Due to a number of spills in the 1960’s contamination had leached through the predominantly sandy ground to reach the water table. As a result of tidal and ground water movement the plume was making its way toward the open water of Botany Bay. To capture the plume a number of vertical wells were drilled that were then linked using surface and underground pipes to a decontamination plant on the Orica site.
UEA was engaged to carry out two bores as part of the project to link the wells to the plant. Bore 1 was to install 150 metres of 400mm diameter polyethylene carrier pipe and 4 x 110mm PVDF carrier pipes under a railway line. Bore 2 was to bore 520 metres from Foreshore Rd to Orica’s Southlands site and install 1 x 250mm poly carrier pipe and 4 x 63mm electrical conduits.
The purpose of this bore was to install a connecting pipeline from the wells on the “Southlands” site to the decontamination plant on the Orica site. This involved Horizontal Directional Drilling (HDD) under the main container terminal rail line, under a transmission HV easement approximately 20 metres wide and under two high pressure gas mains. Energy Australia also insisted that the HV run was further protected by ramming sheet piles to 4 metres below the invert of the cables on the approach side of the bore to act as a barrier. Rail Infrastructure also required the rail line to be surveyed prior to the project starting and after each drilling or reaming pass.
This bore was to link the wells located along Foreshore Road back to the Southlands site for connection back into the main pipeline. Horizontal Directional Drilling was the obvious choice so as to reduce the impact on the local golf course whilst avoiding the many major utilities along the bore path.
For more information about this project or UEA Trenchless, please send enquiries to Steven Hopkins.