Associate Professor Mohsen Yahyaei

Program Leader - Advanced Process

Julius Kruttschnitt Mineral Research Centre
Sustainable Minerals Institute
m.yahyaei@uq.edu.au
+61 7 334 65989

Overview

I hold a Ph.D. in mineral processing and I have more than 13 years industrial and academic experience. My goal is to learn how to implement fundamental understandings in my research for offering solutions to minerals industry and also educate engineers and researchers with problem solving skills for tackling future challenges of our industry.

Planning and implementing multi-disciplinary projects in comminution, flotation and thickening for numbers of funded industrial project provided me with a strong desire to conduct applied research underpinned by sound fundamental understanding. Having opportunity of being in a high calibre research team in the JKMRC, a world leading research centre in mineral processing, and actively collaborating with the international community of researchers has broadened my vision on issues associated with minerals industry. In light of that vision, I have focused my research on a new approach in ore characterisation for comminution which is a crucial step in the path way toward developing mechanistic breakage models. However, I am still continuing the research I did in my Ph.D. to develop a predictive liner wear model.

The joy I experienced as a superintendent engineer in a coal processing plant always keeps me motivated to conduct industry based projects. Coordinating and conducting a couple of successful industrial surveys in Iran and Australia's most recognised mine sites, is due to my passion for being on mine sites and be involved in real world issues. Working with large processing plants which have a high level of safety standards made me an expert in the assessment of safety and risks of conducting industry-based research. Leading a large group of researchers and students and collaborating with site personnel is another invaluable skill I learned while conducting site work. I enjoy presenting my research outcomes to the international research community and discussing the future challenges of mineral processing. I have a great honour of being in the JKMRC which offers a sustainable process for the minerals industry.

Research Interests

  • Mill liner design and wear modelling
    An integrated approach in mill liner design and management to enhance the grinding efficiency through collaboration between operations, liner suppliers, and relining crew
  • Mechanistic approach in liner wear modelling
    Incorporating factors affecting liner wear in the structure of a mechanistic wear model
  • Study surface breakage of rock particles
    Measuring surface breakage of rocks under different loading mechanisms to inform mechanistic breakage models
  • Dynamic modelling for process control and optimisation
    New approach in implementing dynamic modelling of mineral processing circuits for developing process control strategies and accessing process performance

Research Impacts

I have a successful background in industry-based work which enables me to speak with industry in a practical sense. Therefore, my connections with industry have grown substantially in the past few years. This enables me to become a self-sustainable researcher for funding my basic research. I received a good response from industry regarding the "Mill internal design and management" project and I was able to acquire funding from industry and university through applying for competitive grants.

My background and publications in different areas of mineral processing such as comminution, dewatering, coal processing and flotation are recognised by universities, conferences, and journals and I have been asked for examining thesis for different universities internationally, and reviewing journal articles and conference papers in all of these areas.

Working in JKMRC introduced me to a wider research community and offered me opportunities of working with more mine sites, suppliers and engineering companies which make me feel satisfied as an applied researcher.

Qualifications

  • Master of Business Administration, The University of Queensland
  • Doctor of Engineering, Shahid Bahonar University of Kerman

Publications

View all Publications

Supervision

  • Doctor Philosophy

  • Doctor Philosophy

  • Doctor Philosophy

View all Supervision

Available Projects

  • Project Description

    A wide range of process control strategies have been developed for stabilising grinding circuits. Various degrees of control technology are applied ranging from simple PID feedback loops to advanced process control systems including expert systems, machine learning and model predictive controllers. The difference with respect to plant production performance can be substantial. However, advanced controllers are usually installed as a control system upgrade and due to their complexity, their performance can be unreliable. It is all too frequent that advanced control systems in grinding circuits are switched off to revert to conventional controllers. This PhD project aims to investigate this problem by analysing industrial case studies of advanced controllers and their effectiveness. This includes simulating the grinding circuits in Matlab/Simulink and developing a set of metrics that allow the effectiveness of the advanced control systems to be evaluated.

    Project Objectives

    This HDR project aims to develop a framework for assessing the effectiveness of different advanced process control strategies and tools to understand how to select process control strategies in grinding circuit applications.

  • Project Description

    For the past two decades, large mining companies have made major investments in “digitisation” projects to integrate sensor technologies and data flows across their operations with process control and management systems using sophisticated data analytics and upgraded IT infrastructure. The explosion of new advances in this area has seen the recent availability of low-cost hardware based on open standards and high-quality open source software toolsets that can be applied digitisation projects at mine sites. The proposed PhD project will review which digitisation strategies have been successful in the minerals industry and which strategies already used in larger operations can be translated to smaller scale mining and processing operations.

    Project Objectives

    This HDR project is focused at mining companies that have not yet implemented large digitisation/data analytics/big data projects, nor installed centralised process control centres. The project aims to identify specific opportunities and data analytics work flow with the aim of demonstrating the value of digitisation technologies. It is intended that the study will work closely with a small-medium mining company and result in a work-flow and tool set framework for real-time data analytics and case-study implementation of ideas generated during the study.

