Micro- and batch flotation tests were conducted to explore the use of silica sol to control metal ions to reduce accidental activation and misplacement of minerals. As a comparison other 'metal control reagents', ethylenediaminetetraacetic acid (EDTA) and polyphosphate were also tested. X-ray photoelectron spectroscopy (XPS) was used to probe the silica sol-mineral interaction mechanism. / Micro flotation was performed on single mineral samples over a pH range 7 to 11. It was found that silica sol depressed all Cu minerals, Cu and Pb activated pyrite and Pb activated sphalerite but did not depress Cu activated sphalerite. XPS analysis revealed that silica sol adsorbed on all Cu minerals and Cu and Pb activated pyrite. Silica sol partially removed Pb from Pb activated sphalerite and had no apparent interaction with Cu activated sphalerite. The depressant action, therefore, appeared to be primarily adsorption of silica sol to form hydrophilic sites. / In the batch tests, generally, silica sol, polyphosphate and EDTA increased the rate of flotation in the Cu stage and in the Zn stage. This is attributed to removal of hydrophilic metal hydroxy species, i.e., surface 'cleaning'. Polyphosphate, and to a lesser extent EDTA, improved selectivity in the Zn stage for Les Mines Selbaie and Mine Louvicourt and arguably for Hudson Bay Mining and Smelting. This selectivity was not identified in the trials at Brunswick Mine directly on Zn stage flotation feed. The varying effect of polyphosphate on selectivity is attributed to the level of 'excess Cu' used in Zn activation: the higher the excess, the greater the effect of polyphosphate. In conclusion, silica sol has some metal ion control capability but seems less attractive in this role than say polyphosphate.

A field trial was conducted to demonstrate the applicability of a self-boring pressuremeter probe for in situ testing of cemented paste backfill. This technology proved to be efficient in evaluating behaviour of in situ conditions of mine backfill underground. Effectively, laboratory experience shows that it is not possible to insure that all physical and mechanical conditions prevailing underground are respected when samples are prepared and tested in the lab. Moreover, sampling by coring backfill underground proved to be sometimes not very efficient and the question of sample disturbance is a major concern. / This thesis aims at presenting the considerations leading to the probe selection and the technical aspects related to conducting pressuremeter tests in an underground mine. A preliminary analysis of the experimental pressuremeter curves is presented with the derived in situ properties obtained from a paste backfill in a Canadian mine. It is shown that the selected instrument fulfilled the main objective of the project, which was the in situ characterization of a paste backfill. Recommendations are given for future applications of this testing technique for mine backfill and improve the efficiency of the work underground. Also, recommendations are given to improve test analysis and consequently the quality of the results obtained with the self-boring pressuremeter technique.

This study presents methodology for technical and economic performance analysis of conventional grinding circuits supported by two industrial cases. A review of the strengths and weaknesses of Bond work index and population balance modelling approaches to plant circuit analysis discloses the need to refine work index determinations, and to establish a system of more meaningful ball mill circuit performance parameters. / The statistical reliability of carefully determined rod mill work index efficiency ratings is presented. Technical and economic performance improvements through rod mill speed and feed water rate adjustments are presented. / Parameters which separately characterize overall ball mill circuit classification and breakage efficiency are presented. Their relationships with circuit design and operating variables and overall circuit efficiency and economy are discussed. The particle size dependence of flotation is used to estimate the value of the grinding circuit product, and thus to integrate grinding into the overall economics of a flotation concentrator.

Rotary blasthole drills operating in a western Canadian surface coal mine were instrumented with microprocessor-based monitoring equipment. During routine production drilling, the performance parameters of penetration rate, torque, rotary speed, pulldown and bailing air pressure were monitored at sampling intervals of 10 centimeters (4 inches). The acquired digital data were subsequently correlated with both geological and geomechanical rock properties permitting a detailed examination of machine-rock interaction. The results from a statistical analysis of the drill data identified unique ranges of performance parameters for the sandstone, siltstone, mudstone and coal units encountered at the mine. Correlation of these ranges with geophysical logs in the monitored boreholes, enabled a further calibration of drilling parameter variation to rock type. A relationship between drill performance parameter responses and rock compressive and shear strength was established. This correlation demonstrated the possibility of estimating rock strength properties based on drill performance data. Trend analysis techniques applied to the monitored drill data permitted a further understanding of the nature of tricone bit wear for the particular study environment. The applications of drill monitoring techniques are illustrated in terms of geological exploration, mine planning, tricone bit selection and wear evaluation, and drill automation and control.

