The Economic Case for Electric Mining Equipment and Technical Considerations Relating to their Implementation

Underground hardrock mining can be very energy intensive and in large part this can be attributed to the power consumption of underground ventilation systems. In general, the power consumed by a mine’s ventilation system and its overall scale are closely related to the amount of diesel power in operation. This is because diesel exhaust is a major source of underground air pollution, including diesel particulate matter (DPM), NO2 and heat, and because regulations tie air volumes to diesel engines. Furthermore, assuming the size of airways remains constant, the power consumption of the main system increases exponentially with the volume of air supplied to the mine. Therefore large diesel fleets lead to increased energy consumption and can also necessitate large capital expenditures on ventilation infrastructure in order to manage power requirements. Meeting ventilation requirements for equipment in a heading can result in a similar scenario with the biggest pieces leading to higher energy consumption and potentially necessitating larger ventilation tubing and taller drifts. Depending on the climate where the mine is located, large volumes of air can have a third impact on ventilation costs if heating or cooling the air is necessary. Annual heating and cooling costs, as well as the cost of the associated infrastructure, are directly related to the volume of air sent underground. This thesis considers electric mining equipment as a means for reducing the intensity and cost of energy consumption at underground, hardrock mines. Potentially, electric equipment could greatly reduce the volume of air needed to ventilate an entire mine as well as individual headings because they do not emit many of the contaminants found in diesel exhaust and because regulations do not connect air volumes to electric motors. Because of the exponential relationship between power consumption and air volumes, this could greatly reduce the amount of power required for mine ventilation as well as the capital cost of ventilation infrastructure. As heating and cooling costs are also directly linked to air volumes, the cost and energy intensity of heating and cooling the air would also be significantly reduced. A further incentive is that powering equipment from the grid is substantially cheaper than fuelling them with diesel and can also produce far fewer GHGs. Therefore, by eliminating diesel from the underground workers will enjoy safer working conditions and operators and society at large will gain from a smaller impact on the environment. Despite their significant potential, in order to produce a credible economic assessment of electric mining equipment their impact on underground systems must be understood and considered in their evaluation. Accordingly, a good deal of this thesis reviews technical considerations related to the use of electric mining equipment, especially ones that impact the economics of their implementation. The goal of this thesis will then be to present the economic potential of implementing the equipment, as well as to outline the key inputs which are necessary to support an evaluation and to provide a model and an approach which can be used by others if the relevant information is available and acceptable assumptions can be made.

Bridging the link between trauma, brain development and depression: epigenetic mechanisms

Despite its large impact on the individual and society, we currently have only a rudimentary understanding of the biological basis of Major Depressive Disorder, even less so in adolescent populations. This thesis focuses on two research questions. First, how do adolescents with depression differ from adolescents who have never been depressed on (1a) brain morphology and (1b) DNA methylation? We studied differences in the fronto-limbic system (a collection of areas responsible for emotion regulation) and methylation at the serotonin transporter (SLC6A4) and FK506 binding protein gene (FKBP5) genes (two genes strongly linked to stress regulation and depression). Second, how does childhood trauma, which is known to increase risk for depression, affect (2a) brain development and (2b) SLC6A4 and FKBP5 methylation? Further, (2c) how might DNA methylation explain how trauma affects brain development in depression? We studied these questions in 24 adolescent depressed patients and 21 controls. We found that (1a) depressed adolescents had decreased left precuneus volume and greater volume of the left precentral gyrus compared to controls; however, no differences in fronto-limbic morphology were identified. Moreover, (1b) individuals with depression had lower levels of FKBP5 methylation than controls. In line with our second hypothesis (2a) greater levels of trauma were associated with decreased volume of a number of fronto-limbic regions. Further, we found that (2b) greater trauma was associated with decreased SLC6A4, but not FKBP5, methylation. Finally, (2c) greater FKBP5, but not SLC6A4, methylation was associated with decreased volume of a number of fronto-limbic regions. The results of this study suggest an association among trauma, DNA methylation and brain development in youth, but the direction of these relationships appears to be inconsistent. Future studies using a longitudinal design will be necessary to clarify these results and help us understand how the brain and epigenome change over time in depressed youth.

British Romantic Criticism and the Fine Arts: A Study in Philosophical Theories of Literary Unity

This dissertation is an exploration of how a small but important group of Romantic critics, finding fault in the ideal of three unities developed by neoclassical Academicians and wrongly attributed to Aristotle, turned to the terminology and practices of the fine arts to emphasize their conception of organic unity in literature. The Romantic analogy to painting in particular enables a philosophical criticism of literature to present the aesthetic semblance of painting, the comprehension of a multitude of details in a harmonious whole that is a natural unity to its medium, as a paradigm of modern-romantic poetry and its aspirations to similar complexity, particularity, and imaginative colour. Further, in extension of the French Querelle des anciens et des modernes of the seventeenth century, the division of ancient and romantic art by Romantic critics like August Schlegel, Samuel Taylor Coleridge, and William Hazlitt not only establishes an ethnological and historical difference between the artistic productions of these two cultural periods but also allows, unlike the neoclassical unities, a non-anachronistic philosophical vocabulary of whole and parts or of the general and particular in the criticism of poetry, which involution provides a “rule” more consonant with the laws of the imagination rather than with the rhetorical and absolutist dicta that were thither available in the literary canon.