A real “clearer”

Bell B45E 4x4 at Ostrauer Kalkwerke

1 During the 2025 overburden campaign at Ostrauer Kalkwerke, the Bell B45E 4x4 impressed with its strong performance on the most difficult terrain

2 At around 20 m, the overburden in the Ostrau quarry is just as thick as the underlying dolomite rock

3 Perfect match: The Hitachi ZX490 LCH-7 large excavator with a 3.2 m³ backhoe bucket needs just 7 to 8 quick loading cycles to load the Bell B45E 4x4

45 With its extended body and automatic tailgate, the Bell B45E 4x4 can handle up to 44 t of overburden, even on gradients of around 20 %

5 Thanks to its standard body heating and 55° tipping angle, the flat rock body of the Bell B45E 4x4 also proves its worth when tipping cohesive overburden onto the stockpile

6 The Bell B45E 4x4 at the 60 m³ feed hopper of the Ostrau primary crusher

7 Performance in a package: As part of the Kiesel system solution, the Bell B45E 4x4 is also perfectly matched to the 4.5 m³ Hitachi ZW310 large wheel loader

8 On-site visit (from left): Bell Sales Manager Andreas Reinert, Workshop Manager Enrico Hoffmann, Driver/Technician Sebastian Fuchs, both from Kalkwerke Ostrau, and Gravel Extraction Expert Walter Michels

Since early 2025, an articulated dump truck Bell B45E 4x4 has proven itself as a new key machine in dolomite mining at Ostrauer Kalkwerke. The decision to purchase the 41-ton truck was made after impressive practical experience under extreme conditions during the winter overburden campaign. As part of a system solution from Bell’s sales partner Kiesel, the all-wheel-drive two-axle truck now ensures economical transport in production, site development, and backfilling.

The mining and processing of dolomite as a natural raw material for the mineral optimization of soils in agriculture and forestry has a long tradition in Saxony. In the Döbeln region alone – halfway between Leipzig and Dresden – the calcium- and magnesium-rich mineral was mined in several companies until the middle of the last century. The last remaining producer is Ostrauer Kalkwerke in the district of the same name in the municipality of Jahnatal, which was taken over by its current owners, led by managing director Ulrich Dürasch, after privatization in the wake of German reunification in mid-1991.

Today, a total of 35 people work for the company, which has significantly expanded its product range in recent years alongside extensive investments in processing technology and logistics. In addition to dolomite lime products for agriculture, which are supplied throughout Germany and to neighboring countries via distribution partners, the company has added its own line of high-quality stable hygiene products. The other raw materials produced in the approximately 25-ha quarry are also marketed in a targeted manner: the characteristic ochre, anthracite, and red-colored rock is used in landscaping and surface design as base layers, grit and gravel mixtures, or as gabion filling. Clay building materials and the relevant aggregates for road and path construction round off the product range offered by Ostrauer Kalkwerke, which also accepts uncontaminated construction waste and soil for professional recycling or backfilling.

Conveyor chain rebuilt

With thicknesses of 10 to 20 m, the plate dolomite in Ostrau is selectively mined using explosives. However, the overburden of topsoil and marl-containing material, which is up to 25 m high, must first be removed and backfilled according to plan as part of the ongoing recultivation process. With production continuing at the processing plant, which is designed for a maximum of 300 t/h, this is expected to take several months during the winter season, when sales are lower.

Around 200 000 m³ of overburden covering an area of 1.5 ha was excavated for the 2025 campaign between January and mid-April. The 50-ton Hitachi ZX 490 LCH-7 excavator with a 3.2 m³ backhoe bucket, which was acquired in 2022, removed the material directly in layers up to 2 m thick. In previous years, up to four rented 30-ton articulated trucks were used to transport the material to the approximately 1000 m long and, in adverse weather conditions, very demanding routes to the spoil heap. This year, for the first time, Ostrauer Kalkwerke opted for the articulated all-wheel drive two-axle Bell B45E 4x4.

