A topic of much debate, both inside Bluefield and across the mining industry in general, is the use of pre-service inspections.
Do they add value?
Are they an unconscious acknowledgement that maintenance tasks (of all sorts, both preventive and corrective) are not being completed to the right standard or at the right time to achieve reliable equipment?
Or, is the implementation of pre-service inspections a proactive maintenance intervention that provides a short-term super-charge of the preventative maintenance cycle?
At Bluefield, we’ve seen numerous variations of pre-service inspections. While many add no value, one of the best outcomes was at a coal mine in Central Queensland. Equipment reliability, while OK, was not where the mine plan needed it to be. In the Mobile Maintenance Department, each shift had one fitter as an equipment inspector. While the resources were in place, there was no strategy and no dedicated inspection sheet and routine.
The four inspectors were brought back to dayshift and worked back- to-back doubled up. Their first task was to create a dedicated inspection sheet for their function, to be completed routinely each shift. Next, they had to collaborate with Production as to where, how and when the trucks would be inspected.
Inspectors then liaised with their planner to create a schedule for each truck with a target of a pre-inspection being completed 7- 10 days out from a scheduled service. You could easily argue that an inspection 7 to 10 days out from the service is not what many people term a pre-service inspection. It is really part of the scheduled downtime strategy in order to create a system of weekly inspections.
The inspectors were then re-located from sitting beside the shift-supervisor to sitting beside the maintenance planner. The process was then implemented with some clear boundaries for the pre-inspection function in place including a target duration of 4 hours per truck.
On commencement, the duration was difficult to achieve, but as the inspectors streamlined their process and become more efficient, this was easily met. Initially, the targeted inspection created approximately a 30% increase in defect identification and notifications across the truck fleet.
Additional short term resources were approved for the servicing/corrective work team to accommodate the bow wave of detailed planned work the inspectors created. Within a 3 month period of the process going live, the workload was becoming under control. The inspectors were also reporting back they were starting to see “clean” trucks on their inspections and were diverting to work on detailed planning for larger known defects or component changeouts.
Ultimately a decision will need to be made around continuing pre-service inspections or tackling the work quality piece or using a combination of both. On this site, this campaign together with improved planned maintenance, contributed to an improved truck availability of several points.
By John Thomsen