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Acid Mine Drainage (AMD) is a consequence of mining activity; it results from bacterial and chemical oxidation of pyrite and other sulfide minerals in waste rock and tailings. AMD is characterized by low pH, and elevated sulfate, iron and often heavy metal concentrations that cause severe damage to the environment. Microorganisms indigenous to highly acidic environments are very diverse and include microorganisms capable of generating alkalinity. The objective of this research was to investigate the biological attenuation of AMD in Davis Mine, an abandoned pyrite mine in Western Massachusetts. The main focus was to evaluate the effects of dissimilatory iron reducing bacteria (DIRB) and sulfate-reducing bacteria (SRB) on the geochemistry of Davis Mine using in situ (ISM) and laboratory (LBM) microcosms. Evidence of ongoing microbial activity was indicated by geochemical changes observed only in live LBMs: increase in concentration of ferrous iron over time, the development of reducing conditions, increase in pH and the development of black precipitates. Data showed that indigenous bacteria change the water chemistry and mineral composition favoring the natural attenuation of the site. However, the results from this study were not sufficient to confirm whether or not SRB or DIRB were metabolically active. The LBM experiments showed that in a closed system and under favorable environmental conditions (temperature, Eh, pH) biological reduction was one of the main mechanisms for the remediation of AMD. Indigenous bacteria were capable of remediating AMD without the addition of an external carbon source, and attenuation rates increased with the addition of glycerol, nitrogen and phosphorous. A program for aqueous geochemical calculations, PHREEQC, confirmed the precipitation of some minerals from the water geochemistry resulting from the microbial activity. Due to hydrological problems in the ISM, it was not possible to obtain in situ rates of degradation. The ISM was affected by the introduction of water with different chemical characteristics. The in situ experiments showed that groundwater transport and diffusion played an important role in the groundwater chemistry. Further in situ experiments are needed to account for environmental factors such as soil pore diameter, temperature, groundwater flow and geochemical processes, availability of electron donor and nutrients in order to determine the rate of microbial activities.

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Forging a Technocratic Elite in Colombia: A History of the Escuela Nacional de Minas of Medellin, 1887-1970 examines the history of an engineering school that has played an important role in the formation of a national bourgeoisie in Colombia. Besides civil and mining engineers, the Escuela produced leaders of industry and government--technocrates who have shaped the country's development in the twentieth century. It did so through a program which emphasized practical knowledge and above all, devotion to 'Progress'. Engineers were to be agents of Progress through their adhesion to the ethical virtues of hard work, honesty and integrity. This was the vision of founder Tulio Ospina Vasquez who implanted the program with a distinct, missionary-like identity. Indeed, during the first three decades of the twentieth century, the Escuela reflected the values and goals of the wealthy, politically ascendant elite to which Ospina belonged. Changes in the program over time reflected the impact of trends affecting both Colombian society and higher education: the growth of middle-class participation and nationalism as well as increasing reliance on U.S. culture and scientific knowledge. Nevertheless, the Escuela retained its essentially elitist orientation, one that fit in with the technocratic style and development strategy of the National Front and survived through the structural reforms overseen by Rector Peter Santamaria during the 1960s. In this sense, it embodies a unique case study of Colombian higher education overall / acase@tulane.edu

