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Downer Pipetech were engaged by Sydney Water to install 870m of sewer main. Bortec Laser Bore were then engaged by Downer Pipetech to perform the under-bore in 10 bore sections. The completed Bore distance made up a total of approx 830m of the project. This was opposed to an open cut excavation approach.


Under-Boring was the most feasible option due to the depth reaching 13m at the deepest point, accessibility to private property, working under power lines, and above ground obstructions such as trees and power poles.


Bortec Laser Bore were engaged to complete the bores over a duration of 8 months with a start date in June 2019 and completion in February 2020.

Project Requirements:

  • Confined Space ticketed workers

  • Crane and Dog man tickets

  • Downer online and site-specific inductions

  • Supply of all labour, plant and equipment to complete the works as per plans

  • Mobilisation and demobilisation

  • Endeavour Energy working near overhead power accreditation for work inside exclusion zones

  • All material handling for the micro-tunnelling process including crane hire where necessary

  • Supply, welding and installation of DN450 Mild steel casing

  • Installation of DN225 PVC carrier pipe into steel casing

  • Supply and installation of centralisers at a minimum 2m centres

  • Supply and installation of grout fill

  • Testing and CCTV of installed sewer main to relevant standards

  • Removal of spoil/slurry from launch pit to either a skip bin or bunded area

  • Stockpile excess spoil on site for disposal by others

  • Provide red pen mark-up with levels, extent of encasement and daily bore logs, ITP’s and checklists

Challenges with the Project:

  • Deep Manholes up to 13m deep

  • Pits 1,2,3,4,5 – Caisson Shafts 5m diameter

  • Pits 6,7,8,9 – Sheet Piling 6m x 3m

  • Pits 10,11 – Shoring Boxes 6m x 3m

  • Due to the great depths of the manholes, the work became a high-risk job due to air regulation in a confined space, and risk of falls at height.

  • The depths of manhole’s also meant that ground water was an issue, meaning water was pumped into storage tanks, treated and removed from site.

  • Due to changing ground conditions, our pilot tube method was used in the softer displaceable soil and we used the front steer method in the harder clay and soft sandstone areas.

Notable Achievements:

  • Successful completion of project safely and at high quality without incidents

  • Job completed within schedule and on budget. 

  • Required monthly reporting successfully completed which included:

    • Labour hours

    • Material consumption

    • Resource consumption

    • Daily bore logs (Meters bored, and daily tasks completed)

    • Inspection and Test plans (ITP’s)

    • Daily Toolbox meetings

    • Daily permits (hot work, confined space)

    • Daily plant inspections

    • Rescue plan for each manhole

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