Stabilise your circuits. Reduce variability. Prepare for APC.
At a glance
1. Diagnose
2. Optimise
3. Validate
What is Loop Tuning & why it matters in mining
Loop tuning adjusts PID controller parameters (and related control logic) to align with actual process dynamics, accounting for lags, deadtime, non-linearities, and disturbances. In mining, where circuits run close to constraints, well-tuned loops translate into:
- Stable operation: Less oscillation in critical variables (e.g., density, level, flow, grind size).
- Fewer manual interventions: Operators spend less time switching modes and chasing setpoints.
- APC readiness: Robust base-layer control that supports advanced strategies (MPC, constraint control).
When base-layer control is tight, process variability drops, recovery improves, and bottlenecks become easier to identify and address.
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.
Benefits of PID Loop Tuning for mining operations
Reduced variability
Higher throughput within constraints
Improved energy efficiency
Operator confidence & safety
Foundation for APC and digital optimisation
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 unit operations
- Controllers bypassed or run in manual
- Output saturation and integral wind‑up
- Poor setpoint tracking; sluggish or aggressive responses
- Actuator and valve issues
What does this cost you?
- Recovery losses from reagent, air, pH and level variability
- Lower throughput due to milling or pump instability
- Unnecessary spend on reagents and power from instabilty poor control
- Higher energy draw from load swings
- Unplanned trips and increased wear from choppy control
Where it delivers the biggest impact
- Grinding circuits: Mill load, power, density, water addition, sump level toreduce cycling and improve grind stability.
- Flotation: Level, air flow, reagent dosing, froth depth tostabilise flotation cells to enhance recovery.
- Leaching & hydromet: pH, ORP, flow, temperature. Tighten control to improve reaction efficiency and consistency.
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 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
3.
- Apply proven PID tuning methodologies that respect process dynamics
- Implement cascade, feedforward, ratio, and decoupling techniques, where they simplify the operator’s job and improve disturbance rejection
- Improve base‑layer stability in complex circuits to enable Advanced Process Control readiness
4.
Implementation and validation
- Deploy tuning parameters in a controlled manner 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 and process distrubances
Improved metallurgical recovery via tighter pH, air, level and reagent control
Reduced energy consumption 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?
Mining-first expertise
Decades of on-site experience across commodities and geographies.
Practical, operator-led engagement:
Proven methodology
Pathway to APC
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 Metallurgy, EIC and operations teams
- 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.
Ready to optimise your control loops?
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 schedule a discovery call and align objectives, scope, and timing.
Some the questions we get asked
What’s different about Mipac’s tuning approach?
Why is everyone still using PID?
How long does a typical tuning engagement take?
What do you need from us?
Do we need new instrumentation to see benefits?
What results should we expect?
Will this disrupt operations?
Can you support across multiple sites?
Read more on process optimisation from the Mipac Insights library
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Mipac are global leaders in operational technology, control systems and engineering services.
We go beyond the expected solutions to deliver:
With 3 decades of experience, our team of engineers, project managers, and solutions developers has worked on more than 720 projects across 110 client operations.
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