Preventive Maintenance (PM) is defined as regularly scheduled maintenance intervals which are based on the average failure rate of a component and which may also be dictated by a production schedule. There are numerous cited advantages to preventive maintenance including potential extension to equipment life, greater uptime and cohesiveness with production schedules. The mining industry presents a distinct challenge to preventive maintenance due to the non constant operating conditions that vary from operation, site and even plant unit. This research thesis critically reviewed the application of preventive maintenance in the mining industry using operations from the Thiess Pty Ltd Australian Mining business unit as case studies.
The research study was conducted in three phases. The first phase involved an in depth literature review in order to gain a grounding for industry best practices as well as methods of optimisation and analysis of a maintenance operation. The second phase consisted of data collection and analysis. Using the tools for maintenance analysis determined in the literature review, key performance indicators were calculated and collected, then modelled over time to highlight the maintenance trend versus time, machine age and location. The third phase used a strengths, weaknesses, opportunities and threats (SWOT) analysis to develop recommendations which would bring the current maintenance system into line with industry best practice and provide measures for continuous improvement of its efficiency.
Following the maintenance performance and subsequent SWOT analysis, it was concluded that preventive maintenance is suitable and effective in the context of the mining industry. However a number of weaknesses were identified in the current maintenance system including inaccurate recording keeping leading to misguiding key performance indicator reports, a determined lack of investigation into root cause failure mechanisms, unrealistic planning targets, specific component groups leading to unscheduled maintenance and the insufficient information available on the condition of plant before maintenance is scheduled.
Furthermore a number of external threats to the effectiveness of the maintenance system were identified as a difference in the maintenance performance from site to site and a lack of evidence for continuous improvement as determined throughout the analysis phase. Potential opportunities uncovered during the study were taking advantage of a number of technological developments in predictive and condition monitoring systems as well as adopting reliability centred and total productive maintenance methodologies. Findings which were not attributed to a particular section of the SWOT analysis were the potential for monitoring the life of components versus the expected life as specified by the original equipment manufacturer and the need for standardised reporting of work order summaries to aid in continuous improvement.
The subsequent recommendations made from the SWOT analysis were then split into three groups. The first group was recommendations affecting aspects of the maintenance system which already exist and however are not working to the full potential. This included a review and standardisation of the metrics used to monitor plant performance and a review of the maintenance schedule estimation strategy. The second category was recommendations which use existing resources and are not currently part of the formal maintenance system. This included implementation of total productive maintenance initiatives and implementation of root cause analysis methodology into the current maintenance system. The third category was recommendations pertaining to new strategies and technologies which do not exist within the current maintenance system which involved implementing new condition monitoring technologies such as vibration monitoring. The thesis successfully answered the research questions and achieved the established research aims.