McMahon Services is brought on board to install major pipework at two former ExxonMobil sites in New South Wales
Two teams from McMahon Services based in Queensland mobilised to New South Wales to undertake the installation of major pipework at two former ExxonMobil sites.
The first team arrived at the former Mobil Young Depot back in January – situated in the south west region of southern NSW – to commence trenching, pipework and wellhead pit installation for a groundwater remediation system.
The purpose of the system is to remediate the subsurface soils and groundwater impacted by petroleum hydrocarbons, which consists of 22 multi-phase extraction wells connected via underground pipes.
McMahon Services installed 1500 metres of 100 millimetres pressure pipes and manifold, and removed approximately 80 tonnes of soil classed as general solid waste.
The remediation pipework required trenching on-site and across a joining roadway, using 100 tonnes of crushed rock and 40 cubic metres of concrete. All road surfaces were then repaired by the Young Shire Council.
“The main challenge on this project was working on a fully operational site, allowing for the supply of fuel to be loaded and unloaded throughout the duration of the works” said Project Manager, Mark Hayes.
“The team was also required to work under the strict ExxonMobil permitting system and the Mobil and OTEK health and safety systems due to the dynamic nature of the site” said Mark.
In May, the second team mobilised to the former Mobil Mudgee Depot, located 261 kilometres north-west of Sydney. Similar to the Young Depot, this project also required the installation of a remediation piping system for the treatment and removal of contaminated ground water.
McMahon Services installed 900 metres of pressure pipe from eight multi-phase extraction wells, along with the construction of 600 x 600 concrete pits to connect the manifold, install a sewer line and new inspection riser measuring over 60 metres.
During trenching works, the project team discovered that the old tank area had not been backfilled and compacted properly, so 12 tonnes of 80 millimetre rock was brought in to provide a support base while walking in the trench.
The team was also awarded additional work, including the removal and transportation of 350 tonnes of soil to Sydney ready for landfill.
Both depots required traffic management along with provisions for sufficient dust, soil, silt and water controls to avoid contamination in the stormwater systems. Furthermore, special care was needed at locations where excavation works intersected existing underground services.
