Methods for availability improvements of a scaling machine system

Abstract: Scaling is the process of cleaning loose material from the roof, face and wall of the mine room in underground mining. The purpose of scaling is to make the mine room safe for the next operation. Due to the nature of the task, scaling has been identified as an operation with a high number of accident occurrences. The use of a scaling machine to replace hand scaling has successfully reduced the number of scaling-related accidents. However, due to the combination of a hostile environment (such as falling rock, dust, high humidity, etc.), the operation context (e.g. significant vibrations), and reliability and maintainability issues, the scaling machine is identified as one of the major contributors to unplanned downtime. The purpose of this research is to develop methods that can be used for identifying the availability related problems and improving the availability of the scaling machine system in a cost effective way. To achieve the purpose of this research, literature studies, case studies, and simulationsstudy have been conducted. Empirical data have been collected from field measurements, document studies, interviews, and observations. For data analysis, theories and methodologies within reliability, availability and maintainability (RAM), ergonomics and optimization have been combined with the best practices from the related industry. A first result of this study is the development of a method for visualization of the downtime that provides a visualization of the downtime estimation and the precision and the uncertainty of the estimation at a given confidence level, as well as factors influencing the failure. Second result is the identification of components that significantly contribute to the downtime and the reason for that downtime (reliability and/or maintainability problem). Based on the failures analysis, suggestion for the improvement of the critical component is also proposed. Third result is the identification and analyzing of performance shaping factors (PSFs) that can affect to the reliability of scaling machine system. Fourth result is a proposed methodology that can help the design team to select which components of a system are needed to be improved and to which level the improvement should be done to optimize the availability of system in a cost effective way. Finally, the fifth result is a proposed method for a robust-optimum multi-attribute age-based replacement policy. The proposed approach can be used to determine the interval time for preventive replacement that provides a robust and optimum solution for a multi-attribute age-based replacement policy. These results are related to specific industrial challenges, and are expected to enhance the capability for improving the availability of the scaling machine system in a cost effective way. The results have been verified through interaction with experienced practitioners from both the manufacture and the user (i.e. mining company) of the scaling machine.