Rügen Chalk

Old chalk quarry in Sassnitz

By 1720, chalk was used in the Granitz for the production of quicklime (CaO) in quarries. However, the foundation for the Rügen chalk industry was not laid until the first half of the 19th century. It was laid by the entrepreneur and naturalist Friedrich von Hagenow (1797-1865). In 1832 he leased the chalk quarries in the Stubnitz, and in the same year he opened a chalk factory in Greifswald. At that time, the raw chalk came by ship from Jasmund to Hagenow's factory. By slurrying, the raw chalk was separated from the undesirable rock components such as flint (firestones, see above) and finer-grained impurities (so-called Grand), and the same principle is still used today. In the days of Hagenows and also long after, however, the excavation and preparation of the chalk were carried out almost exclusively with human muscle power and the work was physically very strenuous.

During the late 19th century, the fishing village of Sassnitz, located in the immediate vicinity of the Stubnitz, slowly developed into a centre of the chalk industry, not least because most of the chalk pits were on the Jasmund. A fierce competition developed between the individual chalk plants. Von Hagenow had to give up his business in 1850. As a result, 17 companies with 23 chalk plants merged in 1899 to form a cartel and set up limits on all member's production volumes and prices.[5] In 1928, around 500,000 tonnes of rough chalk from the Jasmunder fractures were mined in Martinshafen at Großer Jasmunder Bodden and loaded in Sassnitz. With 80,000 tonnes of capacity, however, the mud chalk production on the Jasmund played only a minor role at that time. The buyers of the raw chalk were mainly the Portland cement plants in Wolgast, Lebbin and Stettin. So some pits and chalk plants on the Jasmund belonged directly to the Stettiner Portlandzementfabrik A. G. of Martin Quistorp. The other major chalk and cement producer and most important player in the Rügen Chalk Cartel[5] was the Pommersche Industrieverein a. A. founded in 1872 by Johannes Quistorp.

With the collapse at the end of the Second World War, chalk extraction and processing came to a temporary standstill. Some facilities, including the chalk cable car to Sassnitz harbor, were dismantled and brought to the Soviet Union as war reparations.[6] In addition, the fact that the island of Rügen belonged to the Soviet occupation zone and later to the GDR meant the elimination of private economic structures in the Rügen chalk industry for the next 45 years. It was only in this period that modern technology completely replaced strenuous physical work in many areas. Since chalk was soon in demand again as a raw material with the reconstruction, a total of 19 chalk quarries started operations on Rügen after 1945, which were combined in the VEB Vereinigte Kreidewerke Rügen after 1957. By 1945, the dismantling has been stopped in the oldest quarries on the eastern edge of the Jasmund and at Lohme, as well as in the quarries from Dumsevitz, Rosengarten and Altkamp Südrügen. With the completion of a large and modern chalk works in Klementelvitz between Sassnitz and Sagard, many other smaller chalk quarries were closed after 1962 and the company was renamed "VEB Kreidewerk Rügen". During the GDR era, the company belonged to various institutions. It was temporarily subordinate to the Rat des Bezirkes (District Council) Rostock, then belonged to the Association of VEB Bindebaustoffe Halle and then to the "VVB Zement Dessau", which was later renamed "VEB Zementkombinat Dessau" (ZEKOM). In 1984 the legal independence of the VEB Kreidewerk Rügen was finally abolished and it was assigned to the "VEB Zementwerke Rüdersdorf" as "Operating Part 6". Under favorable conditions, the Klementelvitz chalk works, which after commissioning was considered to be one of the most modern chalk works in Europe, achieved an annual production of 185,000 t chalk and 55,000 t Grand.

