Picture this: there is a critical equipment issue that needs to be solved, and the solution itself is relatively simple. However, in fixing this primary issue, several new issues are created. How could we recognise and address these secondary issues before we fix the primary issue? The answer is often to follow a management of change (MoC) procedure.
Let’s discuss the issues that can be caused when a management of change procedure is not followed (or in this case, does not exist).
The maintenance nightmare
My first role as an expatriate took me to a mine in Central Asia. I at the time knew no better, but nothing was planned properly; there were no procedures, no crew training matrices, no LOTO, no JSA, no SWP, no equipment inspections and maintenance was 100% reactive.
Additionally, no CMMS existed and no equipment history was kept, meaning some repairs which may have been out of the ordinary (as a lot of the repairs at this site were) simply went off into the annals of history.
In my role as maintenance supervisor (then superintendent), I wore many hats – I was the maintenance engineer, reliability engineer, maintenance planner, call-out supervisor, and whatever else was needed at the time.
The equipment in the plant was a mix of former Soviet Bloc and Western process equipment, and the maintenance requirements of the two régimes were very different, as you would expect. The Western equipment required very specific maintenance tasks, whereas the Soviet equipment was very simple to repair, service and keep running.
One job was to overhaul a Western multi-stage freshwater pump (2 of which were installed). The pumps were used to lift fresh water around 400m up and around 2km back to the water storage tanks above the process plant. I discovered that the previous expatriate trainer had only involved the local workers with minimum ability to complete the job.
Training and coaching
I printed a few copies of the exploded diagram of the pump and handed them out to the crew. I had the pump brought to the workshop and, suddenly, the crew who had been kept away from working on these pumps were swarming all over it, chattering in the local language about the hows and whys of the pump.
The pump was stripped down, the replacement parts were received from the warehouse and the rebuild began. I watched, diagram in hand, as the crew rebuilt the pump, checking on the drawing and talking to their supervisor as they worked.
It took around a day to get the pump up to the workshop, two to strip and rebuild it and another day to get it back to the freshwater pond and re-installed. During this process I learned that these pumps required rebuilding after around 6 months of operation.
The need for change
I returned to site after my usual break period to be told that there was a massive, mine-closing issue with the freshwater pumps. It had been decided (unbeknownst to me), to change the suction from what had been a 2-meter suction head to a flooded suction. This was done whilst I was on R&R.
The pumps which usually ran at 3000rpm pulling 600A, now tried to pull 900A, made a screaming noise and stopped, dead.
Taking a handful of the crew with me, we opened up the first pump and discovered that the impellers and diffusers had welded together – there appeared to be a lack of lubricant inside the pump.
After numerous strips and rebuilds, and a lot of head scratching, it was decided to skim the impellers down by 15mm incrementally from their original outer diameter, which allowed the pumps to run up to 3000rpm, pulling 600A.
Due to the severe water shortage the change to the pump intake had caused, I decided to task another team to get a Soviet 12-stage pump and a Bulgarian motor prepared on a skid, in-case our trials with the Western pumps failed.
By the end of the week, with more mounting pressure, we managed to get both the Western pumps and the Soviet pump running, though, due to the flow characteristics, only one pump could be ran at a time.
For me personally, whilst getting all 3 pumps operational was quite a satisfying victory, the satisfaction of repairing something so critical was somewhat diluted when no-one else on site had any idea of what to do.
Indeed, the pumps needed to be changed from a negative suction to a flooded suction, the freshwater dam level was falling, and the pump’s suction lines were in danger of being out of the water.
The issue was, in implementing the required changes, all the other necessary changes were totally overlooked – putting the mine at risk of closure and placing extra pressure on the already stressed maintenance team.
No thought was paid to the available pump spares, no back-up plan was put in place, no thought was given to how a flooded suction would affect pump performance. Additionally, had the crew not been trained on the rebuilding of the Western pumps, I am unsure if the task could have been completed before the mine ran out of water.
Had proper management of change been in place, we could have addressed some of these issues:
- The effect of changing the Western pumps suction setup would have been recognised;
- The Russian pump back-up plan would have already been in place, rather as a reaction to the Western pumps failing;
- The situation with available pump spares would have been known, and impellers already skimmed down; and
- The requirement for the impeller changes would have been known to begin with.
We have observed in the past the impact operations can have on equipment reliability, and how improvements to maintenance processes can help to avoid unnecessary shutdowns. In our experience, poor equipment reliability often costs organisations more than they realise.
If your organisation needs assistance in improving equipment reliability, we would be happy to discuss the challenges you are facing. An obligation-free discussion with our consultants can help you to understand your options moving forward, and may offer advice that you can take away and begin to implement immediately.