Slimes Management Workshop

Dr Elizabeth Gibson, General Manager CMPA gives highlights of the CMPA Slimes Management Workshop.

The CMPA held a Slimes Management Workshop in San Remo on the 27 March 2025 to review and update the current CMPA Template / Guideline on Slimes Management. The intention was to enable an understanding of how to manage slimes and assist with achieving compliance with regulations. The event was a great success with 55 attendees and a waiting list due to the restricted capacity of the room. The day was sponsored by CDE Global and Terex Washing Systems.

Earth Resources Regulator (ERR),
Resources Victoria, DEECA

Approvals: Leo Guaraldo, Assistant Director, Assessments

Leo commenced his presentation with an overview of the legislative context surrounding slimes management and an outline of the work plan approvals process.

Alternatives to wet storage systems were strongly encouraged due to the following benefits:

• Reduction in risk associated with slimes dams and potential impact on the environment and the community.
• May reduce the overall disturbance footprint of quarry
• Can facilitate progressive rehabilitation, which can help reduce rehabilitation liability and time taken to complete rehabilitation post operation phase.
• Can reduce the approval input requirement, particularly when approval is sought for large dams (ANCOLD structures)
• Opportunity for improved water conservation

The CMPA Slimes Management Guideline was highlighted followed by ERR approval requirements for slimes dams. ERR Environmental guidelines for the management of small tailings storage facilities 2004 was mentioned together with reference to the ERR Design and Management of Tailings Storage Facilities 2017 where the document states “The majority of large TSFs are within the mining sector and that, accordingly, is the focus of this document”.

Technical: Karen Sonnekus, Principal Geotechnical Engineer, Technical Service

Karen discussed the design, construction, management and closure of slimes storage structures. The key takeaways included:

• If the combined storage capacity of all the Tailings (slimes) Storage Facilities on the site is 50ML (50,000 m3) or more then the ANCOLD Guidelines on Tailings Dams (2019) is triggered.
• The design of a slimes storage structure should be conducted by an experienced and suitably qualified specialist.
• Construction must be carried out in accordance with the approved design.
• Appropriate documentation and processes are required to ensure sound operation and management of waste storages.
• Decommissioning will require a period of time for successful drying of waste materials.

Compliance: Barry Strong, Deputy Chief Inspector East

The final presenter from ERR was Barry on compliance considerations of slimes storage structures who stressed the importance of knowing what was approved:

• Work Authority and conditions
• Approved work plan and conditions
• Planning permit and any conditions
• Any other requirements (e.g. WorkSafe, EPA)

Understanding slimes management: Cameron Black, BCA Consulting

Cameron gave an informative presentation on understanding slimes management. The key takeaways being:

• Know your resource and its variability
• Understand how your slimes behave
• Understand slimes management is a key driver
• Plan for slimes storage
• Not everyone needs a mud plant

Firstly, understand your resource by undertaking the following:

• Non-invasive investigation
• Drilling
• Trenching
• Geological interpretation / model
• Groundwater

Firstly, understand your resource by undertaking the following:

• Non-invasive investigation
• Drilling
• Trenching
• Geological interpretation / model
• Groundwater

Do the laboratory test work:

• Importance of representative samples
• Particle size distributions of raw feed – and plant underflow
• Determine the silt/clay content
• Do any laboratory test work with your slimes and your polymers

Plan your development:

• Can you produce the air space you need?
• Do you need the water?
• Consider multiple treatment methods
• Plan in a contingency

Not everyone needs a mud plant:

• What is the purpose of the mud plant?
• Do you need the water?
• Capital costs of slimes plants is substantial
• Operating costs can be significant (power, floc, management)

Slimes Recovery Plant & Lang Lang: Clive Thomas/Bruce Webster (Barro Group) – Summary

• Do the test work and laboratory work
• Understand how your slimes behave
• Be innovative but do the planning

Many thanks to Robbie Viglietti for leading the informative site tour.
Attendee comments:
“Learning different options on how to wash and process slimes.”
“Good content mix. Great to have ERR and others.”
“Great range of presenters from ERR, to consultants then solution providers.”

From the presentations at the workshop the CMPA Slimes Management Guideline 2020 will be reviewed and updated by BCA
Consulting for release in the latter part of 2025.

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