“Is there a more spectacular sight than a 75-ton excavator at work in a lava trench?” wrote board member Cornelius Kirsche on AG für Steinindustrie’s Facebook page in March. “The latest addition to our portfolio is just a joy to witness. What more is there to add?”, he continued. In mid-2018, the CASE dealer in Andernach, Germany, supplied German mining company AG für Steinindustrie with a CASE CX750D from the company’s latest D-Series range of excavators.
Since then, the high-performance machine has been serving the company reliably at the Ochtendung lava plant, located southeast of Kruft in the Fresserhöfe mining region. AG für Steinindustrie has an excellent pedigree in this region, having conducted mining, processing and shipping operations there since the seventies. The company’s specific operation is to mine lava from the Tönchesberg, one of the volcanic cinder cones that gives the volcanic area of eastern Eifel its distinctive landscape.
The CASE CX750D is used for the direct extraction of raw materials in the lower part of the mines. Volcanic clinker and lava sands are present naturally as loose rock and are separated directly from the mine wall using the machine. After this, the material is loaded onto dump trucks or broken down on site with a mobile crusher to a size that allows for easy processing.
Despite the relatively low weight of the material, the work required by the fixtures and hydraulics of the CX750D should not be underestimated. The extreme abrasiveness of the lava material demands high performance from the bucket and arm. In addition, the mining area is crisscrossed with numerous basalt deposits, which, for safety reasons, must be washed away repeatedly in the course of the excavation process.
For this reason, AG für Steinindustrie opted to purchase the Mass Excavator (ME) version of the CASE CX750D, which - with a maximum breakaway force of some 366 kN, a larger bucket cylinder and optimised kinematics - is perfectly suited for tough extraction jobs. The fixtures are also designed for extreme loads, with a reinforced HD boom, a shortened 3.02 m HD arm and an armoured 4.00 m3 rock bucket. A solid cab guard for the driver is a vital addition when working directly on the mine wall.
The generous ground clearance provided by the heavy diagonal undercarriage of the CASE CX750D allows easy passage over smaller material residues and basalt blocks, which is important when the excavator is moved to a different location on the site or used to expand the mining area or construct a road. Moreover, the special design of the crawler tracks and bevelled track carriers prevents the build-up of material under the chain.
Bernd Kump, Area Sales Manager at the Andernach dealership, explains how the CASE CX750D is supported by a CASE CX350D, which is brought into play when the sizeable power of its larger cousin is not required. Like the CASE CX750D, this 35-ton excavator handles the extraction and pre-sorting of the material in a quick, smooth manner. Due to its greater manoeuvrability, the CASE CX350D is used at a variety of locations within the mine, either for extraction of raw materials or for maintenance of the road network.
For Mine Manager Thomas Schaefer, the CASE CX750D is a key asset: “The machine delivers impressive performance, works reliably despite the challenging conditions and is economically efficient in comparison to its competitors. We use it primarily for extracting material from the natural rock wall, where it performs an excellent job.”