Burglary (shooting)

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As slump is known in mining while shooting the first in blown-up portion of the charge details. The break-in creates a cavity and thus several free areas when shooting. In addition, the collapse reduces the tension in the mountains. The explosive charges subsequently ignited can then act in the free space created by the break-in.

Basics

When shooting, it is of great use if there are enough free areas in which the shots can work, so that the cohesion of the mountains can be overcome more easily. There are usually several free areas in the quarrying process , so that the mineral can be blown into the open space shot by shot. However, apart from the face, there are no other free areas when driving the road . The more free areas there are, the better the effect of the explosive charges. If there are no free areas in sufficient numbers, the miner tries to create these free areas. In the past, if possible, a sufficiently deep scraper was made in the mountains . When the shots are fired, the mountains are pushed towards the Schram. Instead of the Schram you can also create a break in during the blast. Establishing the right break-in is the toughest task in shooting. Burglary shooting is nowadays usually used for conventional road driving.

Burglaries

To create the collapse, one or more boreholes are placed in such a way that a piece of the rock is blasted out. Depending on the direction in which the penetration boreholes are created in relation to the driving direction, a distinction is made between two basic forms of penetration, parallel penetration and angled penetration. To create these types of incursions, holes are either drilled parallel or inclined into the rock. There are also mixed forms of incursions in which both parallel and inclined boreholes are used in one incursion. Further forms of break-in are burner break-in, large borehole break-in, staggered break-in, cone break-in, wedge break-in, fan break-in and fan wedge break-in. Another type of break-in is loosening break-in, in which one makes use of the stratification of the rock layers. A distinction is made here between ridge, butt and sole loosening. There are also other varieties of the aforementioned types of intrusion, such as B. the scissor plow break-in. Which intrusion is ultimately optimal for the respective tunneling can be determined with one or more test blasts.

Parallel break-ins

The parallel intrusions are also called fragmentation intrusions. This basic form of notches is applied to a free area such as B. placed the face . The parallel break-ins include the burner break-in, the large borehole break-in and the relay break-in. Burner penetration has been used for a long time in potash and salt mining, sometimes also in ore mining. There this form of break-in is also known as cannon shooting. It is the oldest type of collapse with parallel boreholes. The break-in is tubularly shot out by means of four to nine parallel boreholes, only a part of which is loaded. The uncharged holes can either be placed in the middle between the charged holes or vice versa. These boreholes, known as relief holes, must be drilled with a larger borehole diameter. When a large borehole collapses, one or more larger boreholes with a minimum diameter of 65 millimeters are drilled parallel into the mineral. If only one large borehole is used, this borehole is drilled with a diameter of up to 300 millimeters. Several blast holes, which have a smaller diameter, are drilled around the unoccupied large boreholes. These drill holes can be arranged in parallel or in a spiral shape around the large drill holes. If there is only one large borehole, the spiral arrangement of the blast holes is the more suitable arrangement. The large borehole can either be drilled as long as the blast holes or as long as the length of the driveway is one week. Boreholes of different lengths are drilled for the gradual break-in. With this type of break-in, it is important that the explosives charging columns of the long and short holes do not overlap. In some mountain areas, the form of the break in is also known as a step break. When firing the relay break-in, a wedge-shaped slot is blasted out of the face.

Diagonal drops

These forms of incursion are also known as conical incursions in some mountain areas. The boreholes for these types of incursions are drilled in the rock at an angle. In the case of these breaks, the length of the cut depends on the cross-section of the respective mine construction to be created . The incursions with oblique boreholes include the cone incursion, the wedge incision, the fan break and the fan wedge break. When the cone collapses, the individual boreholes are drilled in such a way that they are as close together as possible in the deepest part of the borehole. Care must be taken that the drill holes do not come together at the bottom of the drill hole. The number of holes to be drilled is usually three or four holes. During this break-in, the guidance of the boreholes ensures that the explosive force is concentrated at the point of greatest resistance. The cone collapse is well suited for hard rock . In some mountain areas outside Germany, this type of collapse is also known as a pyramid collapse or a diamond collapse. The wedge collapse is very similar to the cone collapse. During this break-in, the boreholes are guided in such a way that they taper symmetrically to a usually perpendicular center line of the cross-section of the route. The difference to the collapse of the cone is that in the case of a wedge collapse the rock to be loosened is attacked by several pairs of shots from the side and not from behind, as is the case with the collapse of the cone. When the fan collapses, a horizontal or vertical row of blast holes is drilled into the rock. To do this, start in the sole area and drill three to four rows with three holes each (shots). This arrangement of the boreholes removes the rock from the association in a fan-like manner. The middle shots serve as a breaker, the side shots are intended to expand the break-in. A variant of the fan break is the fan wedge break, which can be used both in routes with a smaller and in routes with a larger cross-section.

Individual evidence

  1. ^ A b c d Walter Bischoff, Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining encyclopedia. 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .
  2. ↑ a b c d Horst Roschlau, Wolfram Heinze, SDAG Wismut (Hrsg.): Knowledge storage mining technology. 1st edition. German publishing house for basic industry, Leipzig 1974, pp. 51–58.
  3. ^ Tilo Cramm, Joachim Huske: Miners' language in the Ruhr area. 5th revised and redesigned edition, Regio-Verlag, Werne 2002, ISBN 3-929158-14-0 .
  4. ^ A b Fritz Heise, Fritz Herbst: Textbook of mining science with special consideration of hard coal mining. First volume, fifth improved edition, published by Julius Springer, Berlin 1923, pp. 270-272.
  5. ↑ a b c d Fritz Heise, Fritz Herbst: Textbook of mining science with special consideration of hard coal mining. First volume, published by Julius Springer, Berlin 1908, pp. 231–233.
  6. ↑ a b c d e f g h i j k G. Lathan: Drilling and shooting in mining. Volume II Shooting, Fachbuchverlag Leipzig, Leipzig 1958, pp. 102–116.
  7. ↑ a b c d e f g h Carl Hellmut Fritzsche: Textbook of mining science. First volume, ninth completely revised edition, Springer Verlag, Berlin / Heidelberg 1955, pp. 193–205.
  8. ↑ a b c d e f g h i j k l m n o p q r s Ernst-Ulrich Reuther: Textbook of mining science. First volume, 12th edition, VGE Verlag GmbH, Essen 2010, ISBN 978-3-86797-076-1 , pp. 193-205.
  9. ^ BW Boki, Gregor Panschin: Bergbaukunde. Kulturfond der DDR (Ed.), Verlag Technik Berlin, Berlin 1952, p. 214.