📋 Case Study

Underground Copper Mine Primary Crusher Bearing Replacement Strategy

Unplanned crusher main shaft bearing failures every 4–6 months causing >120 hr/yr downtime

🏗️ Project Overview

Deep-level block cave operation in northern Chile

🎯 Challenge

Unplanned crusher main shaft bearing failures every 4–6 months causing >120 hr/yr downtime

🔧 Design Approach

Implemented vibration envelope analysis + oil debris monitoring + Weibull-based replacement schedule aligned with mine production windows

📐 Design Diagram

Main ShaftCondition Monitoring SystemVibration
EnvelopeOil Debris
MonitorWeibull
SchedulerUnplanned Failure
(4–6 mo)>120 hr/yr downtimeProactive Replacement StrategyB10 Life = 5,240 hrDebris threshold: ≥8 particles
>100µm / 10mlProduction-aligned replacement windows✓ Scheduled
during low-production

AI-generated project design illustration

📐 Key Calculations

B10 Life (Weibull)

η × (ln(1/(1−0.1)))^(1/β)

Result: 5,240 hr

Set PM interval at 4,500 hr with 95% confidence

Debris Count Threshold

≥8 particles >100µm in 10ml sample

Result: Triggered immediate investigation

Detected incipient spalling 120+ hrs before failure

📊 Results

Zero unplanned bearing failures in 21 months; 97% planned maintenance execution rate; 34% reduction in spare bearing inventory

💡 Lessons Learned

• •Oil debris analysis outperforms vibration alone for rolling element fatigue
• •PM scheduling must integrate geological stopes sequencing

✅ Key Takeaways

• 1Oil debris analysis outperforms vibration alone for rolling element fatigue
• 2PM scheduling must integrate geological stopes sequencing