Coal mines of the Upper Hunter Valley District are planned to be many years away from closure. Nevertheless, regionally operators have collectively begun closure planning for voids as pit lakes under the auspices of the New South Wales Minerals Council and ahead of regulatory requirements. Pit lakes of this region will feature a range of areas, depth and shapes.
Currently, most pits are still operationally utilised and pit lake planning is only at a very high conceptual planning stage that has not extended to planning of individual operations. Consequently, efforts have not yet been made by operators to reshape pit walls, cover exposed coal measures, revegetate surrounding landforms, etc.
A review of national and international grey (e.g. reports) and peer-reviewed (e.g. conference proceedings, books and industry and academic journal papers) literature was undertaken to provide examples of leading industry practice mine pit void beneficial end uses examples suitable for both dry and wet pits (lakes) of the Upper Hunter Valley coal mining region.
These final pit lakes will take a variety of forms, depending upon the context and final end use. Some will be completely backfilled, some partially and some not backfilled at all. Final mine closure landforms for representative mining projects have been summarised across the regional landscape to provide a snap-shot of current regional closure planning.
Pit lake water quality for representative pit voids of the region was also summarised and extrapolated for future water quality expectations and issues. Recommendations of potential end uses options for the region were then made based upon their suitability in this mining industry and socio-environmental context.
Study presentation, media and engagement with industry members, regulators and community stakeholders was undertaken. An open workshop undertook a Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis to broadly define regional possible sustainable end uses with key stakeholders from regulators, industry and community.