Drilling for pipes so much better

In she goes: In Havelock North there are new sewer and water pipes being installed. This sewer pipe is being fed through the pre-drilled tunnel in St Hill’s Lane.

The bulk of the work to install a new larger water main under Heretaunga St is done, with the hi-tech underground drill moved off site last week.

The technology had been “fantastic”, said Hastings District Council’s works and services committee chairman Kevin Watkins.

“It’s not that long ago that a job of this size, installing a new water main, would have meant tearing up the whole road – probably having to close it in some places at times, and then a long job to get it back to a normal surface.

“There has of course been some disruption but nothing like traditional open trenching would have caused. We are very pleased at the way this project is progressing.”

Contractor Monadelphous used a technique called ‘horizontal directional drilling’ which used a drill to bore a tunnel from one pit to another. The use of the method allowed the work to be done via three smaller pits rather than an open cut trench down the full length of the work site.

Pipes were then pulled through overnight, avoiding the busiest times of the day.

The project was about two-thirds complete. The next piece of work was to ‘slip-line’ a pipe through the old main, which would become the feeder pipe for the homes and businesses on the north side of the street. That involved digging down to the connections for each business on that side of the road. That would take about two months. After that would come the repairs to the road and footpath surfaces.

The same contractors are installing new water and sewer mains along Te Mata Rd and in St Hill Lane. That work had started about two weeks ago using the same drilling technique. The first ‘pipe pull’ is due to be carried out this week.

The length of pipe, corners and gradient of the two streets meant there would be more drill pits for the Havelock North project and up to three drill rigs spread across the length of the site at times.