In the course of the economic upheavals following the Peaceful Revolution in 1989 and 1990, VEB Zementwerke Rüdersdorf was taken over by Readymix AG and the chalk factory in Klementelvitz was spun off, converted into a GmbH and initially remained with the Treuhandanstalt. The operation of the mine railways for the transport of raw chalk from the Wittenfelde open pit mine north of Klementelvitz, the only active chalk pit on Rügen at that time, was discontinued. On August 13, 1993, after clarification of all land ownership issues, the Kreidewerk Rügen GmbH was taken over by the Vereinigte Kreidewerke Dammann KG and thus the Swiss Omya AG. [7] By then, the company's sales had fallen to only 25,000 t.[7] Omya invested in total by 2010 almost € 50 million [7] and built a state-of-the-art facility for chalk production - from excavation to loading. At the end of the 1990s, the Wittenfelde open pit mine was shut down [8] and in its place the Promoisel open pit mine about 1 km further west was put into operation. At the start of mining, around 25 million t of raw chalk was available there. The freshly broken chalk now reaches the factory via a 2 km long conveyor system, where it is processed into refined chalk in different grain sizes using the new wet processing technology. The annual production of the plant is now up to 500,000 t. [7] In 2009 the planning approval was issued for the future Goldberg / Lancken-Dubnitz mining field south of Klementelvitz for production through 2117 of 35 million t of chalk. [9]

Chalk bridge in the port of Wiek on Rügen before renovation

Historical illustration of chalk mining in the Buddenhagen quarry (1963)

In the 19th and early 20th century, the chalk had to be dislodged from a steep mine face with pickaxes and transported on lorries to the so-called agitators. In large vats, in which iron hooks rotated, the chalk was stirred with the addition of water. In this step, the coarsest components, mostly flint, were separated. The chalk and water mixture, also called Kreidemilch or Kreidetrübe, was passed through separation tanks where the finer impurities, the Grand, settled out. The chalk suspension freed from the grand finally ended up in the settling basin, in which the still- suspended particles settled out and accumulated into a layer about 30 cm thick. The now no longer cloudy water was drained and the basin was filled with fresh chalk suspension, so that the fine particles could settle again. The whole process was repeated until the sediment reached a thickness of approximately 1.5 meters. The finished fine chalk still had a water content of 30 to 35%. This heavy, mass was then knocked out, that is, it was shoveled out of the settling basins into carts. The workers who carried out the work steps from dismantling to knocking out were called sludgers.

Other workers, the so-called formers, transported the wet chalk with the carts to the dry sheds, and formed the chalk into shovel-sized masses and laid them out there for drying. The chalk had to be relayered several times during the dry season of about four weeks. With a residual moisture of approximately 5%, the chalk was ready for shipping at that time.

From the turn of the 19th to the 20th century, the mining and processing of the chalk became increasingly industrialized, which significantly increased the production volume of raw chalk and the prepared chalk (known in German as Schlämmkreide.) Even before 1945, about a dozen excavators were in operation during chalk mining. From the Jasmund quarries, the rough chalk came either via a railway line, the Kreidebahn, to Martinshafen near Sagard (there are also old quarries[10]) or with a cable car to the Port of Sassnitz. The chalk railway forked towards the mining area into a northern and a southern section of the line. The southern line ran from Wittenfelde via Klementelvitz and Quatzendorf to Marlow, where it merged with the northern line from Gummanz. The Rügen Kleinbahn also played an important role in transport to the ports. In 1914, in order to relieve the ports of Sassnitz and Martinshafen, Wiek on the Wittow completed the so-called Kreidebrücke for loading the chalk on barges, which was reopened 100 years later as a "floating promenade".[11]

Production continued after 1945 with pre-war technology. In order to increase the flow rate and at the same time to guarantee a consistent quality of the chalk with a residual moisture of about 0.5% and grain sizes not above 63 microns, new technologies were developed and a new chalk plant constructed in Klementelvitz[12] after 1958 for 30 million Mark (DDR).[13] In this context, the heavy physical work in the mine face was completely replaced by modern conveyors such as the excavator UB 80, a GDR standard excavator of the 1960s and 1970s. Both the raw chalk and the debris were transported by railways. With the completion of this plant in 1962 (initially trial operation, from 1963 regular production) the production time from excavation to shipping was reduced to only 80 minutes. Until then, it was up to 80 days.

The chalk lorries and the excavators later became larger (UB 162-1), and on an experimental basis, 20-m³ lorries designed for lignite open pit mining were also used in the mines, after the tracks had been converted accordingly. Depending on the ground conditions, heavy trucks also took over the removal of debris, and special excavators were used for the installation of preassembled tracks. The chalk was also partially preprocessed in open-cast mining using a "mobile sludge device".