Long history, top quality
The Stentenberg quarry is located in a hilly forested area east of Cologne and already has a long history as a well-known producer of high-quality aggregates. For over 50 years, the hilly benches have been extracted down, creating a green-colored pond at the bottom.
Already in the 1950s, Clemens used several MK series jaw crushers from Metso. The main end-products crushed are screened of hard and homogenous, PSV 59-rated, high-quality greywacke. The end products of Clemens fulfill even the strictest quality requirements and are suited as valuable aggregates for concrete, asphalt and road base materials.
The Clemens quarry operations were bought by the Dutch company Van Niewport 11 years ago. A new expansion currently under way is widening the quarry face even further, securing full operational life for several decades to come. The average daily production is about 4,000 tons, working in one shift.
Three Metso jaws take care of primary crushing
After Udo Noss joined Clemens as Quarry Manager four years ago, the quarry has been modernized by adding new crushers to the process.
A Nordberg C106 was the first Metso C series jaw crusher to be installed to the stationary process. It was soon followed by the bigger C120 jaw model. The latest purchase, the brand new C150 jaw, was installed in May 2014.
Today, all blasted, 0–1,000-mm-sized boulders pass through the C150 primary jaw, operated at a 250-mm closed side setting. After the primary crushing, the aggregates are screened and conveyed to an intermediate storage.
The further processing is executed using two different production lines. The “Edelsplitt” line starts with the C120 jaw crusher, followed by other crushers and screens, including Metso’s smallest GP100 cone crusher. From this line, the highest quality “Edelsplitt” grades with excellent cubicity are produced. The second line starts with Metso’s C106 jaw crusher and produces different-sized aggregates grades.
"We want to ensure the quality"
"Because of today’s competition, we want to ensure the quality and cubicity of the end products we produce. For our quarry, we require crushers that can be operated at 100 percent efficiency from day-one without any rebuilds," Udo Noss stresses.
"One way to keep our quality high is to invest in state-of-the-art equipment. We are fully convinced that Metso makes the best jaws in the world. We also believe in keeping the amount of unnecessary fines as low as possible with the GP100 cone," he adds.
At the Clemens quarry, basic crusher maintenance is done by the company itself; that way they know what’s really inside the crusher.
Two million tons with the same wears
The new Nordberg C150 jaw crusher can be fitted either with one-piece or two-piece wear parts, securing even wear by turning the parts, adding wear part lifetime. After 500,000 tons, no turning or changing of wears has been needed, and no actual wear was yet visible.
"With hard, but not too abrasive, greywacke as our rock type, we estimate that we’ll crush up to two million tons with the same wear parts," Quarry Manager Udo Noss concludes.
