Directional drilling is a trenchless technology that allows us to lay pipelines with little excavation. It uses a steerable drill head that uses guidance systems and a transmitter to report its position, depth, pitch, and roll to the pilot. Directional drilling offers a host of advantages over traditional “cut-and-cover” pipeline installations – it is fast, cost-competitive, and has a minimal impact on the surface.  

Directional drilling is often used to fix pipelines that are beyond repair. They may have problems with gradients, such as dips or bellies, which make them difficult to rehabilitate. Pipe bursting or lining would only replicate these problems in the rehabilitated pipe. In this scenario, directional drilling can create a new, straight pipe next to the existing one – without resorting to excavation.

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Our teams can lay pipelines with directional drilling from 50 mm to 1200 mm in diameter. They will need to conduct a survey to understand the ground conditions and locate all buried structures, utilities, and building foundations.

Once this survey is complete, they draw up a plan and get to work. The first step is to dig launch and reception pits at either end of the bore. Our technicians test the drill head transmitter for functionality and accuracy before they begin to drill.

Initially, our technicians drill a pilot bore using a narrow drill head. This allows them to check that the new line is at the same level in both the launch and reception pits. Once the pilot bore is complete, they replace the drill head with a hole opening device known as a reamer. The reamer rotates through the pilot bore, carving out more material to increase its diameter. They inject drilling mud to secure the new bore hole’s integrity.  Once again, they check to see that the hole is at the same level in both the launch and reception pits. They then install the new pipe, pulling it through the bore hole using a winch and swivelled towing head. Finally, the team fills in and makes good the launch and reception pits.

Directional drilling requires considerable technical expertise and is best attempted by technicians with years of expertise. McAllister has just the experience and technology to get the job done reliably, every time. We enjoy close working relationships with our equipment and plant suppliers, who provide training on the very latest innovations.

These delicate procedures require experienced technicians using the latest equipment. Get McAllister’s expertise on your side.

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