LakeCoal Pty Ltd, the client, faced a challenging contamination management programme at the Catherine Hill Bay Coal Handling and Preparation Plant (CHPP) on the central coast of NSW. This site, with a rich history of coal mining dating back to 1873, required comprehensive environmental rehabilitation due to the historical impacts on soil, groundwater, and nearby surface waters.
The contamination issues were a result of decades of coal handling operations (road, sea and rail logistical services) and supporting operations (bulk diesel fuel storage, coal grading and preparation infrastructure, laboratory services). To support the cessation of their Consolidated Coal Lease (CCL) regulated by the Minig Act 1992, LakeCoal were required to manage human health and ecological risks posed by residual contamination onsite, and subsequently engaged the EESI NSW team to address the regulatory requirements and rehabilitate the site.
After review of historical information EESI conducted a data gap assessment to ascertain what risk linkages required further assessment. Following the data gap assessment EESI conducted a large-scale multi staged detailed site investigation (DSI) between 2012 and 2014 that included soil, groundwater and soil vapour assessment at seven specific areas of potential concern where contamination risks were suspected. Based upon results and findings the EESI team were able to prepare a comprehensive remediation action plan (RAP) to document the methodology for management of contamination that would ensure no unacceptable risks existed for future receptors. This RAP covered remediation of the following identified issues of concern:
- Managing primary source removal of historical above-ground and underground petroleum storage systems (UPSS).
- Excavation and onsite bioremediation of diesel-impacted soil with material validation for reuse.
- Active and passive remediation of light non-aqueous phase liquids (LNAPL) in groundwater with program for monitored natural attenuation (MNA).
- Remediation of elevated monocyclic aromatic hydrocarbon (MAH) impact to groundwater near a former chemical storage facility.
- Remediation of volatile organic compound (VOC) impact to soil from former operations of a coal grading laboratory, with identified chlorinated solvent impact to soil and soil vapour subjected to onsite landfarming / bioremediation.
- Management of localised asbestos contamination in soil following demolition of former buildings.
The EESI NSW team further acted as a consulting advisor for the remediation works conducted from 2015 to 2019, supervising cleanup activities and conducting associated validation processes.
Thanks to the comprehensive services by the EESI NSW team, the site was successfully remediated to a condition that satisfied CCL requirements. This remediation culminated in the transformation of the site into open space land.
The validation process confirmed that the contamination was effectively addressed, and received a site audit statement (SAS) from a NSW EPA accredited contained sites auditor confirming successful remediation outcome and that the site was suitable for future open space / recreational land use to support cessation of the CCL.
The benefits to the client included compliance with regulatory requirements and the removal of potential environmental liabilities associated with the site. The successful remediation also opened new opportunities for the utilisation of the land for residential development which was another added value.