<p> The Cuyuna Range is a former North American iron mining district about 90 miles(145 kilometers) west of Duluth in central Minnesota. The district was the furthest south and west of the three Minnesota iron ranges (Vermilion, Mesabi, and Cuyuna). In 2011, Students and staff from Michigan Technological University's Department of Social Sciences were asked to identify and promote features of the Cuyuna Range's mining heritage. Methods and approaches of mulitsited archaeology were used to unify the diverse places and themes into a more cohesive narrative. Their investigations focused on sites of technological innovation, social conflict, and important people. One collaborative project involved training a team of local volunteers to survey seven iron mining communities to identify sites with historic importance. In total, 876 sites were documented. The data generated from this effort can be used to develop plans for cultural tourism focused on the iron mining heritage of the Cuyuna Iron Range. It was found that using multiple themes from multisited archaeology strengthened the region&rsquo;s narrative better than simply focusing on sites from a single thematic viewpoint</p>

The research is directed towards modelling the chiller set, the heat rejection and the load subsystems of a complete mine refrigeration system and simulating the performance in order that the design can be optimised and the most cost effective control system determined. The refrigeration load profile for a mechanised mine is complex and primarily a function of surface climatic variations, the strongly cyclic sources of heat resulting from the operation of diesel powered mining equipment and the associated differences in thermal environmental acceptance criteria. Modelling of the central element of the system, the compressor, is based on empirical relationships which use the actual cooling duty and input power rather than general compressor curves using theoretical flow and head coefficients. This has a more general application and is not restricted to a single compressor type. The steady state modelling of five refrigeration systems has included two types of compressor, four types of evaporator, three types of condenser, two types of cooling tower and five types of mine cooling appliances. The research has extended modelling of refrigeration systems by incorporating fully the heat rejection and load subsystems and has demonstrated that relatively complex mine refrigeration systems can be modelled and the simulation results related to actual measurements with an acceptable accuracy. This has been further improved by testing the system elements and adjusting the theoretical performance analysis where necessary. These adjustments concern either the more difficult to assess factors such as evaporating and condensing heat transfer coefficients or factors influenced by unusual operating conditions. The research has shown that, despite the complexity of the load profile and the refrigeration system, modelling and simulation can be used effectively to optimise both the design and the control system.

The current trends towards increased coal production from seams at greater depth has led to increased demands being placed on the methane drainage and mine ventilation systems. This study has been directed towards the development of computer models to simulate and analyse the gas flows in methane drainage ranges and the airflow and pressure distribution in mine ventilation networks. The first part of this thesis describes the conventional techniques of methane drainage currently employed and the mathematical approach used to model gas flow in the methane drainage range. It also discusses how, when combined with measured underground data, predicted results can be used to assess the performance of the range. Subsequent analysis techniques will suggest measures that can be undertaken to optimise this performance and assess the effect of selective network reconfiguration. The second part of the thesis includes a discussion of the increasing application of booster fans in U.K. underground coal mines and a critical analysis of the mathematical methods used to model airflow and pressure distribution in mine ventilation networks. One particular method was adopted in a simulation model used to analyse networks with booster fans and specified face airflows. Both simulation models developed have been used to analyse representative underground methane drainage ranges and mine ventilation networks. The thesis concludes that the accuracy of the methane drainage models can only be guaranteed when developed in conjunction with suitable measured data. The mine ventilation model requires user guidance through the solution and analysis procedure. Results are presented in a simple graphical manner and this approach, rather than the 'black box' non interactive approach, is to be favoured in the analysis of mine ventilation networks.

Geologic information extraction and integration are the main goals of this study. Tools are designed to aid in exploration for common mineral deposits by intelligently and efficiently processing spatial geological data. Gabor filters, comprising Gaussian-attenuated sinusoidal weight vectors, are used for textural discrimination. A highly non-linear logic operator was designed for "valley", "ridge", edge, and intersection extraction from multispectral images to cover most of the possible local lineament types. A zonation detector (a non-linear logic operator) indicates the presence or absence of lithologic zonation, the number and the types of zones using a series of automatically expanding moving windows. The ultimate window size represents the zonation size. Two different types of raster-based expert systems help optimize pixel-by-pixel knowledge extraction and representation over the spatial information and throughout the different raster feature layers. First a 2-D expert system is used for classification, ranking, recognition and searching for important pattern associations in the feature space. Second, a multilayer adaptive raster-based expert system allows the processing of multiple geologic features, and operates over each pattern in the feature layers. The fuzzy integral method of evidence fusion is used to integrate information from a variety of mineral exploration sources. This nonlinearly combines objective mineral occurrence evidence, in the form of a fuzzy membership function, with subjective evaluation of the worth of the sources with respect to the decision. An application of these methods to the Tombstone mineral district in southern Arizona demonstrates its ability to pick out circular features from TM imagery, Gabor transforms and lineament patterns, as well as identify favorable zonation for new mineral occurrence. The final product at this time is a probability map to guide the exploration geologist.

