NZ's biggest drill: The "boring" facts

The whole of the South Pacific is opening up as a potential market to Cambridge-based Smythe Contractors following its acquisition of a new American Augers DD440T directional drilling machine.   BY HUGH DE LACY

Drill.jpgAt an all-up cost of $2.5 million, Smythe Contractors’ new 45-tonne directional drill, recently arrived in New Zealand. It has five times the capacity of Smythe’s biggest existing drill, its well-performed Vermeer D80. Where the Vermeer can install steel and high-density polyethylene pipes up to 700 metres long and with a diameter of 300mm, the American Augers machine can manage a kilometre of one metre diameter pipes, or two kilometres of 600mm.

The new machine’s capacity far exceeds that of any other machine in New Zealand, and its presence here is likely to attract clients from throughout the South Pacific, according to Smythe’s general manager, Simon Payne.

“There’s nothing in concrete yet, but a lot of island nations have subsidies for that sort of work, so we can see demand developing beyond New Zealand,” Smythe told Contractor. Initially though the challenge will be to make New Zealand councils and consultants aware of the new machine’s capacity, “as this maxi-drill is new territory for  our industry and they can now start designing  jobs with that capability in mind,” he says.

Payne expects most demand for the machine’s services to come from drainage reticulation beneath estuaries, large residential areas and reserves. He is also interested in potential coal-seam gas extraction using directional drillings techniques.

The track-mounted DD440T has a 200 tonne pullback, compared to the Vermeer’s 40 tonne, and is specifically designed for setting up in the soft ground conditions common in

New Zealand. Powered by a 540hp Caterpillar engine and mounted on 600mm Grouser tracks, the machine has a maximum torque of 60,000 foot-pounds, and is 14.93 metres long, 2.46 metres wide and 3.6 metres high. Moving the beast from site to site requires a seven-axle trailer accompanied by three pilot vehicles.

The machine’s hydraulic pinion and gears drive a pilot drilling pipe of 115mm internal diameter (ID) by 9.45 metres long, and its presence in New Zealand will be of interest especially to designers who have in the past been constrained by the challenges of installing long and deep lengths of pipe by trenchless means. This long-range method of pipe installation minimises the need for intermediate manholes, and eliminates pump-stations and deep manholes.

It works in the conventional way of most directional drills, with the pilot hole entering the ground at an angle, and flattening out when it reaches the target depth. Once the drill has travelled the required distance, the head is replaced with a back-cutting reamer that the machine pulls towards itself, with the spoil being flushed as a slurry that contains bentonite as a lubricant.

The returning slurry and spoil are taken up by a sucker-truck for disposal. The reaming process might require a couple of passes to widen the hole to the right size, which is usually 25 percent greater in diameter than the pipe to be installed.

Once the reaming of the hole is complete, the new pipes are pulled back through the hole using the DD440’s 200 tonne carriage. At the same time, the drill rods are removed in a seamless operation that stops only to allow the next string of pipes to be welded in situ before the pull-back is completed.

Smythe Contractors is a 40-year-old company whose existing Vermeer D80 is one of the highest-capacity directional drills in New Zealand at the moment, so the new American Augers machine gives the company a new dimension within the local no-dig pipe-laying industry.

The new machine brings to eight the number of directional drills the company operates, and where previously Smythe’s have tended to concentrate on the North Island market, the DD440T will bring the whole of the country, no less than the South Pacific, within its ambit. Already the company, which offers open-cut as well as trenchless services but specialises in the latter, is looking at a job in Twizel among others in the South.

Smythe’s Contractors is based at Hautapu, near Cambridge, and is a private company owned by Mike Smythe and family. Besides Simon Payne, it employs two contracts engineers and up to 20 operating staff, producing an annual turnover of about $5 million.

“We expect this new drill to double our annual turnover to $10 million once it’s up and running,” Payne says.

Smythe’s installs up to 80 kilometres of pipelines a year under rivers – including the Waikato several times – estuaries, state highways and environmentally sensitive sites such as reserves and built-up areas. The underground utilities the company has installed range from 25mm cables to 2.3 metre diameter pipes, and from 10 metres to one kilometre.

Recent works include a 710mm diameter pipe that took stormwater from HEB Smithbridge’s Rivergardens development to the Waikato River, and a tricky job for the Rodney District Council that involved seven drills installing 710mm diameter pipes up to 400 metres long at a depth of 40 metres through hard Hibiscus Coast siltstone.

Other jobs have included 6300 metres of triple 140 and single 110 duct installations for Siemens Energy Services to reinforce the 33kV cable at Albany, and 150-25 MDPE mains for the entire Hibiscus Coast gas reticulation system.

Owner Mike Smythe is a member of the International Society for Trenchless Technology, and has been a pioneer of directional drilling in New Zealand. He gained his early training and experience in the United States through a series of annual study trips that continue to this day.

General manager Simon Payne is a civil engineer with well over 30 years in the civil construction industry, including 17 years as structures assets manager for NZ Rail. During the electrification of the North Island Main Trunk railway line in the 1980s he served as earthworks co-ordinator for over 30 construction projects in the King Country and Waikato.

Payne says he’s excited by the potential of the American Augers DD440T, and not only because of its stated capacity of one metre diameter pipes up to a kilometre long.

“That’s bread and butter for that type of drill, but by applying a little Smythe innovation and kiwi magic, we’ll be stretching those boundaries beyond the American manufacturer’s dreams,” he says.  

Contractor Vol.32  No.7  August 2008
All articles on this website are copyright to Contrafed Publishing Co. Ltd.