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Environmental Engineering

Environmental Site Assessment

RCA recently undertook a Phase 1 Environmental Site Assessment and prepared an Acid Sulfate Soil Management Plan for a site at Wickham proposed for redevelopment as a multi-storey residential complex.  The works were undertaken to assist in the determination of potential environmental constraints at the site prior to submission of a development application.

Whilst no sampling was undertaken, there were potential sources of contamination noted such as fill material likely to have been used at the site.  An inspection of the surrounding area identified the presence of possible decommissioned underground storage tanks (fill points were full of concrete) located upgradient of the site and a groundwater monitoring well network across the road from the tank location closer to the site.  RCA considered that the presence of the wells indicates a potentially significant local contamination issue which may impact on and/or be a constraint to the proposed development.  RCA recommended assessment of the on site fill material and of potential hydrocarbon contamination originating from the offsite source.

RCA Environmental Fill Points


Site Investigations for Hunter Development Corporation

RCA Australia environmental section has recently undertaken targeted site investigations for Hunter Development Corporation (HDC) on the former steelworks site as part of Stage 2 works to determine specific locations of contaminated soils and underground structures.  The work was undertaken with the aid of old BHP drawings, site knowledge of former activities and structures, using CAD to determine GPS co-ordinates, followed by test pitting on site.

These investigations were to provide additional information that had not been gathered during the original investigations undertaken by BHP prior to closure and demolition.  This information will assist the civil contractor to plan site activities during contouring works which will commence shortly.

Aerial view of HDC Remediation of Former Steelworks Site

Test Pitting with an Excavator through Fill Material

Excavated Material showing Slag, Iron Ore, Process Dusts and Sand

Test Pit through Slag into Natural Sand

Test Pit Material Showing Slag Skulls, Iron and Building Rubble

Koppers Barrier Cut-off Wall

On behalf of Koppers Carbon Materials and Chemicals, RCA is about to commence supervision of a significant cement bentonite slurry barrier cut-off wall and environmental monitoring at the Mayfield site in Newcastle.  The wall, which will be 417m in length and have an average depth of 18m, will isolate DNAPL contaminants (mainly Poly Aromatic Hydrocarbons) originating from tar from groundwater and is to be constructed by Keller Ground Engineering.

RCA’s ongoing involvement with Koppers follows on from many years of assistance at the site with ground assessments, groundwater modeling, assessing remediation options and developing a strategy/action plan and has involved close liaison with DECCW and a NSW Accredited Site Auditor.

The works will last approximately three months and will be followed by further hotspot remediation of free phase hydrocarbons in soils, capping of the site, pump and treat of groundwater contamination and ground water monitoring from an attenuation bore field.

Southern wall section pre-trenching in very hard slag fill with long reach excavator

Part western section completed cut off wall prior to trim and cap

Kooragang Island Waste Emplacement Facility (KIWEF) Closure Works

RCA was engaged by SMEC as specialist geotechnical/environmental sub-consultants as part of the overall provision by SMEC for detailed design, documentation and other services for Hunter Development Corporation. Specifically, RCA has provided review and assessments of previous information as part of a Design Reference Report for the capping of the landfill which, in total, is a 61ha area and comprises nine separate areas.

RCA has had a long history of providing geotechnical and environmental advice to various clients  ( Delta EMD, PWCS, BHP, RLMC, HDC, NCIG) at Kooragang Island particularly in connection with landfill closure and redevelopment options. KIWEF is one of the most intensely investigated pieces of land in Australia and RCA understands the ground conditions and issues associated with environmental and geotechnical constraints.

Pasminco Cockle Creek Smelter site

RCA has been sub-consultant to WSP Environmental on the ongoing remediation of the former Pasminco Cockle Creek Smelter in Boolaroo since early 2006. The project manager for the remediation and development of the site is Ferrier Hodgson. The site is being remediated to address, predominantly, lead contaminated soils originating from both dust deposition and the placement of waste materials resulting from the smelter operations which occurred from the late nineteenth century until late 2003.

The remedial strategy is primarily based on the excavation of contaminated soils and waste materials across a site area of approximately 122ha and emplacement of these in a designated containment cell being constructed on site.  The site is being remediated to allow for future residential, commercial and industrial redevelopment.

RCA’s involvement with this remediation project involves assistance to WSP Environmental with environmental documentation prior to the commencement of remediation, ongoing remedial supervision and validation sampling from the commencement of the remedial works and preparation of final validation reports to meet the requirements of the NSW EPA Accredited Site Auditor.

Excavation of contaminated soils and transport to site containment cell

Soil remediation following decommissioning of surface infrastructure

Containment cell construction with contaminated soils and waste material from smelter operations