The Challenge
Milling is one of the most energy-intensive operations in mineral processing. To optimise efficiency and maintain grind quality, operators must closely manage mill loading relative to power input. However, real-world plant conditions—such as process drift, disturbances, suboptimal control limits, and feed variability—often obscure whether the mill is underloaded, overloaded, or operating at peak efficiency.
In response, Opti-Num was engaged to develop the Power Load Curve (PL Curve) Tool, a data-driven application that fits a dynamical model to power versus load data. The aim was to deliver a fast, visual method for diagnosing mill performance deviations and guiding operational improvements.
The PL Curve Tool integrates with plant systems to monitor live milling data, fitting a quadratic model on historical data to identify optimal operating points and track deviations over time.
Technical uncertainties included fluctuating signal quality, variability in data resolution, the reliability of curve fits under short-term plant noise and mill liner changes.
The Solution
Opti-Num developed a MATLAB-based tool that uses statistical curve fitting to model mill performance and generate real-time insights. The solution was designed to support both historical diagnostics and live monitoring via integration with plant data platforms.
- Real-Time Monitoring and Visualisation
The tool fits a parabolic curve to power vs. load data to identify the mill’s peak efficiency point. It provides engineers and operators with visualisations to quickly assess whether the mill is operating near that peak—or drifting away into less efficient milling regions. - Data Integration
The tool is integrated with the plant data platform to acquire and monitor live data and ensures automatic ingestion of load, power, and other relevant variables. - Refitting Logic
The model dynamically checks for changes in plant conditions that require curve re-fitting. - User-Friendly Interface
Delivered as a HTML dashboard and MATLAB GUI application, the tool allows plant personnel to explore different mill curves, assess current trends, and view suggested operating limits against current operating limits.
The Outcome
The PL Curve Tool provides plant engineers with a practical, insight-driven solution to improve milling control:
- Optimised Mill Operation – Operators can detect and correct underloading or overloading conditions early, preventing energy inefficiencies and poor grind quality.
- Improved Energy Efficiency – By continuously guiding operations toward the mill’s peak performance zone, the tool can lead to measurable reductions in energy consumption.
- Stronger Control Foundations – The PL Curve approach enables data-backed adjustment of control limits and supports the development of future closed-loop control strategies.
- Operator Confidence and Usability – Built with end-users in mind, the tool is visual, interpretable, and integrated into a plant data platform.
- Scalability – The methodology and interface are general is able across other milling units or sites using similar process control infrastructure.
By combining statistical modelling with real-world control knowledge, Opti-Num delivered a tool that enables data-driven milling decisions—advancing both plant performance and the foundation for autonomous optimisation.
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