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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Avian population and community dynamics in response to vegetation restoration on reclaimed mine lands in southwest Virginia

Latimer, Chris E. 29 May 2012 (has links)
Coal surface-mining is often implicated for its negative impacts on native flora and fauna. However, some studies suggest that, in reclaiming land after mining, there may be potential to create early successional habitat needed by many avian species currently in decline throughout eastern North America. I evaluated nest-site selection and nest success for on reclaimed mine lands in southwest Virginia during the summers of 2010 and 2011. For this nest-site analysis, I focused on 2 bird species common to reclaimed mine lands in southwest Virginia: field sparrows (Spizella pusillia) and indigo buntings (Passerina cyanea). In addition, I assessed bird community attributes in relation to various surface-mine reclamation regimens over a 5-year period from 2007-2011. For both species, I found estimates of daily nest success to be higher than other estimates reported in the literature; however, empirical estimates of adult and juvenile survival are needed to provide better estimates of population status. For field sparrows, models of avian nest success support the hypothesis that a tradeoff exists between nest concealment and a view of the surroundings for field sparrows. For indigo buntings, year explained the most variation in nest success, with much lower estimates of daily nest survival in 2010, possibly as a result of increased precipitation. I also assessed avian community dynamics in relation to vegetation changes on reclaimed mine sites and observed a total of 96 species throughout the 4 years of sampling. Local species persistence and species turnover were comparable to another continental scale study conducted using breeding bird survey (BBS) data. Observed changes in community vital rates were likely a result of changes in certain habitat attributes over the 5-year period. Lastly, seven species were unique to certain cover types, suggesting the need to consider landscape level processes when developing restoration guidelines for reclaimed coal surface-mines. / Master of Science
32

Demonstration of Direct-on-filter FTIR to Estimate Silica, Kaolinite, and Calcite Mineral Fraction in Respirable Coal Mine Dust Samples

Pokhrel, Nishan 09 September 2021 (has links)
Respirable coal mine dust (RCMD) has long been recognized as an occupational health hazard. In addition to coal, RCMD can contain minerals such as crystalline silica (i.e., most often present as quartz). There has been a resurgence of lung diseases among US coal miners since the late-1990s which has emphasized the need for better quartz monitoring, and better dust characterization in general. Quartz monitoring in coal mines has traditionally used infrared (IR) spectroscopy-based analytical methods such as the MSHA Method P7 that require significant sample preparation and must be performed in a centralized lab. There are generally thus days to weeks between dust sample collection and reporting of results, which can prevent the prompt mitigation efforts to better control dust and reduce exposures. Recently, a rapid analysis method for quartz has been developed by the US National Institute for Occupational Safety and Health (NIOSH) using direct-on-filter (DOF) Fourier Transform Infrared (FTIR) spectroscopy. The method has been demonstrated in a number of NIOSH-led studies using both laboratory and field samples, and the results show very good accuracy relative to the Method P7 reference. However, it has heretofore not been widely used by others or compared to results from other non-IR analytical methods. Moreover, while FTIR can allow the measurement of additional analytes, this has not yet been a focus of DOF FTIR for RCMD analysis. Analytes such as kaolinite and calcite could be of particular interest in the context of RCMD source apportionment. In this thesis, the DOF FTIR method is used to estimate silica, kaolinite, and calcite mineral fraction in RCMD samples collected in 16 coal mines, and in the laboratory using dust source materials from those same mines. The results are compared to results from other dust characterization methods such as mass-based thermogravimetric analysis (TGA) and particle-based scanning electron microscopy with energy dispersive X-ray (SEM-EDX). Results indicate the usefulness of the DOF FTIR method, and comparison suggests the presence of significant non-carbonate minerals other than silica and kaolinite in the coal mine dust. The results also show that SEM-EDX frequently indicates more mineral content (primarily other aluminosilicates), than that is predicted by either FTIR or the TGA. Additionally, by focusing mainly on calcite (generally sourced from limestone-based rock dust used in coal mines to prevent coal dust explosion), the second part of this study explores basic source apportionment by analyzing mine samples and samples of major dust source materials (such as run-of-mine coal, rock strata, and rock dust products). Results show that calcite can serve as a suitable proxy for rock dust in coal mine dust, and the results are consistent with expectations surrounding the contribution of dust from different mine locations and sample sources. Additionally, the DOF FTIR also showed good agreement with the TGA and SEM-EDX. / Master of Science / Respirable dust generated in coal mines has long been recognized as an occupational health hazard. In addition to coal, coal mine dust can contain minerals such as crystalline silica, which is particularly hazardous. Since the mid-1990s, there has been an alarming and unexpected increase in lung diseases in coal miners. Respirable crystalline silica is assumed to be a likely causal factor for this resurgence of lung diseases, and this has emphasized the need for better respirable crystalline silica monitoring and to better understand coal mine dust composition. The standard method of measurement of silica (called the MSHA Method P7) generally takes days to weeks between dust sample collection and reporting of results, which can prevent the mine from taking prompt mitigative efforts to better control dust and reduce exposures. Recently, a rapid analysis method for silica has been developed by the US National Institute for Occupational Safety and Health (NIOSH) called the DOF FTIR (direct-on-filter Fourier Transform Infrared Spectroscopy). This method has been shown to have very good accuracy relative to the standard method (MSHA P7). However, it has heretofore not been widely used by others or compared to results from other analytical methods. Moreover, DOF FTIR can also be used to estimate other minerals of interest such as kaolinite and calcite, which can be important in the context of understanding coal mine dust sources. In this thesis, the DOF FTIR method is used to estimate silica, kaolinite, and calcite mineral fraction in coal mine dust samples collected in 16 coal mines, and in the laboratory using dust source materials from those same mines. The results are compared to results from other dust analysis methods such as mass-based TGA (thermogravimetric analysis) and particle-based SEM-EDX (scanning electron microscopy with energy dispersive X-ray). Results indicate the usefulness of the DOF FTIR method, and comparison suggests the presence of significant non-carbonate minerals other than silica and kaolinite in the coal mine dust. The results also show that SEM-EDX frequently indicates more mineral content than that is predicted by either FTIR or the TGA. Additionally, by focusing mainly on calcite—which is generally sourced from limestone-based rock dust used in coal mines to prevent coal dust explosion—the second part of this study explores the sources of the dust by analysing samples collected in mines, and samples generated in lab from major dust source materials (such as the raw coal, rock strata, and rock dust products obtained from the mines). Results show that calcite can be representative of rock dust in coal mine dust, and the results are consistent with expectations surrounding the contribution of dust from different mine locations and sample sources. Additionally, the DOF FTIR also showed good agreement with the TGA and SEM-EDX.
33

