General Aspects of Aquatic Colloids in Environmental Geochemistry
J.F. Ranville, R.L. Schmiermund, 1997. "General Aspects of Aquatic Colloids in Environmental Geochemistry", The Environmental Geochemistry of Mineral Deposits: Part A: Processes, Techniques, and Health Issues Part B: Case Studies and Research Topics, G.S. Plumlee, M.J. Logsdon, L.F. Filipek
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A recent emphasis in society is on conducting mining activities with the least environmental impact possible. A manifestation of this is the costonitoring of contaminant levels in surface and ground waters, usually in order to meet specific environmental regulations. However the simple collection of monitoring data may not provide understanding of either the actual impact of mining on the environment or suggest the most appropriate treatment processes for specific mining wastes. More detailed information on the chemical and physical forms of contaminants is needed. One aspect of this is that the occurrence and distribution of natural and anthropogenic chemicals in natural water systems is strongly influenced by their partitioning between solid and aqueous phases (Allan, 1986). Therefore contaminant behavior is generally defined in terms of “two-phase” water-rock interactions where metals, for example, are present either in the stationary solid phases of the country rock, ore pad, waste rock pile, tailings empound- ment, or slag heap or they are present as mobile, aqueous phase solutes. For groundwater the solid phase is considered to be the stationary aquifer material. In surface waters the solid phases generally considered are the sediments in the stream, pond, or lake bottom. Accordingly, computer models have been developed that address dissolution, precipitation, adsorption, and desorption between the solid and aqueous phases as well as the formation of various solute species and complexes.
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The Environmental Geochemistry of Mineral Deposits: Part A: Processes, Techniques, and Health Issues Part B: Case Studies and Research Topics
Environmental issues have become important, if not critical, factors in the success of proposed mining projects worldwide. In an ongoing and intense public debate about mining and its perceived environmental impacts, the mining industry points out that there are many examples of environmentally responsible mining currently being carried out (e.g., Todd and Struhsacker, 1997). The industry also emphasizes that the majority of mining-environmental problems facing society today are legacies from the past when environmental consequences of mining were poorly understood, not regulated, or viewed as secondary in importance to societal needs for the resources being extracted. On the other hand, environmental organizations (e.g., Mineral Policy Center, 1999) point to recent environmental problems, such as those stemming from open-pit gold mining at Summitville, Colorado, in the late 1980s (see Summitville summaries in Posey et al., 1995; Danielson and Alms, 1995; Williams, 1995; Plumlee, 1999), or those associated with a 1998 tailings dam collapse in Spain (van Geen and Chase, 1998), as an indication that environmental problems (whether accidental or resulting from inappropriate practices) can still occur in modern mining. Recent legislation imposing a moratorium on new mining in Wisconsin, and banning new mining in Montana using cyanide heap-leach extraction methods further underscore the seriousness of the debate and its implications for mineral resource extraction.
In this debate, one certainty exists: there will always be a need for mineral resources in developed and developing societies. Although recycling and substitution will help meet some of the worlds resource needs, mining will always be relied upon to meet the remaining needs. The challenge will be to continue to improve the ways in which mining is done so as to minimize its environmental effects.
The earth, engineering, and life sciences (which we group here under the term “earth-system sciences,” or ESS for short) provide an ample toolkit that can be drawn upon in the quest for environmentally friendly mineral resource development. The papers in this two-part volume provide many details on tools in the scientific toolkit, and how these tools can be used to better understand, anticipate, prevent, mitigate, and remediate the environmental effects of mining and mineral processing.
As with any toolkit, it is the professional’s responsibility to choose the tool(s) best suited to a specific job. By describing the tools now available, we do not mean to imply that all of these tools need even be considered at any given site, nor that