M. Tech. Industrial Engineering / The Reconfigurable Vibrating Screen is a newly designed beneficiation machine to be used for mineral particle separation in mines and quarries with adjustable screen capacity and structure in order to respond to changes in production and quantity demand required by the customers. In order to increase the durability, availability, reliability and maintainability of a reconfigurable vibrating screen, an effective method is required to functionally appraise and improve its working condition. The aim of this study is to develop a tool for functionally assessing reconfigurable vibrating screens and existing vibrating screens.

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Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1939. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed March 25, 2010) Includes bibliographical references (p. 123).

Thesis (Ph. D.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xviii, 193 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 191-193).

M.Phil. / In an ever - increasing competitive business world it is essential to optimise the replacement of expensive mining equipment. The decisions regarding the replacement of assets used in a coal mine are usually based on life cycle costing models. Financial methods such as Net Present Value, Internal Rate of Return or Payback are applied to determine the feasibility of replacement of the asset. Whereas these methods and other models such as life cycle costing, challenger / defender and the Non-Homogeneous Poisson Process models can be applied in most cases, it is deemed to be insufficient as the sole decision making tool for the replacement of mining equipment. The development of another tool to assist in the decision making process is required for specific use by the engineer to be used in conjunction with the traditional financial models. Key performance indicators are used extensively in the mining industry to manage the performance of equipment and are deemed to be essential components in achieving the organisation's objectives. There are certain limitations when using only the traditional financial life cycle costing methods when viewed from the engineer's perspective, since they do not directly incorporate the level of the maintenance function and the performance effectiveness of the asset. The engineer usually requires more insight into the performance of the asset to assess the feasibility of replacement, hence the need for an additional tool that incorporates these key performance indicators. In most cases there are relationships between the various key performance indicators themselves as well as between them and the operating and maintenance cost of the asset. The key performance indicators used are availability, reliability (mean time to failure), maintainability (mean time to repair) and the operability (tons per direct operating hour). There are certain factors that may lead to the excessive operating and maintenance cost of an asset, especially if there is no investigation into the reasons for the excessive cost. Examples are sub-standard maintenance practices and an insufficient level of service from suppliers. Both are issues that can be resolved with a consequent decrease in the cost of ownership of the asset. Cost as the only indicator of the feasibility of replacement may therefore not be a true reflection of the real status of the performance of the asset. Weighting factors are used to allocate values to the key performance indicators in terms of their contribution towards achieving the organisational objectives. The equipment effectiveness is derived from these values to give an indication of how well the equipment is performing against predetermined benchmarks. This dissertation attempts tb find a solution to the problem through the use of the key performance indicators in addition to the existing models that focus on the financial aspect in order to provide a more accurate assessment of the replacement requirement of an asset in an opencast coal mine.

D.Ing. / The research described in this thesis is an investigation into fundamental aspects of the mechanical excavation of hard rock using free rolling cutters, currently being undertaken at the Chamber of Mines of South Africa Research Organization. The motivation for undertaking this study was provided by the need to improve the effectiveness and operational efficiency of this type of tool with regards to its application in the South African gold mining industry. Earlier work has shown that the use of high-pressure water jets enhances the performance of mechanical cutting in hard rock. To assess the potential of this approach for use in conjunction with free rolling cutters, a series of laboratory tests was conducted using both disc and button type cutters, to determine the relative effects, on cutter performance, of variations in the relevant jet and cutting parameters. The parameters investigated were jet pressure, jet configuration, depth and spacing of cuts and cutting speed. Jets of diameter 1,2 mm were used singly and in combination of 2 and 4 jets at pressures in the range of 5 MPa to 40 MPa which gave flow rates of up to 0,3 lis per jet. Cut spacing, cut depth and cutting speed were varied between 15 mm and 90 mm, 2 mm and 6 mm, and 0,1 mls and 1,0 mls respectively. Tests were carried out on a linear rock cutting machine, purpose built according to specifications prepared from measurements made during underground field trials, which gave it the ability to test full-scale cutters under loading conditions representative of those found in the field. All the tests carried out were performed in the constant penetration, multiple pass (groove deepening) cutting mode, using dressed (smooth) and pre-conditioned (pre-roughened) rock surfaces.

Includes bibliographical references. / This project was commissioned in order to provide engineers with the necessary knowledge of steel wire winder ropes so that they may make accurate decisions as to when a rope is near the end of its useful life. For this purpose, a knowledge base was compiled from the experience of experts in the field in order to create an expert system to aid the engineer in his task. The EXSYS expert system shell was used to construct a rule-based program which would be run on a personal computer. The program derived in this thesis is named ROPES, and provides information as to the forms of damage that may be present in a rope and the effect of any defects on rope strength and rope life. Advice is given as to the procedures that should be followed when damage is detected as well as the conditions which would necessitate rope discard and the urgency with which the replacement should take place. The expert system program will provide engineers with the necessary expertise and experience to assess, more accurately than at present, the condition of a winder rope. This should lead to longer rope life and improved safety with the associated cost savings. Rope assessment will also be more uniform with changes to policy being able to be implemented quickly and on an ongoing basis as technology and experience improves. The program ROPES, although compiled from expert knowledge, still requires the further input of personal opinions and inferences to some extent. For this reason, the program cannot be assumed infallible and must be used as an aid only.