  • Project Description

    Due to the complexity of the process dynamics in most SAG mill circuits, their industrial control systems typically comprise cascaded control loops, and often use some form of expert system or advanced control. This HDR project aims to be a case study for the application of the Model-informed Process Control (MiPC) concept to grinding circuits. The MiPC methodology incorporates dynamic models of processing units into a process control layer linked to process sensor data. The unit models for the grinding and classification units in the circuit are to be based on the latest theoretical phenomenological models developed at SMI-JKMRC. Unlike standard process control loops based on feedback, using mathematical models which are mathematical analogues of the actual process allows the future process state to be predicted. The methodology therefore aims to forward-predict effects of disturbances and respond accordingly, and to infer process conditions that cannot be easily measured with instrumentation such as changes in ore hardness. The project will require the researcher to travel to a mine site to help design an appropriate control strategy, obtain operating data, and to implement process control modifications.

    Project Objectives

    This HDR project aims to demonstrate the effectiveness of Model-informed Process Control in stabilising and operating industrial grinding circuits. The project will also investigate opportunities to collect additional sensor data for interacting with the models. It is intended that the study will begin with laboratory or bench-scale developments which will then be extended to an implementation within an industrial milling circuit.

View all Available Projects

Publications

Book Chapter

  • Yahyaei, Mohsen, Hilden, Marko, Shi, Fengnian, Liu, Lian X., Ballantyne, Grant and Palaniandy, Sam (2016). Comminution. Production, Handling and Characterization of Particulate Materials. (pp. 157-199) edited by Henk G. Merkus and Babriel M.H. Meesters. Switzerland: Springer International Publishing. doi: 10.1007/978-3-319-20949-4

Journal Article

Conference Publication

Grants (Administered at UQ)

PhD and MPhil Supervision

Current Supervision

Possible Research Projects

Note for students: The possible research projects listed on this page may not be comprehensive or up to date. Always feel free to contact the staff for more information, and also with your own research ideas.

  • Project Description

    A wide range of process control strategies have been developed for stabilising grinding circuits. Various degrees of control technology are applied ranging from simple PID feedback loops to advanced process control systems including expert systems, machine learning and model predictive controllers. The difference with respect to plant production performance can be substantial. However, advanced controllers are usually installed as a control system upgrade and due to their complexity, their performance can be unreliable. It is all too frequent that advanced control systems in grinding circuits are switched off to revert to conventional controllers. This PhD project aims to investigate this problem by analysing industrial case studies of advanced controllers and their effectiveness. This includes simulating the grinding circuits in Matlab/Simulink and developing a set of metrics that allow the effectiveness of the advanced control systems to be evaluated.

    Project Objectives

    This HDR project aims to develop a framework for assessing the effectiveness of different advanced process control strategies and tools to understand how to select process control strategies in grinding circuit applications.

  • Project Description

    For the past two decades, large mining companies have made major investments in “digitisation” projects to integrate sensor technologies and data flows across their operations with process control and management systems using sophisticated data analytics and upgraded IT infrastructure. The explosion of new advances in this area has seen the recent availability of low-cost hardware based on open standards and high-quality open source software toolsets that can be applied digitisation projects at mine sites. The proposed PhD project will review which digitisation strategies have been successful in the minerals industry and which strategies already used in larger operations can be translated to smaller scale mining and processing operations.

    Project Objectives

    This HDR project is focused at mining companies that have not yet implemented large digitisation/data analytics/big data projects, nor installed centralised process control centres. The project aims to identify specific opportunities and data analytics work flow with the aim of demonstrating the value of digitisation technologies. It is intended that the study will work closely with a small-medium mining company and result in a work-flow and tool set framework for real-time data analytics and case-study implementation of ideas generated during the study.

  • Project Description

    Due to the complexity of the process dynamics in most SAG mill circuits, their industrial control systems typically comprise cascaded control loops, and often use some form of expert system or advanced control. This HDR project aims to be a case study for the application of the Model-informed Process Control (MiPC) concept to grinding circuits. The MiPC methodology incorporates dynamic models of processing units into a process control layer linked to process sensor data. The unit models for the grinding and classification units in the circuit are to be based on the latest theoretical phenomenological models developed at SMI-JKMRC. Unlike standard process control loops based on feedback, using mathematical models which are mathematical analogues of the actual process allows the future process state to be predicted. The methodology therefore aims to forward-predict effects of disturbances and respond accordingly, and to infer process conditions that cannot be easily measured with instrumentation such as changes in ore hardness. The project will require the researcher to travel to a mine site to help design an appropriate control strategy, obtain operating data, and to implement process control modifications.

    Project Objectives

    This HDR project aims to demonstrate the effectiveness of Model-informed Process Control in stabilising and operating industrial grinding circuits. The project will also investigate opportunities to collect additional sensor data for interacting with the models. It is intended that the study will begin with laboratory or bench-scale developments which will then be extended to an implementation within an industrial milling circuit.

