid to managers in optimizing strip mining in southeastern Montana.

AAPG Search and Discovery Article #90979©1975 AAPG – SEPM Rocky Mountain Sections Annual Meeting, Albuquerque, New Mexico