Client name: Flinders Power Partnership

Duration: October 2015 - ongoing

Location: Port Augusta and Leigh Creek, SA, Australia

Phased approach to site contamination assessment at the Port Augusta Power Stations, Leigh Creek Coal Mine and associated rail maintenance area to assist in site closure process.

Site contamination assessment for brownfields

Due to the size and complexity of site historical uses of the Port Augusta Power Stations, Leigh Creek Coal Mine and associated rail maintenance area, a phased approach to site contamination assessment was required as part of the closure process.  

A Voluntary Site Contamination Assessment Proposal was agreed with the Environment Protection Authority and a Site Contamination Auditor was engaged for the Port Augusta Power Stations program of works.

A three-phase approach: PSI, DSI, and remediation works

Two phases of a three phase program of works have been completed to date. Phase 1 being Preliminary Site Investigations (PSIs) and Phase 2 being Detailed Site Investigations (DSIs).

Coffey collated the PSIs (3) utilising desktop information publically available as well as that provided on historic site activities from the client, site staff and detailed site walkovers conducted by the team. The information reviewed identified key areas of environmental concern, potentially contaminating activities undertaken in those areas and the chemicals of potential concern associated with them.

The information presented in the PSIs was utilised to develop robust Sampling, Analysis and Quality Plans (SAQP) as the basis for the implementation of the intrusive DSIs at each site with the objective of determining if historical practices has caused site contamination.

The DSI’s have involved extensive fieldworks programs at all three sites over the course of a six month period. This included numerous test pits, soil bores and groundwater monitoring well installations as well as soil, sediment, groundwater and surface water sampling with a total of 2,000 soil samples and 116 groundwater samples collected across the three sites for selected chemical analysis.

The data was continuously reviewed to ensure quality control and to determine any areas of further assessment needed to provide delineation and close potential data gaps. 

DSI approved by site contamination auditor and Phase 3 underway

DSI project reports have been completed, approved by Site Contamination Auditor for the power station and the EPA for the coal mine and rail maintenance area. The final Phase 3 assessment and risk mitigation works including active site contamination remediation have recently commenced.