Solar Farms to Direct Push to Coring

The Terracon office in Lodi, California, focuses predominantly on geotechnical work and a little bit of environmental. They perform mud rotary, air rotary, CPT and some direct push. While heavily involved in work on solar farms, they added a Geoprobe^® 3145GT to their fleet.

“Originally we looked at a 3230DT. We chose the 3145GT for the solar farm work because it would be easier to get from point A to point B on the Terramac versus following behind a rig with a remote,” said Daniel Del Castillo, local exploration manager.

Crawler Drill Advantages

To him the crawler carrier is “unstoppable.”

“It’s a little tank. It goes anywhere. We can attach a trailer to it and tow equipment we wouldn’t be able to get to remote areas otherwise, sometimes eliminating the need to bring a skid steer or forklift,” Del Castillo said. “Plus you have air conditioning, heater, windshield — all the creature comforts while on site. You kind of look forward to the next boring.”

Since running the rig, he finds the 3145GT offers several other advantages:

• Centerline head side shift: “It allows ease of use when changing different drilling methods.”
• Telescoping winch mast: “It is helpful for giving us access to areas with lower clearance. I like the quick connect winch hook feature that lets you switch between a hook and the overshot.”
• Drill mast oscillation: “It helps you setup on difficult terrain and different angles.”
• Control panel: "The 3145GT gives you a lot of useful real time data on the screen, including rotation and pump speed."

These features were key to doing two 150-foot, 30-degree angle borings to collect intercept cores.

“We drilled from one side at an angle, and then the other to basically make a cone to hopefully intercept one another to collect cores,” Del Castillo said. "We used air rotary at an angle and were able to get the samples right where we needed them."

More Than Solar Farms

While the 3145GT was purchased for solar farms, the Lodi office’s workload has shifted to doing more California Department of Transportation and Department of Health projects.

“Even though our contracts changed from doing the solar farms, we’ve kept the 3145GT moving with these new projects as well,” Del Castillo said. "We’re now doing more work for various state agency projects consisting of more mud rotary and coring work."

These projects have permitted him to test out the range of capabilities for simplifying fieldwork engineered into the 3145GT.

“The 3145GT does very well with direct push work, as well as CPT work if in the right conditions. It does well with coring HQ3 and 134mm,” Del Castillo said. “Using the 325 OTE for environmental is great, we can get enough sample and still push SPT as well. We can do combination geotechnical and environmental to get blow counts on SPT as well. This can also reduce cuttings when soil conditions are right.”

According to him, the overall versatility is the reason he would recommend the 3145GT.

“We can do a lot of different things and to change from one thing to another is really simple. You don’t have to break down to do something else,” Del Castillo said. “We can auger and move to direct push or OTE when conditions permit.”