Outline of the thesis This thesis is comprises three papers that are intended for journal publication. The version provided in the thesis is a bit longer than they will be at final publication. However it was the desire to include some additional documentation that may be omitted in the final versions. Each paper in the manuscript is written as an independent paper. Because all the papers are strongly tied together there is significant repetition partly because the documentation and interpretation of the results in on paper depends on the results documented in another paper. The essence of the three papers are summarised below: Paper 1: Sørensen, B.E. and Larsen R.B. 2007. “Fluid induced multistage recrystallisation microstructures in Quartzites and Quartz veins from the Bamble shear zone complex” Paper 1 deduces basic principles of infiltration, physiochemical alteration processes and deformation mechanisms in quartzites and in quartz veins from the Froland area, the Bamble sector. SEM-CL is used to define generations of recrystallised quartz. A progressive quartz purification process ending with high purity quartz through recrystallisation is documented through LA-ICP-MS. The study demonstrates how fluids provokes recrystallisation and trace element mobilisation from the quartz lattice and at fluid-absent conditions, quartz is resistant to retrograde recrystallisation hence preserving its early high grade metamorphic trace element signature. Evidence of retrograde fluid flow is preserved in fluid channel textures intersecting quartz and documented by SEM-CL images as well as changes in the trace element distribution. Quartz recrystallisation is associated with metasomatic processes in the quartzites such as for example the replacement of ilmenite by rutile and replacement of biotite by muscovite. The strong focus of fluid flow along narrow pathways intersecting the quartzites generates mm-scale differences in the rheological properties of the quartz grains with increased ductility and recovery in recrystallised grains. Therefore, the study demonstrates a strong coupling between strain softening, fluid flow and mass transfer in shearzones in quartz rich rocks. Paper 2: Sørensen, B.E. and Larsen R.B. 2007. “The fluid evolution of the Froland area in the Bamble sector from peak P-T through cooling and uplift: implications for retrograde mineral paragenesis and PT evolution of the Bamble sector” Paper 2 comprises a detailed characterisation of the fluid evolution during cooling and uplift through fluid inclusion studies compared with thermodynamic modelling of calc-silicate volatile dependant mineral equilibria. Fluids are documented to be brines throughout the cooling and uplift path. The paper also includes a detailed discussion of the chemical properties of the aggressive brines and their implications for mineral equilibria during cooling and exhumation. The study also document which fluids that were in equilibrium with quartz recrystallisation and purification. The study focussed on fluids that could be related to the quartz SEM-CL textures documented in Paper 1. Had the main purpose of this thesis been to understand calc-silicate equilibria in the Bamble sector fluid inclusions in the calc-silicates would have been in the focus. Paper 3: Sørensen, B.E, Larsen R.B. and Austrheim, H. 2007. “Metasomatic evolution of the Froland amphibolites during cooling and uplift – textural observations and geochemical evolution of hydrous minerals” Paper 3 comprises a detailed study of alteration processes in amphibolites. The study focuses on the chemistry of amphiboles as a function P, T and the composition of the co-existing fluids. Amphibole and biotite undergo a co-genetic evolution both becoming more Mg-rich during cooling and exhumation. The chemical changes in biotite and amphibole reflects the interaction with the brines present throughout cooling and uplift. A relationship between element depletion in amphibolites and formation of Fe-Cu sulphides is observed. As earlier stated the papers are strongly tied together. In conjunction with each other they deduce the metamorphic and metasomatic evolution of the area and put the observed quartz recrystallisation and purification into a physiochemical framework. The locality numbering varies between the papers because samples from different localities are included in each paper, accordingly a locality termed”1” in one of the papers may have a different number in the next paper. This was done because the papers are supposed to be independent research papers and the numbering logically relate to the context of the single papers and not the thesis as a whole.

Thesis (Ph. D.)--Michigan Technological University, 2003. / Includes bibliographical references. Also available on the World Wide Web.

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St. Barnabé fault, in St. Hyacinthe plain of the St. Lawrence lowlands, was postulated by Clark (1947) on his geological study of this area. Structural features of this type are of great interest to the geophysicist to establish relation between physical quantities measured at the surface and geometry of such structures. A subsurface fault can be diagnosed, under density contrast condition, with surface gravity measurements. The present detailed gravity survey was undertaken to determine if such a condition existed, to correlate geological information with gravity data, and to assess this data in terms of possible parameters of the fault structure. The field work was carried out in the summer months of 1964 with a Worden gravimeter. [...]

