• Isolated location with near vertical faces above and below road.
  • Extreme weather conditions, wind frequently closes road.
  • Working around peak traffic flow times on a major highway.
  • Traffic and helicopter access management plan.

SH2 Muldoon’s Corner upgrade – Opus (Oct/Nov 2007)

Muldoon’s Corner is a difficult section of State Highway 2 which needed realignment. It is located near the summit of the narrow and winding Rimutaka Hill Rd and features tight corners, no shoulder and near vertical faces above and below the road. It is also frequently closed due to extreme wind conditions, making work on site difficult.

Project scope

As part of the planned realignment design our client, Opus International Consultants, needed information from several cored boreholes to be drilled in the middle of the traffic lane. Further holes were required below the road at the base of some of the retaining walls and also on the spurs immediately above the road.

Complicating factors and solutions

The bore holes on the road required that SH2 to be reduced to one lane each day and the rig moved onto the hole in the morning to work before moving off in the afternoon to allow the lane to be reopened in time for peak traffic flows. At the same time a number of other holes were drilled across the site by our light weight rig, which was craned into position onto platforms below the road to carry out a programme of cored boreholes. During this time Griffiths Drilling were also carrying out trial pit investigations by excavator and providing multiple lane closures to allow the client to conduct such things as mapping of rock faces along the road and seismic surveys.

Helicopter access

The programme culminated with the boreholes drilled on the spurs above the road. For this stage a drilling rig was carried into place by helicopter as the only access to site is by foot and using ladders. These holes were also the deepest on the project. 


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This section highlights some key drilling projects that Griffiths Drilling have been involved in. It also includes 'Projects Since 1971' and 'Earlier Projects' pages to showcase our extensive history and experience within the New Zealand drilling industry.

Mackays to Peka Peka Expressway (M2PP)

This $630 million project will deliver approximately 18km of 4 lane expressway through Paraparaumu and Waikanae, including a new bridge over the Waikanae River. Griffiths Drilling has been part of this project from its inception.

Transmission Gully

Transmission Gully is the biggest road construction challenge in the Wellington region. We began exploration work in 2007 for Opus. Further work was undertaken in 2013 for MWH and NZTA, with detailed geotech investigations for Leighton Contractors and Coffey Geotechnical in 2014 and 15.

Tauhara Geothermal - Geotechnical Drilling Adviser & Consultant

Mel Griffiths was engaged by Contact Energy as the Geotechnical Drilling adviser for the Tauhara Geothermal Subsidence project.

Wind Farm

Limited access, steep terrain, wet slippery conditions and very high winds were complicating factors. Also the rock was very fractured due to the proximity of the main fault line.

Dowse to Petone

A $65 million road improvement carried out to enhance the traffic flow on SH2. Flexibility of resources was paramount on this project, which included 45 piles at 7 sites and a new service road, requiring soil nails.

Silverstream Landfill

A large landfill site serving two cities that required anchor and drainage holes in rows along the walls of the gullies. Communication was important as all work was done around the customers programme of concrete spraying.

Centre Point Wharf Piles

This project was carried out over water on a barge in the very busy Wellington Harbour. As if this wasn't enough, matters were further complicated as quality samples had to be recovered from very soft sediments.

Transpower Tower

This project involved upgrading the foundations on transmission line towers in the upper South Island. We are proud to be associated with the 2007 New Zealand Engineering Excellence Awards Supreme Award winner.

Waiwhetu Stream

This project required 35 boreholes and 23 CPTs. Sites included working on the road for bridge pile information, open public areas alongside the stream and in the confirms of industrial operations and a Holiday Park.

Soil Nail Wall

Construction of a retaining wall that included drilling and testing a sacrificial nail for design purposes, drilling and installing production nails, fabrication of nail heads, fixing mesh to the face and applying sprayed concrete.

Projects Since 1971

A list of all the major projects undertaken by Griffiths Drilling since its inception. Work includes some of New Zealand's most challenging and largest drilling projects, including the Clyde dam, Wellington Motorway, Te Papa, Westpac Trust Stadium and the ongoing Transmission Gully work.

Projects from 1948 to 1970

Projects completed before Griffiths Drilling became an official business. They show the experience that is inherent in our drilling business today. Work includes Waikato, Waitaki, Roxborough and Cobb Valley dams, Tongariro Power and Wairakei Geothermal projects along with others.

Water Bores

We have well over 40 years experience in drilling water bores. Most have been carried out in the Wellington, Hutt Valley, Kapiti Coast and Wairarapa regions, giving us an unequaled and comprehensive knowledge of the ground aquifers within these areas.