Improve plant stability, recoveries, and energy efficiency with expert control loop tuning and control strategy optimisation.
We work peer‑to‑peer with operations and metallurgy teams to stabilise base‑layer control, reduce variability, and prepare circuits for advanced control. PID remains the workhorse in industry, but performance depends on tuning, strategy, and valve behaviour.
Key takeaways
- Stabilise base‑layer control to lift throughput and recovery and reduce energy intensity.
- Eliminate cycling, saturation, stiction effects, and fragile control logic.
- Build APC readiness: cascade, feedforward, decoupling and constraint handling done right.
- Validate changes with step tests and objective metrics (e.g., IAE, control variability).
Why control loop tuning & optimisation matters
Even robust plants leave value on the table when loops are oscillatory, left in manual, or constrained by valve non‑linearities (stiction, hysteresis). Over time, small issues can propagate across grinding, flotation, leaching, and thickening, ultimately harming stability, recovery, and operator confidence.
Industry bodies continue to publish guidance that raises the bar for PID performance and terminology, reflecting the significant potential still existing in base-layer control.
Common symptoms we fix
In a typical processing plant, up to 30% of control loops may be underperforming at any time. In these plants, we often see:
- Loop cycling that propagates upstream/downstream
- Controllers bypassed or run in manual, reducing automation value
- Output saturation and integral wind‑up
- Poor setpoint tracking; sluggish or aggressive responses
- Actuator and valve issues (deadband, stiction, positioner mismatch)
What does this cost you
- Recovery losses from reagent, air, pH and level variability
- Lower throughput due to milling or pump instability
- Higher energy draw from load swings
- Unplanned trips and increased wear from choppy control
Our approach to control loop tuning and process control optimisation
1.
Plant assessment and data capture
- Prioritise loops tied to production KPIs and constraints
- Pull historian/DCS data (PI, DeltaV/PCS/800xA, Yokogawa, etc.) and deploy portable logging if needed
2.
Performance analysis (objective metrics)
- Detect abnormal behaviour: dead time, non‑minimum phase, actuator saturation, loop interaction
- Benchmark with IAE Integral Absolute Error) and control variability metrics to quantify improvement opportunities (IAE is widely used in academia and practice for tuning/trade‑off evaluation)
3.
Optimisation and tuning
- Apply proven PID tuning methodologies that respect process dynamics (process gain, time constants, dead time)
- Implement cascade, feedforward, ratio, and decoupling techniques, where they simplify the operator’s job and improve disturbance rejection (standard control structures taught in PD&C curricula)
- Improve base‑layer stability in complex circuits to enable Advanced Process Control readiness
4.
Implementation and validation
- Deploy tuning parameters in a controlled manner (MOC-ready), with step tests and disturbance challenges
- Work closely with operators to build confidence in changes and maintainability
5.
Continuous improvement (optional)
- Set up lightweight dashboards and alerts for ongoing loop performance
- Train metallurgists and operators to maintain loop health and recognise drift
What you can expect
Many sites see measurable wins after a focused tuning campaign:
Throughput uplift from reduced variability in grinding and flotation
Improved metallurgical recovery via tighter pH, air, level and reagent control
Lower energy intensity by stabilising mill load and pump operation
Reduced unplanned downtime through smoother control action and fewer equipment trips.
Results vary by circuit and the quality of the instrumentation.
We validate gains using before-and-after metrics and shift-level feedback.
Why choose Mipac?
You’re not buying a cookie‑cutter “retune.” You’re getting a team that blends control systems, instrumentation, metallurgical, and operating insight. We tune loops with an understanding of the process, and we leave your team with the confidence and tools to keep it tuned.
How we work on site
- Peer‑to‑peer with Processing Managers, superintendents, the Met team and control engineers
- Operator‑friendly changes with clear “why” and “what to watch”
- Minimal disruption; fast, measurable improvements
Case Study: Evolution Northparkes
[Copper/Gold] Grinding & Flotation Control Loop Optimisation
Challenge:
Grinding and flotation circuits were unstable, with poor control of mill load, sump levels and flotation air/levels, leading to variable throughput.
Actions:
Designed and commissioned new control loops with improved instrumentation (flash flotation density control), retuned strategies, and provided operator loop-tuning training.
Outcomes:
More stable SAG mill and flotation operation, improved circuit consistency and throughput, and extended SAG mill liner life.
Book a Control Loop Performance Audit
Get a site‑specific audit and a prioritised action plan within weeks.
We’ll identify the highest-payback loops, implement low-risk improvements, and quantify the gains.
Get in touch with our optimisation team today to start the conversation.
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Some the questions we get asked
What’s different about Mipac’s tuning approach?
Why is everyone still using PID?
Will this prepare us for APC/ML?
How long does it take?
What do you need from us?
Mipac are global leaders in operational technology, control systems and engineering services.
With more than 28 years of experience, our team of engineers, project managers and solutions developers have worked on more than 720 projects. We go beyond the expected solutions to deliver:
- Advanced Process Control
- Industrial Automation, including Main Automation Contracting
- Data Analytics and Visualisation
- Process Optimisation
- Cybersecurity
- Industrial Software Solutions
- Electrical and Instrumentation
- Operations Support, inc Procurement
- Industry 4.0 Consulting
Contact us today and let’s start the conversation about how the Mipac team can bring your next project closer to achieving operational excellence.