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Variety Key to Business for Cenozoic


Exploration in reservoir fill abutment.

Exploration in reservoir fill abutment.

With a bachelor’s degree in geophysics from the University of California Santa Barbara, Jeff Harra’s interest in mining geology, geologic hazards, and equipment design inspired him to develop Cenozoic Exploration in 1993. The Altos, California, company specializes in limited access drilling and sampling for geotechnical and environmental industries and became Cenozoic Exploration LLC in 2018.

The newest addition to their fleet of rigs is a Geoprobe® 7822DT combination rig equipped with auto drop hammer with 140-lb. slug for ASTM sampling. In addition to hollow stem auger drilling and the auto drop hammer SPT sampling, they offer rotary wash, mud rotary, direct push DT22, Macro-Core®, and in situ water sampling.

“This is our preferred rig for installation of groundwater monitoring, vapor extraction, and shallow domestic wells,” Harra said. “We have three independent specialized tool racks that are carried to the boring locations and transport it to sites with our 2014 International 7400 4X6 semi tractor and Gatormade kingpin gooseneck air brake trailer, which makes us California Air Resources Board compliant and tier 4 compatible.”

Since adding the machine in spring 2018, Cenozoic has completed a variety of projects from rotary borings, with sampling to 80 feet, to domestic water wells to 150 feet – all producing drinkable water – with 6-inch tooling, rotary wash. Their deepest push boring has only been limited to 55 feet by their customers need.

“Between direct push projects, we are keeping the 7822DT very busy with geotechnical work, hollow stem auger with detailed sampling, modified California, and SPT,” Harra said.

Harra’s interest in geophysics and equipment design led him to design and build his own hydraulic portable machine and a crawler tractor mounted drilling rig, yet he appreciates the added capacity for their company brought by the 7822DT. “I have 26-years experience with many rigs and I am very happy with our 7822DT,” Harra said.

Contact Us

1835 Wall Street
Salina, Kansas 67401
Phone: (785) 825-1842

Geoprobe® 7822DT Version 3 Updates

7822DT rotary drilling rigs capability with direct push finesse

7822DT Drill Rig

From crowded street corners to far removed places, tackle various environmental, geotechnical and exploration applications with a single machine combining rotary drilling and direct push, saving time and money required to mobilize multiple drill rigs.

Photo Gallery


Exploration in reservoir fill abutment.
Geoprobe® 7822DT installing 2-inch monitoring casing to 30 feet, in remote mountains.
Geoprobe® 7822DT rotary wash drilling to 150 feet with 4.75-inch tri-cone.
Exploration on top of fill edge with hollow stem, auto drop hammer, modified California samples and direct push Macro-Core® sampling to determine fill/native and native/sedimentary formation contacts.
7822DT hollow stem exploration for proposed sidewalks and road shoulder investigation on steep bank.

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