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Well Drillers Near Deadwood, South Dakota

Deadwood area typical geological profile: thin surficial clays/gravel, followed by minor sand/shale, then thick sequences of schist or slate; residential wells usually reach fractured schist/slate for water.

Showing contractors within 60 miles of Deadwood. 15 results found.

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A geological estimate for the Deadwood area.

150 ft

Typical Well Depth

25 ft

Static Water Level

Rotary - Mud Circulation

Recommended Method

Detailed Summary

Based on a synthesis of multiple well logs from the Deadwood, SD area, the typical geology consists of a surficial unit (0-20 ft) of clay, silt, and/or gravel, underlain by weathered shale or sand with cobbles and occasional alluvial material (to ~50 ft). This is typically followed by an alternating sequence of shale, slate, or clay bands, and then a thick interval of fractured and competent schist or slate bedrock extending well below 100 ft. Water is most commonly found in fractures within schist/slate at depths of 70-180 ft. Static water levels are typically 6-50 ft. Drilling is most commonly air rotary or rotary-mud, sometimes with DHH or cable tool. Cement grout is standard, with steel or SDR casing. A typical residential well (5-15+ GPM) targets fractured schist/slate at 100-180 ft. Higher capacity wells may be drilled to 220-300 ft for more or larger fractures.

Expected Geological Layers

Depth (Feet)Formation TypeDescriptionCharacteristics
0 – 4 ftClay with some gravel or cobblesBrown clay (sometimes with silt, cobbles, or minor fill material)Color: Brown/yellow/gray
Hardness: Soft
4 – 20 ftClay, silt, minor sand/gravel, or weathered shaleClay, silt, some thin gravel, occasional weathered shale or sand with cobblesColor: Gray, brown, white
Hardness: Soft to firm
20 – 50 ftShale, sandy shale, or broken slateThinly bedded to fractured, some sand or gravel interbeds, minor quartz lensesColor: Gray, black, yellow, brown
Hardness: Firm to indurated
50 – 90 ftSchist or Slate - weathered and fracturedGray, black, or yellow schist/slate, includes water-bearing fracture zones and minor quartzColor: Gray, black, yellow, reddish
Hardness: Hard
90 – 180 ftHard Schist/SlateCompetent (sometimes fractured) gray/black schist or slate, usually main aquiferColor: Gray to black
Hardness: Very hard
180 – 250 ftHard Schist/Slate and minor shale/limestoneMassive, competent metamorphic rocks with minor zones of shale or limestone lensesColor: Gray, black, tan
Hardness: Very hard
250 – 300 ftSchist/Slate, rare limestone or dolomite lensesContinues as hard metamorphic bedrock; drilling typically terminates here for high-capacity wellsColor: Gray, brown
Hardness: Very hard