Exploration of Respirable Dust Particles Sourced From Rock Strata in an Underground Coal Mine

Gonzalez Jaramillo, Jonathan 12 November 2021 (has links)
Enactment of regulatory standards for respirable coal mine dust (RCMD) concentration and crystalline silica content, and advancements in mine ventilation and dust controls led to a steady decline of occupational lung disease among US coal miners between the early 1970s and the mid-1990s. Since that time, there has been an alarming resurgence of disease especially in central Appalachia—with little hard data to pinpoint the causative factors in the mine environment. This situation has emphasized the knowledge gap surrounding specific dust characteristics and their sources. Key observations from many disease cases have suggested that dust constituents sourced from the rock strata in the mine (i.e., the rock layers that surround the target coal seam) may be particularly important; and this fits with the general tendency to extract thinner coal seams, and thus more rock, in many central Appalachian mines. To explore the characteristics of rock-strata sourced dust and its possible influence on the overall RCMD, this thesis reports two primary research efforts: Chapter 1 encompasses a case study conducted in an underground coal mine in West Virginia. (This chapter was previously published in the proceedings of the 18th North American Mine Ventilation Symposium, and is being reproduced with permission of the licensor through.) Following precedent from other studies, respirable dust samples were collected from key locations including in the intake airway, downwind an operating roof bolter, and adjacent to the feeder breaker. Additionally, three locations downwind the production face were simultaneously sampled during four individual continuous miner cuts—which was a unique feature of the current study. Dust was analyzed using previously established methods, including scanning electron microscopy with energy dispersive X-ray (SEM-EDX) to determine particle size and mineralogy distributions. Where comparable, results were generally consistent with those from other central Appalachian mines. However, the unique production sampling scheme offered new insights regarding the shift in particle characteristics as dust moves downwind from the generation point. Changes in size and mineralogy suggested that rock-strata sourced particles, especially aluminosilicates, might interfere with the SEM-EDX classification of other particles, especially coal. To explore the issue of aluminosilicate interference with coal classification, and the possible reasons, Chapter 2 covers two main lines of study. First, existing RCMD samples and SEM-EDX metadata were re-examined. Results suggested that particle loading effects could be at least partly responsible for the appearance of inordinately high aluminosilicate abundance (and conversely low coal) in some samples (i.e., the mineral particles might deposit on the sample filter in close proximity to the coal). Additionally, the presence of coal-mineral microagglomerates (MAGs) was demonstrated. The second line of study in Chapter 2 was therefore to explore whether MAG formation could be due to the RCMD generation process or environmental conditions—rather than merely an artifact of the sampling procedure—and the dispersibility of MAGs, which may have important implications with respect to dust exposure and biological response. Laboratory-generated samples collected passively demonstrated that coal-mineral MAGs can indeed occur without influence from typical RCMD sampling equipment. MAGs were significantly dispersed by sonication in deionized water, though gentle swirling did not yield consistent results. Moreover, in a surfactant solution that mimics natural lung fluid, MAGs were also dispersed. Compared to deionized water, the surfactant may promote more dispersion of coal particles in particular. / Master of Science / Occupational illnesses such as black lung in underground coal mining are still a worrisome issue in the industry. This research was aimed at gaining insight into rock-strata sourced dust and its possible influence on the overall characteristics of respirable coal mine dust (RCMD). The rock strata surrounding the coal seam is often rich in silicates and silica. A case study of RCMD was conducted in a thin-seam mine in West Virginia. Samples were collected in various locations and analyzed using electron microscopy among other methods. Results indicated that mineral dust, especially aluminosilicates, can be very abundant near the production face and might interfere with the measurement of coal dust. To explore such interference, a follow-up study was performed by revisiting a subset of RCMD samples examined in prior work. This approach yielded evidence of coal-mineral microagglomerates. Additional efforts in the laboratory recreated agglomerate formation and demonstrated their dispersibility. Results suggested that the occurrence of microagglomerates is not entirely a direct consequence of the sampling methodology and highlighted their potential importance within the context of exposure assessment and possible biological response.
34