This dynamic study of investment under uncertainty reveals that conventional analyses of aluminum industry patterns of trade and investment may be based on industrial policy rather than competitive advantages. The study results confirm the hypothesis that, with competition and free trade, U.S. aluminum smelting investment (and capacity) does not decrease, rather it increases as capacity is lost by Pacific Basin (PB) and European (EUR) suppliers, both presently protected with high tariffs. Using a competitive market approach and rational expectations, firms are considered as taking current market prices and acting as if current output and investment decisions will not affect current or future prices. Fixed production proportions of input to output are assumed for all production stages, for efficient-sized plants. Dynamic elements are captured through frictions in adjustment of smelting capacity that restrict the capacity that can be added in a single period. Investment is irreversible except by depreciation. In the resultant expectations framework, supply and demand are not always in sync and random shifts in investment occur across different regions. Rational expectations allows equivalence between a competitive equilibrium and welfare optimization under uncertainty. The study here solves the simpler but equivalent welfare maximization problem. The pattern of investment under free trade shows that, though the Latin American (LA) and (PB) smelting regions have absolute advantages in smelter power costs (typically assumed the determining factor for new investment), total aluminum production costs (including bauxite and alumina) in the eastern U.S. and western North America (US-E and NA-W) are sufficiently below those of (EUR) and PB to maintain the former's competitive advantages. Using World Bank aluminum demand growth rates, US-E capacity increases by 28 percent and NA-W by 49 percent as EUR capacity falls by 22 percent and PB by 32 percent for the year 2010. The results differ markedly from conventional forecasts which have predicted declines in North American investment, inferring that barriers to free trade may be distorting investment patterns.

This study explores the impacts of physical and policy variables on the economics of the development of a hypothetical 500 t/d underground polymetallic (Zn-Ag-Pb) vein deposit in the Sud Lipez region of the Bolivian Altiplano. Because of recent changes in the legal system, it is more attractive, interesting and worthwhile to examine the effects of policy variables that reflect the implications of the new legal system. For this purpose, an holistic investment methodology defined as the Investment-Worth model is developed to evaluate the risks and rewards to capital investments. Results of the study confirm that even in risky environments development of mining activities remain primarily driven by the quality of the ore reserves and the market conditions for the commodities of interest. Under the most probable scenario, the deposit of interest would remain a viable investment opportunity at zinc ore grades greater than 9%. Furthermore, the model demonstrates that the investment worth of a project is not the same across firms in the industry. Attractiveness of a project varies with economic and risk-related characteristics of firms. Specifically, investment in the zinc-based polymetallic deposit in the Altiplano will be more attractive to firms of at least moderate size that possess the required technical knowledge and skills but are not currently involved in zinc production.

No description available.

The objective of this research project was to investigate the effect of microwave treatment on the conversion of pyrite in coal in order to enhance its magnetic properties and to aid subsequent desulphurisation by magnetic separation. Key areas of this investigation include:- a review of the fundamental theoretical aspects of heating in an applied microwave field, a detailed literature survey of the potential applications of microwave heating to aid coal desulphurisation, a study of the transformation mechanisms of pyrite by microwave and conventional heating methods, a comprehensive review of the influence of heterogeneity on the dielectric properties of coals and the effect of high power microwave heating on the decomposition of pyrite in a high sulphur coal. A detailed survey of the literature has shown that although a significant amount of work has been reported on the microwave heating of coal, little information is available which examines the mechanism through which different coals heat in an applied microwave field. A study is therefore presented in this thesis which quantifies, for the first time, the structural ordering of carbon in a range of coals of various ranks and the relationship with their dielectric properties. The results show a clear relationship between the structural ordering of carbon in coal and dielectric loss factor. Essentially, as the structural ordering increases, the level of free charge (per unit volume) increases together with electron mobility which results in an increase in dielectric loss factor. The transformation of pyrite to form the more magnetic pyrrhotite and other related decomposition products by conventional radiant heating has been the focus of much research. However, little attention has been given to the effect of microwave heating on the mechanisms of pyrite transformation in inert and oxygen-containing atmospheres. The study presented in this thesis investigates the effect of temperature, particle size and heat treatment time to establish how these affect the transformation process and the subsequent nature of the final product. This study showed that exposure of pyrite to both conventional and microwave heating methods enhanced its magnetic properties as a result phase alterations at the particle surface. Conventionally heated pyrite samples showed the highest magnetic susceptibility increases, speculated to be due difficulties surrounding the temperature control and measurement of the microwave heated samples. From a review of the literature in this field of research and by SEM observations made for each sample test in this work a general pyrite transformation model as a result of microwave exposure is proposed. The effect of microwave radiation on the conversion of in-situ coal derived pyrite was also investigated. The study presented here extends previous work by others by assessing quantitatively the influence of higher applied microwave power levels on the conversion of pyrite in coal. Samples of run-of-mine high pyritic sulphur content (~12%wt) Kentucky coal were microwave pre-treated at varying exposure times using 8kW and 15kW of microwave power operating at a frequency of 2.45GHz. This work included initial material characterisation which consisted of TGA, optical microscopy and dielectric property measurement, followed by SEM/EDAX characterisation of both microwave treated and untreated sample specimens. This is the first time that microwave treated coal, embedded in a carnauba wax mounting medium, has been observed by this method with focus on the thermal alterations of the pyrite phase. It was demonstrated that with sufficient power and residence time, the conversion of pyrite to the more magnetic pyrrhotite is achievable using microwave irradiation. The amount of pyrrhotite formed as a result of microwave exposure varies with microwave residence time and forward power level. Comparisons of change in the iron sulphide species in the coal was made between microwave treated and untreated material. Using a multimode microwave cavity it was found that significant amounts of pyrrhotite were formed in 20s when using 15kW of microwave power. Treatment at lower power levels in this type of cavity was found to be less effective. The overall effect of treatment on the coal proximate character was minimal.

