📋 Case Study

Deep-Level Gold Mine BEME Fleet Transition (South Africa)

Extreme geothermal heat (>45°C), limited ventilation capacity, and high grid tariff volatility

🏗️ Project Overview

Transition of 24-unit LHD fleet at 3.2 km depth in Mponeng Mine

🎯 Challenge

Extreme geothermal heat (>45°C), limited ventilation capacity, and high grid tariff volatility

🔧 Design Approach

Hybrid opportunity charging + overnight depot charging; liquid-cooled battery packs with mine-water heat exchangers; dynamic load scheduling integrated with onsite solar microgrid

📐 Design Diagram

Deep-Level Gold Mine BEME Fleet Transition (South Africa) Challenges • >45°C geothermal heat • Limited ventilation • Grid tariff volatility BEME Cooling Mine-water HX Opportunity (at shift change) Overnight Depot Solar Microgrid Load Scheduler Thermal Margin 12.3°C Ventilation Load −820 kW

AI-generated project design illustration

📐 Key Calculations

Battery Thermal Margin

(Rated Max Temp − Ambient Temp) × Cooling Coefficient
Result: 12.3°C margin
Ensures <2% SoH loss/year

Ventilation Heat Load Reduction

Diesel Exhaust Heat − BEME Rejected Heat
Result: −820 kW
Enables 23% ventilation fan energy reduction

📊 Results

100% diesel displacement by Year 3; 37% lower OPEX; zero underground NOx emissions; 14-month ROI

💡 Lessons Learned

  • Liquid cooling integration requires early collaboration with ventilation engineers
  • Real-time SoH telemetry reduced unscheduled downtime by 68%
  • Grid-tied solar + storage cut peak demand charges by 41%

Key Takeaways

  • 1Liquid cooling integration requires early collaboration with ventilation engineers
  • 2Real-time SoH telemetry reduced unscheduled downtime by 68%
  • 3Grid-tied solar + storage cut peak demand charges by 41%