Hi Charles,
Some context around the installation and operation would probably help, along with how your operation calculates those metrics. A couple of notes / comments:
- Does you MTTR calculation include or exclude planned stoppages? If it includes your mill relines it will likely be much higher and benchmarking may not make sense. It's much faster to reline a small rubber lined mill than a three-can large Ball Mill.
- What are you looking to get out of benchmarking? I'd normally use those metrics to track performance and improvement over time rather than comparing to other sites that may have vastly different equipment, operating contexts, etc.
I don't have access to enough data to give you a real benchmark on mills, and you would want to compare your site to similar operations. I've mainly worked with Copper and Gold mining clients running two- or three-stage comminution (SAG primary and one or two Ball secondary, some sites with a regrind mill). Performance has varied considerably. Some operations regularly run their mills without failure between their shutdown cycles (8+ weeks), while others regularly experience multiple failures a week.
Having said all that, if you're looking for some rough guidance, anything less than 100 hrs for MTBF indicates significant room for improvement. Excellent performance I'd guess more than 8 weeks (+1344 hrs). Most sites I've worked with would sit somewhere in between (with more sites close to 100hrs than +1000).
MTTR would be heavily dependent on your metric calculation, mill configuration and operating context. I don't remember looking at maintenance ratios on mills recently either.
This is just my 2 cents, and it isn't data backed. I'm interested to hear others experience..
------------------------------
Benjamin Prior CMRP, BEng, MBA
Manager, Physical Asset Management & Reliability
Priority Consulting Inc
Berkeley CA
------------------------------
Original Message:
Sent: 09-01-2023 06:26 AM
From: Charles Britz
Subject: SAG Mill and Ball Mill Maintenance Metrics
Can anyone share standard maintenance metrics benchmarks for SAG Mill and Ball Mills? What's good MTBF & MTTR targets as well as Maintenance Ratios?
Perhaps there is another forum someone might recommend.