This work focuses on the operational and safety issues associated with karst voids in large opening underground mines. Issues include water inrush, structural instability, and engineering uncertainty in these environments. Coupled with the fracturing prevalent in folded sedimentary rocks, karsts are complex and challenging ground control risks. Traditional methods of predicting karst void locations such as probe-drilling are impeded by the inconsistent spatial distribution and variable sizes of the features. Ground penetrating radar (GPR) is a geophysical technique that transmits radio waves into a medium and subsequently detects reflected waves via a receiver. The travel time and energy of received signals are then processed and interpreted. The difference in material properties between limestone and open karst voids causes strong reflections. This work summarizes a series of 2D and 3D GPR surveys for karst void mapping within a mine pillar and within sill pillars between mine levels in a large opening underground limestone mine. In this case study mine, karst voids are hazardous ground control risks that interact with geologic discontinuities, creating free blocks within the rock mass. As tunnels are advanced via blasting, unknown karst voids may be exposed and pose risks to mining personnel. The karst voids also form a hydrogeological network of water reservoirs with spatial locations throughout the rock mass that are difficult to predict with traditional methods such as drilling. While GPR has been utilized throughout several industries for anomaly detection, mapping, and validating other geophysical data sets, this technique has not seen the same proliferation within the mining industry. Regarding published literature, there is a lack of works that detail the applicability of GPR in underground mining scenarios. The aim of this work is to expand on previous methodologies establishing GPR as a useful tool in underground mining applications, and to discuss the benefits and limitations GPR data in such scenarios. / Master of Science / This work focuses on the operational and safety issues associated with karst voids in large opening underground mines. Typical issues include water flooding into the tunnels and rocks falling out from the roof and walls, among other things. Sedimentary rock structures sometimes are geologically complex, and karst voids only add to that complexity. Engineers usually predict karst void locations with drilling or statistics, but this is often challenging as karst voids have various shapes and orientations. Ground penetrating radar (GPR) is a geophysical technique that sends electric signals into the rock; these signals can reflect off of karst voids and other anomalies. The travel time and energy of signals that come back to the antennas are then processed and interpreted. The difference in material properties between limestone and open karst voids causes strong reflections. This work shows a series of 2D and 3D GPR surveys for karst void mapping within a pillar in a stone mine and also below the floor of mine tunnels. In this mine, karst voids are very dangerous and the miners spend significant time and resources to ensure the tunnels walls are stable. As tunnels are blasted, hidden karst voids may be exposed and pose unpredicted risks to miners. The karst voids are also connected by cracks and discontinuities, providing a path for water to travel along. While GPR has been used in various ways among the construction, civil engineering, and tunneling industries, there is not enough literature pertaining to its benefits for mines. The goal of this work is to grow the available literature on GPR in mining and to talk about the best practices for GPR use as a means of improving health and safety for miners underground.

A study was made of the leakage conductance to earth of the neutral of direct-burial concentric-neutral underground primary cable. This study was suggested in conjunction with a paper by Mr. D, L. Stone of the Rural Electrification Administration, "Reduced Concentric Neutral Primary Cable for Underground Rural Distribution." The derivation of an equation for the leakage conductance is presented which takes into account the return of the leakage currents to the neutral of the cable. Calculations were made and are included which show the effects of changes in the leakage conductance of the neutral based on the study. / M.S.

This thesis examines the emergence and current situation of community radio stations in Taiwan, which have been perceived as an important part of a media public sphere for people to access and participate in. It therefore needs to consider community and community radio stations in both Western and Taiwanese contexts, and work by Habermas and others concerning the `public sphere' with reference to the current situation. In-depth interviews, content analysis and document analysis have been used in collecting research data. The factors which influence the development of community radio stations as an aspect of the public sphere in Taiwanese society are shown to be the impact of the state, in the first place, and then commercial market pressures. In addition, the development of communication technology has shown its potential effects by re-defining the meaning of `community' and `radio station'. The research goes on to examine the institution and output of the community radio stations, their interaction with society, and their relationship with their users. We find that the development of community radio stations in Taiwan is characterised by diverse formations: they are public spaces for the members of community to share and discuss public issues; they are hybridised public spheres for people to share personal emotion and talk about private affairs; they are also an expansion of the broadcasting market to further commercial interests. However, this development of community radio stations reflects the social reality of the existing and necessarily plural public spheres

