Preparing for closure—systematic framework for water quality reviews

Authors: Gemson, WJ; Harck, T Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2315_059

Cite As:
Gemson, WJ & Harck, T 2023, 'Preparing for closure—systematic framework for water quality reviews', in B Abbasi, J Parshley, A Fourie & M Tibbett (eds), Mine Closure 2023: Proceedings of the 16th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, https://doi.org/10.36487/ACG_repo/2315_059



Abstract:
Water is the golden thread that runs through closure planning considerations and potential for long-term water quality impacts presents one of the main challenges for effective closure of mine sites. The majority of operating mines sites have existing water quality programmes in place to assess and manage such water quality impacts. However, these programmes often developed organically over time in response to specific matters arising at a site. Operational monitoring programmes further typically have a focus on compliance matters, and monitoring data are at times underutilised when it comes to understanding water quality dynamics at a mine site. In recognition of the above, we have reviewed large water quality datasets forming part of existing monitoring programmes for a range of mines sites (~10 mine sites) in the Pilbara region of Western Australia, with the aim of understanding spatial and temporal trends to support risk management and closure planning. These programmes included compliance monitoring for ground and surface water (water levels and chemistry data) for monitoring as well as production bores and pit water grab sampling data. The objectives of these reviews included assessing whether the existing surface and groundwater monitoring programmes indicate trends in water quality, to identify the geochemical process controlling such trends and whether the existing monitoring plans are fit to address the overall risk management at closure. The reviews identified gaps/improvements in the programmes and the opportunities to develop closure focussed monitoring programmes that prioritise monitoring locations, specify monitoring parameters and frequency to support long term planning. The paper outlines a systematic framework for conducting these reviews and how the outcomes of these reviews can lead to the development of adaptive monitoring programmes in support of closure planning.

Keywords: water quality monitoring, acid and metalliferous drainage, closure planning

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