Stem (mining)

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In mining, the term “ front end ” refers to the form of mining guidance in which the mining is carried out in the direction of the mining limit of the respective construction height . The front structure is also referred to as field-facing construction. In the German hard coal mining, the front end is the most common form of mining guidance.

Requirement, implementation and use

In the case of pre- excavation , the excavation routes are led to the field at the same time as the excavation. There are two variants here. The excavation routes can be driven either as forward or as follow-up routes. In the pre-set routes, the distance z. B. in the longwall between the longwall and the face of the pre-stretched route 50 meters and above. The minimum distance is around five meters. This minimum length is necessary so that the drive station of the tank conveyor still has enough space. In the tracked routes, the dismantling front rushes ahead of the dismantling route, the remaining required route cross-section is created afterwards. With the front end, the flow rate flows in the opposite direction to the mining direction . The weather stream flows back to the starting point of the construction height. The stem is used in mining processes with a long front-like construction such as B. the longwall. However, you can here the reduction in dismantling lead. The porch is also used for the chamber-like and the shock-like construction.

Limits, advantages and disadvantages

When stem needs of drifting with the face advance can keep up. However, the required routes cannot be driven fully mechanically. In contrast to demolition, the nature of the adjacent rock does not have a major influence on the pre-construction . Since the excavation of the mining roads takes place almost at the same time as the mining, the rock pressure can only affect the swelling of the road bottom later . For this reason, the stem is also in seams with slate in the footwall applicable. The front structure offers particular advantages when mining thin seams with a high proportion of tailings , as these can be used as backfill in the old man . However, the costs for ongoing operations are higher for the front end. This is because we in the promotion take into account the contingent by dismantling operations must feed. However, if there is a serious deterioration of the deposit , which makes it impossible to continue the construction height from an economic point of view, there is no loss of capital already invested in the excavation of the mining section.

Individual evidence

  1. ^ A b Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining dictionary. 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .
  2. ^ Tilo Cramm, Joachim Huske: Miners' language in the Ruhr area. 5th revised and redesigned edition, Regio-Verlag, Werne 2002, ISBN 3-929158-14-0 .
  3. ^ Ernst-Ulrich Reuther: Textbook of mining science. First volume, 12th edition, VGE Verlag GmbH, Essen 2010, ISBN 978-3-86797-076-1 .
  4. ^ A b c d e Carl Hellmut Fritzsche: Textbook of mining science. Second volume, 10th edition, Springer Verlag, Berlin / Göttingen / Heidelberg 1962
  5. ^ A b c d Heinrich Otto Buja: Engineering Handbook Mining Technology, Deposits and Extraction Technology. 1st edition, Beuth Verlag GmbH Berlin-Vienna-Zurich, Berlin 2013, ISBN 978-3-410-22618-5 .