From Rock to Gravel (Basalt-Mile)
| From Rock to Gravel (Basalt-Mile) | |
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| GeoStation an der GeoRoute Tertiär - Industrie -Erlebnis Stöffel-Route | |
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| usable QR-Codes | |
| direct QR-Code: | www.qltr.de/qrka0212 |
The Journey of Stöffel Basalt to Small Gravel Stones
The journey begins at the rock face in the quarry. Since basalt is a very hard rock, it must be loosened by blasting. At the Stöffel site, a blasting operation is carried out approximately every three weeks. The volume of the area to be blasted depends on customer demand.
Blasting must be carefully planned. As a first step, the rock face to be blasted is precisely surveyed. All geological features of the rock must be taken into account during blast planning. Then, using a drilling machine, holes are drilled into the rock face. These are placed at defined intervals from the top of the wall. The drill holes are usually about as deep as the rock face is tall.
Shortly before blasting, explosives are placed into the holes and connected to the electric detonator using cables. All drill holes are then sealed with fine crushed rock. This prevents the blasting energy from escaping upwards through the holes. Therefore, a blast in the quarry does not look like a dramatic explosion. Rather, it gives the impression that a slice of the rock face slightly detaches and then collapses in place. The rock pile loosened from the solid cliff in this way is called Haufwerk in german.
From Large to Small
The loosened basalt is then further processed. Using a very large hydraulic excavator, the material is gradually loaded onto so-called heavy-duty trucks. Each of these trucks can carry at least its own empty weight in broken rock. When fully loaded, these trucks weigh over 100 tons. Up to three heavy-duty trucks operate in parallel at the Enspel-Stockum plant for transporting the material.
For sale, the Stöffel basalt must be crushed into different grain sizes in the rock processing plant. To begin this process, the trucks tip the broken rock into the primary crusher feed, from where it enters the primary crusher. A screen is installed in the feed hopper. Stones that are already small enough for further processing are screened out and transported by conveyor belts to the next processing stages.
The remaining rocks enter the so-called jaw crusher, which can reliably crush rock chunks up to 1.4 meters in edge length. The crushed rock then falls onto a conveyor belt below the crusher, which transports it to the subsequent processing steps. These will be described at the next station.
Verfasser: Carolin Geißler, Christoph Eul und Roger Lang
Stand: 4/2025