Pretreatment of Pittsburg seam B coals to decrease its ash content and increase its solvent extractable material was investigated by anodically electrolysing acidified coal-water slurries at potentials around 1.0V SCE. The effects of the pretreatment were examined as functions of coal particle size, acid strength of the slurry, time of electrolysis and applied potential. The coal electrolysis was found to be most efficient at low acid strengths and short electrolysis times. The morphology of the coal surface changed with the conditions of the electrolysis and related to the percentage ash removal and the amount of solvent extractable material present in the coal. The anodic oxidation of the coal is suspected to occur via an electrocatalytic(EC) mechanism, whereby ferrous ions in the coal are first oxidised at the anode to the ferric state. The ferric ions migrate into the coal and accept electrons from accessible bonds in the coal micelle thereby reducing themselves back to ferrous ions and return to the anode for re-oxidation to the ferric state. The acceptance of electrons from certain bonds in the coal micelle results in the break-up of the micelle in to simpler compounds. Accordingly, the solubility of the coal in an organic solvent should increase and this was found to be so when ferrous ions were externally added to the electrolyte. The electrolytic process was also found to transfer metallic ions present in the coal into solution in the electrolyte. / Master of Science

M.S.

A formulation was developed for the rheological characterization of highly concentrated suspensions, accounting for the physical effects of particle size distribution. A number of dimensionless parameters were developed signifying the physical characteristics of the solids and the vehicle fluid, and functionally related to the yield-stress and a flow parameter. Each of these expressions of the formulation contains an empirical dimensionless coefficient accounting for the interparticle and fluid/solid interactions that are not explained by the physical parameters involved. A formulation and a methodology were also developed for predicting the shear viscosity behavior of highly concentrated suspensions at low and high shear-rates through the use of three parameters signifying effects of particle size distribution. A number of applications were made using various non-coal and limited coal-liquid mixture data reported in the literature to demonstrate the general validity of the formulations. A methodology was proposed for the analysis of the particle size distribution effects on the overall optimum energy efficiency during hydraulic transportation and particle size reduction. The computer model developed for this purpose was employed to evaluate the transportation energy consumption and the energy consumed in the grinding process to prepare the slurry, in pipes of various sizes and lengths for a coal slurry of various specified particle size distributions and concentrations. Correlations obtained indicated the sensitivity of transportation energy efficiency to various parameters including the maximum packing concentration, relative concentration, specific surface area of particles, surface area mean size, pipe size and length, and annual mixture throughput. The results of combined energy calculations have shown that the particle size distribution and related physical parameters can significantly affect the energy efficiency due to both grinding and transportation, and the delivered cost of slurry fuels. / Ph. D.

The direct current plasma is an excitation cell that should be well suited to rapid analysis of coal slurries by virtue of its tolerance for various sample matrices. Problems which are encountered in coal analysis by emission spectrometry include incomplete atomization of analyte by formation of metal oxides, lack of adequate methodology for sulfur analysis, and ineffective sample transport for coarse coal slurries. Atomization of metal oxides can be improved by addition of small amounts of propane (Ca 45 mL/min) to the nebulizing argon of the direct current plasma. However, the improved atomization is manifested above the normal viewing zone, and the enhancement effect of propane on analytical signals is offset by severe depression of emission signals caused by temperature reduction in the lower regions of the plasma. Sulfur in coal can be determined by direct current plasma emission spectrometry. Emission lines accessible to the echelle grating of the DCP are not suitable for such analysis, so that the deep-UV lines from 180-183 nm must be utilized for such work. A relatively simple purge system with low argon consumption (5 L/min) is adequate for sulfur analysis, and the beforementioned analytical lines provide detection limits that are adequate for sulfur determination in 1% slurries of coal. However, transport of the coal sample to the plasma is incomplete when compared to that of aqueous solutions, precluding the use of such solutions as calibration standards. Transport of the coal can be improved by increasing the viscosity of sample and standards, which increases the droplet size from the nebulizer and hence the particle size transportable• The increased droplet size causes a decrease in sensitivity due to reduced desolvation/vaporization, but does permit the use of aqueous solutions and as calibration standards for determination of sulfur, iron, aluminum, silicon in coal. / Ph. D.

