Mass balance and process simulation for water management in mineral processing

Water is everywhere in a processing plant. It carries solids, hosts chemical reactions and leaves the site in products, tailings and effluents. To manage it, a plant first needs a water balance it can trust. Data reconciliation turns raw measurements into one consistent set of flows, and simulation then tests new scenarios on top of it. This paper, presented by Etienne Braak at SIM 2026 (French Congress of the Mineral Industries Society, Châlons-en-Champagne), shows how on real plant cases.

Key takeaways

• Water management needs a reliable water balance.
• The observed balance shows the plant as it runs today. Data reconciliation makes plant figures consistent.
• The predictive balance comes from simulation. It tests new configurations, such as more recycling, before any change on site.
• Together, the two balances link raw plant data to operational and strategic decisions.

Why water management matters in mineral processing

The mining and metals industry is highly dependent on water for its operations. Processes cannot run without water. Water carries the ore from one stage to the next, and it is the medium where flotation, leaching and reagent reactions take place.

Plants also need more and more of water. As ore grades fall, plants treat more tonnes of ore to produce the same metal. More tonnes means more water.

Fresh water is not always available, so plants recycle their process water. Recycling has an effect on process performance. Dissolved species and residual reagents build up, and flotation results can change.

On top of that, three types of constraints weigh on the plant:

Water balance frameworks

A water balance is not asked for in the same way everywhere. A plant team uses it to run the circuit, a company uses it to compare its sites, and investors read it in sustainability reports. Each of these stakeholders works with its own framework, and each framework has its own scope, level of detail and frequency. All these frameworks share one thing: they rest on a water balance. The table shows the main ones, level by level. 

USIM PAC process simulation software
Water management flowsheet ITERAMS project

2. Modelling water in a process simulation software such as USIM PAC

A simulator handles water on four fronts:

• Solid/liquid separation models control water quantities
• Water treatment models control water quality
• The circuit tracks how water quality changes from stage to stage
• Process models link water quality to process performance

The last point is the hardest. It answers the question plants ask most: what happens to recovery if we recycle more water? This point will be presented through two simulation studies: the first one with a long loop where process water is treated before it returns to the plant, the second one, a short loop, where water goes straight back after solid/liquid separation.

Mass balance and process simulation: what the tools bring to water management

The mass balance gives the state of the plant at a given moment. That is the observed balance. Process simulation goes one step further and tests new configurations. That is the predictive balance.

Used together, they:

• Gather plant data and make them usable for decisions making
• Give a solid base to monitor operations
• Open up optimisation opportunities
• Improve risk management, for stocks and for planned changes in operating conditions

The two tools connect raw plant data to the decisions that follow, both daily and strategic. The data are gathered in one place, so they are easier to use. Operations rest on a solid base for monitoring, and new ways to optimise become visible. 

The paper presents case studies from real plants and the lessons we drew from them. It also looks at coupling simulation with life cycle assessment (LCA), as part of the Hydroshift project.

Authors

• Etienne Braak, PhD. – CASPEO
• Stéphane Brochot, PhD. – CASPEO
• Marie-Véronique Durance – CASPEO

Etienne Braak will present CASPEO’s methods and tools for water management at the SIM 2026. The SIM congress 2026,  the annual congress-exhibition of the Société de l’Industrie Minérale, the French mineral industry society, is dedicated to water: “Water: essential resource and strategic issues”. It takes place from 6 to 9 October 2026 at Le Capitole, Châlons-en-Champagne. The paper is titled:  ” Balance and simulation: tools for integrated water management in the mining Industry”.