📋 Case Study

Underground Limestone Mine Ventilation Duct Inspection

Manual inspection of 4 km of 1.2 m diameter ducting in confined, low-light, high-dust environment posed fall and respiratory hazards

🏗️ Project Overview

Michigan Limestone & Chemical Co., Rogers City, MI

🎯 Challenge

Manual inspection of 4 km of 1.2 m diameter ducting in confined, low-light, high-dust environment posed fall and respiratory hazards

🔧 Design Approach

Custom VTOL drone with IP67-rated thermal + RGB payload; SLAM navigation in GPS-denied tunnels; AI-powered tear/seam detection trained on 2,400 annotated frames

📐 Design Diagram

AI-generated project design illustration

📐 Key Calculations

Thermal Delta Threshold

ΔT > 4°C indicates insulation breach

Result: 6.8°C

Correlated with 92% of airflow leaks

Inspection Coverage Rate

Linear km/hr

Result: 1.8 km/hr

3× faster than rope-access teams

📊 Results

Reduced inspection cycle from 14 days to 36 hours; identified 17 critical breaches previously missed; zero lost-time incidents over 18-month deployment

💡 Lessons Learned

• •SLAM drift accumulates beyond 800 m—requires periodic visual loop closure
• •Dust deposition on lenses mandates real-time auto-clean cycles every 90 sec

✅ Key Takeaways

• 1SLAM drift accumulates beyond 800 m—requires periodic visual loop closure
• 2Dust deposition on lenses mandates real-time auto-clean cycles every 90 sec