Bluefield Round Table – Worst Defects

Aug 8, 2019 9:50:42 AM

Bluefield regularly undertakes asset inspections and asset integrity assessments that expose us to the best and worst of asset conditions. We’ve learned a lot over the years both from finding major equipment defects, and then understanding how they came to occur. We asked our specialists the following question: 

What's the worst defect you've ever found when inspecting an asset, and what caused the defect to occur? 

Leon Best 

Emergency generator Incoming wiring. The electricians had used a red phase as the earth cable and had also not changed its outer sheath colour to green.  

Bad practice, no documentation, no prior tests completed, client acceptability of finished product. 

Brett Peebles 

Long time since I did inspections! Really bad chassis cracks around the nose cones on 793C dump trucks at a previous site I worked at is probably the worst I can recall. 

Colin Sheldon 

Worst in terms of the extent and the potential consequence - crack initiated failure of the tie-rod clevis on a fleet of mining ultra-class haul trucks. After an initial fracture failure on one machine, we inspected the whole fleet and each truck showed the same cracking within the clevis. We then went looking for a strategy, to find that there was none. Even the OEM recommended minimum inspections were not fully captured within the preventative maintenance check sheets. A lack of maintenance was a certain contributing factor. We implemented a new strategy and checks and raised the defect with the OEM. 

View Colin’s video on his other learnings from previous projects. 

Gerard Wood 

Not a defect that I found on a machine, but I found a report of a HP fuel hose rubbing on an electric cable, and there was no subsequent work order raised in the system, and a fuel hose that was cracking with no notification raised. (See picture below). One of our other specialists found some defects on some machines in a mine which were the exact same defects that had previously caused fires, and no-one had addressed them. 

 HP Fuel Host



Read Gerard’s article on mobile equipment fires here. 

Matthew Grant 

Not so much a defect – more a catastrophic failure at that point.  About two weeks after I’d started a previous job as a reliability engineer, we had an entire cone crusher fall in half and collapse. The flow of ore through the crusher had worn through not only the liners, but the frame itself.   

Three issues came together. Firstly, the process had changed slightly, and the liners were wearing in a different position to normal (and faster than normal). Secondly, the liner inspection and measurement process was haphazard at best. Thirdly, we were not tracking liner wear as part of our maintenance strategy and using this to plan and schedule repairs. All of these were sorted out pretty quickly afterwards, but the damage was obviously done.