Lake Eyre Basin Rivers 178 stakeholders (e.g. investors, shareholders and non-government organisations) (e.g. Mudd 2009 Mudd 2010). As a result, managing and rehabilitating mine wastes is increasingly difficult using standard approaches. I examine these challenges for four mining case studies: Mary Kathleen, Mount Isa, Olympic Dam and Lady Annie. The first three are just outside the margins of the Lake Eyre Basin, but Lady Annie sits across the catchment boundary, with some infrastructure extending into the headwaters of the Lake Eyre Basin. The technical issues and environmental challenges posed by these projects are all symptomatic of the challenges facing the future of mining projects inside or around the Lake Eyre Basin. Mary Kathleen uranium mine The former Mary Kathleen uranium mine (Figs 19.1 and 19.3) operated over 1958–63 and 1976–82. It was rehabilitated during 1982–85, winning a national environmental excellence award in 1986 from Engineers Australia, based on three key claims: minimal seepage from the tailings dam no acid mine drainage and minimal risks of water quality affecting human health or grazing animals – but each claim has proven incorrect (Lottermoser et al. 2005 Lottermoser and Ashley 2008 Lottermoser 2011 Mudd 2014). Further rehabilitation is widely expected to be required, given the exposure of grazing cattle to heavy metals and radionuclides. A challenge, or opportunity, is that the tailings still contain a modest amount of rare earth oxides – opening up the possibility of reprocessing the tailings to extract these and potentially fund further site rehabilitation to a modern standard. Mount Isa mining complex The Mount Isa mining complex (Figs 19.1 and 19.4) is among the larger base metal mines in the world. Discovered in February 1923 and brought into production by 1931, it has produced considerable lead–zinc–silver and copper (Table 19.2). The grades of ore milled and remaining resources have declined for lead and silver but remain similar for zinc, while Fig. 19.3. Former open cut mine at the Mary Kathleen uranium project, showing active weathering (i.e. sulfide oxidation) of the side walls and the lack of any rehabilitation of the former pit where water quality remains poor (photo, G. M. Mudd).
Downloaded from CSIRO with access from at 22.214.171.124 on Oct 23, 2021, 10:51 PM. (c) CSIRO Publishing