AMMJ - Library

Mill Downtime Tracking
Database Analysis
Gilbert Hamambi Ok Tedi Mining Limited
Gilbert.Hamambi@oktedi.com Papua New Guinea
Maintenance efforts need to be directed where it will matter most and the results should be measurable for
determination of success or failure. A systematic approach following Deming’s Plan-Do-Check-Act cycle to
identify short term immediate strategies to improve the Mill Availability at Ok Tedi Mine and put into place long
term strategies to sustain this uptime has been customized from the Mill Downtime Tracking Database.
A facility for drilling down to the dominant equipment failure causes is established. This now means that
rather than focusing on all the equipment the ‘significant few’ affecting Mill Availability can now be quickly
identified and their effects quantified using three key performance indicators: cost, frequency and downtime
duration. Viable solutions and improvement ideas can now be identified and focused at the dominant cause
of plant equipment failure. The drill down facilitation also enables quick justifications and easy tracking of
implemented solutions.
INTRODUCTION
The Mill comprises of two SAG Mills each having two Balls Mills in its circuit. The Mill Downtime Tracking Database
(MDTDB) is used for logging the downtime events of these two SAG Mills and their respective Ball Mills. In total
six mills’ downtime events are logged and tracked. The focus, however, will be on the two SAG Mills and the plant
equipment that have cost their uptime.
The MDTDB Analysis aim was to identify short term immediate strategies to improve the Mill Uptime and put into
place long term strategies to sustain it. The aim was also to provide a facility to drill down into the ‘significant few’
plant equipment rather than focusing on all the equipment. Viable solutions or corrective actions will be identified
for the dominant causes of each plant equipment breakdown which has cost Ok Tedi Mining Limited (OTML) in Mill
Availability. The data extracted for analysis was that logged over 18 months from July 2006 to December 2007.
Figure 1 The MDTDB record fields showing the type of data logged.
Vol 24 No 1