MBMG-3772

Montana Bureau of Mines and Geology

Located in Sheridan County, Montana, this groundwater monitoring location is associated with a water well in the Lower Tertiary aquifers.

Well Construction

Depth Description
0.0-318.0 ft 4.0 in diameter plastic casing
303.0-313.0 ft 4.0 in diameter saw slots screen
Depth Lithology Description
0.0-10.0 ft unknown YELLOW-BROWN SILTY TO V COARSE SAND- CARBONATE RICH
10.0-30.0 ft unknown MEDIUM GRAVEL- THIN SILT INTERBEDS
30.0-40.0 ft unknown YELLOW SILT WITH COAL SLACK
40.0-69.0 ft unknown GRAY SILT WITH COAL SLACK
69.0-81.0 ft unknown VERY COARSE SAND- SOME FINE GRAVEL AND SAND
81.0-100.0 ft unknown DARK GRAY SILTY TILL WITH INTERBEDS OF SILT AND CLAY (LACUSTRINE AT BASE)
100.0-129.0 ft unknown FINE GRAVEL- CARBONATE-RICH- WITH SAND AND COAL SLACK (OUTWASH)
129.0-137.0 ft unknown COARSE GRAVEL (OUTWASH)
137.0-154.0 ft unknown BLACK SILT AND COAL SLACK (LACUSTRINE)
154.0-166.0 ft unknown FINE GRAVEL WITH SOME SILTY CLAY INTERBEDS
166.0-183.0 ft unknown DARK GRAY BROWN SILTY CLAY TILL- BOULDERS AT 174 FEET
183.0-187.0 ft unknown GRAVEL- CARBONATE-RICH (OUTWASH)
187.0-189.0 ft unknown LIGHT GRAY-BROWN SILT- LIMESTONE (?); FORT UNION FORMATION
189.0-232.0 ft unknown DARK BROWN SILTY CLAY- CALCAREOUS- MICACEOUS
232.0-233.0 ft unknown COAL
233.0-245.0 ft unknown MEDIUM GRAY CLAYEY SAND- VERY FINE
245.0-254.0 ft unknown SILTY CARBONACEOUS CLAY
254.0-261.0 ft unknown OLIVE GRAY CLAYEY SAND
261.0-283.0 ft unknown LIGHT OLIVE GRAY SILTY CARBONACEOUS CLAY
283.0-298.0 ft unknown LIGHT MEDIUM GRAY SILT- MICACEOUS
298.0-313.0 ft unknown COAL
313.0-318.0 ft unknown LIGHT MEDIUM GRAY MICACEOUS CLAY

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