Energy Consumption Optimization of Powertrain of Electric Underground Load-Haul-Dump Mining Loader

The emissions of heavy-duty underground machinery endanger the health of human workers and increase the overall maintenance cost of the underground mine due to ventilation expenses. In addition, tightening emission standards for non-road vehicles are pushing towards greener solutions, hence, fully electric powertrains are becoming a viable alternative for many applications. An electric powertrain is not only local emission-free, but also provides a better controllably and a superior energy efficiency compared to the conventional diesel operated machines. The nature of such vehicles and their periodic duty cycles enable energy optimization and a prospect of an improved efficiency. The aim of the thesis was to reduce the energy consumption of an underground load-haul dump mining loader. As most of the energy is consumed by the powertrain of the vehicle, the traction motors are the focus of the optimization. An optimal speed profile was generated by means of Bellman’s dynamic programming algorithm in MATLAB environment. The simulation utilized dynamic asynchronous motor, battery and vehicle models built according to a real-size experimental prototype. The algorithm had been designed to solve discrete time problems; therefore, the model was discretized with adjustable dynamic accuracy where the intermediate points were obtained by linear interpolation. The optimal speed profile demonstrated a 9.1% decrease in energy consumption for a generic duty cycle. Additionally, the asynchronous motors were operated at a higher efficiency area generating less heat and in theory prolonging the lifetime of the powertrain components

MULTIPLE DISCRETE-EVENT SIMULATION AND ANIMATION MODELS TO ASSIST MODERN MINING OPERATIONS

This research investigation was conducted to develop, execute, and analyze a collection of discrete-event system simulation and animation models for different modern mining operations and systems, including two open-pit gold mines, an aggregate mine (sand and gravel), an open-cast (strip) coal mine, and an underground mine evacuation operation. The mine simulation and animation models aimed to study and assess a wide range of practical unique and common "what if?" scenarios that the mine engineers and managers of the case studies posed in different aspects during the research. A comprehensive and detailed literature review was also performed to provide a summary of the published discrete-event system simulation projects and their applications in the mining and mineral industry. The simulation results of the investigation were effectively implemented to assist the engineers in maximizing the productivity of the mines, improving the operation processes, reducing the environmental impact of the haulage operations, and enhancing the equipment utilization in various case studies. In addition, due to the shortage of powerful and flexible computer simulation tools in designing and analyzing underground mining evacuation operations and rescue equipment with respect to the mine operating characteristics and layout, the discrete-event system simulation and animation technique was innovatively implemented for modeling these complex systems. GPSS/H® and PROOF Professional® were the simulation language and animation software used for this research work

Novel air monitoring technologies for volatile and semi-volatile organic compounds for sustainable development

Thesis (PhD (Chemistry))--University of Pretoria, 2023.Environmental protection and the search for cleaner, more sustainable fuels are two of the most important concerns modern society is facing. This research aims to determine whether a transition from fossil fuels to the use of biofuels will significantly lead to reductions in air emissions of potentially harmful substances, and thus to healthier, sustainable development. In this regard, assessing combustion emissions from key sectors and developing and testing novel monitoring technologies, such as a graphene-based sampler that offers sustainable advantages over currently available options, can facilitate extensive monitoring and management of volatile and semi-volatile atmospheric pollutants in a cost effective and efficient manner.NRF, grant number 105877Impala Platinum LtdChemistryPhD (Chemistry)Unrestricte

Prevention of Backing Fatalities in Construction Work Zones: Final Report

0-6703Construction, repair, and maintenance work zones are always hazardous environments, particularly given the dangerous combinations of pedestrian workers and large trucks, bulldozers, rollers, and other moving machinery. Workers are exposed to moving traffic near the work zone with the risk of errant vehicles entering the work zone area. Pedestrian workers are exposed to construction vehicle crashes within the work zone. Between 70 and 80 pedestrian construction workers are struck and killed each year by construction vehicles within a work zone. From 1995 to 2002, 844 worker deaths occurred in roadway work zones, of which 91% were related to motor vehicle traffic or construction equipment. Construction vehicle related deaths were responsible for more than half of these deaths. Dump trucks accounted for 41% of pedestrian-worker deaths and 52% of these involved dump trucks backing up. The American Road & Transportation Builders Association (ARTBA) named run-overs and back-overs as the leading cause of death for roadway construction workers, with over half occurring when workers were struck by construction vehicles or equipment inside the work zone. The purpose of this study was to review current practices and procedures to prevent backing fatalities, identify and analyze appropriate responses, and test commercially available systems for prevention of backing fatalities. Guidelines and recommendations for Texas Department of Transportation (TxDOT) traffic control practices, which incorporate commercially available systems for the prevention of backing fatalities in work zone operations, are also provided in this study