Associated Event

26th International Conference on Paste, Thickened and Filtered Tailings
16–18 April 2024 | Pullman Melbourne on the Park, Melbourne, Australia

Troubleshooting Your Flocculation and Thickening Processes Workshop

14 April 2024 | Melbourne, Australia

About the workshop 

Thickening is a key unit operation in mineral processing; where suspended particles are separated by gravity settling. The addition of polymer flocculants promotes aggregation that accelerates settling and increases throughputs, but their performance can be highly sensitive to conditions. While monitoring underflow, rheology is the best means of controlling thickeners to optimise downstream outcomes. Most thickeners are controlled to an underflow solids concentration, generally because that is easier and rheology is harder. 

Much of the academic literature in this area gives too much weight to insights gained in wastewater studies. As a consequence, some wrong assumptions are made, and testing methods can be sub-optimal or incorrect for mineral processing applications. The presenters will draw on their own research and other published studies (good and bad) to highlight the key sensitivities in tailings flocculation and how to get the most out of test work in a variety of situations. This will be extended to flocculation in full-scale feedwell applications, with guidance on how to identify and respond to performance issues through modifying operating procedure or designs.  


The intent of this curriculum is intended to provide practical knowledge and tools to help industry professionals better understand: 

  • Which tests do you need to run to get the right answer?
  • How do you interpret your test work?
  • What testing issues can you run into and what are the associated operational issues?
  • When  do you do this yourself, and when do you call in an expert? 

At the end of the workshop, participants will be able to:

  • Recognise how feed characteristics including density, particle size and mineralogy will impact expected flocculant and coagulant dosage.
  • Discriminate between problems caused by flocculant product choice, the applied conditions or unrealistic expectations.
  • Select and implement flocculant products more effectively for a chosen application.
  • Identify the applications and limitations of rheometry for concentrated suspensions, noting the measurement artefacts in rheological measurements.
  • Predict how changes in feed and thickener operation (e.g. mineralogy, polymer dosage and water chemistry) will change the yield stress and deviation from Newtonian behaviour of thickener underflow.
  • Critique laboratory and pilot-scale test work results (and maybe say how it can be done better).
  • Recognise the potential full-scale thickener implications from deficiencies in flocculation.
  • Troubleshoot for common feedwell flocculation operational and design issues.  

Who should attend? 

This workshop is most relevant to thickener operators across mining sectors, as well as the upstream/downstream roles that support successful solid-liquid separation including flocculant suppliers and researchers.  

Workshop material 

Participants will receive an electronic copy of the presentation materials prior to the workshop. 

Collaborating Organisation


  • Feed characterisation: Particle size measurement, minerology, Methylene Blue Index, and major anions and cations (water chemistry). Watch out for clays. 
  • Know your thickener: Overview of thickener and feedwell design and the levers available to achieve various operational objectives.
  • Flocculation: What makes flocculation of mineral systems hard, and feedwell flocculation harder?
  • Have you got the right flocculant?
  • Settling tests: How small-scale cylinder testing can go wrong, and how to do small-scale testing for high solids flocculation.
  • Rheology: A look at what suspension rheology is driven by, how it is best measured and how it affects thickener performance.
  • Troubleshooting thickeners (1): Understanding what feedwells should do, how different designs impact flows, and the pursuit of solids dilution.
  • Troubleshooting thickeners (2): Making and raking a bed, the joys of dosing flocculants, and approaching the feedwell optimisation process.

Workshop Program*

Time Topic
Introduction, overview and safety
Feed characterisation
Know your thickener
Settling tests
Rheology - underflow transport properties
Troubleshooting thickeners - debottlenecking
Troubleshooting thickeners - underflow and overflow
Questions and wrap-up

*Program subject to change.


Dr Andrew Chryss
Senior Research Engineer
CSIRO Mineral Resources

After 20 years with RMIT University’s Rheology and Materials Processing Centre, Andrew joined CSIRO in 2008, bringing extensive experience characterising complex fluids (non-Newtonian, viscoelastic and multi-phase) in pipeline flow, free surface flow and mixing applications. He provided fluid/suspension characterisation for AMIRA P266F, and then was research coordinator for the AMIRA P1087 Integrated Tailings Management Project (2012–2015). Andrew has established procedures to measure complex rheology on concentrated suspensions and leads the development of several instruments, including an online rheometer for underflow/tailings suspensions.

Dr Phillip Fawell
Senior Principal Research Scientist
CSIRO Mineral Resources

Phillip joined CSIRO in 1993 with the launch of the Parker Centre for Hydrometallurgy, primarily to develop techniques for flocculant and aggregate characterisation. He also contributed to the AMIRA P266 Improving Thickener Technology series of projects, later taking leadership of flocculation studies and then becoming overall research coordinator. He led the final stage of the project (P266G), as well as being responsible for technology transfer.

Phillip has conducted thickening appraisals and workshops around the world, also creating an online thickener self-appraisal tool for project sponsors that drew heavily upon extensive P266 computational modelling of feedwell flocculation. He currently leads CSIRO’s Suspensions and Tailings team, which is focusing on developing better test methods and instruments to study and monitor tailings systems.

Dr Heather Kaminsky
NSERC IRCC in Oil Sands Tailings Management
Northern Alberta Institute of Technology, Canada

Heather is the Natural Sciences and Engineering Research Council of Canada Industrial Research Chair for Colleges in Oil Sands Tailings Management, joining the Northern Alberta Institute of Technology after tenure at Suncor Energy and Total E&P Canada in tailings technology development. Her specialty in fundamental structures of clay and heavy minerals in oil sands has enhanced her work in advanced ore characterisation, bitumen extraction, tailings, materials wear and corrosion, water treatment, water chemistry modelling and waste valorisation.

Heather has a passion for clays and tailings and hopes to play a key role in solving tailings as an issue for the oil sands industry. Heather was recently recognised by SHEInnovates as one of the women advancing innovation in Alberta.


Andrea Sedgwick
Ledcor Applied Research Chair in Oil Sands Environmental Sustainability
Northern Alberta Institute of Technology, Canada

Andrea joined the Northern Alberta Institute of Technology in 2015 and is the Ledcor Applied Research Chair in Environmental Sustainability at the Centre for Oil Sands Sustainability. Andrea has 27 years of experience in coal and oil sands with 16 years of related tailings knowledge. Andrea has obtained a deep level of design and industrial research and development experience across all aspects of oil sands mining including the key focal areas of mining, ore characterisation, water treatment, tailings management and bitumen extraction.

Her key accomplishments include initiating the Canada’s Oil Sands Innovation Alliance Tailings Research Working Group and chairing it for three years, gaining a deep knowledge in tailings research by working with international tailings research projects through AMIRA/CSIRO, and Canadian universities and colleges. She currently leads a group of 25 researchers who are passionate about moving new technologies to commercialisation and improving sustainability in the energy industry.

Expanded versions of this workshop have been presented by the same instructors three times in the past four years. The content has been adjusted to suit the audience and time frame, and ensure participants walk away with practical tools to improve their practice.