Explanipedia

Reinforcement learning based automatic tuning of PID controllers in multivariable grinding mill circuits Open

J.A. Van Niekerk, J.D. le Roux, I.K. Craig · 2025

Bayesian optimization for automatic tuning of a MIMO controller of a flotation bank Open

Albertus V. Richter, J.D. le Roux, I.K. Craig · 2025

The Effect of Disturbances on Plant-Model Mismatch Detection using the Plant-Model Ratio: A Surge Tank Case Study Open

Heinz K. Mittermaier, J.D. le Roux, I.K. Craig · 2024

The surge tank in a bulk tailings treatment plant aims to reject flow and density disturbances. However, for large disturbances, there may be an inversion in the gain between the water inflow and tank slurry density for a linearized model …

Modelling of consumer dynamics to improve fuel gas blending control Open

Malusi Sibiya, A.J. Wiid, J.D. le Roux, I.K. Craig · 2024

Non-linear Model Predictive Control to Improve the Mineralogical Efficiency of Flotation Circuits Open

D.J. Oosthuizen, J.D. le Roux, I.K. Craig · 2024

Time Based Stiction Compensation Open

Gustaf Zacharias Gous, J.D. le Roux, I.K. Craig · 2024

Sticking valves tend to cause cycles in control systems used in industry, degrading product quality and yield. Many attempts have been made to alleviate the impact of stiction. Mechanical knockers are used with success to knock loose the s…

Model-Plant Mismatch Detection Using the Plant-Model Ratio: The Influence of Multivariable Systems Containing Both Fast and Slow Dynamics. Open

Heinz K. Mittermaier, J.D. le Roux, I.K. Craig · 2024

Automatic Tuning of Level Controllers in a Flotation Bank using Bayesian Optimisation Open

Albertus V. Richter, J.D. le Roux, I.K. Craig · 2024

On-line automatic controller tuning of a multivariable grinding mill circuit using Bayesian optimisation Open

J.A. Van Niekerk, J.D. le Roux, I.K. Craig · 2023

Process controllers are abundant in the industry and require attentive tuning to achieve optimal performance. While tuning controllers by the most primitive method of trial and error is possible, it often leads to sub-optimal performance i…

Observable Dynamic Models of Reagent Effects for Model-based Froth Flotation Control* Open

Jaco-Louis Venter, J.D. le Roux, I.K. Craig · 2022

This article demonstrates the feasibility of including simple reagent addition models in an existing observable dynamic model of a froth flotation circuit. The existing model has full state observability and parameter identifiability using…

Controlling a Grinding Mill Circuit using Constrained Model Predictive Static Programming Open

Zander M. Noome, J.D. le Roux · 2022

A constrained Model Predictive Static Programming (MPSP) method is implemented in simulation to a single-stage grinding mill circuit model. The results are compared to a constrained Nonlinear Model Predictive Control (NMPC) method. Both th…

On-line automatic controller tuning using Bayesian optimisation - a bulk tailings treatment plant case study Open

J.A. Van Niekerk, J.D. le Roux, I.K. Craig · 2022

The automatic tuning problem of multiple-input-multiple-output (MIMO) controllers is considered within the framework of Bayesian optimisation and applied in simulation to a bulk tailings treatment process. The aim is to develop a model fre…

Comparison of Semirigorous and Empirical Models Derived Using Data Quality Assessment Methods Open

Kevin Brooks, J.D. le Roux, Yuri A.W. Shardt, Chris Steyn · 2021

With the increase in available data and the stricter control requirements for mineral processes, the development of automated methods for data processing and model creation are becoming increasingly important. In this paper, the applicatio…

Optimizing grinding mill performance using extremum seeking control Open

Łukasz Ziółkowski, J.D. le Roux, I.K. Craig · 2021

Decentralised Model Predictive Control For Parallel Unit Operation Optimisation Open

A.J. Wiid, J.D. le Roux, I.K. Craig · 2021

This paper describes the application of decentralised model predictive control (DMPC) to parallel unit operations. A decentralised approach may provide advantages in terms of maintenance, online time, and tuning complexity. Total flow cont…

Reconstructing faulty measurements at a tailings treatment surge tank Open

K. Sekila, J.D. le Roux · 2021

Measurement faults in processing plants can cause the performance of a process to deteriorate. Once the failure of a sensor is identified, it is possible to reconstruct the missing measurement using the measurements of other sensors. Plant…

