Rock Coring Methods Power Through Quartz and Granite

Securing a mineral exploration job doing nine borings running 300- to 400- feet deep through quartz and granite, Catawba Valley Engineering and Testing knew it was time to up their drilling power with the Geoprobe^® 3135GT delivering 10,000 ft-lbs of torque.

“We’ve cored to 300 feet with our 3126GT, but the maximum rpms were falling off and the pump struggled to keep up with the water needed at that depth,” Cody Dobbins, drilling operations manager, said. “With the 3135GT, it still has a lot left to give at 400 feet. I was a little surprised by how well it handled it and am excited to take it deeper when we get the chance.”

Built for Rock Coring Methods

Dobbins said the 3135GT’s rock coring “bells and whistles” make a real difference in the field:

• Weight-on-Bit: “It allows for hands-free coring, allowing us to dial in the head pressure for different formations of rock we’re in.”
• 10,000 ft-lbs Torque, 1,000 rpm: “The higher torque allows us to maintain high rpms for coring at depth.”
• Hands-free Rotation: “Makes rock coring or standard drilling easier. You’re able to do other tasks while the machine is doing the work, whether dialing in the weight-on-bit or getting another rod. You can just be more efficient.”
• Three Winches: “You can pull more tooling at one time without going back in and out of the hole.”

Results that Pay Off

That performance helped Catawba Valley secure annual coring contracts with mining clients. The upgrade in torque and rpms provides production confidence for their service area.

“The 3135GT also speeds up hollow stem auger drilling through dense piedmont residual soils in Western North Carolina,” Dobbins said.