An Ecotoxicological Assessment of a Treated Coal-mining Effluent in the Leading Creek Watershed, Meigs County, Ohio

Kennedy, Alan James 06 January 2003 (has links)
The majority of research studying the ecological impacts of the coal mining industry on freshwater systems has focused on abandoned-mined land, and the associated acid drainage and metals toxicity. Treated discharges from active mining and preparation facilities, however, can also impair lotic ecosystems through total dissolved solids (TDS) toxicity, caused primarily by the reagents used for pH modifications and the oxidation of reduced sulfur. Such impairment was best detected through application of (1) benthic macroinvertebrate surveys using metrics of biotic impairment such as relative Ephemeroptera abundance and Ephemeroptera-Plecoptera-Trichoptera (EPT) minus the tolerant caddisfly family Hydropsychidae (2) in situ growth of Corbicula fluminea during 96-d exposure and (3) laboratory testing using Ceriodaphnia dubia. Traditional metrics such as total taxa richness, EPT, diversity and biotic indices were not sensitive to elevated TDS levels. Further study using strength of evidence, regression analysis and manipulation of laboratory formulated media, indicated that the mine effluent was the primary causal agent of the observed biotic impairment, and its toxicity could be attributed to sodium/sulfate-dominated TDS, which is significantly ameliorated by water hardness. Finally, although testing with lentic cladocerans, such as Ceriodaphnia, is consistent, cost-effective and sensitive to TDS related toxicity, the ecological relevance and protective capability of such testing is questionable when assessing contaminant effects on sensitive macroinvertebrates indigenous to lotic systems. A more ecologically relevant laboratory bioassay using the mayfly, Isonychia bicolor, in simulated lotic microcosms provided more sensitive endpoints than Ceriodaphnia and Pimephales promelas. Although the heartiness of Isonychia in laboratory conditions is poorly understood relative to standardized test organisms, these results, along with potential toxic impacts from numerous sodium/sulfate-dominated wastewaters discharging into freshwater systems, may have important implications to future national pollution discharge and elimination system (NPDES) permit testing. Currently, however, strong recommendations can only be made using Ceriodaphnia endpoints. Potential acute toxicity to aquatic organisms in high hardness solution (~790 mg/L as CaCO₃) is possible where sodium/sulfate-dominated TDS levels exceed ~7000 uS/cm (5167 mg/L), with potential chronic toxicity occurring at ~3200 uS/cm (2342 mg/L). These endpoints were significantly reduced in solutions of lower hardness (88 mg/L as CaCO₃), with acute and chronic toxicity occurring at 5100 uS/cm (3754 mg/L) and ~2100 uS/cm (1523 mg/L), respectively. Point source discharges causing instream TDS concentrations to exceed these levels risk impairment to aquatic life. / Master of Science
35

