DRILLINGTechnique
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Geologists working in the Atlantic Coastal Plain have always sought subsurface information to augment sparse outcrops. Over thirty years ago a power auger system was purchased to meet this need and facilitate the location of concealed shallow contacts. Success with this approach and the expanding need for documenting the timing of seismic events lead to the procurement of coring capability and a full time driller. Coring technology and skill have continued to expand to meet needs of various projects and collaborators. Currently, the drilling crew includes three full time people who are cross-trained and fully qualified to operate a Mobil B-61 drill equipped for wire line retrieval of a 94 mm Christiansen coring system. Specially adapted components and a sophisticated mud system, designed and perfected by our drillers have facilitated a very high rate of 2 1/2 inch diameter core recovery (greater than 90% in unconsolidated sand, silt, clay) from depths in excess of 1500 ft. |
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URL http://geology.cr.usgs.gov/capabilities/speccap/drill/tech.html |