This thesis addresses rheological characterization of mine tailings and paste materials as saturated solid-liquid or homogenous mixtures. Thickened tailings and paste fill can be classified as viscoplastic or time-independent non-Newtonian fluid material. Viscoplastic fluids deform plastically when the applied shear stress is less than a critical stress, which is known as "yield stress". When the shear stress exceeds the yield stress this type of fluid flows like a viscous material with finite viscosity. / In terms of pipeline design for transportation of mine tailings or paste material, one of the most important rheological parameters that must be measured would be yield stress. There are numerous techniques and equipment that can be used for rheological characterization and specifically for yield stress measurements. Literature review shows that the vane method is one of the best rheometery techniques for determining the yield stress of homogeneous fluids directly. / There is also a method for calculating the yield stress from slump height. Any geometry of slump moulds, cone or cylinder, with different dimensions can be applied in this method. The standard conical slump test is basically used for controlling the workability of fresh concrete. This method was then modified for yield stress and viscosity calculation of cemented mixtures. These slump tests can be categorized as in-situ methods of yield stress measurements. / Several rheometery and in-situ experiments were carried out to measure the yield stress of two mine tailings samples in this study. A rheometer was used in controlled shear rate and controlled shear stress modes for yield stress measurements with the vane method. The results were satisfactory for cemented and non-cemented mixtures. The effect of mixing time on the yield stress of material combined with cement was also assessed using the vane method. No significant difference emerged between increased yield stress of the mixtures after 4 minutes and 12 minutes of mixing. / The accuracy of calculated yield stress values using in-situ methods was also determined by drawing comparisons between these series of data and actual yield stresses measured using a rheometer. Modified conical slump tests overestimated the values of yield stress and did not obtain reliable data for viscosity calculation of the mixtures.

Many parts of the world are introducing geothermal heat pumps as alternatives to conventional heating and cooling systems. This thesis investigates how this renewable energy resource can be exploited using underground mine water from active mines in Canada. A few cases located in Europe and North America are presented where buildings are utilizing thermal energy generated from open loop mine water systems found in nearby abandoned mines. This report involved two studies. The initial one is a preliminary survey involving twelve active mine sites in Canada. Site visits were conducted at all twelve mines to collect information about the operation, mine water temperature and water pumping rates. From this data, the thermal capacity of the underground resource was calculated and verified using heat pump catalogues. Economic and environmental assessments were conducted for each proposed geothermal heat pump design. These preliminary results were promising and a larger assessment, which included a total of 23 mines, was conducted. The results from this assessment found that the overall potential heat gain from these mines is 20,900 kW annually, which translates into heating 69,150 average Canadian homes. Canadians have the potential to realize an annual savings from $1.5 to $4.9 million, with a potential reduction in carbon dioxide emissions varying from 16,850 to 19,300 tonnes per year. / Dans plusieurs parties du monde, l'installation de pompes à chaleurs géothermiques agissant comme alternatives aux systèmes de chauffage traditionnels et devient une tendance importante. Ce document a l'intention d'examiner cette forme d'énergie renouvelable en utilisant comme source l'eau qui s'écoule des mines souterraines au Canada. Certains exemples de ces types de systèmes, retrouvés principalement en Europe et en Amérique du Nord, seront présentés. Pour les cas mentionnés, plusieurs bâtiments et immeubles utilisent l'énergie géothermique générée par des systèmes d'eau à boucle ouverte installés dans des mines abandonnées. De plus, des études préliminaires ont été acheminées pour douze sites miniers en opération au Canada. Des visites souterraines ont été menées à chaqu'un de ces sites pour recueillir des informations importantes concernant les activités minières, les températures des eaux souterraines et les capacités de pompage. Les capacités thermiques des eaux souterraines ont été calculées et ensuite comparées aux spécifications techniques des pompes à chaleur. Les résultats préliminaires ont été encourageants, incitant donc une enquête pour déterminer le potentiel de cette source d'énergie à l'échelle nationale. Cette évaluation comprend un total de vingt-trois sites miniers. Leur évaluation a constaté que le potentiel de gain de chaleur combiné est de 20,900 kW. Ce gain peut fournir un an de chauffage pour l'équivalent de 69,150 maisons. Les économies annuelles qui peuvent être réalisées en remplaçant un système de réchauffement traditionnel (soit au gaz naturel ou chauffage électrique) par un système géothermique dont la source provient des opérations minières, sera entre $1.5 et $4.9 millions. De plus, l'exploitation de cette forme d'énergie a le potentiel de réduire les émissions de dioxyde de carbone par un facteur de 16,850 à 19,300 tonnes par année.

Mining automation has over the past two decades progressed incrementally from line-of-sight remote operation to teleoperation and automatic control of mining equipment. This last development has been mainly due to recent significant advances made in underground communications technologies. A new robotic mining environment is being created that will see mobile machinery as well as stationary equipment fully integrated with a mine-wide information system overseeing all aspects of the mining operation via a high-bandwidth communications network. / Teleoperation of multiple semi-automated machines by one operator from a remote site (control room on surface) forms the basis of current efforts in underground hard-rock mine automation. This thesis attempts to outline the state of teleoperated mining systems in use today and highlights some of the key issues encountered when introducing this new technology into actual production settings. An actual case study on teleoperated uphole Data Solo drills at Inco Limited's Stobie Mine in Sudbury, Ontario, is used to demonstrate these issues during the various phases of project implementation.

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