From small exploration companies to multi-national mining houses all at some point in the project lifetime embark on evaluation studies where the most value-generating method of extracting the ore is investigated. Early phases in exploration projects will have the need for an order-of-magnitude estimation as to the scale of the potential operation, and advanced projects will have detailed mine and financial plans to guide them to execution. In both instances this thesis provides a method of optimising the mining rate to deliver the highest possible value to the mining company whilst considering the possible risks from changes in the market. This can be compared to the value the country gains from the exploitation of its natural resources to find a mutually beneficial solution. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Geology / unrestricted

Mining activities, particularly coal mining, lead to the excavation of large volumes of pyrite rich soils. When exposed to air (oxygen) and water these pyrite complexes are oxidised to form highly acidic and corrosive wastewaters collectively termed acid mine drainage (AMD). Containing elevated levels of sulphates (SO42-) and toxic dissolved heavy metals, AMD seeping from mining sites, active or abandoned, poses a major environmental risk to aquatic bio-systems – not only in South Africa but globally. Chemical neutralization of AMD is expensive and often challenging. Biological sulphate reduction provides a promising and cheaper alternative to the treatment of sulphate rich wastewaters. Little, however, is known about the microbial communities involved in biological treatment systems and the effect of external factors thereon. Studying microorganisms in their natural environment is extremely difficult. The limitations of culture-based methods only provide a limited insight into the bacterial diversity of natural habitats and the microbial communities present. With the progressive advances in molecular biology, non culture-based tools such as DGGE, FISH and more recently t-RFLP allow easier and much more accurate studies of microbial communities within their natural as well as man-made environments. This study specifically investigated the use of t-RFLP to study microbial communities and dynamics within sulphate removing bioreactors. The set up and optimization of a t-RFLP system to specifically study microbial communities from sulphate removing bioreactors were investigated and the applicability of t-RFLP demonstrated. Copyright / Dissertation (MSc)--University of Pretoria, 2009. / Microbiology and Plant Pathology / unrestricted

The coal mining industry has played a significant role in the development of the South African economy. Coal supplies about 70% of South Africa's primary energy and is likely to remain the country's major source of energy despite the increasing trends towards renewable energy. Even though the industry has significantly contributed to the development of the country, it has also caused significant impacts on the environment with concomitant socio-economic impacts. Historically, once a coal measure was exhausted, mining companies would cease production and abandon the mines without proper rehabilitation of the environmental degradation caused by their mining activities. As a result of this, the South African Government introduced mining and rehabilitation legislation to mitigate the environmental and associated socio-economic impacts of mining. Rehabilitation guidelines for opencast coal mines were developed to provide detailed guidance for achieving successful and sustainable rehabilitation, to mitigate pollution post-mining. Despite the more stringent legislative framework and the development of international standard rehabilitation guidelines, successful mine rehabilitation remains a challenge. This research project aims to develop a better qualitative understanding of the status, challenges, gaps and opportunities pertaining to current rehabilitation practices in the case of opencast coal mines in the Mpumalanga Province of South Africa, and in so doing, establish the contributing factors of unsuccessful rehabilitation. The dissertation draws on a comprehensive review of published literature and an analysis of semi-structured interviews with rehabilitation experts. The study found that the current rehabilitation practices in the Mpumalanga opencast mines are not to the standard required by the legislative framework nor prescribed by rehabilitation guidelines. As such, the current rehabilitation practices are not yielding successful and sustainable rehabilitation. According to the findings, the rehabilitation practices are hampered by physical and non-physical systemic challenges that thwart the achievement of successful rehabilitation. The study analysis shows that shortcomings in the application and enforcement of the legislative framework contributes to the legislation not achieving its intended objectives as well as the development of other physical and non-physical systemic challenges that hamper the achievement of successful rehabilitation.

No description available.

No description available.

Pocahontas High School, the smallest of four Tazewell County high schools, is presently located in the historic town of Pocahontas, Virginia. From the school's establishment in 1908 until 1955, the high school was located at the top of Water Street within the town limits. In 1955, students were moved to a new building at its present site just inside the town's corporate limits. The school today serves the communities of Abbs Valley, Boissevain, and the Town of Pocahontas, Virginia. This study included an examination of the role of the school in the mining community, and the relationship between the coal company and the school. Thus, the researcher reviewed literature-surrounding life in mining industrial towns to determine whether Pocahontas conformed to the conventional interpretations of such mining-industrial communities. The researcher also considered the life of the school and community following the cessation of mining operations in Pocahontas. An examination of the reasons for the school having remained open despite declining enrollment and the importance of the school to its communities was examined through the eyes of local community leaders, residents, and graduates of Pocahontas High School. This study employed conventional historical research methods in order to document the history of Pocahontas High School. The data collected from documents and interviews were handled qualitatively, with some data appearing in the form of numbers and graphs. Data gathered for this study were derived from both primary and secondary sources. This study used written, pictorial, and oral sources. Oral materials included oral history interviews with local historians, public officials and individuals involved with Pocahontas High School during the period of study. Triangulation verification techniques were used to accurately describe the impact of coal mining and the closing of the mine on the development, growth, and decline of the school and community. / Ed. D.