Co-disposal of rejects from coal and sand mining operations in the Blue Mountains : a feasibility study

Gosling, Christine, University of Western Sydney, School of Civic Engineering and Environment January 1999 (has links)
This thesis presents details of investigations into the potential for co-disposal of the two rejects from Clarence Colliery and Kable's Transport Sand Mine. Column experiments were undertaken to simulate field conditions. The experiment consisted of: 1/. creating the required co-disposal arrangement and structure in containers 2/. infiltrating water through each container and measuring the rates of infiltration and overflow 3/. measuring the chemical properties of the leachate water. Geotechnical tests of co-disposal pile stability were undertaken using a specially constructed shear box. Results of this study suggest the co-disposal of course coal washery reject from Clarence Colliery with clay tailings from Kable's Transport Sand Mine is a feasible option for managing the generation of acetic drainage. It is recommended that field trials comprise layers of coal reject and clay tailings in a 9:1 ratio. Layering the coal reject with clay tailings creates a semi-permeable barrier which acts to restrict water percolation through the reject as well as reacting with the leachate to increase the leachate pH and adsorb metals / Master of Engineering (Hons)
36

A Numerical Analysis of Mine Intersections and Support Systems for Stability

Abbasi, Behrooz 01 December 2010 (has links)
AN ABSTRACT OF THE THESIS OF Behrooz Abbasi, for the Master of Science Degree in Mining and Mineral Resources Engineering, at Southern Illinois University Carbondale TITLE: A NUMERICAL ANALYSIS OF MINE INTERSECTIONS AND SUPPORT SYSTEMS FOR STABILITY MAJOR PROFESSOR: Dr. Yoginder P. Chugh Back ground: Partial extraction room-and-pillar mining systems provide about 60 % of the underground coal mined in the USA. This mining system develops 3-way and 4-way intersections. Rock falls related to fatal and nonfatal injuries in the USA for the period 2002 to 2007 identified that about 70% of these falls occur at intersections even though they represent only about 20-25 % of the area mined. A recent study on 2004 to 2008 roof-falls data base (RFDB) for Illinois mines, found that over 80% of these falls occurred at intersections. Thus, there is a significant need to improve stability of coal mine intersections if fatal and nonfatal injuries are to be controlled. The overall goal of this research is to develop an improved scientific understanding of stress distribution and instability around a 4-way intersection. An additional goal is to evaluate primary and secondary support layouts for improved stability around 4-way intersections. The following specific tasks were established for this research. * Perform 3-D numerical analyses to develop a better understanding of stress, strain and displacement distributions and associated instabilities around a 4-way intersection to identify ground support requirements. * Identify primary and secondary supports systems that may be suited to meet ground support requirements in (1) above. * Perform numerical analyses with identified primary and secondary supports installed to assess improvements in stability around an intersection. Analyses results show that pillar ribs across an intersection fail first and lead to progressive failure of immediate roof layers. The failure of immediate roof layers extends about 1.8m. In detail, coal ribs around the intersection corners mostly fail due to tensile stress, while roof and floor strata fail due to shear stresses and rib center fail due to combination of shear and tension mechanism. Primary supports significantly improve stability, but they are not adequate to ensure stability of four-way intersections. Secondary supports are needed to further improve stability of intersections. Also, based on the failure analysis a new secondary support system plan was proposed and analyzed.
37

