Route expansion

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In mining, all types of expansion in underground routes are referred to as route expansion . The expansion of the route will be created in different cross-sectional shapes and with different expansion materials .

history

Track rooming

Up until the first half of the 20th century, the route extension was usually made of wood . In the straightening sections and the cross passages, polygon-shaped timber construction was used in different variants, in the dismantling sections mostly the door frame construction . The first attempts to upgrade the track made of cast iron were carried out in the second half of the 19th century on a mine in the Ruhr area. At the beginning of the 1950s, steel construction began to be used in the main lines. The wooden door frame was initially still used in the mining sections , but here the arched structure made of steel gradually replaced the wooden structure. The main reason was the increasing mountain pressure in the greater depths . From around 1960, the first attempts to use rock anchors for expansion began in the Ruhr mining industry. However, anchor removal in the hard coal industry was not able to prevail over the long term. In 1977 and 1978, the Emil Mayrisch, Rheinpreussen and Niederberg mines were filled with fillings , crosscuts and rock sections using the new Austrian tunneling method (NÖT) with anchors and shotcrete . In 1979, a 1.5-kilometer straightening section was excavated at the Nordstern mine using the NET .

Basics

Wood, bricks, steel and concrete are available to the miner as construction materials for the extension of the route . Which finishing materials are ultimately used depends on several factors. In particular, the pressure conditions at the place of use, but also economic efficiency, play a role in the selection of the route extension. There are four different cross-sectional shapes for the extension of the route, the rectangular extension , the ring extension , the arch extension and the polygon or polygon extension . With the rectangular extension, there is the normal rectangular extension in wood and steel and the door frame extension. Further variants of the rectangular extension are the steel cap on wooden boxes and the steel cap on brickwork. The ring expansion is a closed expansion in which lateral or swelling forces occur due to the rock pressure. The arch extension is a partially closed extension. With this type of construction, the ridge areas are mainly stressed by the rock pressure. The polygon extension is usually built in as a support extension. Which expansion cross-section is used in the respective routes depends on the type of route, the position of the route to the adjacent rock and the rock pressure. The size of the route cross-section depends on the required amount of weather and the thickness of the seam. Depending on the required route cross-section, only certain construction materials can be used. The track extension in wood can be used in hard coal mining with track cross-sections of four to a maximum of six square meters. In favorable mountain conditions, steel caps with wooden stamps can be used for cross-sections of six to ten square meters. If the cross-section is twelve or more square meters, timber construction is no longer possible. Steel lining is used for such cross-sections. For larger rooms, artificial stone is often used.

Timber construction

Timber construction

The route expansion using wood is also called route rooming. The simplest form of the route carpentry is the box carpentry using so-called ridge stamps. This form of expansion is also called cap expansion. This form of track rooming only serves to protect against falling stones from the hanging wall . Here, the are in the field ridges in one of the side impacts called Bühnlöcher caulked . A roof punch is inserted into each stage hole and struck from top to bottom on the opposite joint side. As a result, the ridge stamp is wedged between the bottom of the stage hole and the joint. The ridge punch then sits at a slight angle between the two joints. The ridge stamp can also be burned into the mountain in both joints. Instead of the stage holes, the ridge stamps can also be placed on recovery boxes , recovery walls or wooden boxes . Delay is then applied to the ridge stamp and covered with stones. If one or both joints have to be secured, the door frame extension is used.

Another form of route carpentry is broken Swedish carpentry. Here, the individual pieces of wood are sawn so that they narrow in the ridge area. Two shorter pieces of wood are attached to two stamps , which in turn are connected with a cross piece, the cap. The connection points are cut with a miter . The extension then has an almost inverted U-shape. If the sole swells, the expansion is made in the form of the rafter cap. To do this, two shorter pieces of wood are connected to one another in the sole area. The stamps are attached to these pieces of wood, which in turn are connected in the ridge area with a cross piece of wood. This gives the expansion an almost V-shape. In the case of pressurized mountains, the polygonal structure is used. The polygon extension is always designed to be articulated and is also used to reinforce the door frame.

Masonry

Wall lining in the area of ​​the filling point

In the case of the route walling, the expansion is created using bricked stones . The route walling is used for routes that are to remain in place for a longer period of time. The route walling is particularly preferable in the routes that have been driven in floating mountains. The penetration of the pit water is prevented by the masonry. But also in stretches that were driven in brittle rock, the route walling has advantages over the route room. When the tunnel is being built , the tunnel mouth holes are bricked up. There are two types of section walls, the disc wall and the vault wall. In the case of the disk wall, the stones lie parallel next to and on top of each other. Due to this construction method, one or two surfaces form the levels of the wall. The base of the wall is called the foot , the surface facing the route is called the forehead and the side facing the joint is called the back . There are straight-fronted and crooked-fronted slab walls. The front side of the straight-fronted disc wall forms a plane. This side is either plumb or regularly sloped. These walls withstand mostly vertical pressure from above, so they correspond to a stamp. It offers less resistance to lateral pressure, which in turn depends on its weight. In the crooked wall, the forehead is arched and thus forms the transition to the vault. The curvature is vertical on flat stretches. In the case of vaulting, the wall is created from one or more wedge-shaped curved pieces. The arch pieces are made in a regular curved line. The wall joints exactly follow the wall's radius of curvature. In the vaulted wall, the stones support each other. With this form of masonry, external pressure is evenly distributed and dissipated on the wall.