M. S.

The Clinch and Powell Rivers located in Southwestern Virginia contain some of the most diverse freshwater mussel assemblages found throughout North America. However, in recent decades mussel species decline has been documented by researchers. The presence of coal mining activity in the watersheds has been hypothesized to be linked to the decline of numerous species and the extirpation of others. The effects of various discharges from an active coal preparation plant facility located in Honaker, Virginia were evaluated for acute and chronic toxicity using field and laboratory tests. The results of the study suggested that the primary effluent from the coal preparation facility had acute and chronic toxicity; however, the settling pond system utilized at this plant mitigated the impacts of the plant from reaching the Clinch River. Along with active mine discharges, acid mine drainage (AMD) has been documented as another potential stressor. Ecotoxicological recovery was evaluated in two acid mine drainage impacted subwatersheds (Black Creek and Ely Creek) in the Powell River watershed following remediation. The results in Ely Creek suggested that successive alkalinity producing systems were effective in mitigating the harmful impacts of AMD as previously impacted sites had decreased water column aluminum and iron levels in conjunction with increased survival in laboratory toxicity tests conducted with Ceriodaphnia dubia and Daphnia magna. Corbicula fluminea (Asian clam) in-situ tests confirmed the results in the laboratory tests as all sites located below the remediated areas had improved survival. However, active AMD influences and loss of quality habitat seemed to be hindering the recovery of the benthic macroinvertebrate community located in Ely Creek. In Black Creek, re-mining and outlet control pond construction have not resulted in a successful remediation in the lower subwatershed. A decrease in Ecotoxicological Ratings at some of the lowest mainstem sites compared to pre-remediation data was observed. Furthermore, decreased survival in sediment associated toxicity tests with D. magna in 2007-08 was supported by 100% Asian clam mortality at the LBC-5 and LBC-6 sites in 2007, while growth impairment in 2008 was observed at the LBC-6 site. / Master of Science

No description available.

This dissertation examines the contestations over the politics of knowledge, risk, and environmental justice in three fenceline sites. Mobilizing the fenceline standpoint to study risk strengthens our objective understanding of the social situatedness of risk. To illustrate how a fenceline standpoint contributes to stronger objectivity of risk contestations, I survey public discourse of coal slurry extraction in Black Mesa, Arizona using an environmental justice framework. Discursive justifications for the construction of the slurry pipeline reveal how environmental injustice in the fenceline community emerged through urban controversies over water and power generation that excluded a fenceline standpoint. Insights from Black Mesa frame the next two cases: open burning hazardous waste at Radford Army Ammunition Plant, and M6 Disposal at Camp Minden, Louisiana. At Radford, scholar-activist research examines the contestations of risk at one of the most hazardous waste facilities in the nation. I analyze the construction of risk from open burning of hazardous waste from a fenceline standpoint. I discursively situate the controversy over fenceline community risk from open burning, by showing the inadequacies of official risk assessments. Critical discourse analysis of risk shows the extant contestations over the practice of open burning. In juxtaposition to Radford, the Camp Minden open burn controversy demonstrates how a fenceline movement successfully constructed alternatives to open burning. Fenceline success in Minden is forcing scrutiny over the risks produced by the practice of open burning explosives across the United States. The activation of fenceline knowledge and expertise, through grassroots organizing, is propelling inquiry from scientific and technical experts of the American Chemical Society who are questioning why the Department of Defense and the Environmental Protection Agency have approved the use of open burning at other sites despite safer alternative technology. Synthetically, each case illustrates the importance of fenceline knowledge as a crucial site of expertise. I present an argument for how a fenceline standpoint can challenge regulatory and producer constructions of fenceline risk. The creation of a program of research: Critical Risk Analysis, offers a model for scholar-activist intervention on the fenceline. The Camp Minden Dialogue demonstrates a successful example of how fenceline expert-activists can influence the construction of risk. Normatively, I build the argument that environmental justice research within Science and Technology Studies ought to situate the fenceline standpoint as equal to the competing epistemological claims of production and regulatory experts in order to strengthen the objectivity of our research in contested fenceline sites. / Ph. D.