Regardless of the objective sought, the conclusions drawn from seismic monitoring can only be as good as the quality of the recorded data: the importance of properly capturing relevant raw vibrational information in the first place is thus absolutely crucial. The difficulty is that blast-induced vibration monitoring is site specific and that general formulas do not apply: every situation will correspond to a unique combination of objectives, ground conditions, blast design and explosive types, and will need to be monitored accordingly. To adequately acquire all the pertinent seismic information, a number of points must be successfully addressed, such as the choice of sensors, their location, number, orientation and anchoring, the transmission of the captured signals from these gauges to the recording equipment, and the choice and set-up of the data acquisition system. / It is the purpose of this thesis to address these questions in some detail, in an attempt to provide the reader with an understanding of how all the components involved in blast-induced vibration monitoring interact, and on how the choices made at each step can significantly affect overall results. (Abstract shortened by UMI.)

The steeply dipping vein orebody of Bousquet 2 mine is extracted by sublevel open stope method. The presence of structural discontinuities, high induced stress distribution, and narrow stope widths are major factors which can seriously affect ore dilution. Therefore, strict ore dilution control is necessary in order to keep the mine competitive. The thesis describes the selective mining method adapted to this type of orebody, and subsequent measures taken to minimize ore dilution. For this study, the locations of stress relaxation are taken as failures zones. Therefore, these zones are more important since they are subjected to very low stresses which can provoke rock block sliding or local wall caving (tension failure). Tracing the zone of tensile stress in the stope wall gives reasonable prediction of dilution and permits to calibrate the numerical model using the field data obtained from the cavity Monitoring System (CMS). Stope mining is made in several cuts according to the width of the ore zone. For an improved recovery, some stopes are mined using primary and secondary stoping. Blasthole pattern and mining sequences are closely linked to the ore zone configuration. The main causes of ore dilution are summarized. They are a combination of several factors such as ground conditions, blasting damage, state of stresses around the stope, and stope design. In order to minimize ore dilution from hanging-wall and foot-wall, cable support is installed. Numerical modelling is carried out for a typical cable bolt pattern. The results of modelling have demonstrated that the cable bolts were necessary to control hanging wall caving. This is accompanied by a reduction of ore dilution. Consequently the study has shown the effectiveness of cables bolt as pre-support of the schistose walls in Bousquet sublevel stoping environment.

Isolated high grade and low tonnage uranium ore pods are prevalent in Saskatchewan. This thesis reviews mining such a pod with both conventional and unconventional methods. The geomechanical characteristics of the overburden and the bedrock in the area of the pods must be investigated before evaluating the technical feasibility of possible mining methods. Conventional ore recovery techniques appraised include open pit and underground mining. The unconventional mining techniques considered are blind boring and jet boring from surface. These last two techniques can offer a greater degree of selectivity, although ground reinforcement techniques had to be considered due to the poor quality of the ground. Ground reinforcement techniques considered were shaft lining, grouting, and ground freezing. This mining design challenge was found to be feasible with the combination of jet boring and freezing. Recommendations are presented to define future areas of study for blind boring, jet boring, grouting, and freezing.

Composite material tendons are considered in this thesis as interior ground support for underground excavations. The physical and mechanical properties of composite tendons critical to mining requirements were identified. Preliminary laboratory investigations were also undertaken to evaluate their performance as fully grouted reinforcing tendons. Arapree, a flexible tendon, and Weldgrip, a solid tendon, are the two patented composite tendons found to be superior in pull out testing. Their load carrying capacity and ductility in the elastic range is similar to that of existing steel supports, although their post peak performance is different. Rigid composite bolts have more load sustaining capacity than their steel counterparts, while flexible composite tendons have less capacity than conventional seven wire flexible steel cable. The shear capacity of fully grouted Weldgrip bolts was found to be in the range of 100 kN. As part of studies of flexible tendons, conventional steel cable was also used to investigate other parameters, since it was found to be identical in pull out behaviour to composite flexible cable. It was found that the effect of grout strength and modulus, radial confinement and host medium strength and stiffness is significant in controlling the performance of steel cable. The laboratory investigation also found that different grouting materials, such as conventional to high strength cement grout and polyester resin grout greatly influence the pull out performance of both steel and composite tendons.

Disposal of acid generating sulphidic tailings is a major environmental problem facing the Canadian as well as the international mining and mineral industries. If the deposited tailings are not treated the sulphide minerals oxidise and create an acidic environment. The leachate from such a site is rich in soluble heavy metals and has the potential to contaminate the groundwater as well as the local surface watercourses. This thesis explores an alternative treatment method via ettringite formation, which stabilises and solidifies these highly reactive tailings. / Ettringite has the capacity of uptaking other metals into its structure by isomorphous substitution. Ettringite has also a negative surface charge, which makes it a good adsorbent for positively charged cations. Furthermore, the high pH solution required for ettringite formation will cause the precipitation of heavy metals from the solution. Therefore, ettringite in a lime-remediated sulphate rich acid mine drainage system could serve as a physical and chemical stabilization agent, which could also reduce the remediation costs over other commercially available stabilization technology. / In order to assess the feasibility of forming ettringite in sulphide rich tailings, a thermodynamic model was used to investigate the optimal geochemical parameters. The model predicts that ettringite is stable over a wide range of compositions and pH. Results presented in this thesis show that the sulphate content of the tailings samples could limit the precipitation of ettringite, and monosulphate could be the end-precipitate. / Long-term leachability and durability analysis showed that ettringite can be formed as a stable mineral in lime, fly ash, and aluminum rich sulphidic tailings samples. Ettringite formation reduced the leachability of the heavy metals and improved the geotechnical characteristics of the treated samples. Freeze and thaw analyses showed that formation of ettringite produce a low permeability and high strength tailings sample capable of withstanding harsh environmental fluctuations.

This thesis aims to develop a comprehensive strategy for automatic control of the ITH percussive drilling process. Such automation would provide the benefits of improved productivity and quality in terms of penetration rate and hole deviation, as well as enhanced hole quality and machine life. / Analysis of field data acquired from drilling experiments performed at INCO's Little Stobie Mine is presented. As a result of this analysis, a control algorithm is formulated to enhance the drilling process efficiency. This algorithm calculates the specific energy (SE) of the rock and adjusts the applied feed force based on this SE value, using a relationship obtained from the field data analysis. / A model of the percussive drilling process is developed and simulated in software. The proposed control algorithm is tested through simulations on this simulated drilling process. The results of the simulation show a significant increase in efficiency of the drilling process. / As a result of vibration data analysis it is concluded that vibration should be controlled through an improved design of the shock-absorber, rather than through drilling variables. A detailed shock-absorber test data analysis is therefore presented. Recommendations for design changes in the shock-absorber are also given. / Deviation analysis is also presented in the thesis, which shows a poor correlation between the machine variables and the hole deviation data. Hence, it is recommended that deviation be controlled by steering. An innovative guided drilling mechanism for controlling the hole deviation is also proposed. This mechanism consists of an eccentric ITH percussive hammer with controlled rotational speed, which can be employed as an actuator to steer the drill string in a desired direction without using any down hole instrumentation. Modelling and simulation analysis of this system is also presented.

A method to determine the amount of gravity recoverable gold in an ore sample with a 7.5 cm (3 inch) Knelson Centrifugal Concentrator is presented. The method is based on sequential comminution and recovery steps, the first at 100% $-$841 $ mu$m, the second at approximately 50% $-$74 $ mu$m and the third at final grind (typically 75 to 90% $-$74 $ mu$m). The mass processed depends on the gold grade and particle size, and commonly varies from 25 to 100 kg. / The method was used to determine the gravity recoverable gold in nine different ore samples. The grade of these ores ranged from 3 g/t to 45 g/t. Both massive sulfide and silicate ores were tested. Gold in the ores ranged from fine (90% $-$210 $ mu$m) to coarse (60% +841 $ mu$m). The amount of gravity recoverable gold ranged from 29 to 93%. Results from the proposed test compare favorably with mineralogical studies and data from industrial gravity recovery circuits. Some problems arose while testing the various ores; minor adjustments to the procedure were made to correct these. These corrections and other caveats for the test procedure are discussed. / This test yields an essential component of an algorithm that can be used to predict the amount of gold that can be recovered by installing a gravity circuit. This algorithm is referenced and an example of its use is included. Information from the test can be used to evaluate circuit performance and indicate if the performance is equipment or process limited. The test will quickly indicate if a gravity circuit is an option. / Results indicate that sizing material before it is processed with a Laboratory Knelson Concentrator leads to significant increases in recovery (48% without screen to 64% with). Industrial results are not yet available to verify this.

Pickforce sensing is a method demonstrating a promising future in automating coal mining machines. The method is based on the ability to determine the vertical location of a rotary cutting machine from the force measured at the point of contact between the machine and the coal seam. A major problem that may degrade the reliability of the pickforce data is vibration and is the major concern of this study. To analyze the effects of vibration on pickforce sensing, a vibration model of the cutting process is first developed. Then, a stochastic model of the coal seam is constructed. Subsequently, the vibration model is simulated in three stages. In these stages, the machine is assumed to be cutting through three types of coal seam: homogeneous, predetermined heterogeneous, and heterogeneous stochastic model. The first stage is conducted to prove that pickforce data always contains a degree of phase shift between successive half revolutions. This eliminates the effect of repetitive or orderly vibration that may mask the pickforce data. In addition, both the first and second stages are conducted to find ways to improve the reliability of pickforce data by adjusting a few parameters within the machine. The third stage is conducted to prove that the chaotic appearance of the pickforce data does not eliminate the features that are used to determine the vertical location. The present study concludes that vibration has a minor effect, and that pickforce sensing can be improved by adjusting some parameters of the cutting machine.

A new approach to underground excavation design at INCO's Manitoba Division was undertaken by incorporating ground and support monitoring, and numerical modelling into an empirical framework. / In the first phase of the study, a field measurement geomechanics guideline was developed for the Manitoba Division. Work in instrumentation led to the development of a new cable bolt monitoring device by INCO Ltd. and McGill University. This device has the ability to measure cable bolt performance reliably and at a low cost. As a result, a cost efficient and effective program is being implemented to monitor cable bolt layouts representatively. / The second phase of the project utilizes the computational power of numerical modelling to aid mine design of stope backs. Results from numerical modelling, presented in the form of stress signatures, suggest that there might be a correlation between back surface stability and calculated values of major and minor principal stresses. / By adding the tools of numerical modelling and instrumentation to traditional rock characterization data, a new data base for empirical modelling is established. The continual expansion of this database will lead to a more comprehensive approach to stope back design in the future.

This thesis reports the formulation and implementation of a finite element model, which is based on the so called Hybrid Stress Finite Element Method. The proposed formulation is based on stress as the primary unknown and is radically different from displacement-based finite element models. / Among the special features of the model are the casting of the element stiffness equations in terms of local rather than global coordinate system, the use of the active column method known as the "Skyline technique for the solution of equilibrium equations", and the use of fast and efficient mesh generation and alteration routines developed specially for geotechnical applications. / Verification tests carried out on problems in elasticity with closed form solutions show that the proposed method is accurate and that it requires relatively fewer elements than displacement-based finite element method to achieve the same accuracy. Results of case history studies done on two mine design problems matched those from other numerical modelling procedures within acceptable limits and showed that the proposed method can be used to solve geomechanics problems efficiently and realistically.