published_or_final_version / Applied Geosciences / Master / Master of Science

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Traditionally, ventilation requirements for modern, mechanized underground mines have been based upon the power of the diesel equipment fleet, with a multiplier (determined from empirical data collected and compiled over a long period of time or required by regulations) being applied in order to determine the total airflow volume requirements of entire mines and/or individual sections or working areas. Often, in the absence of unusual geographic, climatic or geologic conditions that warranted special consideration, the airflow required for the dilution of diesel exhaust products would provide sufficient ventilation for the entire mine. However, recent studies regarding the health-effects of diesel exhaust, particularly the relationship between exposure to diesel emissions and cancer in humans, coupled with additional scrutiny on so called greenhouse gas emissions, have resulted changes to the regulations for engine and equipment manufacturers to provide cleaner burning and less polluting equipment; and are currently causing profound uncertainty in the mining industry. This influence is particularly felt in the case of ventilation engineers and those involved in long-term mine planning who have responsibility for designing the ventilation systems of both existing and future mining projects around the world. This thesis identifies the major parameters affecting airflow requirements for diesel-powered mining equipment and examines how each of them will change in scale and scope in the aftermath of regulatory changes mandating drastic reductions in the type and amount of diesel engine emissions. Culminating from this research, a new procedure for making total airflow determinations based on the underground diesel equipment fleet is proposed and tested with a practical case-study. Ultimately, the determination of the amount of airflow required for an underground mining operation or other sub-surface facility can depend on several factors, including the equipment fleet, ambient temperature, rock type, mining method and airway type (or use). Obtaining a universal, repeatable protocol for determining airflow quantities required for underground diesel equipment fleets is in the best interest of the industry as a whole, including ventilation practitioners, mine-planning engineers, mining financiers, executives, equipment manufacturers, and of course, the mine workers themselves, who perhaps have the most at stake of anyone involved in the equation. / Thesis (Master, Mining Engineering) -- Queen's University, 2013-05-23 22:33:11.36

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering Johannesburg, 29 August 2016 / This study discusses underground coal gasification (UCG) and the analysis thereof. Two main methods were used. The first is the Bond Equivalent Diagram, which gives an ideal of where operations should take place in relation to their coal and product gas compositions. This method was used to analyze several real life sites for their idealized and actual operations. The second consisted of a comparative exergy simulation study. This was done for an air-blown UCG plant with a downstream Fischer-Tropsch reactor and an oxygen-blown UCG plant with upstream air separation. The plants were analyzed by their overall exergy efficiency as well as their exergy outputs with respect to coal inputs (fuel). It was discovered that the air-blown simulation with downstream Fischer-Tropsch was the better choice from an exergy point of view due to it having higher efficiencies (1.5 for overall, 1.38 for fuel) as opposed to the oxygen-blown simulation (0.77 overall, 0.8 for fuel). This coupled with other design and safety factors led to the conclusion that the air-blown simulation was better. / MT2017

Faculty of Health Sciences School of Medical 0212352d dlabuschagne@anglogoldashanti.com / Dust has been recognized as the most serious occupational health hazard across the South African Mining Industry. During 1998 more than 5600 mineworkers were certified with silicosis, a silica related lung disease. The objective of this research project is to describe the trend in respirable dust concentrations in four underground gold mines for the period 1999 to 2002. The mines under discussion are situated in the Klerksdorp area and they were selected because they are a typical representation of deep underground gold mines. Typical gold mines use the same method of ventilation distribution and have similar dust sources e.g. breaking, transporting and tipping of rock. They are all situated in the same geographical area and all make use of conventional mining methods. A total of 4645 previously collected personal respirable dust samples were analysed for this research report making use of a central laboratory situated in the Klerksdorp area. The respirable dust samples were collected by the Occupational Hygienists appointed on the mines for control purposes over the years 1999 to 2002. The arithmetic mean respirable dust concentrations for the four mines in discussion was 0,39mg/m3 in 1999, 0,33mg/m3 in 2000, 0,30mg/m3 in 2001 and 0,31mg/m3 in 2002 against the mine’s internal target of 0,4mg/m3. The report shows a statistically significant downward trend in the proportion of measurements below 0,4mg/m3 for mines 1, 2 and 3. The percentage of respirable dust samples above the internal target of 0,4mg/m3 was 6,78% in 1999, 6,15% in 2000, 4,71% in 2001 and 4,38% in 2002. Although there is a general downwards trend in the percentage of samples above the target, there is an increase in the number of samples above the target. In 1999, 202 samples were above, 310 in 2000, 402 in 2001 and 361 in 2002. The key limitation to the project is the integrity of the data. The major limitations identified include non compliance with the sampling strategy. There is no guarantee that the instrumentations were worn on the body for the whole shift or whether any tampering of the gravimetric pumps took place. The sampling strategy measures all occupations, but all occupations do not receive the same type and amount of exposure, making it impossible to allocate exposure to a certain workplace. Samples could get affected during storage and transport. The most recent audits on the mine’s central laboratory show 100% compliance with the required standards. The mines under study are well in line with the DME requirements on the guidelines for a measurement strategy of airborne pollutants. The gravimetric sampling strategy includes the scheduling of samples managed by the electronic database system. Although the report indicates that the results are pointing in the right direction, the integrity of the data should be tested continuously. Supervision of the pump wearers is of great concern and training of these wearers is essential for explaining the purpose of the personal monitoring strategy. There is a scarcity of published information on respirable dust concentrations in underground gold mines and further research is required.