Mine Éléonore

Eliminating Vibration on Critical 300 hp Mine Fans to Restore 100% Ventilation Capacity

Operating Context

In an underground mine, ventilation systems are essential infrastructure for worker safety, air quality and operational continuity. Any loss of performance can quickly have a significant impact on productivity, equipment availability and working conditions underground.

For mine managers, ventilation superintendents, maintenance managers and reliability engineers, keeping main fans running properly is a strategic priority. Excessive vibration can lead to operating constraints, accelerate component wear, increase the risk of mechanical failure and cause unplanned shutdowns.

That is why Groupe VM brought in Optis Engineering to identify the cause of abnormal vibration affecting two 300 hp intake fans located at the Éléonore mine, located in Eeyou Istchee James Bay, and restore their full operating capacity.

The Challenge

Since they were commissioned in 2017, the two main fans had shown higher-than-expected vibration levels due to installation-related anomalies.

In October 2024, the situation got worse.

Vibration increased significantly, making a critical portion of the operating range, between 60% and 75% of rotational speed (RPM), unusable. As a safety measure, the maximum operating speed also had to be limited to 85% of rated capacity.

These restrictions had serious operational consequences:
✔ a significant reduction in the mine’s ventilation capacity;
✔ reduced operational flexibility;
✔ a higher risk of mechanical breakdowns;
✔ greater maintenance constraints;
✔ a higher risk of unplanned shutdowns;
✔ potential impacts on safety and the productivity of underground operations.

For a mine operator, situations like these can compromise the availability of critical assets and limit the ability to maintain optimal operating conditions.

Project Objectives

Optis Engineering’s mandate was to diagnose the exact source of the vibration and develop a solution to restore the fans’ full operating range.

The objectives were to:
✔ identify the real causes of the vibration;
✔ characterize the dynamic behaviour of the fans;
✔ eliminate resonance;
✔ restore full operating capacity;
✔ improve the mechanical reliability of the equipment;
✔ reduce the risk of failure;
✔ extend the service life of critical assets;
✔ support the safety and continuity of mining operations.

Beyond solving the immediate problem, the goal was to ensure more reliable and sustainable operation of the ventilation systems.

Engineering Approach

Accurate diagnosis before intervention

At Optis Engineering, solving complex problems relies on an engineering process grounded in measured data, an in-depth understanding of equipment dynamic behaviour and advanced numerical analysis.

A comprehensive measurement campaign was first carried out directly at the mine site to characterize the fans’ actual performance.

Our engineers analyzed:
✔ airflow;
✔ pressures;
✔ vibration levels;
✔ actual operating conditions.

The data collected was then integrated into a structural model and a modal analysis to identify the equipment’s natural frequencies and how they interact with operating conditions.

This process revealed a resonance condition responsible for the high vibration levels.

Solution Developed

CFixing the cause, not the symptoms

Once the source of the problem was identified, Optis Engineering developed a series of targeted modifications to shift the structure’s natural frequencies outside the normal operating range. The repairs and structural modifications were then carried out by our client Groupe VM, a company specializing in fan repair and refurbishment.

Recommendations included:
✔ adding stiffener plates;
✔ reinforcing the motor-rotor assembly;
✔ optimizing the structural stiffness of the fan housing.

The corrective work restored the target dynamic characteristics.

This approach eliminated the root cause of the vibration rather than simply reducing its effects.

Results

Improvements were observed as soon as the fans were returned to service.

Resonance eliminated
The modifications eliminated the modal behaviour responsible for the excessive vibration.

100% of the operating range restored
The fans can now run smoothly across their entire speed range, and even beyond the previously imposed limits.

AugmeIncreased ventilation capacity
Restored performance improves the mine’s ventilation capacity and supports the operational needs of underground activities.

Improved reliability of critical assets
Lower vibration reduces mechanical stress on components, limiting the risk of failure, corrective maintenance needs and unplanned shutdowns.

Safer operations
With its intake fans back to full performance, the mine gains greater operational flexibility and improved worker safety, thanks to more stable and effective ventilation.

What Sets Optis Engineering Apart

With the widespread adoption of variable frequency drives (VFDs) and ventilation on demand (VOD), fan vibration problems are becoming increasingly common. Finding lasting solutions sometimes means questioning the design of the equipment itself.

Abnormal vibration is often the result of complex interactions between the structure, installation conditions, natural frequencies and operating conditions.

At Optis Engineering, we combine:
✔ field expertise and in-situ measurements;
✔ vibration & modal analysis;
✔ structural modelling;
✔ industrial ventilation expertise;
✔ mechanical engineering.

This approach allows us to identify the root cause of problems and develop lasting solutions that improve the reliability, availability and performance of industrial assets, all at once.

Conclusion

This intervention, achieved in collaboration with our client Groupe VM, shows that a rigorous diagnosis can often solve complex problems without replacing existing equipment.

By combining on-site measurements, modal analysis and structural dynamics expertise, Optis Engineering restored full operating capacity to two critical fans while improving asset reliability and the safety of mining operations.

For mine operators, this approach is a practical way to reduce unplanned shutdowns, optimize existing infrastructure and support the long-term performance of ventilation systems.

Need to Solve Vibration Problems or Improve the Reliability of Your Critical Equipment?

Optis Engineering supports mine operators and industrial manufacturers with diagnostics, vibration analysis and ventilation system optimization, helping improve asset availability, worker safety and operational continuity.