  • Project Description

    Successful optimisation of current comminution circuits and the ability to model and simulate novel and complex circuits is likely to become essential to our need to improve the processing efficiency of ore deposits dramatically. However, our ability to understand and simulate the interactions between ore characteristics and operating factors with process efficiency is still limited to empirical models. A fundamental understanding of the under-pinning mechanisms of size reduction is vital for developing a mechanistic model of comminution. To enable this, an appropriate approach in ore characterisation is critical to experimentally test the breakage under conditions as close as possible to those occurring in the size reduction processes. The drop weight test and JKRBT developed in the Julius Kruttschnitt Mineral Research Centre (JKMRC) are well established for characterising the behaviour of ores in impact and incremental breakage. However, there is no such robust methodology for characterising the surface damage behaviour of rocks. Low energy surface damage, even though it occurs at the lower end of the energy spectrum, has a high frequency of occurrence and plays a significant part during any size reduction process. This project aims to investigate the mechanics of surface damage of various materials under different ranges of stress levels and mechanisms to provide a fundamental understanding of surface damage. Specifically, it aims to study characteristics of the surface damage progeny and develop a methodology to classify ores based on their surface damage behaviour in comminution. The project also aims to apply the understanding of superficial breakage mechanisms to develop a mechanical abrasion model, which is applicable within the UCM’s (Unified Comminution Model) framework.

  • More projects are available on Comminution and Classification, Process modelling, Dynamic Modelling, Advanced Process Control and Digitalisation. For details please conact me,

  • Project Description

    Most AG and SAG mills use a pulp lifter to remove slurry from the mill. Slurry and fine particles (but not the grinding media) pass through grate apertures at the discharge end of the mill to enter a series of radial compartments, then as the mill rotates with the slurry inside and the compartment is upended, the slurry pours out of the mill. Reducing the efficiency of discharge are: 1) flowback, which occurs when slurry pours via the apertures back into the mill before able to be discharged and 2) carryover, which occurs when some of the slurry remains within the compartment often due to the centrifugal effect.

    Various pulp lifter designs are available. In addition to the commonly used radial design, various curved designs offer higher capacity. Furthermore, various chamber designs such as the turbo pulp lifter improve discharge efficiency by reducing flowback and carryover.

    The pulp lifter efficiency influences the slurry level for a given throughput, and therefore the grinding performance. There is therefore a link between the lifter design and metallurgical performance of a mill. Unfortunately, models of pulp lifters are inadequate for design and more work needs to be done to understand how various aspects of pulp lifter design impact on the discharge capacity. Moreover, the link between discharge capacity and the grinding performance also needs to be quantified.

    Project Objectives

    Areas of possible research objectives related to the pulp lifter discharge include:

    1. Quantify the relationship between mill holdup (filling) and discharge using scale experiments. Limitations of previous experimental work in this area include 1) use of spherical media/water mixtures 2) use of flat-ended designs (cone angle = 0 deg) 3) test mills lacking geometric scaling to industrial mills. 3D printing technology, for example, would enable more realistic scale models to be constructed quickly and cheaply. Data can be used for developing mathematical models of pulp lifter discharge.
    2. Gain insights into pulp lifter performance including the effect of grate wear on rates of flowback and discharge using numerical methods (DEM/CFD/SPH), and investigate to what extent grate and pulp lifter design can be used to influence this. Data can be used for developing mathematical models or for comparing or developing improved lifter designs.
    3. Measure SAG mill grinding performance under different slurry discharge rates. For example, a high discharge capacity will result in a lower slurry filling, but a low discharge capacity would result in a higher slurry filling and potentially a slurry pool inside the mill for a given mill filling. Its effect on grinding rates can be studied in a pilot scale mill and/or by analysis of industrial-scale mills surveyed at different times. The outcomes could be used for SAG Mill modelling and for optimising the grate relining and mill speed control strategies employed on mine sites.
    4. Develop a mathematical model of the discharge capacity. This should include the sub-processes of flowback and carryover. The model would be useful for process design and optimisation.
    5. Develop methods to monitor pulp lifter performance, such as through the application of sensors. The methodologies developed can be used for process optimisation and improving SAG mill control strategies.
  • Project Description

    Neither the SAG mill nor Ball Mill model contain a mechanistic sub-model of mill transport; and the empirical models used presently encompass other discharge mechanisms such as the pulp lifter and flowback in SAG mills and the flow through the trunnion in ball mills. The transport rate determines the ability of particles and slurry to flow through the mill charge and the axial diffusion rate of particles, and is dependent in particular on charge porosity / tortuosity, slurry rheology, and the mill breakage environment. This HDR project proposes to extend both the AG/SAG mill model and the ball mill model with the inclusion of a new transport sub-model based on the theoretical transport equations. A proposed route for modelling is the application of the model being developed by Prof Indresan Govender at UKZN. Govender’s modelling datasets have used bead media therefore the model needs to be tested on real ore slurries and charges containing coarse particles.

    Project Objectives

    The project objectives are to develop experimental test equipment and procedures to measure transport rate, while controlling slurry viscosity; experimentally and numerically validate the Govender mathematical model of mill charge transport for mineral ore slurries and charge containing balls and coarse particles; and incorporate this model into the AG/SAG and ball mill models.