Critical to the success of the $850 million, 27-kilometre, Transmission Gully motorway project, has been the ability to work around the ecologically-sensitive Horokiri and Te Puka streams.
To meet consents and a “Greenroads” Silver Certification, (a first for a New Zealand motorway) this complex “project within a project” began with steps to protect the native wild life. This included the temporary relocation of 4,500 threatened fish species from the Te Puka stream.
The next challenge, before any of the major construction work could begin, was to create water-free work areas where culverts could be installed and placed along the alignment of the existing streambed. Once complete, this
will allow the water to flow underneath while the highway earthworks are constructed on top. In places, the finished highway will be 14 metres above the original streambed.
Inter-generational, New Zealand company Prime Pump began discussions with the Transmission Gully team in September 2015, when Prime Pump’s Civil and Mining Sales Engineer, Glenn Powell, says the project was still
in the investigative stages.
“We worked closely with the project engineers, scoping the project, and looking at the best solutions for their needs and the unique demands of the site.”
The pumps ultimately selected were the multi-purpose BBA BA150, 6” Autoprime Dewatering and Sewer Bypass Pumps.
Manufactured in The Netherlands they are among the high-performance pumps Prime Pump sources from around the globe. Powell says this approach allows them to draw on international expertise, without compromising their commitment to meeting local needs. “We select the best there is, to do the best job.”
In New Zealand, the BA Series is used almost exclusively for civil construction and mining applications. Typically, this includes sewer bypass, creek diversions, well-pointing and major flood control works. Over 100 of these pumps are currently in use around the country.
The first 11 pumps for Transmission Gully arrived in July 2016, followed by a further four. Capable of pumping 475,000 litres an hour each, the BA 150s will put in thousands of hours before their job is finished.
Currently, work is progressing at the rate of approximately 40-50 metres a day. Around 6 kilometres of pipe will need to be completed, before the major earthworks can begin.
Fully bunded, the pumps are ideal for work around the streams, with no possibility of fuel or oil entering the water flow. They’re also extremely robust. Compact, with solid, well-designed canopies, the 1600kg pumps can be easily moved by excavators using the certified lifting hooks. As every location for a pump may last as little as 2 days, this design means they can be relocated as the construction schedule dictates.
There was also a strong cost-saving aspect to the choice. The pumps’ efficiency reduces fuel consumption to a minimum, running on significantly less than comparable pumps.
Glenn Powell says their all-round performance has been unbeatable. “It’s everything a project like this demands. They help keep things going smoothly, making jobs reliant on water-free work areas easier. This is not the time you want to be worrying about something breaking down. Or not getting the job done.”
(The BA series pumps have also been selected for the $636 million Hamilton by-pass, currently under construction.)
Prime Pump have a smaller 4” BA 100 pump in Transmission Gully too, operating on a water filling station trickle-feeding a large pond, used for dust suppression and clay compaction.
In addition, Prime Pump built one pump specifically for Transmission Gully.
This moves water 350 metres, (with a 30 metre head), to a dust suppression water storage lake. The lake level is controlled by a remote telemetry system so it’s constantly at a pre-selected level, with the pump switching on and off according to the signals it receives.
Because of its relatively remote location, it includes a specialist 1,000 litre, fully-bunded diesel tank that keeps refuelling cycles to a minimum and allows the TG team to focus on bringing the motorway to completion.
For Prime Pump, Transmission Gully is their biggest project yet and Powell, a regular visitor to the site, says it’s satisfying contributing to one of the country’s largest construction projects. “It’s very fulfilling to see the work the pumps are doing. We’re pretty excited about it.”