Disturbance Propagation Through a Grinding-Flotation Circuit Open

D.A. Wepener, J.D. le Roux, I.K. Craig · 2021

A survey on the status of industrial flotation control Open

J.D. le Roux, D.J. Oosthuizen, S M Mantsho, I.K. Craig · 2020

The Use of a Semi-Rigorous SAG Mill Model for a Hands-On Workshop Open

Margret Bauer, Kevin Brooks, J.J. Burchell, Loutjie Coetzee, J.D. le Roux , et al. · 2020

This paper describes the extension of a grinding mill model that is publicly available for educational and training purposes. This industrially derived model of a mill is used to explain complex concepts of advanced process control (APC) s…

Feed Size Distribution Feedforward Control for a Grinding Mill Circuit Open

Michael G. Maritz, J.D. le Roux, I.K. Craig · 2019

This paper proposes a method to measure and reject disturbances caused by changes in the ore distribution of the feed to a grinding mill circuit. A computer vision system is presented to measure the fraction of rocks in the feed, using onl…

State controllability of a froth flotation cell Open

J.D. le Roux, I.K. Craig · 2019

The control goals for a froth flotation cell are to maintain a stable pulp level and maximise the separation between valuable minerals to the concentrate and gangue to the tailings. Only a limited set of manipulated variables are available…

Optimal control of a rougher flotation cell using adaptive dynamic programming Open

Bei Sun, J.D. le Roux, Sirkka‐Liisa Jämsä‐Jounela, I.K. Craig · 2018

The operation of a rougher flotation cell affects the performance of mineral processing plant. The dynamics of a rougher flotation cell varies due to the diversity of the feeding conditions. In order to eliminate the dependence of optimal …

Steam Header State-Space Model Development and Validation Open

Rudzani Dzedzemane, J.D. le Roux, C.J. Muller, I.K. Craig · 2018

Steam distribution networks are used to provide energy to many industrial processes. The dynamic response of these networks is non-linear and multivariable. A system with such a response can be effectively controlled by making use of multi…

Optimised Blending of a Base Metal Refinery Feed Using Evolutionary Programming Open

J.J. Burchell, J.D. le Roux, I.K. Craig · 2018

At Lonmin’s base metal refinery a blending strategy is implemented to minimise variations in the mass flow of silica, iron, selenium, and tellurium into the plant. These impurities contaminate the plant’s products and control adjustments a…

An Industrial PID Data Repository for Control Loop Performance Monitoring (CPM) Open

Margret Bauer, Lidia Auret, J.D. le Roux, Vered Aharonson · 2018

Control loop performance monitoring methods to detect problems in PID loops are developed and tested using industrial data sets. The data is captured from the process, passed on to the researcher who tries out new detection and diagnosis m…

Plant-Wide Control of a Base Metal Refinery: Top-Down Analysis Open

J.J. Burchell, J.D. le Roux, I.K. Craig · 2017

A top-down control structure is presented for the optimal steady-state operation of a base metal refinery. The economic cost function for the plant is derived in terms of the production rate of primary and secondary products, the losses of…

Requirements for estimating the volume of rocks and balls in a grinding mill Open

J.D. le Roux, I.K. Craig · 2017

This study aims to indicate which measurements are required in order to estimate the volume of rocks and balls in a semi-autogenous grinding mill as two separate states. The nonlinear observer model used here includes the following process…

Nonlinear observability of grinding mill conditions Open

J.D. le Roux, Andreas Steinboeck, Andreas Kugi, I.K. Craig · 2016

A nonlinear observer model of a grinding mill is developed. The model distinguishes between the volumetric hold-up of water, solids, rocks and balls in the mill, where solids are all ore small enough to discharge through the end-discharge …

Plant-wide control of grinding mill circuits: Top-down analysis Open

J.D. le Roux, Sigurd Skogestad, I.K. Craig · 2016

A generic top-down control structure is proposed for the optimal steady-state operation of a grinding mill circuit. The economic cost function of the grinding mill circuit is defined with reference to the final product of the larger minera…

State and parameter identifiability of a non-linear grinding mill circuit model Open

J.D. le Roux, I.K. Craig · 2016

The states and unknown parameters of a non-linear model of a grinding mill circuit are shown to be identifiable from manipulated, controlled and measurable variables. All the states in the mill and sump, the breakage rates in the mill, the…

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