Assessment, regulation and management of water pollution from underground coal mines in the Sydney Basin

Abstract

This research surveys water quality and chemistry, river sediment chemistry and aquatic macroinvertebrates in eight streams that are the recipient of coal mine wastewaters from seven collieries across the Sydney Basin. The study also surveyed water quality and chemistry at five of the seven collieries wastewater discharge streams (effluent streams). Most of the coal mine wastewater discharges are licensed and regulated by the New South Wales Environment Protection Authority (NSW EPA) through a series of Environmental Protection Licences (EPL's). During this study four of the collieries were actively mining ore, while three were inactive. One of these had permanently ceased mining more than 20 years previously. Results revealed that all seven mines caused mild to significant modifications to a plethora of water quality and water chemistry parameters, river sediment chemical parameters and macroinvertebrate community structure. Many of the pollutant concentrations recorded in this survey were above, or outside of their respective ANZECC 2000 guidelines for protection of aquatic ecosystems. pH and salinity (electrical conductivity) were often above the recommended guidelines and substantially differing from their background conditions. Of widespread concern are the elevated concentrations of the metals nickel and zinc, with the majority of samples collected from coal mine wastewater streams and downstream of their inflow to rivers well above the recommended ANZECC 2000 guidelines. Iron and manganese were also found to be of elevated ecological concern with aluminium, cadmium, chromium, copper and lead also often above the recommended ANZECC 2000 guidelines for protecting ecosystems. Macroinvertebrates were collected from upstream and downstream of all eight mine wastewater discharges to measure the impact of the coal mine wastewaters on aquatic ecosystems. Results of the study show that the coal mine wastewaters being discharged were having varying negative impacts to the receiving waterways aquatic ecosystem that this research quantified through assessment of aquatic macroinvertebrates. The findings of this research have revealed major flaws in the current environmental regulation of seven licenced coal mine wastewater discharges within the Sydney Basin. This comprehensive research has shown that at many levels the current NSW EPA water pollution regulation of the seven coal mines fails to protect the downstream waterway from the pollution. The NSW EPA regulation of coal mine wastewaters focus on the waste attributes at the 'end-of-pipe' waste discharge. Along with the NSW EPA method of "monthly focus" on a selection of colliery wastewater pollutant concentrations, these approaches do not fully take into account the impact of the waste discharges on the receiving waterways aquatic ecosystems.

Date of Award	2022
Original language	English