10 Apr Achieving higher production and recovery rates at lower costs – the benefits of Advanced Process Control in Mining
by Neels Van Der Walt, Iritron Head of Department Sales and Business Development
The mineral recovery process in the mining industry presents significant process control challenges due to its complex dynamics, including long time delays, dead time, multivariable interactions, and non-linearity. These challenges are present across various operating units such as crushing, grinding, flotation, leaching, thickening, filtration, and reduction kilns. Traditional process control methods often fall short in addressing these complexities, leading to suboptimal performance and requiring constant operator intervention in an attempt to stabilise and optimise plant performance.
Process Control Challenges in Mineral Recovery
The primary process control challenges in mineral recovery processing plants include:
· Complex process dynamics
· Long time delays and dead time
· Multivariable interactions
· Non-linear behaviour
· Variable ore properties
· Equipment configuration changes
These challenges make it difficult for operators, metallurgists, and process control engineers to maintain process stability while maximising production and quality.
Limitations of Traditional Control Approaches
Proportional-Integral-Derivative (PID) controllers, despite being widely used, have significant limitations when dealing with the process dynamics in mineral processing as described above, including:
· Poor performance with challenging loop dynamics
· Inability to handle multiple interacting variables effectively
· Limited optimisation capabilities
Even with enhancements like cascade control, feed-forward control, and ratio control, PID controllers struggle to bring stability to complex mineral recovery processes.
Rule-Based Expert Systems
While rule-based expert systems offer some improvements over PID controllers by mimicking the actions of experienced operators, they still leave a considerable margin for optimisation. These systems cannot fully capitalise on the equipment’s capacity due to their inherent limitations.
Advantages of Advanced Process Control (APC) and Model Predictive Control (MPC)
To address the shortcomings of traditional control methods, the mining industry is increasingly turning to Advanced Process Control (APC) and Model Predictive Control (MPC) technologies.
Benefits of APC and MPC:
· Improved Process Stability: APC and MPC can reduce process variability by up to 50% or more, allowing operations closer to equipment capacity.
· Increased Throughput: Implementation of APC has led to throughput improvements of 1-16% in various mining operations.
· Enhanced Recovery: Gold recovery improvements of up to 3% have been reported with APC implementation.
· Energy Efficiency: Cement mills using APC have seen power consumption reductions of 3.5 KWh/s per ton of cement.
· Optimised Resource Utilisation: APC performs timely adjustments to process parameters, leading to minimised reagent use and increased recovery in flotation circuits.
· Faster ROI: Some mining operations have achieved full return on investment in under 6 months after implementing APC.
MPC Technology Advantages:
· Seamless integration with existing control systems.
· Ability to handle complex dynamics and multivariable interactions.
· Feed-forward capability and automatic model identification.
· Adaptability to process changes.
· Constraint handling for more reliable and autonomous operation.
The automatic process control of mineral recovery processes is crucial for achieving desirable production and quality in high-value mining operations, regardless of the specific mineral being extracted. The technology selection for process control significantly impacts a plant’s optimal performance. Advanced Process Control (APC) and Model Predictive Control (MPC) technologies are becoming increasingly popular in the mining industry due to their ability to address complex process dynamics and optimise operations.
These advanced process control solutions enable metallurgists to operate closer to equipment capacity, achieving higher production and recovery rates at lower costs. By implementing APC and MPC, mining operations can expect more stable processes, increased throughput, improved recovery rates, and enhanced energy efficiency. As the mining industry continues to face challenges
with variable ore properties and complex process dynamics, the adoption of these advanced process control technologies will play a vital role in maximising operational efficiency and profitability.
ENDS (550 words)
Contact:
Neels van der Walt
Head of Department Sales and Business Development | Iritron
Contact: 083 387 7559
Email: neels.vanderwalt@iritron.co.za
Media Contact:
Charles Poulter
Director | SWM Communications
Contact: 076 812 8429
Email: charles@swmcommunications.co.za