Archaeological remains indicate today that Dresden, in eastern Germany, was inhabited as early as the Stone Age. Architectural gems such as the rebuilt Frauenkirche, Semperoper opera house or the Zwinger palace today attract tourists from across the world. These cultural monuments have become a major economic factor in the region. Another mainstay of the local economy is the aggregate supplier Baustoffwerke am Wetterberg (BaW) operating since 1992 at Ebersbach, 25km from the city. Since April 2010, Georg Hans Ohler, technical manager of the quarry, has been admiring the performance of a new generation Sandvik SC screen.
While the predominant construction material in Dresden is sandstone, BaW has always been interested in greywacke stone. Records show that this grey-blue, hard variety of sandstone has been quarried there since the 1920s.
The Ebersbach-based company nowadays belongs to the Gl?ser Group, which celebrated its 150th anniversary in 2010. In addition to the quarry, the facility includes a ballast and asphalt mixing plant.
With its annual production of around 900,000 tonnes, BaW supplies the greater Dresden region as far as Berlin with ballast, chippings and high-grade chippings. With a workforce of 25 plus one trainee, the company makes annual sales of ?10 million (including the asphalt mixing plant).
?Our major references to date include a 200,000 tonne delivery within 10 weeks for the Dresden international airport and an aggregate spread delivery for Neumarkt Square within sight of the Frauenkirche,? says Georg Hans Ohler.
Since the early days, BaW has continuously invested in its operations to guarantee the profitability of the greywacke resource, for which the company has permits up to the year 2036. Backfilling and restoration of the area is to continue until 2080.
Since the construction and start-up of the new crushing plant in 1992, three kestrel pairs have taken up residence at the quarry.
?The birds feel at home here despite our 24 hour a day operations. Perhaps the kestrels already had nests in the old plant, which was dismantled and can today be viewed in the technical museum in Sinsheim,? says Georg.
The managers of BaW and Sandvik can look back to 15 years of constructive and successful co-operation. The staff of the Ebersbach quarry is excited about the capacity of the new Sandvik CH660 cone crusher, which has been in operation since 2008. However, it soon turned out that the downstream screen, designed for the previous crusher, was too small for the new one.
After discussions, the decision was taken to install a new generation Sandvik SC screen in order to improve productivity. Measuring 7200mm x 2400mm (23? x 8?), the Sandvik SC2472 screen is equipped with two decks and modular Sandvik WM 6000 rubber screening media separating 32mm and 16mm aggregate grades. The plant was integrated into the existing process simultaneously with the launch of Sandvik?s new screen line at Bauma, the world?s biggest construction machinery exhibition, in Munich in April 2010.
Sandvik?s SC screen line was developed for all screening applications. Depending on the application, these machines can reach acceleration rates of up to 4.5g. The inclination angle of the screen can be adjusted on-site, and the modular deck design allows the screening plant to be switched from clamped screen media to a modular system without any modifications to the screen frame.
Thanks to its ideal structure, the drive assembly can be replaced as a single unit. This guarantees minimum downtime and fewer costs during regular maintenance and repair work. The 30mm Sandvik rubber wear protection reduces wear and tear in the feed and discharge zones.
Georg Hans Ohler said that he was convinced about the SC screen from start-up. ?Within a very short time we were able to increase daily production by 15 to 20 per cent. The know-how and experience gained will enable us to optimise the processes and accomplish even further improvements.?
The raw material resourcing and processing operations at Ebersbach am Wetterberg are well equipped for their task. Now it?s up to the marketing department to turn the stone products ? ballast, and regular and high-grade chippings ? into hard cash.
Regardless of the application, whether road construction, airport runways or municipal works in Dresden, the spirit of stone can be felt both in Baroque treasures and in massive infrastructure projects.
Source: Sandvik Mining and Construction
.png){kind=small}
