Case study

Logan River HDD Crossing

In 2016, Dunstans Construction Group was awarded a key project by Diona/Energex to install a bundle of five conduits under the Logan River as part of the Loganlea to Jimboomba Power Upgrade Project.

  • Dunstans provided an alternative tender submission to install the conduits below the alluvial formation and in the rock formation, reducing the risk of frac-out below both sections of the Logan River.
  • A forward reaming methodology was employed to avoid any fluid loss through the gravel and cobble section on the exit side of the crossing.
  • Drilling was predominantly through sandstone and coal formations with API Certified tooling utilised.
  • The conduit bundle consisted of five HDPE pipes strapped together. Over 100 of Dunstans own in-house manufactured horizontal and vertical rollers were placed every 8m along the pipe bundle string to greatly reduce pullback forces and prevent damage to the product pipes.
  • The successful completion of the bore and installation of the conduit bundle was achieved despite the varied and challenging geologies that were encountered including sticky clays, cobble, coal seams and sandstone as the bore alignment twice crossed under the Logan River.

One of the largest HDD projects completed on behalf of Energex to date, this installation reduced the impact to landholders and the environment by utilising trenchless technology in lieu of unsightly conventional overhead powerlines in this semi rural setting. This HDD crossing was a key element in a major project, which has been ongoing since 2010.

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Project quick facts

Client

Diona Pty Ltd / Energex Limited

Description

Installation of a bundle of five conduits under two sections of the Logan River in QLD

Project date

July 2016 – September 2016

Project location

Logan Reserve, Brisbane

Pipe type

Bundle of:
3 x 250mm HDPE PN20
2 x 140mm HDPE PN20

Crossing length

810m

Project cost

$1,200,000

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