Mining Interruption: Life, labor and coal after the Soma mine disaster

Az, Elif Irem January 2023 (has links)
“Mining Interruption” tackles the question of how to make sense of disaster by exploring the Soma mine disaster. On May 13, 2014, an explosion in the Eynez underground lignite coal mine caused a fire that blocked the exit, sealing in 301 mineworkers who died of carbon monoxide poisoning in the town of Soma, in the city of Manisa, in Aegean Turkey. While the European Union was becoming relatively greener next door, coal extraction had begun to increase in Turkey after the Justice and Development Party [Adalet ve Kalkınma Partisi] came to power in early 2000s. The relative decline of coal in the Global North paved the way for increased amounts of internal coal extraction and consumption in the energy geographies of the Global South and other non-Western countries as well as of Indigenous lands. The shift created biopolitically, socially, and technologically renewed forms of exploitation of labor, bodies, and nature, which contextualize the Soma mine disaster. Based on 18 months of ethnographic fieldwork and 68 open-ended interviews conducted in the Soma Coal Basin, this dissertation presents one constellation of the disaster by exploring four figures—The Accidented, the Bride, the Deserving, and the Striker—both as effects and as ongoing temporalities of the disaster. It contributes to critical disaster studies by defining and studying disaster not as a category of event, but as a concept through which multiple temporalities, lived experiences, and knowledges hang together. This loose definition of disaster is complemented by a reinterpretation of Walter Benjamin’s take on one of Bertolt Brecht’s most important dramaturgical techniques: interruption. In the dissertation, interruption is re-conceptualized as an experiential (hence temporal) concept that captures out-of-the-ordinary moments or flashes that interrupt everyday life in a way that permits a reevaluation of historical-material conditions. Interruptions are openings through which people may or may not follow an accidental course of action in order to overcome, better deal with, or politically respond to their conditions. The multiplicity of interruptions that are integral to the ongoing Soma mine disaster intersect with labor, fossil fuel production and its toxic effects, disability/debility, gendered oppression, disaster management, and social assistance. Some of these interruptions are experienced as rupturing events while others are perceived below the threshold of the event as such—as noneventful or not-so-eventful sensibilities, intensities and material changes. Each figure in question is a constellation in itself, a web of interdependencies, ruptures and materialities formed among human beings, state actors, coal, land, tobacco and other plants, limbs, organs, and names. In “The Accidented,” by examining mineworkers’ experiences and the terminology of becoming accidented (a direct translation of the term kazalanmak [in infinitive form]) through work accidents, the dissertation presents a critique both of existing disability assessment techniques and processes, and of understandings of disability as identity, which peripheralize labor-related and other experiences of (dis)ability and debility. In “The Bride,” by surveying the pervasive rumors about the widows of the 301 mineworkers, and their naming by the townspeople as “the brides,” the dissertation studies the differential treatment of the families of the 301 and the rest of the mining community through the state’s twofold disaster management strategy, and the ways in which people deal with this treatment through gossip, resentment, and kinship ties. In so doing, the dissertation also explores how affinal kinship relations have been transformed in the region due to the rise of coal mining, which coincides with the heightened neoliberalization of agriculture. In “The Deserving,” by investigating the materiality and movement of the lignite coal that is known as “Soma coal,” the dissertation articulates the ways in which the lives and desires of working-class and peasant communities have been reshaped through coercion, patronage, ideological interpellation, and the subjectivizing effects of Soma coal. It presents Soma coal as a pedagogical infrastructure that has emerged through the materiality of coal, and the regimes and networks of labor and welfare provision in contemporary Turkey. Finally, through the figure of “The Striker,” the dissertation examines the three-year long compensation struggle and protests of Soma and Ermenek mineworkers (2019–2021) as a set of emergency strikes that interrupted various processes, technologies, social networks, and modes of life that are formally and/or really subsumed within capital. The concept of “emergency strike” is used in order to encapsulate a form of strike that emerges with whatever means available in a given context, and as a collective act of seizing perceived last chances. This discussion builds on a recent wave of theorization concerning forms of unconventional strike that aim to disarticulate mechanisms and processes of real subsumption and/or state sovereignty. The dissertation shows how mineworkers organized against the backdrop of the Soma mine disaster. In doing so, it demonstrates how mineworkers re-exceptionalized their living and working conditions under a state of exception that has become the rule in Turkey since the 2016 coup attempt while it had already become the rule in the Soma Basin after May 13, 2014.
38

ROCK DUST SURFACE CHEMISTRY MODIFICATIONS FOR ELIMINATING CAKE FORMATION AND IMPROVING DISPERSION IN COAL DUST EXPLOSION MITIGATION APPLICATIONS

