WA 253-604-4878
OR 360-718-9410

Hollow Stem Auger, Mud Rotary, and Core Drill Rigs

Our auger rigs are designed to efficiently switch from auger to mud rotary to rock coring in minutes! Perfect for environmental, geotechnical, exploration, and construction drilling. With six of the newest combination hollow stem auger / mud rotary /core rigs available in the Pacific Northwest we minimize any down time due to mechanical problems.


Download: Hollow Stem Auger, Mud Rotary, and Core Drill Rig Details

Hollow stem augers are a versatile and effective method for advancing the borehole under certain conditions. They work much like a temporary casing in that the centers of the augers are open to allow for soil, water sampling, and/or well installation. As the augers are advanced into the subsurface, the auger spirals convey the unconsolidated formations to the surface, typically with no drilling fluids. Auger drill rigs are the preferred drilling method for a variety of applications including geotechnical, environmental, and construction drilling. Hollow stem augers are commonly used for soil sampling and ground water monitoring well installations.

SPT Calibration. Our auger drill rigs have calibrated 140 lb. and optional 300 lb. automatic hammers to obtain SPT samples. The calibration testing is typically done on an annual or as needed basis and the results of the testing are available upon request. When drilling with hollow stem augers, if heaving sands that prohibit accurate sampling or auger refusal is reached in dense or consolidated formations, these drills can be converted to drill using the mud rotary method. This is usually predetermined based on expected geological conditions at the site and arrangements have been made to make the rig conversion in the field. Holt's crews have a vast amount of experience drilling using the mud rotary method.

When core samples of hard rock are needed, rest assured that Holt has the equipment and experience to meet your needs. We can core with NQ, HQ3 and PQ3 wireline coring sizes. We also can perform multiple types of packer testing in the core holes. Our drillers have extensive coring experience.

Mud rotary drilling is an open hole, fluid based recirculatory method of drilling. The drilling fluid lubricates the drill bit, carries drill cuttings to the surface, and provides hydrostatic pressure in the borehole to keep the hole open and stable for sampling and installations. Mud rotary drilling is used in geological areas that prohibit the use of hollow stem augers, including: bedrock, broken rock, and dense sand or gravel formations. Our mud rotary drillers are the best in the industry!

Hollow Stem Auger, Mud Rotary, and Coring Drill Rigs

1 - Mobile B-54 track mounted
2 - Mobile B-57 track mounted
2 - Mobile B-58 truck mounted
1 - Mobile B-59 truck mounted
1 - Mobile B-60 truck mounted
1 - LDS 75 track mounted, high torque, limited access rig
2 - CME-75 truck mounted
1 - CME-85 HT truck mounted, high torque
1 - CME-850X track mounted

Contact us today to talk with a drilling professional about putting the efficiency and versatility of a hollow stem auger / mud rotary / core drill rig to work on your next project.

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Washington HQ
10621 Todd Rd. E, Edgewood, WA 98372

Oregon Office

12305 NE 56th St, Vancouver, WA 98682

Washington CL #HOLTSSI898JG
Oregon Construction Contractors Board #198764
Idaho Public Works CL #015401-CC-4
Montana CL #MWC449
Alaska CL #39039
California Type C-57, #1008224
New Mexico CL #5205166
Utah Water Well Driller License #909

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