Earthmoving is a common activity at mines, construction sites, hazardous waste cleanup locations, and road works. Expensive and sophisticated machines such as front-end-loaders (FEL), backhoe loaders, LHD loaders and front shovels are used for these excavation tasks. Autonomous excavation control for these machines has gained considerable attention in order to remove human operators from hazardous environments, improve productivity and utilization, reduce machine abuse, as well as decrease machine operating costs. However, automatic control of excavation tasks for many sites that require digging in rock cannot be implemented using existing factory-based automation techniques. For example, control of bucket motions by simply partitioning the terrain into a set of volumes where each equals the bucket capacity often does not work. Planning in this way is possible only when digging in the materials such as loose soils where bucket motion resistance through the media can be predicted. Resistance predictions are impossible and/or infeasible to generate for excavation in the environments which consists mainly of irregular rigid objects such as rock piles with oversized particles, since no means exists to predetermine subsurface bucket/material interactions that are required to preplan the bucket trajectory. As a result, bucket actions must be determined through on-line decision making based on sensory feedback of the current excavation status in the unpredictable, unstructured and dynamic rock excavation environment. This research proposes a control method for autonomous rock excavation. The control architecture is designed following the behavior-based control concept. That is, the rock excavation control problem is solved by decomposition of the complicated task into a variety of simple elements that can be implemented by excavation behaviors. However, this control approach presents a new structure and operational paradigm that is developed based on, but different from the traditional behavior control method. Here, the behaviors are chosen using fuzzy excavation situation assessment with guidance of excavation task planning which embodies excavation heuristics and human strategies. Task plans are formulated using finite state machines which integrate neural networks for decision making. This organizational structure has the capability to include more excavation goals and to adapt to different environments via learning. Excavation behaviors are performed by primitive and machine executable actions or action sequences structured using finite state machines and simple action arbitration rules. The actions of human FEL operators were observed and analyzed to extract basic bucket actions and define rules of arbitration for different actions or action sequences under particular excavation environments. Fuzzy logic is applied to implement each excavation action where fuzzy rules represent the human experience and heuristics that are intrinsically linguistic, and bucket excavation motions are evaluated based on insufficient and inaccurate input sensory data. A variety of experiments were performed to test the ability of the proposed control algorithm. The laboratory-based experimental autonomous excavation system consists of a robotic arm, an excavation testbed, a force/torque sensor mounted between the robot arm wrist and the excavation bucket, and a control computer. Various rock piles to simulate realistic excavation environments and conditions were generated in the testbed. With these experiments, the control algorithm has demonstrated the ability to execute real-time automated loading cycles effectively and efficiently in complex excavation environments and under difficult digging conditions, through the use of the flexible excavation behaviors.

The objectives of this thesis are to identify key safety concerns related to the introduction of automated underground mining machines. Second, a synthesis of existing standards, and guidelines is required to identify what existing safety standards or parts of standards could apply to mining machine automation systems. Finally, a framework is required for the development of a safety standard or guideline for automated mining machine systems. / Two workshops were organized and facilitated by the author to document as many identified safety concerns as possible from a range of parties with a vested interest. Workshop participants included mine operators, automated mining equipment suppliers, safety professionals, students, and academics. In addition, an analysis of underground mining equipment accidents for the province of Ontario was completed. A review of European, and North American safety standards was performed to identify those safety standards which could be used for mining machine automation systems. A synthesis of applicable safety standards is provided. (Abstract shortened by UMI.)

The aggregate market of the Eastern United States is quantitatively modelled and the interaction of its components measured. Concrete and paving aggregate were the selected types for the purposes of this study. Using 1987 as base year, production is segmented into geographic units by using information obtained from the Mine Safety and Health Administration. The quarry price is given by an empirical relation, accounting for urbanization, and based on an extensive telephone survey. The global demand is determined by econometric procedures. The break-down by geographic unit is performed using construction data in an input/output manner. Transport, which is multi-modal, is simulated by linear programming. These concepts are consolidated by the optimisation of aggregate distribution. The model developed is used to simulate different situations, demonstrating the reliability of the obtained solutions.

Most blasthole drills currently used in the mining industry are manually controlled. The drilling control systems which do exist are based mainly on ladder programming logic techniques. This thesis presents a comprehensive strategy for the automatic control of blasthole drills, based on closed loop feedback control approach. / A detailed model for the controlled process consisting of the drill rig's mechanical actuators, machine structure, and the drilling process at the bit-rock interface is presented. The model equations are refined and validated by experimental (field) testing. The instrumentation of an Ingersoll-Rand DM-45E drill rig and the subsequent drilling tests in a limestone quarry are described, with an in-depth discussion of the field tests results. Analysis of the field tests data establishes the dependencies between the drilling variables and ground conditions during actual drilling. The transfer functions of the mechanical actuators of the machine are also identified. / A strategy for automatic control of feed pressure and rotary speed is proposed. The controller is tested and tuned by interfacing it to a software simulator of the controlled process which implements the relationships identified from field testing. Simulation results are presented and analysed. / Results of implementing the controller on a Gardner-Denver GD-120 electric drill, and an Ingersoll-Rand DM-H hydraulic drill at two surface coal mines in British Columbia, Canada, are also presented. These results validate the drilling controller design and tuning. / The thesis concludes with suggestions for future research and refinement of the control strategy.