Bengalla Mine Transformer Retrofill

Enhancing Fire Safety and Reducing Insurance Costs: Bengalla Mine Transformer Retrofill

This is a MIDEL Case Study.

Overview

Bengalla Mine, a large open-cut coal mining operation in Australia's Sydney Basin, produces up to 15 million tonnes of coal annually. To enhance fire safety and optimise insurance costs, Bengalla Mining Company partnered with Ampcontrol, an Australian electrical engineering firm, to retrofit key transformers with MIDEL eN 1204 natural ester fluid.

Project Scope

The retrofill targeted critical assets across the mine’s switchyard and dragline networks, including:

• Dragline electrical network transformers:
  • 15MVA 22/6.6kV
  • 2.5MVA 22/0.433kV
• Switchyard power transformers:
  • 15MVA 66/22kV (x2)

Ampcontrol recommended replacing mineral oil with MIDEL eN 1204, a rapeseed-based natural ester, offering significant advantages:

• Increased fire safety
• Improved environmental protection
• Superior moisture tolerance
• Extended transformer lifespan
  
  

Implementation Process

Before retrofilling, baseline oil samples were taken to assess transformer conditions. The mineral oil was then drained, with the transformer allowed to drip down to minimise contamination. Minor oil leak repairs were completed during this process. Finally, a full vacuum was applied before refilling the transformers with MIDEL eN 1204.

Results and Benefits

Fire risk reduction was a primary driver for the project, aligning with insurance recommendations from providers such as FM Global. The adoption of fire-safe ester fluids aligns with IEC 61936 standards and FM Global’s transformer installation guidelines, which recognise that retrofilling with esters can influence site design requirements and generate cost savings.

David Sowden, Business Development Manager at MIDEL ANZ, emphasised the importance of this transition: "Bengalla Mine is the latest example of how mining operations worldwide are leveraging MIDEL ester technology to enhance fire safety and reduce insurance costs."

Conclusion

By retrofilling with MIDEL eN 1204, Bengalla Mine has taken proactive steps to improve safety, reduce environmental risks, and cut long-term operational costs. This project serves as a benchmark for other industrial operations looking to upgrade transformer safety with sustainable, fire-safe ester fluids.