Managing heat dissipation in mining transformers: Best practices from the field

For essential equipment like conveyors and grinding mills to function on mining sites, transformers need to operate uninterrupted. They often generate excess energy because they are a cornerstone of operations, producing waste heat that could cause the system to fail. Dissipating thermal accumulation and minimising runaway requires these techniques for the most optimised organisations.

Oil-directed and oil-forced air-forced cooling (ODAF/OFAF)

ODAF and OFAF methods are similar because they both use internal oil flow to manage heat dispersal. OFAF cooling uses external heat exchangers powered by fans to cool the oil and cycle it through even the largest transformers. ODAF streamlines this process by consolidating it into internal windings and directing cooled oil to the transformer’s hot spots. These strategies are helpful, as insulation degradation is a common point of failure in the windings where heat accumulates.

Air-forced (AF) cooling with enhanced filtration

Oil-natural air-natural (ONAN) cooling systems are common for smaller transformers because they rely on passive convection to handle heat. However, this low-maintenance option is further enhanced by AF systems. High-powered fans can provide an extra push to help the ambient air leave the transformer’s vicinity.

It also takes care of any debris and dust that is accumulating around it. The fans are pivotal to this strategy because dust buildup or moisture can cause transformers to overheat — they consider more than how much hot oil impacts the equipment. This is crucial for many components within the transformer, such as switchgears, which can overheat when operating at their rated power.

Oil-forced water-forced (OFWF) heat exchangers

In a similar fashion to OFAF, OFWF leverages outside pumps and a heat exchanger. However, it adds a separate cooling circuit for the water to travel through to absorb residual heat. It is an efficient option, as the mine is full of extra cool water to use from dewatering. The excess can be cycled through and pushed back out, carrying the heat with it.

The method is effective for transformers with high megavolt-ampere ratings, especially in tight spaces such as underground mines. Thermal runaway could cause air to warm rapidly, placing additional strain on employees and transformers and posing a safety risk. Experts can look for OFWF systems with smaller footprints to supplement larger ODAF and OFAF systems.

Immersion cooling

One of the most novel methods for managing heat in a transformer is the use of dielectric-cooling liquid in conjunction with enhanced insulating materials. This combination is proven to improve heat transfer efficiency, while lengthening the lifespan of the transformer. This strategy would also protect equipment from environmental factors such as debris and humidity, as the liquid would serve as a shield for the components. Adopting disruptive methods like immersive cooling could make mining operations more scalable, enabling them to handle high-demand electricity environments with fewer concerns.

Aligning thermal management with production goals

If transformers stop, then disruptions lead to lost productivity and revenue for mining operations. Mitigating these situations requires teams to deploy several techniques to curb thermal accumulation in these essential machines. When achieved, teams will notice a decline in downtime, with more consistent output and efficiency across the board.

Author bio

Jane Marsh is a seasoned environmental journalist and the Editor-in-Chief of Environment.co, specialising in in-depth coverage of environmental trends, sustainability, and the evolving energy landscape. With her work featured on leading platforms like Renewable Energy Magazine, Manufacturing.net, and Nation of Change, Jane brings a keen perspective on the intersection of energy innovation and industry practice.

Read the article online at: https://www.globalminingreview.com/special-reports/02032026/managing-heat-dissipation-in-mining-transformers-best-practices-from-the-field/