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Gullies have been regarded as the "artery" in mining because they provide the only access route for material, people and ore in stopes. It thus becomes vital to provide the industry with suitable guidelines for gully layouts, geometry and the support required at all depths to keep the gully safe at all times. The research has indicated that best practices for gully layouts have been well recognised, but often poorly applied for many years. To address the issue of best gully practices, research was based on a review of past practices, underground visits, mine standards, codes of practice and the use of numerical modelling as a tool to back- analyse the underground conditions observed. The recommendations provided do not attempt to develop any new techniques for gully protection. They try to provide a guide for best practice under various geotechnical conditions. Based on depth, or stress environment, a broad based recommendation for gully geometry is provided. Using numerical modelling calibrated to underground observations, optimum widths and spans for each mining layout used at different depths are provided as a prescriptive guideline. • Sidings can only be omitted where stress damage does not occur. • A minimum siding width of 2m is recommended wherever sidings are cut. • Lagging sidings should be avoided and used only if absolutely essential. • In high stress areas gullies should be footwall lifted behind the stope faces or within wide headings. • All sidings must be cut on reef. Off reef sidings are not acceptable. • Correct blasting practice is essential to ensure stability of gully shoulders. • Gully width and span between support over gullies should be minimised. • Gullies must be kept straight. Excavation and cleaning of downdip sidings remains problematical from a practical mining point of view and future research is recommended in this area. / Dissertation (MSc (Mine Strata Control))--University of Pretoria, 2006. / Mining Engineering / unrestricted

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Economics, 1977. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND DEWEY. / Bibliography: leaves 157-163. / by Leslie I. Boden. / Ph.D.

M.Ing. / Safety within the mining industry is a primary concern for everyone involved. More specifically, active below-ground stope support for South African Mines is becoming increasingly important due to a renewed emphasis on the safety and well-being of the people actually working underground. It is imperative that all stope support systems are rigorously tested, continuously, both under laboratory conditions and in-situ to prove their performance and manufacturing standards. The Rocprop was initially manufactured in 1995 with the first two hundred props being installed at East Driefontein Consolidated Gold Mine in the Carletonville area. In the three years since the first introduction over three hundred thousand Rocprops have been manufactured and sold to South African Mines with the number steadily increasing. The Rocprop is a tubular support consisting of two tubes — a Ø139mm 'inner' tube and a Ø152mm 'outer' tube. One end of each tube is sealed by dome ends which are welded onto the tube mouths. The two tubes, cut to identical lengths, fit inside one another and extend telescopically during installation. Once the desired height has been reached, leaving enough tube overlapping to ensure the support does not buckle, the wedge is hammered in locking the prop at that height. The water is then removed after which the prop will provide active support of the rock mass above it. One of the components responsible for the Rocprops success is a dome end. This is either a forging or a pressing welded onto each end of the support and allows continual concentric loading throughout the life of the Rocprop. At present the dome ends are pressings, manufactured into hemispheres from 10mm mild steel plate in one action. The reason for the Rocprop's success is its performance characteristics. It's all metal construction, ease of installation, reliability and predictability in both seismic and static conditions, fire resistance, blast resistant, economically viability and versatility have made the prop successful. Reasons for the research were to investigate the dome end forming process in general and to investigate current numerical analysis techniques ability to predict loads during manufacture, the final shape, spring-back and other local deformation areas. Also to investigate alternate manufacturing methods such as cold forming, which provides advantages such as better mechanical properties and higher structural capabilities. The use of alternate materials in the Rocprop manufacture has been an ongoing process for MSP, manufacturer and current licensee holder of the Rocprop. A substitute for the current dome end manufactured from mild steel was investigated. For the substitute to be viable the material should be stronger, weigh less and be cost effective. In depth knowledge about the forming of the dome end at various velocities was gathered, providing information for further optimisation of the component.

Experimental and analytical investigations were conducted to evaluate the overall stability for the final slope of the Pit Number One at El Encino mine, an iron ore property in Jalisco, Mexico. Shear strength of the intact rock and fractures was estimated from laboratory tests and back-analyses of previous slope failures. Back-analysis estimates were found to be more appropriate to represent the shear strength of fractures. Equal-area stereoplots were used to analyze geological structure data to differentiate structural domains with similar structural characteristics within the final slope. A kinematic analysis was performed for each structural domain using average joint set orientations and major discontinuities projected onto the final slope. The final pit walls were found to be stable, except for a 36,000 ton wedge and a 12,000 ton plane shear slide. These geometries and other potentially unstable areas were analyzed, and control measures and additional work suggested.

A thesis submitted to the Faculty of Engineering, University of the Witwatersrand, in fulfilment of the requirements for the degree of Doctor of Philosophy in Electrical Engineering. / Lightning causes electrical shocks to people, the premature ignition of explosives, and the ignition of methane underground in coal mines. This study examines this problem using a theoretical study and the results of an extensive measurement programme that was conducted in several coal mines. The work that has been done, particularly in South Africa, is also reviewed. Two mechanisms are responsible for the penetration of lightning surge currents into the underground workings. A direct strike to the service structures leading into a shaft is one of the two mechanisms, and the second is that resulting from lightning strikes to the strata above the underground workings. The frequency and amplitude with which such surges can be expected is quantified using the theoretical study. This model correlates well with the observed frequencies of the empirical studies. The sensitivity of methane to lightning-type sparks is investigated. Currents as low as 10 rnA have been proved to be capable of igniting methane. The sensitivity of conventional detonators is also investigated. The thesis proposes a generalised test which can be applied to both the low-impedance protection method and a high-impedance protection method. The test methodologies have been generalised to make provision for any new innovative detonators that may be used by the industry. A risk evaluation of mines is developed which allows a mine to be categorised according to the likelihood of lightning causing an accident in a mine. The South African Recommended Practice for avoiding such accidents is also reviewed. / Andrew Chakane 2018

