SOURCE: Mining Magazine | May 15, 2026
The environment inside a copper mine is notoriously unforgiving. Equipment must contend with high temperatures, relentless airborne dust, and the potential for water ingress. Bel-Ray worked with a copper mine in South America where a ball mill was an essential step in the concentrator plant. It followed the primary crushing and semi-autogenous grinding mills and prepared the copper ore for downstream flotation, where copper sulfides are separated and concentrated.
Despite using a high viscosity open gear lubricant from a leading competitor, the mine’s critical ball mill was struggling with excessive heat and surface damage, threatening both the equipment and the operation’s bottom line.
The challenge: a harsh environment for heavy equipment
This specific ball mill consisted of a large, horizontally rotating cylinder partially filled with steel grinding balls and a slurry of ore and water. As the mill rotated at 70-80% of its critical speed, the cascading and impacting action generated intense vibration, significant airborne dust from fine particles, and enormous mechanical loads on the drive system, shell, and bearings.
This wet, high-load, and dusty setting consumed substantial energy – often accounting for 30-50% of the concentrator’s total power – while requiring constant monitoring to manage structural fatigue and wear.
The open-gear drive system, comprising the pinion and massive girth gear, faced extreme lubrication demands in this severe environment. Challenges included heavy shock loads, low-speed operation, exposure to abrasive dust, and potential water ingress. The mine was looking for options to improve operating efficiency and extend the life of their gears.
The insight: reducing friction to manage heat
Bel-Ray implemented a consultative approach to fully understand the operating systems and processes. The team observed that the high temperature in the pinion of the ball mill’s gear drive system was a symptom of inadequate lubrication, causing metal-to-metal contact, misalignment, insufficient film strength and overload conditions.
The primary source of heat in an open gear drive system is friction. When a lubricant lacks the film strength to keep gear surfaces separated under heavy shock loads, the resulting friction creates a spike in temperature. This heat then degrades the lubricant further, creating a destructive cycle that leads to premature gear failure and increased energy draw from the motors.
The recommendation was a strategic pivot: move away from the traditional residual lubricant and switch to a high-performance synthetic fluid fortified with extreme pressure additives.
The Solution: Bel-Ray Clear Gear Lubricant
To address these severe conditions, the team introduced Bel-Ray® Clear Gear™ Lubricant. Unlike traditional greases that can trap heat and dust, Clear Gear is a high viscosity synthetic fluid designed for Type 2 open gear systems.
It is formulated to operate in a full fluid film or hydrodynamic mode to virtually eliminate metal to metal contact. Even under the extreme pressures of a ball mill, the synthetic base maintains its integrity, ensuring the pinion and girth gear mesh smoothly without generating excessive heat.
The results: cooler operation and measurable savings
The switch to Bel-Ray Clear Gear lubricant yielded immediate and measurable improvements. The most significant indicator of success was the dramatic drop in pinion operating temperatures. By reducing the heat generation at the source, the mine was able to stop the cycle of lubricant degradation and surface pitting.
The benefits extended beyond just the operating temperatures:
- Energy efficiency: achieved daily electrical consumption energy savings attributable to reduction in friction and wear, demonstrated by the significant drop in pinion operating temperatures – which is a direct indicator of lower heat generation and better surface separation during meshing. This decreased mechanical resistance reduced the workload on the mill motors, resulting in measurable energy savings of 5.61% per unit annually.
- Component longevity: the enhanced lubrication substantially reduced friction and wear, extending gear life significantly.
- Increased uptime: better lubrication resulted in reduced maintenance downtime, which can cost a mine thousands of dollars per hour in lost production.
The copper mines in South American regions are extremely harsh environments, with equipment operating in high-dust and hot-temperature climates. Bel-Ray has proven performance in these conditions, with the capability to protect your cone mill, crusher, and other operating equipment at your mine site.
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