• Steep terrain with limited access
  • Extremely difficult terrain for drilling
  • Wet, slippery conditions and exposure to very high winds
  • Very fractured rock faces due to proximity of fault lines

West Wind Makara - Meridian Energy / OPUS / Tonkin & Taylor (2006) & WWTL - Meridian Energy / BECA (2007)

For this project we had difficult terrain to contend with and very fractured rock due to the close proximity to major fault lines. Compounding this was the very high wind factor and extreme weather conditions in which we were operating.

Project scope

For the wind farm project we drilled more than 30 holes across the site on the ridgelines where the turbines were to be sited. Further bores were drilled for the wharf structure on the beach at Oteranga Bay where the submarine power cables come ashore and other investigations including inclined cored holes for suitable quarry material were carried out across the site.

For the transmission line project we carried out a number of holes at possible tower locations to assist with design of a new transmission line to carry the power from the wind farm to the National Grid.
 

Complicating factors and solutions

Limited access, steep terrain, wet slippery conditions and very high winds were all complicating factors to overcome. The rock was very fractured due to the proximity of the main fault line and required the skills we have developed in working with Wellingtons' difficult ground conditions to successfully core the highly fractured weathered greywacke.

For the the transmission line project no new roading could be constructed across the steep terrain, meaning careful planning and complicated logistics to get to the proposed tower locations. For example, some sites required scaffold to fly the gear onto due to the steepness of the terrain.

Helicopter access

One of our helicopter portable units was used to reach the bore locations high up on the hillside that were only accessible by air. Due to the proximity of the National Grid safety of both the network and all personnel was paramount and required meticulous planning before getting off the ground. This was made easier by our helicopter operator who routinely flies maintenance crews on live line work in and around the lines.

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Projects

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.

Muldoons Corner

This is a difficult section of SH2 which needed realignment. It's located near the summit of the narrow Rimutaka Hill Rd and features tight corners, no shoulder and near vertical faces above and below the road.

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.