A proteção respiratória é largamente utilizada como medida de controle da exposição dos trabalhadores a particulados em suspensão no ar ambiente de trabalho em mineração. A composição química desses particulados influi nos efeitos sobre a saúde dos trabalhadores expostos e também pode afetar o desempenho do material filtrante dos respiradores. Materiais particulados oleosos suspensos no ar encontrados em ambientes de mineração podem afetar desfavoravelmente as cargas eletrostáticas comumente adicionadas às fibras dos filtros para particulados. Por essa razão os testes de laboratório dos filtros procuram simular algumas condições desfavoráveis encontradas nos ambientes de trabalho e incluem nos procedimentos de testes ensaios com substancias oleosas como o óleo de parafina ou o óleo de DOP. Os particulados não oleosos são representados nos ensaios por partículas de cloreto de sódio. O objetivo desta dissertação é comparar três métodos de ensaios para aprovação de filtros para particulados utilizados em respiradores purificadores de ar não motorizados e relacionar as condições de ensaios com as condições onde os filtros são usados em trabalhos de minerações. Para chegar a esse objetivo foram realizadas pesquisas bibliográficas sobre os riscos da exposição a particulados na indústria mineral, o uso de equipamentos de proteção respiratória e mecanismos usados para filtração de particulados; estudados os métodos de teste descritos em três normas (EN 143 européia, 42 CFR 84 norte americana e NBR 13697 brasileira), comparados os princípios de funcionamento dos equipamentos de testes Moore´s e TSI 8110/8130, e analisados resultados de estudos comparativos realizados com esses equipamentos. Conclui que os métodos de testes de desempenho submetem os filtros a condições bem mais agressivas que aquelas encontradas na maioria das condições de trabalho de mineração; que os métodos de testes europeus e norte-americanos submetem os filtros a condições semelhantes, enquanto o método brasileiro é mais brando, uma vez que não requer que a eficiência do filtro seja medida durante e após a deposição de quantidades definidas de aerossol de teste; que equipamentos de testes mais modernos que os utilizados para aprovação de filtros no Brasil incorporam progressos tecnológicos que permitem melhor repetitividade de resultados; que resultados de estudos comparativos realizados entre laboratórios mostram boa correlação entre as medições da eficiência obtidas por equipamentos Moore\'s utilizados na comunidade européia e Brasil, TSI 8110 e TSI 8130, este último utilizado pelo NIOSH nos EUA. / Respiratory protection is widely used in mining operations in order to control the worker\'s exposure to airborne particulates present in the workplaces. Chemical composition of these particulates impacts on the worker\'s health and can also affect the respirator filter media. Oily aerosols found in mining environments affect the electrostatic filter media with enhanced performance over mechanical filters. Therefore, filters laboratory tests include oily substances such as paraffin oil and DOP (Di-octil phthalate) in the test procedures, simulating some workplace unfavorable conditions. Non-oily particulates are represented by sodium chloride particles. This dissertation compares the test methods described in following standards: the European standard EN 143, the document 42 CFR 84 adopted by NIOSH (National Institute for Occupational Safety and Health) in United States of America (USA), and the Brazilian ABNT NBR 13697 adopted by Ministry of Labor of Brazil (MTE) and Fundação Jorge Duprat de Figueiredo (Fundacentro). This dissertation also compares the test methods conditions with the environemntal conditions likely found in mineral industry. The applied methodology includes a bibliographic research about workplace environmental risk in mining industry, the use of respiratory protective devices and particulate filters technology. Also includes a study of the three test methods (EN 143, 42CFR 84 and NBR 13697), principles of Moore´s and TSI 8110/8130 test instruments and analysis of inter- laboratory test studies made in Europe and USA. The conclusion shows that the test methods mentioned above subject the filters to conditions which are much more aggressive than the typical minig environments; that the European and USA test methods subject filters to comparable test conditions, while tests specified in Brazilian standards are more moderate compared to the European and North American, because filter loading is not required during the test; that new technologies incorporated in the test instruments improve repeatability and accuracy of test results; that comparison data obtained with many test instruments, made by various instrument makers allow one to conclude that there is good correlation between these instruments, in general and between the European´s Moore´s 4400 Tester Rig and the two TSI, AFT 8110 and AFT 8130, specifically.

The thesis starts by defining technological change, productivity and safety. Different definitions are discussed and their merits compared. A brief history of coal mining, together with a description of the state of the mining industry at present is given. Technological innovations recently adopted by the industry are discussed. The concept of productivity in relation to the coal industry of the U.K., and the deficiencies of the present measurement technique, are fully explained. Safety in the coal mining industry of the U.K. is investigated. A brief history is given, together with a full discussion of the consequences and costs of accidents. The concept of technical productivity is introduced and its relation to total productivity explained. The total productivity concept is then applied to longwall coal faces. A multi-variable non-linear model is devised which represents mean total productivity of all longwall faces to an accuracy of about J7G. The model is tested and a forecasting method suggested. Total productivity components are analysed and values for the productivity of various inputs during the period 1958-1980 given. Similarly, a model for representing safety, based on costs, is introduced, tested for accuracy and its components analysed. By applying marginal analysis to the total productivity and safety models, the influence of technological change on productivity and safety are quantified. It is concluded that a new method for measuring productivity should be adopted, in which case total productivity would be the most realistic and comprehensive choice. The models introduced can serve as useful tools in planning and forecasting, as well as being used to measure productivity and safety. Since this work has been in progress, work at the NCB has also led to consideration of improved measures of productivity.

No description available.

Thesis (M. E.)--University of New South Wales, 2005. / Also available online.