Environmental Mineralogy: Microbial Interactions, Anthropogenic Influences, Contaminated Land and Waste Management
The past 10 years or so have seen the emergence of a discipline known as ‘Environmental Mineralogy’. This should be regarded not as a new discipline per se, but as a new application of traditional mineralogy. Mineralogists have always sought to understand the chemical and physical environment under which a particular mineral forms and to determine the arrangement of atoms within that mineral. The field of Environmental Mineralogy asks the same questions in a different context. For example, can minerals assist in the remediation of contaminated soils and waters? Which minerals can potentially be deleterious to, inter alia, buildings, ecology and human health? Which minerals are suitable as containment for waste? How does the biota interact with minerals? Environmental Mineralogy is emerging as a field that seeks to define the roles of minerals in all environmental systems, and to work towards the preservation and restoration of such systems. Environmental Mineralogy is achieving prominence because of increasing concern regarding the environments in which we live. Mineralogists have perceived a gap in our understanding of how minerals behave in the surface environment and a need for innovative,‘green’ solutions to the problems of contamination and waste. However, the emergence of Environmental Mineralogy also owes much to modern analytical technology. Many minerals in the surface environment fall within the clay-grade range and therefore, demand high-resolution systems for analysis. Similarly, trace elements are now detectable at exceptionally low concentrations in a wide variety of matrices. Further, many mineral-environment interactions need to be examined at the atomic scale for a greater understanding of the interactive processes involved. This requires the application of the latest technologies such as X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and atomic force microscopy to name but a few. The aim of this monograph is to provide an up-to-date account of the state of this diverse subject area. With chapters containing a strong review element, it is hoped that this volume will appeal to both researchers and students alike. The volume is arranged in four sections: (1) mineral-microbe interactions; (2) anthropogenic influences on mineral interactions; (3) minerals in contaminated environments; and (4) minerals and waste management. These four sections by no means give exhaustive coverage of the subject area, but communicate some of the most important developments taking place at the present time.
The relationship of mineralogy to acid- and neutralization-potential values in ARD
Published:January 01, 2000
J. L. Jambor, 2000. "The relationship of mineralogy to acid- and neutralization-potential values in ARD", Environmental Mineralogy: Microbial Interactions, Anthropogenic Influences, Contaminated Land and Waste Management, J. D. Cotter-Howells, L. S. Campbell, E. Valsami-Jones, M. Batchelder
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Static tests are the most widely used method to assess the net acid-generating potential of rocks at prospective mine sites. The results influence mine plans in which the safe disposal of wastes, such as tailings and waste rocks, is an environmental requirement in most jurisdictions. Static tests are chemical tests that are intended to provide predictions of the extent to which the minerals in representative samples will react to produce acidity, or neutralize acidity, during weathering in potential ARD (acid rock drainage) scenarios. Weathering, however, is not an instantaneous process that affects all minerals equally. Consequently, if static tests are to be interpreted meaningfully, the rates of weathering of the common gangue minerals need to be taken into account. Although the amount of neutralization contributed by an individual mineral during the vigorous reactions in most laboratory static tests is an important measure, it is commonly assumed that this amount of neutralization is directly correlative with that accessible during natural weathering. Static tests by definition exclude mineral-dissolution kinetics, but these vectors are intrinsic to the interpretation and application of the results of static tests. Experimental dissolution rates of silicate and aluminosilicate minerals are rapid relative to normal weathering rates, but most of these minerals react slowly relative to the rapidity at which acid is generated by the oxidation of iron sulphides. Most silicates or aluminosilicates therefore contribute to the attenuation of acidity only after ARD has already been established. For environmental assessments, it is suggested that carbonate contents (calcite and dolomite, but with siderite excluded) provide a more realistic assessment of whether rocks have neutralization potential adequate for the prevention of ARD