Current methods for assessing the integrity of ground anchorages during service are primarily restricted to monitoring by load cells or load lift-off testing. Both are expensive and lift-off testing is time consuming and can damage the anchorage construction below the anchor head. Hence, only typically 5-10% of anchorages are monitored in service. As a result, The Institution of Civil Engineers reported that non-destructive test methods for ground anchorages need to be developed as a high priority (ICE, 1992). The Universities o f Aberdeen and Bradford have been conducting research since 1986 to investigate the response o f rock anchorages to dynamic loading arising from blasting operations. Full scale field trials were conducted during the construction of two tunnels in North Wales. An important finding from the research revealed that certain characteristics of the dynamic response of a rock bolt resulting from blasting operations, were similar for different blast sequences. This indicates that the dynamic response o f an anchorage system is dependant on the construction of the anchorage and the characteristics of the co-vibrating rock mass. Consequently, the University of Aberdeen has developed a new non-destructive condition monitoring and integrity assessment system for ground anchorages (GRANIT ™). A range of patent applications have been successful world-wide and the system has been exclusively licensed to AMEC Civil Engineering Limited. The system operates by applying an axial tensile impact load to the free end of an intact anchorage immediately after installation. The resulting vibrational response is monitored by an accelerometer, located at the anchorage head, which produces a datum signature for that anchorage. The condition of the anchorage is then inferred by comparing subsequent response signatures with the datum. A change in the signature indicates that there may be a potential change in the integrity of the anchorage. Artificial Intelligence systems are employed to compare response signatures. As part of the research programme, the author conducted commissioning tests on small scale laboratory test rigs and was responsible for the development of a prototype non-destructive test system, which included a means of applying an impact load and recording the vibrational response. In addition, the author conducted full scale laboratory tests and field trials to investigate the effect of prestress on the dynamic response of ground anchorage systems. As a result, the prototype non-destructive test system has been employed to successfully predict the amount of load within an anchorage installation.

M.Sc. (Geology) / Analyses show that the effect of inter-panel lag on hanging wall instability is an important factor affecting rock-fall accidents and production losses in gold mines utilising segmented longwall mining methods. The study emphasises the effect of inter-panel lag on the development of mining-induced fractures which are considered a major contributor to hangingwall instability in geologically undisturbed ground. The geology and mining geometry at Western Deep Levels, Limited, particularly at the selected research site, is outlined. The data collection, which is facilitated by the use of stereo-photogrammetry and computer-aided data handling, is described. Three types of mining-induced fracture are evident. The effects of inter-panel lag and geological inhomogeneity on the orientation and density of the mining-induced fractures are illustrated and discussed. The effects of inter-panel lag length on energy release rate are demonstrated and discussed. Microseismic event location data analyses are used to elucidate the fracturing process that takes place in the rock ahead of the mine face. Practical suggestions regarding the reduction in number and length of inter-panel lags are made, in the light of recent developments in the field of rock-burst control.

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A research report submitted to the Faculty of Engineering and the Built Environment, School of Mechanical, Industrial and Aeronautical Engineering, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Engineering. / This study was based on the hypothesis that there are opportunities to maximize production outputs in many existing underground hard rock trackless mining systems using the same or less resources by improvement in decision making paradigms. This is very important in the current operating environments of uncertainties and continued drop in metal prices. The project main goal was thus to carry out a detailed investigation of trackless mining production systems and test how to maximize output by focusing on three objectives, namely: analyzing key technical factors that impact the production rates in terms of tons per hour, identifying major operational activities which impact effective equipment operating hours, and identifying decision support systems (DSS) to improve operational decision making. Regarding the first objective (production rates), through the analysis of trackless mining as a serial production system, it was shown that production rates could be increased by focusing at system level, process level and work station/equipment level decisions. System level decisions must minimize the total residence time of the material (ore) in transit or work in process(WIP). This will open capacity for generating more ore. Process level decisions must reduce the gross cycle times at the work stations to equal or be below the Takt times inorder to smoothen production flow. Takt time is an important factor in a production system which shows the maximum cycle time allowed to meet the daily demand. The third level focuses on the capability of the mining equipment itself through decisions that improves the reliability, maintainability and capacity. Decision tables based on reducing the equipment failure rates (λ), improving the repair rates (µ) and the cycle times were developed to aid in making the reliability, maintainability or capacity decisions. For the second objective (operational activities), the focus is to maximize effective operating times of the equipment through reduction of delays. The study shows this can be achieved through use of real-time decision support systems (DSS) for better control of the operations. The third objective was able to identify functional modern DSS that can be implemented in trackless mining. Effectively, the study was able to highlight opportunities of generating extra capacity for trackless mines at same or less resources by focusing on the above three objectives. / TL2019

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A knowledge of the mechanical behavior of geologic materials (rocks and minerals) has become increasingly important in mining and civil engineering, geology, geophysics and more recently in a number of defense and aerospace fields. This research describes an investigation of one particular aspect of the mechanical behavior of these materials namely the determination of their inelastic properties. The investigation consisted of two stages; first, the development of suitable test facilities and experimental techniques, and second, the detailed study of the deformation properties of a relatively simple geologic materials namely, Wombeyan marble. / Ph. D.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy