Location: Caldwell Road, Auckland
Ross Reid won the $4 million contract and at the beginning of July set about what was always going to be a formidable race against the clock, given Auckland’s reputation for wet winters.
The reason for the urgency was Transpower had discovered an unstable area of ground in East Tamaki on the route where it planned to install an underground cable linking its Pakuranga substation to its new 186km 400kv transmission line from Whakamaru to Brownhill Road, construction of which had to be finished by the following April.
Ross Reid were tasked with building access roads, installing erosion and sediment controls, clearing the works area of trees and vegetation, creating a 1.4km haul road, replacing sections of an existing haul road where the ground was unstable, removing 75,000 cubic metres of soil and transporting it to a site at Wiri, removing existing farm fences and installing temporary fences along the perimeter of the works area, installing cement stabilized soil mixed columns, and stabilizing exposed ground with topsoil and grass seed after completion of the bulk excavation.
Cuts were to a depth of 12 metres and up to 12 truck and trailer loads of soil; about 1200 cubic metres were carted to the Wiri site each day between 7.30am and 6pm. Ross Reid had up to 18 staff on site, plus the drivers of the truck and trailer units. The additional challenges included obtaining the necessary resource consents, meeting Transpower’s stringent health & safety standards, carrying out the works without disruption to either the underground cable installer (Transfield Services) or the adjacent landowners, and managing the main dump-truck movements without causing traffic problems.