Metallurgical process flowsheet development & optimisation consulting services

Mineral processing flowsheet development is the engineering process of designing, evaluating, and selecting the sequence of unit operations used to extract and concentrate value from ore from primary crushing through comminution, classification, and separation to final product.

Flowsheet design determines resource utilisation, operating costs, and environmental footprint. It directly affects recovery, product quality, energy consumption, water balance, and long‑term plant stability. A robust flowsheet reduces risk early in a project and creates a more efficient and sustainable operation.

Effective flowsheet development requires iterative evaluation of competing process routes using ore characterisation data, process mineralogy, and project constraints. Steady-state mass and energy balance modelling provides the quantitative framework for these comparisons. For complex or polymetallic ores, it must account for selectivity requirements and inter-mineral interactions across multiple separation stages. Flowsheet decisions made early are among the highest-leverage and most expensive to reverse technical choices in any project.

Process optimisation addresses how an existing flowsheet is operated improving recovery, reducing costs, and stabilising performance within the current circuit configuration.

Flowsheet development addresses what the circuit looks like designing, evaluating, or revising the sequence and configuration of unit operations.

For complex ores and polymetallic circuits, what appears to be an operational problem often has a flowsheet-level cause particularly when ore zone transitions expose the limits of a circuit designed for different mineralogy or liberation conditions. CASPEO’s audit methodology locates this boundary with evidence, not assumption.

Ore variability affects mineral processing performance through several simultaneous mechanisms:

• Changes in mineralogy alter flotation selectivity and reagent requirements
• Changes in hardness and liberation characteristics affect comminution energy consumption and the particle size
• Changes in head grade and gangue mineralogy affect recovery, concentrate quality, and impurity levels in leach solutions

Most mineral processing plants are designed and optimised for a representative average ore type. When feed deviates from this average, performance deteriorates, sometimes sharply and without an obvious operational explanation.

Managing ore variability requires characterising the full range of feed types the plant will encounter, modelling how each affects circuit performance, and developing operating strategies or flowsheet modifications that maintain acceptable results across that range.

CASPEO addresses all three components in a single, integrated assessment thanks to our proprietary process flowsheet software, USIM PAC.

When a new ore type (different ore zone, new mine feed blend, or a change in mineralogy) enters the plant, the first step is characterisation.

The new ore’s liberation characteristics, mineral associations, hardness, surface chemistry, and penalty element distribution need to be understood before operating parameters are changed, because the optimal response depends entirely on what is different about the ore and which unit operations are most affected.

CASPEO’s approach combines process mineralogy review of the new ore type with steady-state mass balance modelling across the current circuit configuration. We quantify how performance will change and identifying which parameters (grind size, reagent dosages, flotation circuit residence time, leach conditions) need to be adjusted and in which direction. Where the new ore type reveals a structural mismatch with the current flowsheet a more significant circuit revision may be required.

Optimisation adjusts how the plant operates. Revision adjusts what the plant is. When performance gaps persist despite sustained optimisation, the flowsheet configuration itself is often the limiting factor.

Flowsheet revision is typically warranted when:

• The plant consistently fails recovery or grade targets across operating conditions
• Ore zone transitions have brought a different mineralogical domain into the feed that the current flowsheet was not designed for
• A new ore domain with different hardness, liberation, or penalty element profile enters the blend
• Capacity expansion requires structural circuit changes
• Process mineralogy confirms the current separation approach is mismatched to the ore being processed

CASPEO’s audit methodology locates this boundary clearly, so capital is directed to structural changes only when operational improvements have been genuinely explored.

USIM PAC is a specialised process modelling and simulation software used to build, evaluate, and optimise mineral processing and hydrometallurgical flowsheets.

It enables engineers to:

• simulate complete circuits in steady state
• compare alternative flowsheet configurations
• quantify recoveries, mass flows, and energy use
• evaluate ore variability scenarios
• identify bottlenecks and improvement opportunities

USIM PAC integrates all unit operations from crushing to refining within a single modelling environment, making it a reliable tool for flowsheet development, design review, process auditing, and optimisation across the full circuit.

CASPEO’s consulting team uses USIM PAC as the technical engine for all flowsheet design and optimization studies. USIM PAC is also available as subscription-based software license for in-house engineering teams seeking to build and maintain their own simulation capability.

Environmental improvement is most effective when treated as a process engineering challenge:

• Optimising grind size reduces comminution energy: the largest energy consumer in most concentrators
• Reagent optimisation reduces chemical consumption and water quality impacts
• Closing the water circuit reduces freshwater intake and tailings storage pressures
• Flowsheet simplification reduces the number of transformation steps and associated emissions

Steady‑state simulation with a tool like USIM PAC enables engineers to quantify energy–water–reagent trade‑offs and identify optimisation strategies that improve both metallurgical and ESG performance.

▶️ This article could interest you

de Ville d’Avray, M-A., Durance, M-V., Braak, E., Guezennec, A-G. (2019) – A new hydrometallurgical processing route for copper recycling. Proceedings of Copper 2019, Th 59th MetSoc Conference of Metallurgists, Vancouver, Canada.
https://onemine.org/documents/design-and-optimisation-of-a-new-hydrometallurgical-processing-route-for-copper-recycling-using-process-simulation

Geometallurgy provides the framework for understanding how ore characteristics vary across a deposit, and how these variations influence metallurgical performance. It links geological data with processing behaviour to predict plant response before the ore reaches the mill.

Ore variability is the practical expression of that geometallurgical context: differences in mineralogy, hardness, liberation, grain size distribution, alteration, and chemistry that affect how the ore behaves in comminution, flotation, leaching, and downstream circuits.

The process flowsheet must be designed and continuously adapted to handle this variability. A flowsheet tuned to one ore type may fail when the feed changes. A flowsheet grounded in geometallurgical understanding is more robust, predictable, and optimised across the entire orebody.

Geometallurgy characterises ore variability. Ore variability defines the operating envelope. The process flowsheet must be designed to perform reliably across that envelope.

▶️ This article could interest you

González M., Brochot S. and Durance M.-V., “Plant Performance Forecasting Using Geometallurgical Data and Advanced Process Simulation Techniques”, Proceedings of Procemin-Geomet 2017, Santiago, Chile, October 2017.
https://www.researchgate.net/publication/320467286_Plant_Performance_Forecasting_Using_Geometallurgical_Data_and_Advanced_Process_Simulation_Techniques