Star Wars backdrop as an extreme testing ground

The drive into the Hambach open-cast mine is truly impressive. A lunar landscape of gigantic proportions – dominated by eight bucket-wheel excavators that are among the largest of their kind in the world. Sascha Funk has been working for RWE Power AG for ten years and, together with his colleague Jörg Rübsteck, is responsible for procuring materials and vehicles for the gigantic fleet.

"Our total fleet comprises around 800 vehicles, from electric cars for business and courier trips between sites to 40-tonne trucks for transporting materials in the open-cast pit," describes Sascha Funk his area of work. Jörg Rübsteck is primarily occupied with procuring the Unimog for the RWE fleet: "I have been looking after Unimog, specially tailored to our needs, for 15 years; they have been an integral part of our vehicle fleet for over forty years, and a very constructive cooperation has existed ever since," says Jörg Rübsteck. Reliable partner to RWE from advice to service is the Unimog general agency RKF-Bleses GmbH.

The Hambach open-cast mine has long been regarded as an ideal test site – including for the 116 Unimog in the fleet. “Most of our Unimogs are equipped with a flat bed, a crane and a winch; those are the work tools we need here most,” explains Jörg Rübsteck. A U 5023 with a crane body has just been put into service; shortly before that, a U 4023 with a flat bed and a large double cab.

The particular challenge is the difficult ground, a unique mixture of sand, lime, clay, rock and water that continually penetrates into all the vehicle components and causes heavy wear. “We’ve even had vehicles with their brakes completely worn down after just one hard day,” Sascha Funk says of the extreme conditions. That is why all the Unimog units at the Hambach open-cast mine have an encapsulated final reduction gear. As well as dealing with the unusual ground mix, the vehicles are essentially run continuously in heavy mud. The pit is permanently watered in order to prevent huge plumes of dust.

The main areas of operation for the Unimog in open-cast mining are inspections and repairs of the huge conveyor systems. "We constantly have to replace defective parts that can only be moved with a mobile crane," explains Sascha Funk. In addition, the Unimog with a double cab and flatbed is an important transport vehicle in the open-cast mine. A mobile team of technicians with heavy equipment is on duty around the clock to guarantee the pit's conveying capacity – that is 110 kilometres of conveyor belts that, 365 days a year, around the clock, carry the coal out of the pit. To that, Jörg Rübsteck adds: "To ensure the 24-hour schedule, we check the vehicles in the workshop after almost every deployment."

Speaking of output: year after year the eight XXL bucket-wheel excavators extract 40 million tonnes of lignite — a significant factor for Germany’s energy supply. Five of the eight bucket-wheel excavators are the largest in operation worldwide, each of them excavating 240,000 cubic metres of coal per day. And they do it with buckets that can easily accommodate a mid-size car.

Even the most fearless Unimog driver pays respect to the mining giants when he has to approach the monstrous tracks. If a Unimog were actually to end up under an excavator’s track, the excavator operator wouldn’t even feel the slightest vibration. But that has never happened to the team of Jörg Rübsteck and Sascha Funk in all their years at the Hambach open-cast mine — and they will ensure it stays that way.