Connors introduced dual-purpose core/RC drills for underground drilling in 1999. Drills capable of reverse circulation drilling have a booster air compressor, or can be matched with an auxiliary booster compressor. This drilling uses Down Hole Hammers (DHH) and dual tube reverse circulation drill rods. Holes have been drilled to 900 ft. at 4 1/2-inch diameter. Samples are collected whole or split with a rotary splitter.

• Advantages of RC Drilling
• Underground RC Drill Specs
• Applications for Underground RC