Characterisation of Mine Pit Lake Chemistry to Inform Mine Closure And Environmental Management
Topic Presenter: Chemist and Research Officer, ChemCentre
Date: 20 April 2022
Time: 12:30 to 1:30 pm (Australian Western Standard Time)
Presentation Overview: Western Australia has more than 2000 mine voids, many of which fill with water when dewatering of the void is discontinued after mining ceases. Mine pit lakes are complex systems to assess for long-term environmental impact and there are gaps in understanding the geochemistry and environmental impact of the pit lakes that form. In this project, we have compiled the first comprehensive dataset of mine pit lake water quality in Australia, sampling 26 pit lakes across Western Australia. Pit lakes of a variety of ages and environmental conditions, and from a variety of representative geologies, mineralogies and hydrogeological situations have been sampled, providing a “time capsule” of how future systems are likely to behave. The water quality of each mine pit lake was measured at regular depth intervals throughout the water column, in order to identify oxic and anoxic regions within each pit lake. Analysis of water samples include field measurement of water quality parameters (e.g. pH, oxidation/reduction potential, conductivity), and laboratory analysis of a wide suite of major and trace elements, nutrients, salinity, turbidity and dissolved organic carbon. This water quality analysis has been complemented by comprehensive analysis of representative pit wall rock and sediment samples from each pit lake, as well as data mining of existing water quality databases sourced from project collaborators (CSIRO and DWER) and industry participants. This dataset has provided new insight into mine pit lake water quality with the information assisting both Government regulators and industry by providing more certainty for mine closure.
Presenter Profile: Kathryn Linge is an analytical chemist who has worked in government, industry and academia, with a focus on environmental and water research. Since 2018 she has worked at ChemCentre managing research projects in a range of areas, including mine pit lakes and dust source identification. She has also developed new expertise for ChemCentre in the areas of microplastic and nanoparticle characterisation and the use of isotopic ratio signatures for dust source identification and food provenance
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