Fracture (mining)

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A tunnel fracture caused by blasting in the U-relocation of Mittelbau Dora .

In mining, a fracture is both the unforeseen and the planned collapse of rocks or deposits. The scheduled generating fractures is at caving applied unscheduled fractures arise when mines collapse. The collapse, collapse or collapse of a shaft , a tunnel or a stretch of road is what the miner calls a crime . If a mine is broken, it will be buried by the incoming mountains and thus unusable.

Basics

Only in a few mines is the rock so stable that it does not have to be supported by expansion . The pit lining loses its stability over the years and becomes weaker. This applies in particular to the timber construction that was often used in the past. This timber construction becomes rotten over time by pit water and has to be renewed. Failure to do so, the expansion may be the rock pressure not withstand more and breaks. But even a new and completely intact extension can break due to the weight of the mountains. Certain lettige masses inflate when they come into contact with water and also destroy new expansion. Rolling masses can penetrate the mine between the extensions. The effects of degradation lead to convergences and thus to strong pressure on the roof as well as the sole and the bumps.

A tunnel breach secured with concrete supports at the end of the tunnel in Mittelbau Dora, caused by the extraction of the anhydrite above the tunnel in later decades.

consequences

Often the effects are so great that the mine workings can no longer be used and have to be left lying down as having been broken. Mines, are perpetrated, can only with great effort often aufgewältigt be. If a gallery owner had an hereditary gallery , the Wasserseige or the Lichtlöcher crime, the mountain master was authorized to clear this gallery again and to lend it again . If a tunnel became brittle, the tunnel owner no longer received the tunnel below. If a tunnel or a stretch of road is broken, the miners who are in the mine may be buried or trapped in a cavity. Depending on the severity, these miners can either be killed immediately or die of the consequences (e.g. starve to death) if they are not rescued immediately. If it turns out in retrospect that the reason for the crime was inadequate maintenance of the mine support or insufficient construction, this can be punished with severe penalties in accordance with the mining law and the applicable criminal laws.

Geological impact

In almost every rock, dividing surfaces are a natural component. These dividing surfaces arise from normal tectonics or from relief as a result of isostatic uplift and erosion. Tectonic or other stresses cause fractures in the mountains. If underground cavities are created, after the so-called standing time is exceeded, the rock becomes detached. These detachments are intensified and accelerated by the addition of mine water . Often the rock is so brittle that loose rock trickles into the created cavity. Depending on the type of rock, shell-shaped structures can loosen and fall into the cavity created. The rock is supported by the timely introduction of pit lining. If there is now due to overloading of the expansion to the fact that the mine opening verbricht, more can above the breaking point Verbruchsprozesse play. At greater depths of deep mining , the collapse is dead and there is no likelihood of a daybreak . Under certain circumstances, depending on the size of the broken cavity, a depression can be seen in the surface of the day, with the edge areas slightly extending beyond the width of the chimney. In the case of mine workings that were built in near-day mining, a daybreak can occur after a certain time.

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. ↑ Explanatory dictionary of the technical terms and foreign words that occur in mining in metallurgy and in salt works and technical articulations that occur in salt works. Falkenberg'schen Buchhandlung publishing house, Burgsteinfurt 1869.
  3. ↑ Mining dictionary. Johann Christoph Stößel, Chemnitz 1778.
  4. ↑ William Jicinsky, mountain and Hüttenmännischer club Mähr Ostrau (ed.): Catechism of the pit preservation for mine and mine Steiger supervisory bodies. Commissioned by Prokisch's Buchhandlung, Mähr-Ostrau 1876.
  5. ↑ Johann Gottfried Jugel (Ed.): Geometria Subterranea. New improved edition, bookseller Johann Paul Kraus, Vienna 1773.
  6. ^ Heinrich Veith: German mountain dictionary with evidence. Published by Wilhelm Gottlieb Korn, Breslau 1871.
  7. ↑ Carl von Scheuchenstuel : IDIOTICON the Austrian mining and metallurgy language. kk court bookseller Wilhelm Braumüller, Vienna 1856.
  8. ↑ Alexander H. Schneider: Security against collapse in underground mining. ETH dissertation No. 14556, Institute for Geotechnics, vdf Hochschulverlag AG at ETH Zurich, Zurich 2002, ISBN 3-7281-2872-4 .
  9. ↑ Günter Meier: To determine areas of action caused by old mining. In: 9 Altbergbau-Kolloquium Online (last accessed on March 12, 2013) (PDF; 549 kB).

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