At Heidelberg Materials’ Bridgeport Quarry in Texas, engineering upgrades have transformed conveyor roller performance — extending service life from just five weeks to more than three years. The quarry supplies cement and aggregates across the United States, and its main crusher conveyor endures relentless impact from rocks up to 12 inches across dropping 25 feet onto the belt.
Previously, rollers failed every five weeks. Maintenance teams had to replace entire 60-roller sections twice a year. After a few key design changes, the conveyor has now operated maintenance-free for over three years, with upgraded rollers still going strong.
The challenge: constant downtime and high maintenance hours
Three years ago, Bridgeport’s maintenance manager faced constant repairs on the 96-inch conveyor beneath the primary crusher. Standard steel rollers and frames were bending and cracking under extreme loads. Competitor rollers failed just as often.
Each roller failure required removing two or three adjacent units. Because heavy rollers needed multiple people to lift safely, what should have been a quick fix often became a multi-hour shutdown. The team was spending over 50 maintenance hours per year replacing rollers alone.
“With CEMA-D rated idlers, the frames were cracking and bending under heavy load. To get a damaged roller out, they’d have to take two or three out because they were packed so closely in the load zones,” explains Steve McKenna, Account Manager – Central USA at PROK. Daily washdowns accelerated rust, reducing frame integrity further. With rising production demand, this downtime was unsustainable.
Our analysis: extreme impact, underdesigned equipment
Viacore, a PROK partner, brought engineers on-site to inspect the conveyors. The problem was clear: 12-inch rocks falling 25 feet onto a 96-inch belt generated forces beyond what standard CEMA-D steel rollers could handle.
“It really is that simple,” says Steve. “The rocks were too big, impacting the belts hard, and the rollers weren’t heavy-duty enough.”
A deeper review showed the standard three-roller frames concentrated stress on centre rollers. Fixed-frame design also complicated maintenance, forcing crews to remove entire sections to replace a single roller. Inadequate roller strength, weak frames, and difficult maintenance created repeated failures.
Our recommendations
PROK engineers recommended four key changes:
- Upgrade to heavy-duty rollers – Replace with CEMA-E rubber impact rollers featuring higher bearing class, thicker shafts, and improved seals for longevity.
- Redesign frames for better load distribution – Re-engineered impact frames spread load across multiple rollers, protecting the centre roller.
- Improve maintenance safety and access – Introduce retractable frames with sliding rails, letting single rollers be removed individually, reducing manual handling.
- Strengthen and protect frames – Use galvanised, heavy-duty frames with wider bases and reinforced wings to resist impact and corrosion.
Implementation: built in North America, installed with precision
PROK’s North American team custom-built the new rollers, frames, and retractable systems for quick delivery. “The difference is heavier bearings, thicker shafts, better seals — everything’s beefier and better suited for heavy-duty operation,” Steve says.
Despite heavier frames, the retractable design made each roller easier to remove. “What we’ve done is engineered proper retractables. Each roller can be removed individually. You undo the bolts and slide them out. Instead of taking two or three frames out, you can do it individually,” he adds.
Results: less maintenance, more uptime
Maintenance that once took up to two hours and multiple people now takes about 30 minutes for a single technician. The sliding rail system made roller replacement fast, safe, and efficient.
“Since putting in the CEMA Es, they haven’t replaced a single roller in over three years. That’s absolutely amazing for the team,” Steve says. The upgraded system now absorbs the heavy impact that used to destroy rollers every few weeks, cutting maintenance time by over 90%. “From spending 50 maintenance hours per year before, they’re now down to three or four hours,” Steve explains. “That’s eliminated downtime on the primary crusher, which used to stop the entire plant.”
Following the success at Bridgeport, Heidelberg Materials has applied the same upgrades to two 72-inch conveyors and is improving a 60-inch system. CEMA-E rollers are being standardised in high-impact zones, while CEMA-D and HDPE rollers are used elsewhere. What began as a fix for chronic failures has become a blueprint for Heidelberg’s network — conveyors now run reliably, and teams focus on optimisation instead of emergency repairs.