Our dual rotary drill rigs are used when casing has to be socketed into hard bedrock. They can also be used when sand, gravel, cobbles and large boulders make it challenging to drill a cased hole. The versatility of dual rotary drilling makes it one of the most efficient, low-risk and cost-effective methods for drilling in difficult formations.
Dual Rotary Drill systems use a lower rotary drive to advance casing through unconsolidated overburden and, where applicable, socket that casing into bedrock. Rotational forces are transmitted through the lower rotary to the casing, carbide-studded shoes or weld-on bars enable the casing to cut through the overburden boulders and bedrock. A reverse-circulation top drive rotary head and drill string simultaneously rotate to drill inside the casing. The drill string is equipped with either a down-the-hole hammer or a rotary bit to remove material and bring it to the surface. Please see reverse circulation section.
Construction Drilling has dual rotary drill systems that can handle holes from 6” to 10’ (3.05m) in diameter.