The Powell River is located in southwestern Virginia and northeastern Tennessee, USA and supports a diverse freshwater mussel assemblage of 29 extant species. Throughout the river major ion and trace element concentrations have increased over the last several decades due to extensive surface coal-mining in the headwaters in Virginia. As watershed area affected by mining has increased, mussel populations have declined, especially in Virginia where populations have been severely reduced or extirpated. The upper watershed now has been extensively mined for coal, causing widespread effects on water and sediment quality. To investigate how mining may be affecting mussel populations, I first conducted a laboratory bio-assay to assess the effects of elevated major ions and the trace element nickel (Ni) on growth and survival of juvenile mussels, including one common species (Villosa iris) and one endangered species (Epioblasma capsaeformis). No significant differences in overall survival between treatments and control were observed for either species over a 70 day test period. Total growth was not significantly different between treatments and control for either species. However, overall growth varied significantly (p=0.009) between species, with V. iris (2.49 mm) exhibiting greater growth compared to E. capsaeformis (1.97 mm). Results suggest that major ion chronic toxicity alone or in combination with Ni at or below my test concentration is not a likely source of toxicity to juvenile mussels in the Powell River. Secondly, I conducted a field study in the Powell River using two cohorts of juveniles of Villosa iris to assess the effects of trace elements and PAH contamination related to mining on mussel survival and growth. Specific conductance was elevated throughout the Powell River, where site means ranged from 450 to 900 µS/cm. While mortality was high at all eight sites it was not significantly different among these sites (p>0.28); however, growth of juvenile mussels was significantly higher (p<0.001) in the lower river in Tennessee. Regression analysis showed significant relationships (p<0.001) of river kilometer with temperature, specific conductance, and aqueous major ion concentrations. A principal component analysis (PC) was conducted on all trace element data. Growth of Cohort 1 on Day 106 was best explained by the PC dominated by aqueous major ion concentrations (p<0.0001, R2= 0.65) and growth of Cohort 2 on Day 106 was best explained by specific conductance (p<0.0001, R2= 0.68). Growth of Cohort 2 at Day 423 was best explained by tissue trace element concentration PC1 and PC2 (p<0.0001, R2= 0.73). This study suggests major ions and select trace elements (Ba, Ni, Fe, Se, and Sr) in the Powell River are negatively affecting the growth of freshwater mussels and that the source of these contaminants is primarily from mining in the headwaters. / Master of Science / The Powell River is located in southwestern Virginia and northeastern Tennessee, USA and supports a diverse freshwater mussel assemblage of 29 extant species. Throughout the river major ion and trace element concentrations have increased over the last several decades. As watershed area affected by coal mining has increased mussel populations have declined, especially in Virginia where populations have been severely reduced or extirpated. The upper Powell River watershed has been extensively mined for coal, causing widespread decline in the river’s water and sediment quality. My study consisted of a laboratory and field exposure to assess the toxicity of the mining related contaminants, such as major ions, trace elements, and polycyclic aromatic hydrocarbons (PAHs) to freshwater mussels. Further, the study investigated the concentrations of these contaminants in the river and their effects on the survival and growth of exposed juvenile mussels. In my laboratory study, mussels of a common species (Villosa iris) and an endangered species (Epioblasma capsaeformis) showed no effect when exposed to a suite of major ions and the trace element Ni similar to levels measured in the Powell River. When juvenile Villosa iris were exposed in the Powell River at eight sites in Virginia and Tennessee, high rates of mortality were observed at all eight sites and growth of juveniles showed a significant spatial trend, with higher growth observed downstream in Tennessee. Water quality analysis revealed increased concentrations of major ions at all sites but concentrations of trace elements were generally below EPA water quality criteria. Further, many of the major ions and trace elements trended spatially with higher concentrations measured in the headwaters in Virginia and lower concentrations observed downstream in Tennessee. Statistical analysis revealed that major ions and trace elements (Ba, Ni, Fe, Se, and Sr) may have negatively affected growth of exposed mussels. This study revealed that laboratory conditions may not adequately be representing river conditions and that in the river major ions and trace elements likely are negatively effecting growth and survival of freshwater mussels. This study revealed that conditions in the Powell River likely are not suitable for mussel reintroduction and that mining is the main source of the contaminants in the river.

