Ben Sheehan, marketing services manager at Vermeer says he is seeing a major shift from excavators to trenchers for any pipeline or drainage work. He believes that using a trencher may help to increase productivity when compared to an excavator, and that trenchers may also have a stronger resale value.

"Using a trencher can also reduce the amount of fuel needed to complete a ditch when compared to excavators, and can also potentially mean less labour costs to run for the same amount of ditch," says Sheehan.

"A major benefit of trenchers is that they produce re-useable backfill. The spoil from a trencher can be put right back into the trench as backfill, whereas excavator spoil often has to be hauled off and put through a crusher. Also, a trencher can produce a trench with a flat bottom and smooth, straight walls, and only the right amount of dirt is removed to accommodate the pipe.

"Using a laser, trenchers can easily cut to grade without the need for repeated measurements of the ditch."

Vermeer has launched a high capacity bucket wheel attachment for the installation of small diameter cross-country pipelines. It is designed to work with the Vermeer T655 Commander 3 tractor and, depending on the size of bucket used, has the ability to cut 55 cm, 61 cm or 71 cm wide trenches. According to Sheehan, the bucket wheel is aimed at helping to increase productivity in soft soils.

Ditch Witch Australia has released the Tesmec Chain Saw M5 mechanical drive trencher with a Cat C13 440 hp engine. The first example of this machine to arrive in Australia from the US is currently being utilised on the Wetalla Water Project which involves supplying recycled water from the Wetalla Water Reclamation Facility at Toowoomba to the New Acland Coal mine via a 46 km pipeline.

Ken Shaw at Redline Contracting, which is installing the pipeline, says the project requires excavation of a trench 900 mm wide and 1.5m to 2.5m deep to accommodate a 450 mm diameter M-PVC pipe plus a 24 core fibre-optic cable. In addition, two reservoirs and pumping stations are being constructed together with associated electrical installations.

"Due to the tight construction time-frame, we purchased the Tesmec M5 chain trencher to provide optimum trenching rates throughout the project, and it is pleasing that recently the construction of around 1 km of trench was achieved in just 8 hours," says Shaw.

"The M5 series trencher is specifically designed for trenching in rock, having the facility of a low chain speed for increased breakout force. Our production is certainly boosted as the need to use excavators with hydraulic hammers to remove isolated sections of rock is minimised."

Also recently launched by Ditch Witch is the Tesmec TRS-1075 bucket wheel trencher which has a Cat C9 335 hp engine and is fitted with a 711 mm wide cut bucket line capable of digging 2,100 mm deep. A TRS-1075 is currently being used on construction of the Bonaparte gas pipeline in the NT.