BAGASSE reclaimer failures are traceable from 1991 with multiple failures in
2005 and 2006 prompting a formal investigation into the root cause of failure.
The techniques selected for use were Failure Modes and Effects Criticality
Analysis (FMECA) and Root Cause Failure Analysis (RCFA). These are
common and powerful tools applied by reliability and maintenance engineers
involved in the identification of potential hazards, their criticality, and the
ultimate cause of failure. The initial analysis failed due its lack of structured
methodology and inability to look beyond the accepted cause. This root cause
was thought to be simply the introduction of tramp material with little
consideration of other possible causes. Following this first analysis, current
control was installed on the drive and Key Performance Indicators (KPIs) placed
upon fuel suppliers to ensure quality fuel. Twenty months later another failure
occurred, instigating a comprehensive and structured analysis with the
application of FMECA and RCFA. A number of possible failure modes were
identified including inadequate systems control, manufacturing flaws, slip-ring
failure, and transverse impact loading of the drive chain. Failure after
implementation of motor control and KPIs is not attributed to a single root cause
but to a combination of poor design, manufacturing defects and flawed
maintenance procedures. The welded link chain was replaced with a bolted link
configuration in conjunction with routine inspection and maintenance. Chain life
is anticipated to return to design life, with a $60 000 cost saving in the
2008/2009 budget. This initiative has faced cultural resistance but with
persistence has reaped encouraging results. Rewards extend beyond fiscal
integrity with a positive shift in maintenance strategy and attitude.