Evaluating mineralization data from

Combining data from stream sediment analyses with data on historic mining areas, the emission risks of old mine waste sites are evaluated systematically throughout Austria. Univariate and multivariate statistics serve to identify areas with naturally, or anthropogenically, elevated heavy metal concentrations (Fig. 4). Lead and zinc mineralization for... 

In order to evaluate CFSE s from the spectra, correlations of the absorption bands are made with the geometries of the coordination sites. Structural data for most of the minerals described in this chapter are summarized in Appendix 7. In the following sections details about relevant crystal structures precede descriptions of the crystal field spectra of many of the mineral groups. 

The water analyses were coded and then processed with the computer program WATEQ2. This program was modified in several ways to handle acid mine waters (a) the Eh could be calculated from the Fe VFe activity ratio or vice versa, (b) several sulfate minerals were added,(c) metal sulfate and hydroxide complex constants were carefully evaluated and included, and (d) Mn, Cu, Zn and Cd species were added since they are major constituents for several of the water samples. These modifications and the evaluated thermodynamic data are described by Ball, Jenne and Nordstrom in this symposium (32). 

The results of simultaneous weighted least-squares regression of the data and some of the unfitted but derived quantities are shown in Tables la, lb, and 2. Table la displays elemental arsenic, its simple oxides, and the reactions for arsenic oxidizing to arsenic trioxides. Table lb introduces the hydrolysis species for As(III) and As(V) in solution, the hydrolysis reactions, and the solubility reactions for the simple oxides. Single species are shown at the top of each table with the reactions underneath. The following discussion describes some of the mineral occurrences for these substances, describes their relative stabilities from field observations, and considers the implications of the evaluated thermodynamic data in terms of these occurrences. 

Many studies that have investigated the effects of different geochemical properties on adsorption of As species have used controlled laboratory experiments to evaluate adsorption of As by pure mineral phases such as Fe, Al, and Mn oxides, and clay minerals. Since these mineral phases are often components of aquifer solids, the data from such experiments can be used to help interpret the behavior of As in groundwater. Such an approach has commonly been used to assess As adsorption by soils and lacustrine sediments (Belzile and Tessier, 1990 Bowell, 1994 Fordham and Norrish, 1979 Jacobs et al., 1970). 

There are a number of disciplines in addition to geochemistry where judgment guided by experience is required to reach the desired objective. These include medicine, where a diagnosis of the cause of an illness may be based on a physician s subjective evaluation of symptoms as well as on the objective results of laboratory tests. Likewise, in economic geology, a decision of where to drill for mineral deposits depends on the skill of the exploration geologist as well as on data from cores and seismic lines, and on structural, sedimentologic or tectonic conceptual models. 

Reliability of thermodynamic data in program databases are often a subject of controversy. Constants AS AH AZ ° from different sources for the same compound may turn out incompatible. This difference is especially prominent at comparison of the data from domestic and foreign sources. For instance, free enthalpy of KH PO formation after Kraynov et al. (2004) is -1,411.4 kJ-mole and after Lances Handbook of Chemistry (1999) -1,622.85 kj-mole" in case of H AsO " the same parameter has values -593,73 and -587,22 kj-mole in the same sources. Errors associated with this show up at the determination of pH, SI, etc. There is some level of consent between commonly available databases for most common minerals and water components. This does not mean, however, that the results are equally correct or precise. Sometimes it is caused by different notions of precision and correctness. The responsibihty for errors caused by database parameters is on the user, not on the program creator. For this reason critical evaluation of the utilized database by the user is a must. He has the right to edit his databases on his sole discretion regardless of the nature and intent of the program. In this connection he must be appraised of the current literature and current changes in necessary thermodynamic constants. 

Figure 3 Chondrite-normalized REE patterns for common igneous rock-forming minerals. The igneous rock type from which the mineral was extracted is also listed. Data from compilation provided by T ay lor and McLennan. The extreme range of REE and the distinctive patterns for certain minerals is one of the reasons why REE are valuable trace elements for evaluating petrogenesis...

To evaluate this hypothesis, experimentalists have been trying to provide data on mineral solubility and dissolution kinetics as a function of temperature, pH, and fluid composition. Experimental techniques and results of published studies are summarized below along with new data from our laboratory, including the results of pH-buffered, flow-through experiments that track variations in pore-fluid chemistry through time (Reed 1990 Reed and Hajash 1990, 1992 Franklin 1991 Franklin et al. 1990, 1991). 

Finally, to evaluate the membranes, analysis such as X-ray diffraction (XRD), SEM, TEM and light scattering were performed at the School of Mineral and Material Engineering, Universiti Sains Malaysia. The last part of the work, testing the produced membrane to remove emulsifier oil from domestic wastewater, was accomplished on a limited budget. An experimental rig and membrane module were required. Also the need for experimental data for the application of the supported membrane may show the real success of this project. 

Most hydraulic fluid preparations start as chemical mixtures. For instance, there is a considerable area of overlap in the specific petroleum hydrocarbon chemicals contained in the mineral oil and polyalphaolefin hydraulic fluids. For all classes of hydraulic fluids, there may be similarities with other original products intended for use as lubricants. The complications involved in documenting the environmental fate of mixtures increase under conditions encountered at many NPL sites, where it may be hard to determine the precise original product associated with chemicals identified at an area in need of remediation. In most instances, available peer-reviewed literature, supplemented with data obtained from manufacturers of particular formulations and information in trade magazines, can supply information about the original hydraulic fluid preparations. At NPL sites, site-specific evaluations of specific chemicals may be the only feasible way to address concerns over environmental fate and potential exposure risks. 

Are the equilibrium constants for the important reactions in the thermodynamic dataset sufficiently accurate The collection of thermodynamic data is subject to error in the experiment, chemical analysis, and interpretation of the experimental results. Error margins, however, are seldom reported and never seem to appear in data compilations. Compiled data, furthermore, have generally been extrapolated from the temperature of measurement to that of interest (e.g., Helgeson, 1969). The stabilities of many aqueous species have been determined only at room temperature, for example, and mineral solubilities many times are measured at high temperatures where reactions approach equilibrium most rapidly. Evaluating the stabilities and sometimes even the stoichiometries of complex species is especially difficult and prone to inaccuracy. 

The Non-renewable Resource Assessments (NRAs) are part of step 5 in an 8-step process that may ultimately result in (partial or limited) protection of certain areas from development. Phase 1 of an NRA is a desktop exercise that evaluates all existing mineral deposit and survey data for an area from all sources, determines knowledge gaps of the mineral potential, and suggests an approach for Phase 2 follow-up work. Phase 2 of the NRA typically involves field and analytical work designed to lead to a better understanding of the resource potential for a candidate protected area. 

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