Salinization of freshwaters by human activities is of growing concern globally. Salt pollution can cause adverse effects to aquatic biodiversity, ecosystem function, ecosystem services, and human health. In many regions of the world, and in coal-mining-influenced streams of the temperate forests of Appalachia USA, specific conductance (SC), a surrogate measure for the dissolved major ions composing salinity, has been linked to decreased diversity of benthic macroinvertebrates. However, assessments used to reach this conclusion have generally not accounted for temporal variability of salinity, as most studies use "snapshot" SC data collected concurrently with biological data at a single point in time. Effective management of salinization requires tools to accurately monitor and predict salinity while accounting for temporal variability. To improve those tools, I conducted analyses of 4.5 years of salinity and benthic macroinvertebrate data from 25 forested headwater streams spanning a gradient of salinity where non-salinity stressors were minimized. My objectives were to: 1) model the annual pattern of salinity, 2) determine if salinity measures derived from continuous data are more precise than snapshot SC as predictors of aquatic biology, and 3) quantify response to salinity of the benthic macroinvertebrate community. A sinusoidal model of the annual cycle of SC using daily measurements for 4.5 years revealed that salinity naturally deviated ± 20% from annual mean levels, with minimum SC occurring in late winter and maximum SC occurring in late summer. The pattern was responsive to seasonal dilution as driven by catchment evapotranspiration dynamics. Alternative discrete sampling intervals can approximate the pattern revealed by continuous SC data if sampling intervals are ≤ 30 days. Continuous SC variables did not significantly improve precision for prediction of benthic macroinvertebrate metrics (p > 0.1) as compared to snapshot SC using generalized additive mixed models. Results suggest that snapshot SC is a capable predictor of benthic macroinvertebrate community structure if sampling is carefully timed. However, continuous SC data can quantify chronic salt exposure, which supports a hypothesis to explain how temporal variability of field-based observations of salt sensitivity of benthic macroinvertebrate taxa may be influenced by life stage. Benthic macroinvertebrate community structure diverged from reference condition as salinity increased, with stronger relationships in Spring than in Fall. Intra-seasonal variation in community structure was also revealed across sampling dates. Non-Baetidae Ephemeroptera were most sensitive to salinity, with richness and abundance lower than reference at SC > 200 =µS/cm in Spring based on snapshot SC. Equivalent effects were predicted by mean monthly SC of 250-300 µS/cm from the prior Fall. Continuous conductivity monitoring may improve assessment of salinity effects because they can describe life-cycle exposure, which may aid investigations of mechanisms driving field-based observations of benthic-macroinvertebrate community alteration. / Ph. D. / Freshwater ecosystems around the world are at risk of contamination from salt pollution resulting from a variety of human activities. All natural freshwaters contain low levels of dissolved minerals, or salts, the combined concentration of which is referred to as salinity. Activities such as crop irrigation, road de-icing, and mining can cause salt pollution in streams and rivers, and excessive salinity can be toxic to many aquatic organisms. In many regions of the world, including in coal-mining-influenced streams of Appalachia USA, elevated salinity has been linked to decreased diversity of benthic macroinvertebrates, which are primarily aquatic insects, a group critical to healthy stream ecosystems. However, assessments used to reach this conclusion have generally not accounted for annual variability of salinity, as most studies use “snapshot” salinity data collected concurrently with biological data at a single point in time. Effective management of salinity impacts requires tools to accurately monitor and predict salinity while accounting for annual variability. Toward improving those tools, I conducted analyses of 4.5 years of salinity and aquatic insect data from 25 small central Appalachian mountain streams spanning a gradient of salinity. My objectives were to: 1) characterize the annual pattern of salinity using high-frequency salinity data, 2) determine if high-frequency salinity data is better than snapshot data for predicting aquatic insect diversity, and 3) measure the response to salinity of the aquatic insect community and identify salinity levels associated with insect biodiversity loss. High-frequency (daily) data revealed that salinity exhibited a predictable cyclic annual pattern with seasonal deviations of ± 20% from annual average salinity levels. Minimum salinity occurred during late winter and maximum salinity occurred in late summer. Lower-frequency salinity data can approximate the annual pattern if sampling interval is ≤ 30 days. Snapshot salinity was equally capable as high-frequency data of predicting aquatic insect diversity provided that snapshot salinity sampling is carefully timed. Diversity of many aquatic insects, especially mayflies, declined with increasing salinity, with stronger relationships in Spring than in Fall. Variation in diversity measures was also somewhat related to sample timing within seasons. Alteration of aquatic insect communities was evident at total salt concentrations levels of approximately 130 – 200 parts per million, depending on time of year. Efforts to manage salinity impacts to aquatic life may be improved by integrating knowledge of annual salinity patterns with how aquatic insects respond to salt pollution.

none available / Master of Science

Underground coal mine ground control persists as a unique challenge in rock mass engineering. Fall of roof and rib continue to present a hazard to underground personnel. Stability of underground openings is a prerequisite for successful underground coal mine workings. An adaptation of a civil engineering design standard for analyzing the stability of underground excavations for mining geometries is given here. The ground response curve--developed over seventy years ago for assessing tunnel stability--has significant implications for the design of underground excavations, but has seen little use in complex mining applications. The interaction between the small scale (pillar stress-strain) and the large scale (ground response curve) is studied. Further analysis between these two length scales is conducted to estimate the stress on pillars in a room-and-pillar coal mine. These studies are performed in FLAC3D by implementing a two-scale, two-step approach. This two-scale approach allows for the interaction between the small, pillar scale and the large, panel scale to be studied in a computationally efficient manner. / Ph. D.