Moranbah North Mine: MG-113 Conveyor Control System Upgrade

The Challenge

Moranbah North’s MG-113 conveyor---a critical long-haul, high-lift system handling material across the mine---was experiencing control instability during operation. The existing PLC code relied on tuned PID control loops that struggled to maintain consistent load-sharing across multiple 630kW drive motors fitted with hydro-viscous clutches, particularly as system dynamics changed during material loading cycles.

Our Approach

Based on engineering analysis by E.J. O’Donovan & Associates, Deftec redesigned the control philosophy from complex PID-based algorithms to a proportional, hard-coded approach optimised for the MG-113’s specific operating conditions. Our team implemented revised logic for head-end secondary drive control and tripper-section drive management, with carefully filtered motor current feedback to enable stable load-sharing between the dual 630kW primary and secondary drives. The work encompassed full code development, simulation testing prior to commissioning, comprehensive documentation, and on-site validation to ensure the system responded correctly across all start, run, and stop scenarios.

The Outcome

The upgraded control system delivered reliable, predictable load-sharing between drives during both transient and steady-state operation. The proportional algorithm responds smoothly to changing conveyor load, eliminating the tuning drift that plagued the previous PID implementation. Moranbah North gained a control platform that scales with operational changes---critical for a system that experiences significant variations in material mass as it loads over extended cycle times.

Technologies and Capabilities

• PLC Programming and SCADA Systems — GE PLC code development and optimisation
• Conveyor Drive Control — Multi-motor load-sharing logic for hydro-viscous clutches
• Control Algorithm Design — Proportional feedback systems with heavy filtering for stability
• Dynamic Systems Analysis — Integration of third-party engineering recommendations into working control code
• Commissioning and Testing — On-site validation and performance tuning
• Technical Documentation — Detailed code specifications and test procedures for ongoing operations