Steel construction

Rigid route expansion

Different cross-sectional shapes are used when extending the steel line. Due to its unfavorable static shape, the door frame is the weakest type of steel construction. Nowadays, multi-part extensions made of steel profiles are usually used for route extensions. A distinction is made between rigid expansion and flexible expansion. The flexible expansion is also known as a sliding arch expansion . The rigid extension consists of multi-part arches made of web profiles. The individual expansion segments are designed in such a way that they butt against each other during assembly. The extension segments are connected to one another by brackets. Due to this type of construction, the individual expansion segments cannot shift into one another and are deformed or even destroyed if the rock pressure is too great. The rigid support is mainly used in rock stretches in which little rock pressure or no convergences from the mining are to be expected. The flexible extension consists of channel profiles that are assembled so that they overlap. The extension segments are connected by clip straps. Depending on the construction, the expansion segments can be shifted into one another during flexible expansion, so that the expansion can absorb the rock pressure within certain limits and is not destroyed. The sliding arch support is usually installed in excavation sections. The code number "SA" is used to assess the workability of a steel line extension. This code number is used to determine the steel expenditure for the respective route. The code number SA represents the ratio of the weight of the material used to the space used. On the basis of the expected convergence and the rock index, the steel expenditure for a stretch to be expanded can be calculated in advance.

Mixed expansion

Mixed expansion

In the case of mixed finishing, different finishing materials are combined with one another in order to combine the positive properties of the finishing materials. First, the mixed expansion was used for the door frame expansion. The aim here was to strengthen the canopy and make it more resistant. With the mixed door frame construction, the cap is made of steel and the stamp is made of wood. To increase the compressive strength, instead of straight caps, upwardly curved caps are used. Angle irons are riveted to the caps, with which the caps are attached to the wooden stamps. Another variant of the mixed extension is the mixed two-part articulated arch extension. With this type of construction, two of the wooden components are replaced by steel arches. In the case of longwall mining , wooden or recovery boxes are brought in to secure the rear edge of the route .

Individual evidence

  1. ↑ a b c d e Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining dictionary . 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .
  2. ^ Ernst-Ulrich Reuther: Textbook of mining science. First volume, 12th edition, VGE Verlag GmbH, Essen 2010, ISBN 978-3-86797-076-1 , 367-400.
  3. ^ A b Association for Mining Interests in the Upper Mining District Dortmund (ed.): The development of the Lower Rhine-Westphalian hard coal mining in the second half of the 19th century. Julius Springer's publishing bookstore, Berlin 1902.
  4. ↑ Joachim Huske: The hard coal mining in the Ruhr area from its beginnings to the year 2000. 2nd edition, Regio-Verlag Peter Voß, Werne, 2001, ISBN 3-929158-12-4
  5. ↑ Franz Pacher, Alfred Ries: The new Austrian tunnel construction method and its application in mining : In Unser Betrieb No. 23, born in 1979, Deilmann Haniel Online (accessed on November 10, 2011; PDF; 9.8 MB)
  6. ↑ a b c d e f Ernst-Ulrich Reuther: Introduction to mining. 1st edition, Verlag Glückauf GmbH, Essen, 1982, ISBN 3-7739-0390-1 .
  7. ↑ a b c d e f g h Carl Hellmut Fritzsche: Textbook of mining science. Second volume, 10th edition, Springer Verlag, Berlin / Göttingen / Heidelberg 1962.
  8. ↑ K. Eisenmenger: Development and status of the expansion of main lines in Ruhr mining. In: Glückauf, Berg- und Hüttenmännische magazine. Association for Mining Interests in the Dortmund Oberbergamtsgebiet (Ed.), 71st year, January 5, 1935, pp. 2-10.
  9. ^ Heinrich Veith: German mountain dictionary with evidence. Published by Wilhelm Gottlieb Korn, Breslau 1871.
  10. ^ A b c Emil Stöhr, Emil Treptow: Basics of mining science including processing. Spielhagen & Schurich publishing house, Vienna 1892.
  11. ^ Gustav Köhler: Textbook of mining science. 2nd edition, published by Wilhelm Engelmann, Leipzig 1887.
  12. ^ A b Carl Hartmann: Handbuch der Bergbaukunst . First volume, Verlag Bernhard Friedrich Voigt, Weimar 1852.
  13. ^ A b Albert Serlo: Guide to mining science. First volume, published by Julius Springer, Berlin 1884.
  14. ^ A b c Heinz M. Hiersig (Ed.): VDI-Lexikon Maschinenbau . VDI-Verlag GmbH, Düsseldorf 1995, ISBN 9783540621331 .

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