Sand track (mining)
A dirt track is a mining railway , which has the task of the necessary offset materials for filling ausgekohlter of underground mine workings in hard coal and lignite mining heranzuschaffen. In general, gravel and sand are used for this , which are washed into the disused mining fields. These railways were characterized by high axle loads and the use of locomotives that were designed to transport the heaviest trains over short distances. Sand tracks still exist today in the coal mining area in Upper Silesia .
general basics
The usual method in underground coal mining is still longwall mining , in which the coal seam in the mountains is completely cleared. Then the overlying overburden is brought to break in a controlled manner. This break continues over time to the surface of the earth. In the final state, the mountain subsides by the amount of the height of the seam that has been mined. In the case of very thick seams, such subsidence can be ten meters or more. Damage to buildings such as cracks or inclinations then occurs on the surface of the earth. Typical features of such areas are also sinks without drainage, which in built-up areas, for example , have to be drained with pumps as a perpetual burden. If rivers are affected by subsidence, the receiving water can be disrupted . A more recent example of this is the Walsum colliery near Duisburg , which was abandoned because of possible subsidence under the Rhine .
The only way to reduce such subsidence is to fill the charred areas with overburden or added backfill material. Since the overburden that accumulates in the pit is usually insufficient, sand and gravel are usually used, which are washed in from above with water. However, this is only possible where these materials can be extracted as close as possible to the mine.
The railways built to transport the backfill material had to be designed to transport large quantities, regardless of the speed being driven. The problem is the high specific density of sand, which is almost twice that of the extracted coal. As a rule, this required the creation of dedicated lines, which were also designed for very high axle loads .
Sand railways to mining areas
North Bohemian Basin
In the North Bohemian Basin , only the Brucher Coal Works Union , based in Teplitz-Schönau (today: Teplice), operated its own sand track from 1912. This stretch, known as the Brucher Sandbahn , ran from the sand pits near Prohn (Braňany) to the shafts near Bruch (Lom u Mostu). The route was operated by the Aussig-Teplitz Railway (ATE) and later the Czechoslovak State Railways (ČSD) with the vehicles of the mining company. With the conversion of coal production in the North Bohemian Basin to open-cast mining after the Second World War, the line became non-functional and abandoned.
Upper Silesia
Sand tracks were most widespread in the Upper Silesian coal mining area , where such tracks still exist today. Before 1945 the following sand railway companies existed in the Upper Silesian Revier:
- Sand railway company of the Count of Ballestrem (formerly the sand railway company of the Graefl. V. Ballestremsch'en and Borsig'schen coal works )
- Sand track of the Schaffgott'schen Werke
- Sand tracks of the Prussian Hütten- und Bergwerks AG
After the nationalization of all Upper Silesian mines as a result of World War II, the sand railways were combined in 1950 in the state sand railway company Przedsiębiorstwo Materiałów Podsadzkowych Przemysłu Węglowego (PMPPW). This company was only dissolved again in 1991. Today the sand tracks u. a. operated by the successor companies CTL Maczki-Bór and DB Cargo Polska (formerly PCC Rail).
Zwickau district
In the Zwickau coal field , the Erzgebirgische Steinkohlenverein (EStAV) began developing the coal fields under today's Zwickau old town from 1903 . Initially, dead rock from the company's own extraction was used as backfill, later a separate sand pit near Oberrothenbach was used to extract flushing sand. The loading point of the Oberrothenbach sand works was set up on the existing Zwickau – Crossen – Mosel industrial railway , so that no separate sand railway had to be built. From 1909 the Royal Saxon State Railways and later the Deutsche Reichsbahn transported backfill material to the unloading point at the trust shaft four times a day. These traffic ended in 1948 with the cessation of coal production under the Zwickau urban area.
vehicles
Locomotives
During the steam locomotive era in particular, the locomotives used on the sand railways were mostly special designs that were tailored to the particular operating conditions. In many cases the built locomotives were stepping motors of technical development in steam locomotive construction. The steam locomotives delivered to the Brucher Coal Works in Northern Bohemia in 1912 were the first five-coupled tank locomotives in Austria . A type of locomotive was developed for the Altenberg union in Upper Silesia , the design of which was later exemplary for the tier-class locomotives of the Halberstadt-Blankenburg Railway and for the Prussian T 20 . The largest German tank locomotives at all were sand railway locomotives. These giants with almost 140 tons of service weight were delivered in 1936 with the numbers 8 and 9 to the Preußische Bergwerks- und Hütten AG in Upper Silesia.
The Polish state sand railway Przedsiębiorstwo Materiałów Podsadzkowych Przemysłu Węglowego (PMPPW) then also used normal freight train locomotives with a tender after the Second World War, which could be purchased second-hand from the Polish State Railways (PKP). Only in the 1980s did Poland gradually switch to diesel and electric locomotives, for which part of the sand railways were even electrified with the 3 kV direct current system of PKP.
See also
Individual evidence
- ↑ Norbert Peschke : The Zwickau hard coal mining and its coal railways . Zschiesche GmbH, Wilkau-Haßlau 2007, ISBN 3-9808512-9-X , p. 234 .
- ↑ Wolfram Brozeit, Hans Müller, Günter Bölke: Class 95. The curriculum vitae of the "Mountain Queen" ; transpress Verlagsgesellschaft, Berlin, 1990, ISBN 3-344-00377-1 ; P. 104f
- ↑ railway courier Special 85/2007: Railways in Silesia Part 2. EK-Verlag, Freiburg, 2007