Browsing by Author "Knights, PF"

Now showing 1 - 7 of 7
  • No Thumbnail Available
    Item
    A model for optimal armature maintenance in electric haul truck wheel motors: a case study
    (2004) Lhorente, B; Lugtigheid, D; Knights, PF; Santana, A
    The objective of the work presented in this paper is the determination of an optimal age-based maintenance strategy for wheel motor armatures of a fleet of Komatsu haul trucks in a mining application in Chile. For such purpose, four years of maintenance data of these components were analyzed to estimate their failure distribution and a model was created to simulate the maintenance process and its restrictions. The model incorporates the impact of successive corrective (on-failure) and preventive maintenance on necessary new component investments. The analysis of the failure data showed a significant difference in failure distribution of new armatures versus armatures that had already undergone one or several preventive maintenance actions. Finally, the model was applied to calculate estimated costs per unit time for different preventive maintenance intervals. From the resulting relationship an optimal preventive maintenance interval was determined and the operational and economical consequences and effects with respect to the actual strategy were quantified. The application of the model resulted in the optimal preventive maintenance interval of 14,500 operational hours. Considering the failure distribution of the armatures, this optimal strategy is very close to a run-to-failure scenario. (C) 2004 Elsevier Ltd. All rights reserved.
  • No Thumbnail Available
    Item
    Drawpoint control using radio frequency identification systems
    (1996) Knights, PF; Henderson, E; Daneshmend, LK
    Drawpoint control is critical in determining the cutoff point for load-haul-dump mucking operations to minimize dilution. it is also necessary to ensure even mucking distribution and to prevent possible hang-up of material within a slope. A prototype production monitoring and reporting system has been developed for load-haul-dump operations in underground mines. The system generates accurate and timely information regarding mucked tonnages and drawpoint and ore/waste pass utilization. The monitoring system integrates a PLC-based load weighing system with a radio frequency identification (RFID) system for locating the vehicle. The system records the identification and time of entry and exit of each drawpoint and ore/waste pass visited during a shift as well as the weight of each bucket load. A trial of the system was conducted at the CAN-MET Experimental Mine near Val d'Or, Quebec. The monitoring and reporting system functioned as designed, with the exception that the maximum read range of the RFID rags under dynamic conditions was found to be a limitation. RFID systems with greater range capabilities have been identified for a second generation system, The system is the first of its type in North America to demonstrate that RFID tags can be successfully applied to locate trackless underground equipment. Because of their ability to locate equipment and personnel within underground mines, RFID systems should be considered a key technology for future mine information and process control systems.
  • Thumbnail Image
    Item
    Labor productivity and comparative advantage in mining: The copper industry in Chile
    (ELSEVIER SCI LTD, 2001) Garcia, P; Knights, PF; Tilton, JE
    Over the past two decades, the copper industry has enjoyed dramatic increases in labor productivity in both Chile and the United States. Recent research attributes most of the increase in the United States to innovation and technological change, rather than the exploitation of higher quality copper deposits due to the development of new mines and a shift in output from low to high productivity mines.
  • No Thumbnail Available
    Item
    Open systems standards for computing in the mining industry
    (CANADIAN INST MINING METALLURGY PETROLEUM, 2000) Knights, PF; Daneshmend, LK
    Key issues in managing information systems in the minerals industry will likely continue to be those relating to the integration and interoperability of disparate systems. This paper argues that, in order to harness the promised benefits of information technologies, the mining industry should adopt a set of open systems standards to define data formats and protocols for seamless data exchange. This is in direct contrast to the present situation where mining equipment, software and instrument suppliers rigidly adhere to proprietary standards for fear of losing competitive advantage. Benefits to the mining sector resulting from the adoption of such standards would be: the provision of near-time data for executive decision support and the freedom to choose best technologies. The principal benefits to the leading mining software suppliers will be increased market share as a result of "captive sites " converting to open systems standards, Examples are given of open systems standards developed for related industries such as the Petroleum Open Systems Corporation (POSC) and the Machinery information Management Open Systems Alliance (MIMOSA).
  • No Thumbnail Available
    Item
    Reliability model for the optimal replacement of shovel cables
    (INST MINING METALLURGY, 1999) Knights, PF; Segovia, RA
    A reliability model has been developed for the optimal replacement of mining shovel cables on the basis of adherence to a replacement policy governed by number of hours. Change-out times are determined that minimize the expected cost per operating hour for cable replacements. The model is generic in nature and can be applied to non-repairable components subject to wear that have high capital and installation costs and do not lend themselves to continuous condition monitoring. The model incorporates the effect of periodic inspections and provides a methodology for the calculation of confidence intervals associated with replacement times and hourly operating costs.
  • No Thumbnail Available
    Item
    Simulation of initiatives to improve mine maintenance
    (INST MINING METALLURGY, 2001) Louit, DM; Knights, PF
    Synopsis
  • No Thumbnail Available
    Item
    Statistical correlation of off-highway tire failures with openpit haulage routes
    (SOC MINING METALLURGY EXPLORATION INC, 2001) Knights, PF; Boerner, AL
    Off-highway tire costs represent a significant portion of the total mining costs in openpit, truck-shovel operations. To extend the lives of tires, the site-specific factors influencing tire life should be investigated. Valuable data can be obtained by combining historical operational data captured by a mine dispatch system with detailed tire and maintenance histories. Assuming that failure counts satisfy a Poisson distribution, F-tests can be applied to determine significant deviations from desired or target counts.