The American Augers Maxi Drill rig has 285 tonnes of pullback capacity with 80,000 foot-pounds of rotary torque. The drilling rig comes with a Zap-A-Lert safety system and an entry/exit side lock-out safety system.

McConnell Dowell has used the horizontal directional drilling (HDD) rig to complete works on the Murray River crossing as part of the Dampier to Bunbury Natural Gas Pipeline (DBNGP) Stage 5B Expansion, and the crossing of the Collie River for the Western Australian Water Corporation.

These two projects utilised the same directional drilling works by drilling a pilot bore through the ground along a predetermined profile. Once the pilot bore was successfully drilled, the hole was enlarged by using reaming tools to achieve the desired diameter, then the product pipe was pulled back through the bore.

In addition, McConnell Dowell has taken delivery of a 35 tonne Vermeer D80 x 100 HDD rig.

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This unit boasts 10,000 foot-pounds of rotary torque and incorporates the Strike Alert safety system package, which warns the operator if the drill hits an underground power source. The safety system package is in keeping with McConnell Dowell’s commitment to safety.

The new HDD rig complements the American Augers DD625 rig and has been used to complete a number of road crossings on the DBNGP project, including some rock crossings in and around the Dampier area.

With the purchase of these two rigs McConnell Dowell has the ability to construct a wide range of directional drills from large diameter and long crossings to smaller road crossings and smaller footprint projects.

HDD provides the lowest environmental impact of any alternative crossing method, allowing for maximum depth under the obstruction, and minimising the chance of damage to the pipeline in the future.

The technique limits the interruption to road or river traffic and generally requires less public interaction, leading to a lower social cost. HDD construction sites usually involve a smaller ecological footprint and, due to the short construction schedule, directional drilling is usually a cheaper alternative to other methods.

A bentonite-based mud is normally used to keep the hole from collapsing and to bring the cuttings from the face. The bentonite transports the cuttings to a recycling system that allows the mud to be reused.

McConnell Dowell’s expertise can deliver a complete HDD solutions package from design and engineering, to project execution and reinstatement.