2018-2023: BHP Whaleback Mine Including Orebody 29/30/35
North of Orebody (OB) 29
The area north of OB29 contains a Fuel Farm, Former Power Station, Rail Loop Ponds and Mobile Equipment Workshop. Fire suppression foam was reportedly stored in the Fuel Farm and Former Power Station areas, as fuels were historically stored and/or dispensed in this area. The area also includes a former oil water separation pond. The Rail Loop Ponds site contains
former oily wastewater evaporation ponds and wastewater treatment ponds, both of which are unlined. Extensive soil and groundwater investigations as well as remediation by low-permeability capping has been undertaken at the former evaporation ponds. This site is now subject to a site management plan under the CS Act (BHP 2023). The mobile equipment workshop is used for maintenance of heavy equipment and associated accessories, and it includes an oily wastewater treatment plant and a lined pond area. It is reported that fire extinguishers in mobile equipment have been replaced at the workshop and foam within some of the expired extinguishers may have been discharged into the oily wastewater treatment plant. PFAS concentrations in the groundwater north of OB29 exceeded the PFAS NEMP human health Australian drinking water guideline (DWG) value (0.07 µg/L) but were below the recreational use guideline value (2 µg/L) for Sum (PFOS+PFHxS) and
exceeded the ecological 95% species protection level (SPL) guideline value (0.13 µg/L) for PFOS (Golder 2018, 2019b, 2021a; ERM 2022, 2023). PFOA was detected in a small subset of the wells at trace concentrations well below the DWG (0.56 µg/L) and 99% SPL (19 µg/L). The Sum (PFOS+PFHXs) concentrations in the groundwater abstraction bores located near
OB29 were well below the NEMP human health drinking water quality guideline value of 0.07 μg/L.
Source: EPA Western Australia OB29/30/35 Water (PFAS) Management Plan