Project : Wet Well Modification – PARR Alliance, for Sydney Water Corporation (2008)
Project Date : 2008
Project Location : Sydney, Australia
Project Client : PARR Alliance for Sydney Water Corporation
The Northside Storage Tunnel (NST) Wet Well Modification at the North Head Sewerage Treatment Plant (STP) required Silver Raven to work in a challenging underground location. This project allowed us to demonstrate an ability to provide innovative solutions while maintaining the highest level of safety in high risk environments.
To ensure these works were completed as efficiently as possible, Silver Raven committed to the North Head STP Wet Well and Tunnel Pump Station (TPS) project 24 hours per day, 7 days a week.
Silver Raven was responsible for:
- Management of personnel and plant movements in and out of the NST, as the NST is a confined space, this exercise required a complex traffic management plan that incorporated Sydney Water confined space protocols (HSP-001) and extensive emergency evacuation procedures capable of coordinating the safe evacuation or rescue of up to 50 men
- Establish and maintain constant communications between all personnel in a challenging underground environment
- Take possession of the TPS, modify the existing pump system to include additional dewatering pumps to provide greater more efficient dewatering rates and allow pumping of higher silt content
- De-water the NST via the TPS
- Install twin coffer dams in the NST and manage tunnel flow levels via the installation of a decline tunnel de-watering pumps
- Excavate over 3,000m³ of silt from the NST wet well
- Relocate excavated silt to the decline tunnel and stabilise with shotcrete
- Manage tunnel rock-falls, document, inspect and stabilise with shotcrete and mesh as required
- Design and fabricate steel formwork for wet well concrete pour
- Install formwork in wet well
- Install concrete pumping lines from TPS to NST wet well (via wet well/TPS pump lines)
- Pour 300m³ of concrete for the modification in a single pour
- Strip formwork and thoroughly clean site to ensure no tools or materials remain in the NST