In order to ascertain whether kerogen and the heavy oil or bitumen generated during the initial stages of source rock maturation then go on to produce similar gas yields compared to the natural situation when they are present in source rocks, a study has been conducted on an immature type II Kimmeridge Clay Formation (KCF) source rock (Dorset, United Kingdom) with different total organic carbon contents (14, 25 and 30 % TOC), and all having an initial vitrinite reflectance (VR) of approx. 0.4 % Ro. Anhydrous and hydrous pyrolysis experiments were conducted on the whole immature source rock, the isolated partially matured bitumen-extracted source rock and the isolated bitumen (bitumen generated and extracted from the initial source rock) and mixtures of the isolated partially matured source rock and bitumen using two types of Hastalloy vessels (22 and 25 ml) at 320-420 °C for 7-48 h over a pressure range of 115-900 bar. Hydrocarbon gas yields and the increase in VR were greater from the whole rock experiments compared to the experiments on the isolated partially matured source rock and isolated bitumen (no mineral matter present), as well as the experiments on mixtures of the isolated partially matured isolated source rock and bitumen combined. The effect of particle size were also found to be of significance as higher gas yields were obtained from recombined mixture experiments using powdered samples (14 % TOC source rocks) compared to using rock chips (30 % TOC source rocks). Hydrocarbon gas yields, pyrobitumen yields, and VR values were found to decrease as pressure increases towards 500 and 900 bar compared to 180 bar at 350 °C where the effects of pressure retardation were found to be much more significant from the partially matured source rock maturation and bitumen in isolation than from the whole source rock. At 420 °C, gas generation, bitumen plus oil and coke yields were not affected by pressure, but VR decreases going from 310 bar to 500 and 900 bar. The results obtained demonstrate that the interplay of inherent mineral matter, reactant phase, source rock/kerogen, bitumen and pressure are key factors in determining the extent of hydrocarbon generation and source rock maturation in geological basins.

Recent research developments have suggested that microwave assisted comminution could provide a step change in ore processing. This is based on the fact that microwave-absorbent phases within a multi-mineral ore can be selectively heated by microwave energy hence inducing internal stresses that create fracture. A detailed review of existing literature revealed that little or no information is available which relates and examines the influence of hydrated minerals on microwave assisted fracture despite the fact that most important ores are associated with phyllosilicates, the vast majority of which are hydrated. A study was carried out on two Kimberlite diamond ores containing various types of hydrated minerals but devoid of any semiconducting minerals which are known to be good microwave heaters. The results confirmed that dehydration of minerals containing interlayer adsorbed water induces significant micro and macro fractures after microwave treatment. The significance of microwave induced fracture on beneficiation was investigated by conducting liberation and flotation tests on two porphyry copper ores. It was demonstrated that microwave pre-treatment improves beneficiation at sizes suitable for flotation and that higher improvements in degree of liberation are attained in coarser particle sizes between 212 and 425 µm. Flotation tests demonstrated a potential for real economic benefits in terms of value proposition. An increase of 8-10% in copper sulphides recovery from coarse sized particles (-400+200 µm) and an overall increase in grade/recovery of between 1-2% was obtained. The results also showed that microwave pre-treatment enhances selective mineral recovery as the grade-recovery of iron sulphides decreased in all but one microwave treated samples. The major drawback to further developments towards industrial scale application was found to be the lack of an effective continuous processing microwave applicator. Any future applicator designs must be able to ensure localised hot spots and confinement of all the microwave energy.