The 41-ton truck arrived in Ostrava in early January as part of a field test to assess its suitability as an all-season all-rounder within a system solution developed by Bell’s distribution partner Kiesel. Together with an existing 35-ton rigid truck as a “backup,” it will work in conjunction with the Hitachi large excavator and a 4.5 m³ Hitachi ZW310 wheel loader to supply the processing plant, which usually operates in two shifts.

“The integration of the Bell B45E 4x4 into the Ostrau production processes went smoothly, as expected,” reports Walter Michels, Kiesel Product Manager for dump trucks and jointly responsible for system solutions in the extraction sector at Bell’s sales partner. “All parameters were right: starting with the loading capacity from stockpiles, where the rock bin with a capacity of around 28.5 m³ with body extension and tailgate ensures a very good fill level, thus maintaining the batch capacity at the nominal 41 t of the Bell B45E 4x4.” The Bell two-axle truck also plays to its strengths on the approximately 2000 m long circuits with gradients of up to 20 %. “The all-wheel drive and the fully automatic retarder function on all four wheels offer added safety on the route, which translates directly into guaranteed availability, especially at the Ostrau limestone plant with its year-round multi-shift operation.”

A test under extreme conditions

“Of course, we also included overburden in our calculations,” explains Walter Michels. “On paper, everything looked fine again – but our first impressions on site raised doubts about the 100 % suitability of the all-wheel-drive two-axle vehicle.” In extremely wet weather, even 6x6 dump trucks literally dug themselves in on particularly loamy-sandy passages. Even with constant lane changes, these areas often became so difficult to pass that productive transport was hardly possible anymore.

Nevertheless, the Ostrau team led by workshop manager Enrico Hoffmann took on the challenge. What’s more, thanks to the payload and volume advantages of the Bell B45E 4x4, they did not send four dump trucks into the race as before, but instead supplemented the two-axle vehicle with just two rented 6x6 thirty-ton trucks. The standard onboard scales of the Bell two-axle truck showed an average of around 44 t of the highly cohesive freight – with 17.5 m³ dump trucks, the 30-ton trucks used carried individual loads of just over 28 t.

The Bell 4x4 also proved its worth on the nearly 1000-m-long haul roads with gradients of up to 20 %, delivering the 390 kW of its Mercedes-Benz six-cylinder engine to both axles via an Allison seven-speed automatic transmission and a Kessler transfer case with automatic differential lock. Traction control systems ensure safe propulsion, supported on both rear wheels by speed sensors and the measured activation of powerful oil bath brakes.

“The standard tires, with wide 775/65R29 tires at the front and 21.00R35 twin sets at the rear, absorb the loads that occur under all load conditions well and have proven themselves particularly well in quarry applications from an economic point of view – keyword: wear,” explains Walter Michels. “Under extreme conditions such as those found in the Ostrau overburden, however, low ground pressure combined with maximum traction is essential, and we were actually a little curious to see how the Bell B45E 4x4 would perform in practice.” The result surprised even the long-time practitioner: where the 6x6 30-ton trucks with their 750 flotation tires had real difficulties in their own, ever-deepening ruts, the Bell two-axle truck with its different axle tracks and contact areas literally drove right over them. And that was even after several crossings and without any interim road maintenance.

As economical as ever

“Of course, we’re not selling the Bell B45E 4x4 as the ultimate off-road machine,” says Kiesel application specialist Walter Michels. “It is and remains an all-rounder with real strengths in quarries and great capabilities on difficult terrain. However, we rate the latter much higher after Ostrau, which will also be directly incorporated into our specific application consultations and the resulting system solutions under the keyword ‘availability’.” Another measurement from Ostrau’s practical experience will tend to confirm this: the on-board electronics showed an average of 20.6 l/h for the Bell B45E 4x4 after just under 1200 operating hours, mostly in spoil with maximum loads of up to 44 t. In a direct comparison, the two 30-ton trucks used with single loads of 28 to 29 tons consumed 17 l – a 25 % advantage for the Bell two-axle truck when converted to tons.

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