Huang, Qingqing 01 January 2016 (has links)
Rock dust has been historically applied to mitigate the coal dust explosion in either dry or wet form. Dry rock dust performs best in inerting the potential coal dust explosion due to the greatest dispersive properties. However, it undesirably exposes underground coal miners to respirable dust particles which imposes a severe health danger. Wet dust application is able to significantly reduce the floatable dust particles but another problem associated with caking is predominant. Caking phenomenon is usually used to describe the change of free-flowing bulk solids into agglomerated chunks. Unfortunately, the environmental conditions of an underground mine have the potential to cause caking of the rock dust, especially for wet dust application, which reduces the dispersive characteristics needed for effective explosion mitigation and is also the focus of the present study. Surface modification of rock dust to generate a hydrophobic surface is believed to alleviate the caking problem by allowing instant water drainage and eliminating the formation of water and solid bridges. Surface modification of rock dust was evaluated in the present study with a series of potential modifying reagents including oleic acid, sodium oleate and stearic acid. The modification efficiency in terms of measured contact angle, zeta potential and dispersibility values was investigated with sodium oleate generating the best modification effect. Dispersants were investigated as well in the present work aiming to further increase the particles dispersibility in addition to the excellent hydrophobization effect generated by sodium oleate. However, dispersibility test results indicated that the adsorption of dispersant and sodium oleate was competitive. The preferential adsorption of dispersants over oleate deteriorated the surface hydrophobicity of particles and the dispersibility was decreased as a result. As anticipated, dry rock dust always provided the best dispersibility with almost 95% of the dust remaining in suspension at a dispersion time of 30 seconds. The percentage dust dispersion values of sodium oleate treated rock dust was increased to as high as 71% in contrast to 47% of untreated wet rock dust and the explosion potential was correspondingly reduced by almost 83%. The effect of sodium oleate was further studied as a function of reagent concentration to determine the optimum application condition. The dispersibility of rock dust particles was initially increased until the application of 0.1 wt% sodium oleate, after which it slightly decreased up to 0.5 wt% oleate. When the concentration was above 0.5 wt%, the dispersibility of dust particles substantially decreased to a value lower than the value obtained for regular wet dust. The optimum sodium oleate concentration was thus determined at approximately 0.1 by weight of rock dust particles with a corresponding contact angle of around 110 degrees. The pivotal of rock dust modification efficiency is its long-term stability which can be corroborated by irreversible chemical adsorption rather than the short-term physical adsorption. Therefore, the fundamental adsorption mechanism of sodium oleate on rock dust surface was continuously investigated by means of using surface tension measurements, FTIR, Thermogravimetric, SEM analyses and constructing the species distribution diagram. Based on the surface tension measurements and calculated apparent surface area occupied by per oleate molecule, the monolayer adsorption of oleate on dust surface was proposed with oleate concentration falling between 0.1-0.15 wt% which guarantees the long-term surface modification efficiency. Calcium oleate started precipitating out of bulk solution and depositing on the dust surface when the oleate concentration was above 0.15 wt% which became more predominant under high oleate concentration. Super hydrophobic particles together with nucleated calcium oleate nanoparticles tend to increase particles aggregation significantly through attractive hydrophobic particle-particle interactive force, which renders the particles more agglomerated instead of dispersed. Systematic and economic evaluation of the wet form rock dusting process in underground coal mine applications was conducted at the end to determine the safety effects, potential benefits and improvement for future implementation. Suggestions for future work were given as well to shed light on the dusting process together with rock dust surface chemistry modification.
39

The Redevelopment of Plant Community Diversity on a Surface Coal Mine in Southwestern Wyoming

Hatton, Thomas Joseph 01 May 1986 (has links)
A study was initiated in 1981 to investigate the redevelopment of plant communities on a recontoured, surface-mined site in southwestern Wyoming. The landscape pattern of vegetation was compared with topographic position, the initial topsoil pattern, and cultural practices including shrub planting density, shrub planting pattern and topsoil treatments for the years 1982-1985. In addition, differences in vascular plant species diversity within these various factors and treatments were determined, along with the trend in intracommunity (alpha), intercommunity (beta) and landscape (gamma) diversity for the entire study area. The influence of site factors and tested cultural practices on the differentiation of the landscape vegetation pattern generally declined over time. There were no persistent differences in diversity among any cultural treatments or topographic positions, with the exception of plan ting pattern. The vegetation classified by cultural treatment, topographic position, or the initial plant comm uni ties identified in 1982 showed strong successional convergence by 1985. This is reflected in a decline in be ta and gamma diversity over the period 1984-1985. Alpha diversity remained stable over this same period, though species richness increased, indicating that a subset of species is becoming more dominant. The landscape vegetation pattern apparently converged to a rather uniform composition, increasingly dominated by perennial grasses, forbs and shrubs.
40

AN ANALYSIS OF COMBUSTION WITHIN SURFACE MINE SPOILS AND OF ITS CONSEQUENT EFFECTS ON THE ENVIRONMENT AND RECLAMATION PRACTICES

Leonhart, Leo S. January 1978 (has links)
No description available.

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