Takeaways
Regular maintenance on equipment can be life or death. Here, possible lives & hundreds of thousands of dollars were saved after detecting a bearing failure in a seemingly okay Man & Product Hoist.
Intro
On December 7th, 2020, Electrical Mechanic Mark Bay was called out to one of the world’s most profitable lead mines to perform routine maintenance, our Vibration PMP service. This was the first time the client had called us back to this operation since the Covid-19 pandemic slowed production. We’re glad that they did!
Client
Missouri Copper/Lead Mine
Equipment
Man & Product Hoist
Service
“This was very concerning
to me because this could be
a defective cage in the bearing”
The client brought us back on a limited route to perform Vibration testing on what they considered their most critical units. One of those units was the Man and Product Hoist at one of their biggest operations. While testing the vibration levels in the DC Motor and its two pillow block bearings on each side of the Pinion Gear, I noticed a difference in the readings when the hoist was spooling in verses when the hoist was spooling out.
I also noticed that there was also a faint ticking sound when the hoist was spooling in that I couldn’t hear when it was spooling out. This was very concerning to me because this could be a defective cage in the bearing. I stopped and decided to take several additional readings at each of the pillow block bearings with the cable being spooled in and out.
After analyzing the data, I contacted the maintenance staff with my findings. They took me into the sites managers office to discuss the situation and discuss how much time they had to deal with the situation. I told or rather warned them that they didn’t have any time. Given that this bearing is carrying thousands of pounds of product every minute of the day and more importantly it was carrying people in the shafts elevator, I felt that this should be dealt with immediately. If this bearings cage fails, the bearing as a whole would fail and cause a catastrophic event due to a chain reaction. Their maintenance staff took the hoist off line and proceeded to take the appropriate steps to replace the two bearings in the pillow blocks. On my next visit, the maintenance lead showed me the bearings and the cage was worn and had enough damage that when they took the bearing out, the rollers fell out!
With Covid-19 going on, I was glad that we were able to return to the mines in time to catch this before any failures occurred. The maintenance lead stated that a failure in these bearings would have cost the company hundreds of thousands of dollars in equipment and lost production. More importantly, what would it have cost if the hoist failed with men on the hoist. That would have been a tragedy you could not put a price on.