MBMG-1846

Montana Bureau of Mines and Geology

Located in Prairie County, Montana, this groundwater monitoring location is associated with a water well in the Upper Cretaceous aquifers.

Well Construction

Depth Description
0.0-778.0 ft 4.0 in diameter 11 lb steel casing
778.0-973.0 ft 6.0 in diameter open hole screen
Depth Lithology Description
0.0-19.0 ft unknown SAND;YELLOW-SOFT VFG-SILTY-POORLY CONSOLIDATED.
19.0-20.0 ft unknown COAL SOFT
20.0-28.0 ft unknown CLAY; SOFT MED GRAY W/CARBONACEOUS STREAKS- BENT.
28.0-32.0 ft unknown COAL; SOFT
32.0-41.0 ft unknown CLAY; AS ABOVE
41.0-42.0 ft unknown COAL
42.0-46.0 ft unknown CLAY; LT-MED. GRAY AS ABOVE
46.0-59.0 ft unknown CLAY; MED. GRAY- SOFT V SILTY
59.0-60.0 ft unknown COAL
60.0-65.0 ft unknown CLAY; AS ABOVE- BENTONITIC
65.0-68.0 ft unknown COAL; HARD
68.0-70.0 ft unknown CLAY; AS ABOVE
70.0-80.0 ft unknown SAND; LT GRAY- VFG- SILTY- SOFT
80.0-91.0 ft unknown CLAY; MED GRAY- W/CARBONACEOUS STREAKS- BENTONITIC SOFT
91.0-100.0 ft unknown COAL
100.0-133.0 ft unknown SILTSTONE- V HARD
133.0-142.0 ft unknown CLAY; AS ABOVE
142.0-150.0 ft unknown SHALE; GREEN GRAY- V SILTY- FIRM
150.0-156.0 ft unknown SILT; GRAY- P CONSOLIDATED- CLAYEY
156.0-157.0 ft unknown SILTSTONE; V HARD GRAY-BROWN
157.0-178.0 ft unknown SHALE;LIGHT-GRAY BROWN- PART CARBONACEOUS- PART V BENTONITIC
178.0-182.0 ft unknown COAL; VERY HARD
182.0-199.0 ft unknown SHALE; GRAY-GREEN V SILTY
199.0-203.0 ft unknown SILT; SOFT- V CLAYEY
203.0-210.0 ft unknown SHALE; GRAY-GREEN V SILTY
210.0-213.0 ft unknown COAL
213.0-227.0 ft unknown SILT; LIGHT GRAY- PART V CLAYEY
227.0-228.0 ft unknown SILTSTONE; GREEN- V HARD
228.0-245.0 ft unknown SHALE; GRAY-GREEN GRAY-BROWN PART CARBONACEOUS PART BENTONITIC
245.0-288.0 ft unknown SAND; VERY-FINE-GRAINED AND SILT; GRAY- POORLY CONSOLIDATED
288.0-291.0 ft unknown SHALE; SOFT CARBONACEOUS
291.0-305.0 ft unknown SAND; GRAY- VERY-FINE-GRAINED VERY SILTY
305.0-340.0 ft unknown SHALE; DARK GRAY- BROWN- CARBONACEOUS- INTERBEDDED WITH THIN SILT BEDS
340.0-342.0 ft unknown COAL
342.0-378.0 ft unknown SHALE; AS ABOVE
378.0-379.0 ft unknown COAL
379.0-384.0 ft unknown SHALE; AS ABOVE
384.0-385.0 ft unknown COAL
385.0-390.0 ft unknown SHALE; AS ABOVE
390.0-392.0 ft unknown COAL
392.0-419.0 ft unknown SHALE; AS ABOVE
419.0-465.0 ft unknown SILT; GREEN-GRAY SOFT- CLAYEY
465.0-518.0 ft unknown SAND; VERY-FINE- TO FINE-GRAINED- GRAY- 'SALT AND PEPPER'- ANGULAR-SLIGHTLY MICACEOUS- SILTY- SILTY- MODERATELY CONSOLIDATED.
518.0-520.0 ft unknown SILTSTONE; GRAY-BROWN V HARD
520.0-540.0 ft unknown SHALE; GREEN- 'GREASY'- SOFT
540.0-542.0 ft unknown COAL
542.0-547.0 ft unknown SHALE; AS ABOVE
547.0-564.0 ft unknown SHALE; AS ABOVE- V SILTY
564.0-566.0 ft unknown COAL WITH OXIDIZED FRACTURE SURFACES
566.0-584.0 ft unknown CLAY; MOSTLY BENTONITIC- WHITE- LIGHT GRAY
584.0-659.0 ft unknown SHALE; GRAY-GREEN SILTY- FIRM
659.0-660.0 ft unknown SILTSTONE; VERY HARD
660.0-687.0 ft unknown SAND; VERY-FINE-GRAINED- SILTY- SOFT
687.0-708.0 ft unknown SHALE; LT GRAY- BENTONITIC- 'GREASY'
708.0-723.0 ft unknown SAND; GRAY- 'SALT AND PEPPER' VERY-FINE-GRAINED- SILTY- SOFT
723.0-730.0 ft unknown SHALE; GRAY BROWN- SILTY- SOFT
730.0-762.0 ft unknown SAND; VERY-FINE- TO COARSE-GRAINED- GRAY- 'SALT AND PEPPER'- SOFT
762.0-784.0 ft unknown SHALE; GRAY-BROWN- SILTY- SOFT
784.0-819.0 ft unknown SAND; FINE- TO COARSE-GRAINED- POORLY CONSOLIDATED SUB-ANGULAR
819.0-820.0 ft unknown SILTSTONE; GRAY- V HARD
820.0-831.0 ft unknown SAND; LIGHT GRAY- 'SALT AND PEPPET'- VERY-FINE- GRAINED- POORLY CONSOLIDATED
831.0-838.0 ft unknown SANDSTONE; LT GRAY- VERY-FINE-GRAINED- WELL CEMENTED- V HARD
838.0-859.0 ft unknown SAND; LT GRAY- MEDIUM GRAY- VERY-FINE-GRAINED- POORLY CONSOLIDATED- VERY SOFT.
859.0-866.0 ft unknown SHALE; GRAY- BROWN- SOFT
866.0-918.0 ft unknown SAND; LIGHT GRAY- VERY-FINE-GRAINED- SILTY- POORLY CONSOLIDATED- VERY SOFT
918.0-947.0 ft unknown SHALE; GRAY-BROWN- SILTY- INCREASING FIRMNESS WITH DEPTH
947.0-973.0 ft unknown SHALE; GRAY-BROWN- 'GREASY'- V FIRM HOLE COMPLETED TO 973 FEET. HOLE COLLAPSED AT 860 FEET BELOW LAND SURFACE.

Operated in cooperation with: