Cable bolt supports are widely used as ground support in underground hard rock and coal mines. During the last two decades, the cable bolt technology has improved significantly and new types of cable bolts, new grouts and new installation methods and pumps have been introduced and successfully developed. The design of cable bolts is currently attempted by empirical methods based on rockmass characterization. However, until such methods do not take into account all the important parameters affecting the mechanical behaviour of cable bolts namely, the type of cable geometry, grout quality, stiffness of the host medium, the amount of confining pressure and the presence of end anchorage and pretension. / This thesis deals with the numerical modelling of cable bolts considering all of the above mentioned factors. To evaluate the shear bond stiffness of cable bolts, which simulate the interface between the cable bolt and the rockmass, a new empirical model is developed. A database with data of pull-out tests is constructed. Empirical relations were derived between the shear bond stiffness and the variation of confining pressure, the modulus of elasticity of host medium and the water:cement ratio. The relations were derived for three types of cables (standard cable, nutcase cable and garford bulb cable). A new numerical model using the finite element method is developed for the numerical simulation of cable bolts. Together with the empirical model for shear bond stiffness, the numerical model computes the load distribution along the cable bolt and thus can simulate fully grouted, partially grouted, end anchored and tensioned cable bolts. The model is implemented in an existing finite element code (e-z tools). Parametric analyses are performed on the new model, and proved useful in the demonstration of the role of each design parameter. / A new design methodology is proposed to evaluate the load distribution along the cable bolt. Two case studies are presented: a stope hanging-wall support by cable bolt in a hardrock mine and a tailgate secondary supports in a coal mine. A comparison with measurements in the field shows good agreement with computed forces.

A review of automation, robotics and communications technology has established the need for the development of a communications infrastructure capable of supporting future underground hard rock mine automation systems. A series of underground experiments were undertaken at Copper Cliff North Mine to evaluate the design criteria and performance of several communications infrastructures. The work successfully demonstrated the capability of real-time operation of voice, data and stationary video communication as well as surface-to-underground tele-operation of a load-haul-dump machine. This was achieved with a communications system consisting of a broadband bus linked to leaky feeder coaxial cables by means of distributed antenna translators. The success of the trials permitted a strategy for mine automation to be devised. The economic benefits of mine automation were estimated by means of economic models developed for the mine. Projected benefits, evaluated in terms of mining cost reduction, throughput time and quality improvement, were concluded to be significant. As a result of the analysis, future research and development is concluded to be best targeted at improving ore grade, optimizing process productivity and maximizing machine utilization.

The depth at which underground mines operate has been increasing continuously which is particularly true in the case of hard rock mining. The stability issues associated with mining at great depth pose tough challenges to engineers and researchers alike. Long-term mine developments in deep hard rock mines such as haulage drifts need to be functional during the entire life of the mine plan without posing any major stability concerns, which will otherwise hamper the production and other logistics associated with mining operations. High convergence and rockburst hazards are the main problems due to high stress and mining-induced seismicity in deep hard rock mining. In such circumstances, the understanding of drift support behavior under static and dynamic conditions is crucial for mining engineers when dealing with drift stability in deep, hard rock mines. In this thesis, current design methods for selecting drift support systems are reviewed, which are mostly dependent on empirical approaches and are geared towards static support design. Based on this, the current research focuses on ground support analysis under both static and dynamic conditions to understand drift support behavior with respect to nearby mining. Numerical modeling of drift primary and secondary supports is performed by developing two models using the 2-dimensional FLAC code. Axial loads induced in the drift support system under static and dynamic conditions are estimated for the case study hard rock mine in Canada at a depth of 1500 m. The results of numerical modeling are obtained in terms of axial loads in the drift support system, wall damage due to tension under dynamic conditions, and the extent of rock mass yielding around the drift. It is found that mining on the same level is critical to drift stability under static conditions, and rock mass yielding in the south wall of the drift (towards the ore body) extends beyond the bolting horizon once this stage begins. The results also show that by providing secondary support before same level mining commences, drift stability is greatly enhanced. The static model is calibrated through the implementation of an in-situ monitoring program of axial loads induced at the head of the rockbolt. A new load monitoring device called U-cell is successfully used for this purpose. Measured and estimated axial loads are then compared and found to be in good agreement. The preliminary dynamic analysis shows that a peak particle velocity of 2.0 m/s at the periphery of the drift will cause wall damage more than 1.0 m when only primary supports are provided, and around 0.5 m when secondary supports are installed along with the primary ones, and when there is no nearby mining taking place. The effects of lower level and same level mining under dynamic conditions are also examined, and wall damage and rock mass yielding are estimated. The estimation of wall damage depth is crucial in designing dynamic rock supports. It is demonstrated that wall damage due to various levels of ground motion can be estimated by dynamic numerical modeling. Finally, a methodology for the design of dynamic rock supports is presented, which is based on the selection of yielding support type and pattern, the estimation of the ejection velocity, and the volume of wall damage as obtained from dynamic modeling. / La profondeur des mines souterraines a augmenté de manière continue, particulièrement en ce qui concerne les mines en roches dures. Les problèmes de stabilité associés aux mines profondes représentent comme des defis pour les exploitants, comme pour les chercheurs. Les développements miniers à longue durée de vie dans les mines profondes, tels que les galléries de roulage, doivent rester fonctionnels pour toute la durée de l'exploitation, sans poser de soucis majeurs, qui, sinon, nuiraient à la productivité et à l'organisation des opérations minières. Les fortes convergences et le risque de coup de terrain constituent les principaux problèmes dus aux fortes concentrations de contraintes et à la sismicité minière induite dans les mines profondes en roches dures. Dans de telles circonstances, la compréhension du comportement du soutènement des galeries sous l'effet de chargements statiques et dynamiques est essentielle pour les ingénieurs miniers confrontés aux questions de stabilité dans les mines profondes en roches dures. Dans cette thèse, nous exposons les méthodes courantes de dimensionnement du soutènement des galeries, qui reposent principalement sur des approches empiriques et ont pour objectif d'assurer la stabilité sous chargement statique. Sur cette base, la recherche se concentre sur des méthodes de dimensionnement du soutènement sous des charges statiques et dynamiques, dans le but de comprendre le comportement du soutènement des galeries adjacentes aux zones en cours d'exploitation. La modélisation numérique du soutènement primaire et secondaire des galeries est réalisée en développant deux méthodes recourant au code bidimensionnel FLAC. Les charges axiales dans le soutènement des galeries sont estimées sous des sollicitations statiques et dynamiques, dans le cas d'une mine canadienne en roche dure, à 1500 m de profondeur. Les résultats de la modélisation numérique sont présentés en termes de charge axiale dans le soutènement, d'endommagement des parois sous l'effet des tractions induites par les sollicitations dynamiques et de l'extension de la zone rompue autour des galeries. Nous montrons ainsi que l'exploitation sur le même niveau a des conséquences importantes sur la stabilité des galeries en chargement statique, et qu'au niveau du parement sud (i.e. du côté du gisement), la zone rompue s'étend au-delà de la longueur des boulons au début de cette étape. Les résultats montrent aussi que la stabilité de la galerie de roulage est très nettement améliorée si un soutènement secondaire est mis en œuvre lorsque commence l'exploitation sur le même niveau. Le modèle statique est calibré en utilisant des mesures in situ de la charge axiale sur les têtes de boulons. Pour ce faire, un nouveau dispositif de mesure de la charge, appelé « U-cell » a été utilisé avec succès. Les mesures de charge et les résultats de la modélisation sont comparés et sont en bon accord. L'étude dynamique préliminaire montre que des vitesses de points matériels de l'ordre de 2.0 m/s à la périphérie de la galerie de roulage induisent un endommagement au delà de 1.0 m de profondeur lorsque seul le soutènement primaire est mis en œuvre, et au delà de 0.5 m lorsqu'un soutènement secondaire est installé, pour peu qu'il n'y ait pas de zone en exploitation à proximité. Les effets de l'exploitation sur le même niveau et sur un niveau inférieur sont également comparés; l'endommagement des parois et la rupture de massifs rocheux sont estimés. L'estimation de l'endommagement de la paroi est essentielle afin de dimensionner le soutènement dynamique. On montre que l'endommagement de la paroi peut être estimé par modélisation numérique, pour différents niveaux de vitesses du terrain. Pour finir, une méthodologie pour le dimensionnement du soutènement dynamique est présentée; elle est basée sur la sélection du type et de la géométrie du soutènement. La vitesse d'éjection et l'endommagement de la paroi sont estimés par modélisation numérique.

Mine developments such as haulage drifts and cross-cuts are the primary access to the mining blocks of an orebody in multilevel mining systems for tabular ore deposits. Thus, their stability is of utmost importance during the planned period of production or the life of a mine plan. Many Canadian underground mines use longitudinal and transverse stoping with delayed backfill to extract tabular ore deposits. These methods require access to the orebody through a number of sill drives or cross-cuts which link the orezone to the haulage drift hence creating intersections on multiple levels. Mine development instability could lead to serious consequences such as injuries, production delays and higher operational cost. The objective of this research is to develop a hybrid approach in which deterministic numerical modelling is integrated with probabilistic methods to evaluate the stability of mine developments due to nearby mining activity. A case study comprising four consecutive mine levels in a deep underground metal mine in Sudbury, Ontario has been adopted for this study. The stability performance of the haulage drift is assessed using two separate evaluation criteria, namely Mohr-Coulomb yield function and Brittle Shear Failure. Random Monte-Carlo (RMC) technique is then employed in conjunction with Finite difference modelling software FLAC to determine the probability of instability or unsatisfactory performance of the haulage drift with respect to nearby mining sequence. In this study, the haulage drift performance is considered unsatisfactory when the yield zones or brittle shear failure around the haulage drift extend beyond the anchorage limit of the rock support. A comparison of the results from Mohr-Coulomb and Brittle Shear conditions has revealed that Mohr-Coulomb is more conservative from a design point of view. A three-dimensional, elastoplastic, finite difference model (FLAC 3D) is then constructed to simulate the case study mining orezone. The unsatisfactory performance of the intersection is evaluated with respect to mining sequence in terms of the strength-to-stress ratio computed by FLAC3D. Unsatisfactory stability performance is defined by a strength-to-stress ratio that is less than 1.4 and its corresponding extent into the rockmass around the intersection. Due to the large size of the FLAC3D model, the probabilistic simulations are conducted with the Point-Estimate Method (PEM), which requires significantly lesser number of simulations than Random Monte-Carlo (RMC). The results are presented and categorized with respect to probability, instability, and mining stage. In order to validate the numerical model, Multi-point borehole extensometers (MPBX) are installed at selected intersections to monitor the rock deformations as mining activities progress. The monitoring results revealed a lateral shift of the drift walls toward the orebody and much less deformations in the drift back. Finally, a methodology is developed to estimate the geotechnical risk of drift instability by considering the probability of failure and cost of consequence of such failure at an intersection. A 5-level risk index is derived which ranges from low to extreme. The methodology is demonstrated through an intersection from the case study mine, and the risk index is shown to vary with mining sequence. It is shown that the risk-index methodology can be used to confirm the need for enhanced supports, but it can also be used as basis for the comparison alternative mine designs. / Les développements miniers tels que les galeries de roulage et les travers-bancs constituent les accès principaux au gisement lors de l'exploitation d'un gisement tabulaire sur plusieurs niveaux. C'est pourquoi leur stabilité est d'une importance primordiale pendant la période de production ou pendant la planification d'une l'exploitation. De nombreuses mines souterraines canadiennes emploient des méthodes d'abatage par chambres avec remblayage différé pour exploiter les gisements tabulaires. Ces méthodes nécessitent un accès au gisement par de nombreux travers-bancs qui relient le gisement aux galeries de roulage, créant des intersections à de nombreux niveaux. L'instabilité de ces galeries peut conduire à de graves conséquences mettant en jeu la sécurité du personnel, à des retards de production et à des couts d'opération plus importants. L'objectif de cette recherche est de développer une approche hybride, basée sur une modélisation numérique déterministe intégrant des méthodes probabilistes, pour évaluer la stabilité d'une galerie d'avancement en fonction de la proximité de l'activité minière. Nous présentons une application à une mine métallique située à Sudbury, en Ontario, dans laquelle l'exploitation est réalisée sur 4 sous-niveaux.La stabilité d'une galerie de roulage est calculée à partir des 2 critères suivants: critère de plasticité de Mohr-Coulomb et « Brittle Shear Failure ». La méthode de simulation aléatoire de Monte Carlo (RMC) est utilisée conjointement avec le logiciel de différences finies FLAC pour déterminer la probabilité d'instabilité de la galerie de roulage en fonction de la séquence d'exploitation choisie. La stabilité de la galerie de roulage est considérée comme non satisfaisante dès lors que la zone de plasticité autour de la galerie excède la longueur des boulons. Une comparaison entre les critères d'évaluation montre que le critère de plasticité est le plus sécuritaire pour témoigner de l'influence de la séquence d'exploitation. Un modèle élasto-plastique en 3 dimensions, calculé par la méthode des différences finies (FLAC-3D), est crée pour simuler le cas d'application. La performance insatisfaisante d'une intersection est évaluée au moyen du ratio contrainte/résistance. La stabilité non satisfaisante est définie par un ratio inférieur au seuil de 1,4 et par l'étendue de la zone correspondante autour de l'intersection. Du fait de la grande taille du modèle numérique, les simulations probabilistes sont réalisées avec la méthode d'estimation ponctuelle qui nécessite un nombre significativement moins important de calculs que la méthode de Monte-Carlo aléatoire. Les résultats sont présentés et classés selon leurs probabilités, leur degré d'instabilité et l'état d'avancement de la séquence d'exploitation. Des extensomètres de forage à points de mesure multiples (MPBX) sont utilisés pour mesurer les déformations rocheuses d'une intersection au fur et à mesure de l'excavation. Les résultats sont utilisés pour calibrer le modèle FLAC-3D. L'auscultation a montré l'existence d'un déplacement latéral des parois de la galerie de roulage en direction du gisement et une déformation moindre du toit. Le coût des conséquences de la rupture d'une intersection est estimé par le cout de développement d'un contournement. Une échelle de risque à 5 niveaux, allant de « faible » à « extrême », est proposée. Cette échelle de risque est appliquée à une intersection de la mine étudiée et on montre que le niveau de risque dépend de la séquence d'exploitation. On montre également que cette méthodologie peut être mise en œuvre afin de confirmer la nécessité d'un soutènement amélioré. Elle peut aussi servir pour la comparaison entre différentes méthodes d'exploitation.

One of the main problems facing mining engineers when dealing with deep, hard rock mines is to prevent and/or reduce rockburst hazard around mine openings. Rockburst is a phenomenon which is characterised by violent rock failure. The current research focuses on the assessment and control of rockbursts in deep, hard rock mines. / Strainbursts, or strain-type rockbursts, occur in the vicinity of mine openings and are generally provoked by high stress conditions in a brittle rock mass. A new theory has been developed for the assessment of the potential of violent rock failure by strainburst, in underground hard rock mines. In this theory, the mining-induced energy parameters are used to calculate the so-called burst potential index (BPI). When the BPI reaches or exceeds 100%, the method predicts a burst prone situation. One of the most commonly used methods to control strainbursts in hard rock mines is destress blasting. / Motivated by the lack of a dedicated analysis tool to help assess destress blasting, a new, geomechanical model was developed. The technique employs two newly introduced parameters, alpha, a rock fragmentation factor, and beta, a stress dissipation factor, inside the modelled, fractured zone. Implemented in a 3-dimensional finite element code developed by the author, the new model simulates the damage zone induced by destress blasting of a mining face to help evaluate the efficiency of destress blasting. Extensive model verification and parametric studies have been undertaken. The effects of the destress blasting pattern, premining stresses and their orientation, and the two destress blasting factors (rock fragmentation factor, and stress dissipation factor) are studied. The model has been applied successfully to Canadian mine case histories. A detailed case study of a cut-and-fill mine stope involving crown and sill pillar destressing has been carried out. It is shown that the new method can be useful in the assessment of destress blasting in deep drift face development and the crown/sill pillar problems in cut-and-fill mine stopes.

Mining operations produce large amounts of tailings that are either disposed of in surface impoundments or used in the production of backfill to be placed underground. Their mineralogy is determined by the local geology, and it is not uncommon to come across tailings with a relatively high sulphide mineral content, including pyrite and pyrrhotite. Sulphides oxidize in the presence of oxygen and water to produce sulphate and acidity. In the concrete industry, sulphate is known to produce detrimental effects by reacting with the cement paste to produce the minerals ettringite and gypsum. Because mine backfill uses tailings and binders – including cement – it is therefore prone to sulphate attack where the required conditions are met. Currently, laboratory tests on mine backfill mostly measure mechanical properties such as strength parameters, and the study of the chemical aspects is restricted to the impact of tailings on the environment. The potential of sulphate attack in mine backfill has not been studied at length, and no tests are conducted on binders used in backfill for their resistance to attack. Current ASTM guidelines for sulphate attack tests have been deemed inadequate by several authors due to their measurement of only expansion as an indicator of attack. Furthermore, the tests take too long to perform or are restricted to cement mortars only, and not to mixed binders that include pozzolans. Based on these, an accelerated test for sulphate attack was developed in this work through modifying and compiling procedures that had been suggested by different authors. Small cubes of two different binders were fully immersed in daily-monitored sodium sulphate and sulphuric acid solutions for a total of 28 days, after 7 days of accelerated curing at 50ºC. In addition, four binders were partially immersed in the same solutions for 8 days for an accelerated attack process. The two procedures were conducted in tandem with leach tests using a mixed solution of / Les opérations minières produisent de grandes quantités de rejets miniers qui sont soit stockés en surface dans des haldes, soit réutilisés comme remblais sous terre. La minéralogie de ces déchets est dictée par la géologie des lieux, et il est commun de trouver des rejets qui ont une teneur élevée en minéraux sulfurés comme la pyrite et la pyrrhotite. Les sulfures sont oxydés en présence d’eau et d’oxygène et produisent une eau acide et riche en sulfates. Dans l’industrie du béton, un des grands problèmes provient de la réaction des sulfates de sources externes avec le ciment du béton pour former de l’ettringite et du gypse. Étant donné que les remblais dans les mines se servent des rejets et d’agents de liaison comme le ciment, ils sont sensibles aux attaques des sulfates si les conditions sont propices. En ce moment dans les laboratoires, on s’intéresse surtout aux paramètres mécaniques comme la résistance en compression et l’impact chimique que les rejets miniers ont sur l’environnement. Aucune recherche concrète n’a été faite sur les dangers de l’attaque des sulfates sur les remblais dans les mines et sur les différents agents de liaisons, afin de déterminer leurs résistances à de telles attaques.Les directives actuelles de l’ASTM pour tester l’attaque des sulfates se sont avérées inadéquates. En effet, ces tests sont seulement basés sur l’expansion, ce qui ne se produit pas forcément lors de l’attaque par des sulfates. De plus, ces tests sont trop longs et ne peuvent s’appliquer qu’à certains mélanges spécifiques de ciment et pas à d’autres comme la pouzzolane. Sur ces faits, un test accéléré a été mis en place par certains chercheurs. Après un séchage accéléré dans un four à 50ºC, des échantillons sont immergés dans des solutions de sulfate de sodium et d’acide sulfurique pendant 28 jours d’une part. D’autre part, d’autres échantillons sont immergés à moi

Tunnelling machines are utilized for many types of excavations in mining and civil engineering applications. To date, the control of tunnelling machines has not been automated to any significant extent. This thesis investigates the dynamic control of a vertical turret, boom-type tunnelling machine. Models of the actuators, kinematics, rigid body dynamics, and cutter-rock interaction are formulated. These models are validated through computer simulation. Controllers are then designed for the actuators using the pole-placement technique, in both continuous and discrete time. The controllers are tested in a variety of operational modes, using the computer simulation of the machine model. Results show that good tracking and disturbance rejection is achieved.

Note: / The object of the present thesis was the development of a mathematical model suitable for computer simulation of hydrometallurgical processes. The model formulation was made for a strongly exothermic three-phase reaction system, namely the pressure oxidation process as applied to the treatment of refractory gold ores and concentrates. The steps followed during the course of this work involved first, the experimental identification of the intrinsic kinetics of the two principal refractory gold minerals, arsenopyrite and pyrite, and second, the development of reactor models describing the isothermal and non-isothermal behaviour of batch and multi-stage continuous reactors at steady state. Emphasis was given to the identification of feed conditions for autothermal operation.The key features of the developed model are the coupling of both mass and heat balance equations, the description of the non-isothermal performance of a multistage continuous reactor, and the treatment of a two-mineral mixture concentrate. In addition, continuous functions are used to describe the size distribution of reacting particles and gas-liquid mass transfer rate limitations are assessed.The model predictions were in good agreement with pilot-plant scale industrial data. Simulation runs of alternative reactor configurations and feed compositions elucidated the impact of the size of the first reactor stage, the rate limiting regime, and the sulphur content of the feed on the attainment of autogenous performance. / Le but de cette etude etait de developper un modele mathematique pour la simulation par ordinateur des processus hydrometallurgiques. La formulation du modele a ete faite pour un systeme de reaction de trois phases fortement exothermique, Ie processus d'oxidation sous pression applique au traitement des minerais et des concentres refract aires d'or. Les etapes suivies au cours de cette etude necessitaient premierement l'identification experiment ale de la cinetique intrinseque des deux principaux mineraux d'or, l'arsenopyrite et la pyrite, et par la suite, Ie developpement de modeies de reacteurs decrivant Ie comportement isothermique et non-isothermique de reacteurs en discontinu et de reacteurs en sene continus a Petat d'equilibre. L'emphase a ete donnee al'identification des conditions d'alimentation pouvant produire une operation autothermique.Les principales caracteristiques du modele developpe sont: la combinaison de deux equations d'equilibre de la masse et de la chaleur, la description de la performance non-isothermique de reacteurs en serie continus, Ie traitement d'un con centre d'unmeiange des deux mineraux, l'emploi de fonctions [...]

Dissolution, rest potential, cyclic voltammetry and contact angle studies have been conducted on the components of INCO matte, chalcocite (Cu4$ sb{2}$S) and heazlewoodite (Ni$ sb{3}$S$ sb{2}$), in water and collector solutions. / Dissolution of Ni from heazlewoodite was observed at pH .25 V. A reaction for MBT on chalcocite at $-$0.06 V, not reported previously, was proposed. / Contact angle measurements were performed with chalcocite and heazlewoodite in the presence of 2 $ times$ 10$ sp{-3}$ M NaEX over a range of potential and pH values. A significant difference in contact angle between chalcocite and heazlewoodite was observed. There was general agreement between cyclic voltammograms and contact angle measurements: For example, the contact angle on Cu$ sb{2}$S in the presence of NaEX increased significantly at the potential range corresponding to passivation. No bubble contact was observed in the presence of 2 $ times$ 10$ sp{-3}$ M MBT.

This thesis explores the possibility of using both miniature reflection (MSR-IE) and Ultrasonic (PUNDIT) techniques for the appraisal of paste backfill. / The use of paste backfill is gaining popularity, however various technical, environmental and regulatory constraints complexify the study of its behaviour. There are various laboratory experiments available for the appraisal of this material; however the results do not necessarily correspond to its in-situ response. The main objective of this experimentation is to evaluate the quality of the fill by the study of its P-wave velocity, hence establish a relationship between the curing-time, strength and P-wave velocity of the material. This preliminary analysis in the field of mining demonstrates the possibility of finding an easy, reliable and cost effective in-situ method of appraising paste backfill. / Given the complexity of the research project, the work focuses on correlating the quality of the paste fill, with the MSR-IE and PUNDIT systems, in a laboratory environment. The results demonstrate the potential of the MSR-IE investigation on Paste backfill and the near future possibility of in-situ testing with this method.