MBMG-248640

Montana Bureau of Mines and Geology

Located in Lewis and Clark County, Montana, this groundwater monitoring location is associated with a water well in the Northern Rocky Mountains Intermontane Basins aquifer systems.

Well Construction

Depth Description
-2.0-69.4 ft 2.0 in diameter pvc casing
-2.0-2.0 ft 6.0 in diameter steel casing
49.0-69.0 ft 2.0 in diameter factory slotted screen
Depth Lithology Description
0.0-5.0 ft unknown METAMORPHIC ROCK FRAGMENTS AND BUFF CLAY - DRY
5.0-10.0 ft unknown METAMORPHIC ROCK FRAGMENTS ARE QUARTZITE AND GRAY-GREEN ARGILLITE. DRY
10.0-15.0 ft unknown AS ABOVE - DRY
15.0-20.0 ft unknown AS ABOVE - DRY. WELDED CASING SHOE ON 6-IN ID STEEL CASING. DRIVING 6-IN STEEL CASING. POURED SACKS POWDERED BENTONITE IN ANNULAR SPACE AT SURFACE
20.0-25.0 ft unknown AS ABOVE (5 PERCENT BLACK ARGILLITE) - MORE PERCENTAGE ROCK FRAGMENTS. DRY. POSSIBLEY FROM UP HOLE
25.0-30.0 ft unknown AS ABOVE. DRY. NO BLACK ARGILLITE
30.0-35.0 ft unknown CLAY- GRAYISH GREEN WITH ROCK FRAGMENTS (ARGILLITE AND QUARTZITE). DRY. 50 PERCENT CLAY
35.0-40.0 ft unknown AS ABOVE. GREY-GREEN ARGILLITE AND LIGHT COLORED CLAY. DRY
40.0-45.0 ft unknown AS ABOVE. DRY
45.0-50.0 ft unknown AS ABOVE. DRY. CLAY APPEARS KAOLINITIC.
50.0-55.0 ft unknown AS ABOVE. UP TO 80 PERCENT CLAY. DRY
55.0-60.0 ft unknown INCREASE IN ROCK FRAGMENTS. POSSIBLY CARBONATES. FINE GRAINED WITH IRON STAINING. DRY. CIRCULATING. SOME MINOR WATER ENTRY AT 60 FT BELOW LAND SURFACE.
60.0-65.0 ft unknown CLAY AS ABOVE. 20-30 PERCENT ROCK FRAGMENTS. CIRCULATING. LIMITED WATER ENTRY.
65.0-70.0 ft unknown DEEPENED TO 70 FT. LITHOLOGY AS ABOVE. 50-80 PERCENT CLAY WITH ROCK FRAGMENTS. CIRCULATING. GETTING STEADY INFLOW. WILL BUILD WELL WITH 20-FT OF 20 SLOT SCREEN FROM 50-70 FT BELOW LAND SURFACE.

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