Conveyor systems are the lifeblood of South Africa’s mining and quarrying operations. From coal and copper to aggregates and cement, these systems move massive volumes of material every day – often under punishing conditions. Dust, moisture, misalignment and heavy loads all conspire to shorten the life of critical components, especially bearings. And when bearings fail, the cost of downtime can be staggering.

Global engineered bearings manufacturer Timken says in underground and surface operations alike, conveyor stoppages can cost thousands of rands an hour in lost productivity.

“But there’s good news. A growing number of operators are turning to solid-block housed bearing units to extend equipment life, reduce maintenance and keep production on track.”

The Problem with Standard Bearings

Traditional split-block and unsealed bearing designs often fall short in mining environments. Bearings in head pulleys, tail pulleys, drive shafts and take-up positions are exposed to abrasive dust, water ingress and chemical contaminants. In many cases, open bearings fail within six to 12 months – far short of the two to four years operators expect, advises Timken.

“One South African coal mine, for example, was experiencing bearing failures every eight weeks in its tail pulley system. The root causes? Fractured housings, poor sealing performance and excessive maintenance cycles. Each failure meant up to 90 minutes of downtime per unit and the cost of replacement parts and labour.”

A Better Bearing Solution

Timken’s solid-block housed units are engineered to thrive in harsh conditions. These units feature high-performance spherical roller bearings housed in durable cast steel, with multiple sealing options that block out contaminants and retain lubrication.

Unlike split-block designs, Timken’s housed units are sealed at the factory and ready to install straight from the shelf. Installation takes 30 minutes, which is less than half the time required for traditional units, says Timken, adding that robust sealing systems also mean minimal re-lubrication and a longer service life.

The sealing options include labyrinth and triple-lip designs made from advanced materials like Teflon, nitrile and urethane. These seals resist chemical attack and operate at higher temperatures than standard alternatives. A secondary seal protects the primary seal, and the space between them acts as a grease cavity for added protection.

“Spherical roller bearings also accommodate shaft misalignment up to about 1.5º, helping conveyors run smoothly even when alignment isn’t perfect,” notes the company.

Proven Performance in South Africa

At the New Clydesdale Colliery in Mpumalanga, Timken’s solid-block housed units have transformed conveyor reliability. After switching from split-block designs to Timken’s solution, the mine saw immediate improvements. Installation time dropped from 90 minutes to 30 minutes, and the original units continued running reliably for over a year – far exceeding previous performance.

The mine has since expanded the use of solid-block housed units across its conveyor system, reducing maintenance cycles and improving uptime. This has resulted in lower operating costs and greater confidence in equipment performance, highlights Timken.

Lubrication is the Unsung Hero

Even the best bearing design cannot perform without proper lubrication. Yet poor lubrication practices, not poor lubricants, are the leading cause of bearing failure.

Timken recommends using greases specifically formulated for bearings in heavy- duty applications. These greases resist extreme pressure, combat corrosion and maintain mechanical stability under load.

“Equally important is following a strict relubrication schedule. Over-lubrication can be just as harmful as under-lubrication, leading to collapsed seals and elevated operating temperatures.

“Timken’s housed units simplify this process with purge-friendly seals and relief valves that prevent over-greasing. Our local lubrication experts can also help operators select the right grease and establish best practices tailored to their equipment and operating conditions.”

Why It Matters

For South African mines and quarries, every hour of uptime counts. Conveyor systems must operate reliably to meet production targets and control costs. Timken says its housed bearing units offer a proven way to extend bearing life, reduce maintenance and improve overall system performance.

Whether it is a coal mine in Mpumalanga or a quarry in the Western Cape, operators face similar challenges, and Timken’s solutions are designed to meet them head-on, states the company.