There will be two types of racing at Ellerslie Race Course in Auckland over summer, horse racing and tunnelling, but the public will be blissfully unaware of the underground race.

Not so the Harker Underground Construction team, who, over six months, will pipejack a 380m long tunnel almost two metres in diameter, 18 metres under the race course.

Pipejacking is a method of tunnel construction where hydraulic jacks are used to push specially made pipes through the ground behind a tunnel boring machine or shield. The boring machine is craned into position down a pre-constructed shaft. Often referred to as trenchless construction, this method has distinct advantages in minimising impacts to the public and the environment with the bulk of construction underground.

The $3.8 million contract is part of Auckland Council’s sewage and stormwater infrastructure upgrade.

It is now six months since Harker’s became part of McConnell Group.
GM, Leigh Bishop, explains the crux of the business.

“Basically we are a tunnelling business with 35 years of ‘underground’ problem solving experience. We have been involved in some of the most challenging and technically difficult tunnelling, pipejacking and microtunnelling projects in New Zealand. We work where the sun doesn’t shine – through clay and gravels to running sand and hard rock. Across central city and confined sites, environmentally sensitive areas and remote locations. And the solution might not always involve a tunnel boring machine - on the West Coast of the South Island, an hour inland from Hokitika, we devised an alternative solution for the deviation of a hydro tunnel, a traditional drill and blast project, through Southern Alp schist rock,” says Leigh.

“In today’s market we are getting increasingly involved in the preliminary design phase for projects identifying the potential risks, assisting with pre-construction design and methodology, and giving rough order costs.”

Harker’s culture fits well with McConnell Group.

“Graeme Harker founded this business in 1975 - a New Zealand based family business with loyal, very capable staff, passionate about delivering successful construction projects. While Graeme is no longer part of the business these values are, and that’s our core fit with McConnell Group.

“The governance and management structure that McConnell Group has put in place, together with the additional financial resource, provides stability and strength. At the same time there is respect for our independence and that’s important to us,” says Leigh.