General coastal mining impacts
Coastal mining, and mining in general, have several adverse environmental impacts, although these are gradually being reduced with improved legislative controls, attitudes in the mining industry, technology, and management practices. A useful summary of the environmental effects of mining in general (not just in the coastal zone) can be found in Hore-Lacy and Webb (1996). Coastal mining and its associated infrastructure, such as road access, storage facilities, and power facilities, often have irreversible or long-term environmental effects, and affect both land and water. These effects can include:
• large open pits which provide opportunities for waste dumps
• transport and disposal of products (sometimes hazardous), and increased risks in the further spread of introduced species and diseases
• fuel and oil spills into coastal waters and groundwater
• low water permeability of mined sites, and impacts on groundwater regeneration and revegetation attempts for rehabilitation
• impacts of sand mining even after mine closure (e.g. groundwater movement or dam collapse)
• loss of biodiversity and coastal habitats (including the buffering and nursery roles of mangroves and seagrasses)
• visual impacts
• noise impacts from heavy machinery
• health effects for coastal residents who live near mines or industries (e.g. silica can be carcinogenic and can cause lung damage; consumption of contaminated seafood)
• loss of wilderness and public access areas in the coastal zone
• coastal erosion and loss of natural dune systems and soil profiles
• impacts on coastal archaeological sites
• impacts on water quality from the discharge or leaching from spoils or tailings (accidental or otherwise) of untreated or even treated waste water.
In the last effect listed, toxins from discharges into catchments, groundwater and coastal waters accumulate in sediments and biota, frequently are acidic and contain toxic heavy metals and excess nutrients, and can have high salinity levels. Increased discharge of particulates can also cause sedimentation and turbidity in coastal waters, and increased nutrients can cause or exacerbate eutrophication. A combination of these effects can cause habitat loss and death or other effects in flora and fauna, such as behavioural or genetic changes, reproductive failures, problems with photosynthesis, respiration and feeding, and subsequent effects on the broader food chain (Burton et al. 1994, Jia 1994, Batley 1995, Viles & Spencer 1995, Young 1996, DME 1999).
Although in the 1970s the Australian Conservation Foundation (ACF) believed that we were a 'mineral civilization', it stated: 'Mining by its very nature is always antagonistic to environmental values. It must dig holes, dump overburdens, discharge tailings, create dust and noise, rip open country to bring in power and water supples, construct roads, change drainage systems and even establish towns where there is no other reason for their existence' (ACF 1974, p. 116). In the 1980s it was strongly opposed to the impact of coastal mining on the east coast of Australia, and noted the significant and irreversible impacts on both aesthetic and scientific values (ACF 1981):
Miners claim that their operations are not permanently detrimental to the natural environment. However, the opposing sides have different standards. Miners claim to be able to rehabilitate to a semblance of naturalness acceptable to the general public ... To be fair, they have achieved just this in some 'easy' areas, assisted by increasing skill in later years. But they admit that they cannot restore to full pre-mining ecological conditions, and it is indeed obvious that they are unable to reconstruct the complex soil structures and water table level variations and the many plant associations which depend largely upon these factors. They have failed to return more than about 50% of pre-mining species ... Furthermore, mining destroys the geological and archaeological history of the area.
In contrast, there is a strong view from the mining industry that the impacts are substantially less than other activities (e.g. primary production, rural industries, city population growth, road and infrastructure construction; Mawby 1974, Lewis et al. 1998). It has been noted that: the 'compactness of any mining operation, in relation to its importance, creates relatively little disturbance to the environment. In certain mining, for example some sand mining operations, beach facilities are not despoiled but through the rehabilitation of foreshore areas improvements are often made ... ' (Mawby 1974, p. 111). Lewis et al. (1998, p. 74) considered, for example, that mining's impact on biodiversity is low, and that there 'appears little reason why the same conclusion should not apply in marine and estuarine environments with appropriate management systems and objectives in place'.