ABSTRACT
Earlier, a preliminary investigation into the reliability characteristics of a fleet of load-haul-dump (LHD) machines deployed at Kiruna mine showed that the engine and the hydraulics are the two most critical subsystems. Hydraulic systems are selected for further study because such systems are still under a development phase. Maintenance data for two years for these machines are analyzed. The tests for trends and serial correlation showed that times between between successive failures for the hydraulic subsystems are not in most cases independent and identically distributed. Therefore, the times between failures (TBFs) data are analyzed using non-homogeneous Poisson process models like the power law process. The results indicate that the TBFs of the hydraulic systems are gradually decreasing. Emphasis is on the use of graphical methods for data analysis.