Unplanned ore dilution or stope overbreak, which has a direct and large influence on the cost of a stope, and ultimately on the profitability of a mining operation, can be attributed to both the mining process and to geologic setting. The research undertaken in this document, applicable to a wide range of underground mines employing the blasthole mining method to extract tabular orebodies, focuses on examining factors attributable to the generation of unstable stope hanging-walls. / The primary objective of the research undertaken is to establish new models for stope and orezone design, with respect to anticipated stope overbreak, focusing on the position and type of stope within the orezone extraction sequence. Identified factors influencing unplanned dilution, such as: induced stress environment, stope geometry, and the setting of individual stopes are considered. / The research undertaken incorporates a variety of components, including (i) parametric 3-D numerical modelling to examine influences of individual factors on hanging-wall overbreak, (ii) case example analysis, and (iii) orezone extraction sequence simulation, using 3-D elastic numerical modelling. Design criteria, developed from the parametric modelling, was applied to the orezone sequence modelling to develop trends for stope dilution, as functions of stope design and construction. / It was found that hanging-wall overbreak is not significantly influenced by depth alone, and that stopes with large vertical and short horizontal dimensions or stopes having long horizontal and short vertical dimensions are more stable than large square-like stopes. Also, through parametric and case studies, it was demonstrated that, in addition to stope dimension, the amount of unplanned dilution differed according to stope type. Five stope types were identified, based on their position within a tabular blasthole mining sequence. Measured overbreak varies with stope type, with secondary stopes generating a greater volume of hanging-wall dilution than do primary stopes. A pillarless mining sequence will generate less overall dilution than a primary stope: secondary pillar mining sequence.

Coal workers’ pneumoconiosis (CWP), commonly referred to as black lung, is a chronic lung disease that results from the inhalation and deposition of coal dust in the lungs. While this disease continues to afflict coal miners, its prevalence has steadily declined over three decades since 1970. Based on a voluntary X-ray surveillance program, conducted by the National Institute for Occupational Safety and Health (NIOSH), this downward trend, however, ended in 2000 and has actually begun to rise. The Mine Safety and Health Administration (MSHA) instituted a Comprehensive Initiative to “End Black Lung” to combat the reported upturn in black lung disease. Rulemaking, with the intent of strengthening respirable dust regulations, is a major part of this initiative. This thesis addresses a controversial aspect of the newly proposed rules – single-shift compliance sampling. Establishing new requirements for respirable dust compliance requires an understanding of both the accuracy and variability of measurements. Measurement variability is especially important in underground mining where the workplace is constantly moving and ventilation controls are continually changing. The results of a ventilation study performed in three underground coal mines are presented in this thesis. A total of 600 dust-concentration measurements were obtained in this study using Continuous Personal Dust Monitors (CPDMs). The data was analyzed to determine the variability associated with taking dust measurements in the mining workplace. The Johnson transformation was found to produce the best-fit distribution model for the data. This thesis summarizes the results of this study and presents a statistical procedure for establishing an exposure limit.

Froth flotation is the most efficient method for phosphate separation, which is a physic-chemical separation process based on the difference of surface properties between the valuable minerals and unwanted gangue minerals. However, the presence of clay slimes in the slurry after grinding consumes a large amount of reagents, decreases the collision probability between bubbles and minerals, prevents phosphate particle attachment to air bubbles, and thus considerably reduces flotation recovery and concentrate grade. Georgia Pacific Chemical, LLC has recently developed novel depressants, i.e., clay binders, which are a series of low molecular weight specialty polymers to help improve phosphate flotation performance by selectively agglomerating and depressing clay particles, thus lowering their surface area and reducing the adsorption of surfactants. This thesis addresses the effects of clay binders on phosphate flotation performance and their adsorption behavior on different minerals in a sedimentary phosphate ore. Quartz Crystal Microbalance with Dissipation technique (QCM-D) was used to study adsorption characteristics of clay binders and batch flotation tests were performed under different conditions to investigate phosphate flotation performance. The experimental results have shown that clay binders significantly improved phosphate flotation selectivity and reduced the dosages of collector and sodium silicate used as dispersant in the industry.

In 2006, Congress passed the MINER Act requiring mine operators to submit an emergency response plan that included post-accident communications and tracking systems to MSHA within three years of the Act. These systems were required to be designed for maximum survivability after a catastrophic event, such as a fire or explosion, and to be permissible (meets MSHA criteria for explosion-proof). At that time, no commercially available systems existed that met these standards. Several companies undertook developing new, or enhancing existing, technologies to meet these requirements. This research presents the results of a study that was conducted to determine the present day types of systems being used, along with their average annual worker hours, coal production, number of mechanized mining units, and type of communications and tracking systems installed. Furthermore, 10 mines were visited to obtain detailed information related to the various technologies. It was found the most influential parameters on system selection include MSHA district, mining method, and number of underground workers.