Equipment Care in Limestone Mining: Overcoming Challenges at Belgium’s Sagrex Beez Quarry

From a distance, bright yellow trucks lumber across a muddy expanse, resembling children’s toys in a vast sandbox. Yet, as they roll by, the two‑meter‑high wheels and the rumble of their engines reveal the true scale of Belgium’s Beez quarry, a limestone pit carved into the earth’s face and plunging 80 metres from top to bottom.

The Sagrex Beez quarry sits on the northern flank of the Namur syncline—a geological fold that formed over 300 million years ago. According to director Jean‑Michel Van Peteghem, the limestone seam here was deposited when the region was once underwater and the plates shifted, leaving fossilised layers that now provide a valuable building material.

Covering 85 hectares along the Meuse River, the quarry has operated since 1848, when stone extraction relied solely on human and horse power. Quarrying on this site is licensed for only another five to ten years; once the limestone runs out, extraction will move to a nearby location.

Belgian quarries pull out roughly 50 million tonnes of aggregate each year, feeding a spectrum of industries from civil engineering to toothpaste production, glass and plastic manufacturing, housing construction, and railway ballast.

“The limestone we produce is exceptionally suited for concrete,” Van Peteghem explains. “It’s used in breakwaters, harbour construction, civil engineering projects, and a range of chemical, iron‑and‑steel, and agribusiness applications.”

Finished products span from fine sand to 300‑kilogram rubble stones, the latter used exclusively in Dutch dyke construction.

The extraction process begins with dynamite blasting the quarry face, after which diggers load the material onto trucks for transport. The stones are then fed into a jaw crusher that breaks them into manageable sizes. Before further crushing, a rotary screen washer removes the clay that clings to the stones, a critical step that strengthens the resulting concrete.

At Sagrex Beez, the washing process receives meticulous attention. “If clay isn’t removed properly, the concrete weakens and becomes less resistant,” Van Peteghem says. “Clean stone means less waste, higher yields, and a superior product—hence our investment in rotary washers. Few quarries have such a system, and it has made us highly successful.”

The quarry houses two side‑by‑side rotary screen washers in a dedicated building. Each unit measures three metres in diameter and 10 metres long, sitting horizontally on two rows of nine wheels linked by couplings. One row is powered by a 132‑kilowatt motor and reduction gear.

Aggregate enters at one end, mixed with water. As the drums rotate, stones pound against each other, dislodging clay that dissolves in the water, which is then recycled. Inside, machinery, rocks, and water create a 120‑decibel environment—roughly the noise of a take‑off jet—so earplugs are mandatory.

We installed the washers in 1992, and they performed well until bearings failed every three months, forcing eight‑hour shutdowns for axle removal and workshop replacement. In 2007, we partnered with SKF to devise a solution that would reduce downtime and simplify maintenance.

SKF’s comprehensive upgrade included new axles compatible with standard SKF bearings, split bearing housings that allow the entire wheel set to lift without dismounting bearings, and a smaller‑diameter, high‑load bearing that fits directly over the wheel. The housings feature efficient seals to protect bearings in a damp environment and maintain proper lubrication. Consequently, tire‑replacement downtime fell by 50 percent.

On the driven side, irregular wear on mechanical couplings between axles caused frequent repairs. SKF addressed this by installing identical axles and a gear coupling that distributes weight evenly across all wheels, ensuring consistent drive and eliminating uneven wear. The smaller tires can be swapped by simply removing bolts, and the entire system is laser‑aligned to further reduce wear.

FACTS:
- Sagrex Beez quarry opened in 1848.
- 40 employees work at the site.
- Annual extraction of 1.7 million tonnes of limestone.
- Products range from fine sand to 300‑kg rubble stones.
- 60 % of production is river‑transported; 40 % by truck.
- Beez quarry is owned by Sagrex, a subsidiary of Heidelberg Cement, the global leader in aggregates.

This article was written by SKF and published in the company’s Evolution magazine. To learn more, visit www.skf.com.