Drilling flushing system

In salt mining, a drilling flushing works is an underground cavity created by mining that serves as a mining chamber for the extraction of salt . The salt is in the mining works, removed with the help of fresh water by leaching from the salt-containing rocks and further processing by over days pumped. The operating life of a drilling and flushing plant is around 30 years. In the course of its operating life, an average of 1.1 million cubic meters of brine can be extracted from a drilling flushing plant , from which 350,000 tons of evaporated salt are produced.

Basics

When mining salt, the miner can use two different mining methods, dry mining and wet mining. In the case of dry mining, chamber construction is predominantly used as the mining method. In wet mining, the salt is removed from the rock by flushing with water and the resulting brine is pumped out with pumps for further processing. A distinction is made between two methods, dismantling by means of a normal plant and dismantling by means of a drilling and flushing plant. Degradation is only prepared if the sodium chloride content averages 30 percent by mass. Dismantling by means of a drilling fluid, also known as the borehole probe method, has been used in salt mining since the mid-1960s. It is used in reservoirs with a horizontal size of at least 120 by 160 meters and a vertical dimension of at least 125 meters.

contraption

In order to be able to remove the salt from the rock by means of wet mining, a cavity must first be tapped. For this purpose, first from the pit building an access route either conventionally or by means of roadheader ascended . In addition, a drilling chamber must be created at the end of the route. From there, a borehole will be drilled into the deposit at a depth of 125 meters below the bottom level . The borehole is created with an airlift drilling system and has a diameter of 670 millimeters. The cuttings produced are dumped in suitable caverns in the mine. After reaching the final depth, an initial cavity with a volume of around 3500 to 5000 cubic meters is created at the base of the borehole. To do this, the area at the base is rinsed out with fresh water. After the water is saturated with salt, it is pumped out by means of a suspended pump. The brine residues, which essentially consist of clay and anhydrite , are pumped out together with the brine. This process must be repeated several times. The ceiling surface of the cavity, which the miners call the sky surface, has to reach an area of around 3000 square meters. Ideally, this creates a cylindrical cavity with vertical walls. The creation of the initial cavity takes up to three months. With the generated initial cavity, on the one hand, a sufficiently large attack surface is created for the later salt extraction and, on the other hand, the remaining mountains can be deposited in the cavity . As a final step, the well is a die with a diameter of about three meters drilled . The drilling takes place by means of drilling and shooting operation , the resulting aggregate is allowed to fall in the initial cavity. After the borehole has been completely expanded, the flushing rods are installed. In addition, trips are made in the die.

Extraction

After all fixture work has been completed, brine production begins. This process is known as the main solution. A certain amount of fresh water is now always introduced into the cavity. The water dissolves the water-soluble components from the mountain range on all sides until it has a salt content of around 26.5 percent. The saturated brine is then pumped out and a corresponding amount of fresh water is introduced again. The fresh water is introduced in the middle of the brine level so that no major turbulence occurs. This means that there is no mixing of fresh water and remaining brine. Since the fresh water is lighter than the brine, it spreads on top of the brine and can further dissolve salts from the mountains. The insoluble components of the rock sink down and settle on the bottom of the cavern. In order to be able to monitor the fill level in the drilling and flushing works, ultrasonic fill level measuring devices are used, which are connected to a process computer that controls the entire process. The drilling flush works continuously from bottom to top. Around one centimeter of material is removed from the mountain range every day. As a result, the cavity created becomes larger and larger over time. As soon as the leached cavity has reached a height of 100 meters, measured from the deepest point, the drilling and flushing works stop.

Individual evidence

^ ^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 .
↑ ^a ^b ^c ^d ^e ^f Heinrich Otto Buja: Germany's mineral treasures. Geology-Exploration-Extraction, 2nd edition, Verlag Cornelius GmbH, Norderstedt 2010, ISBN 978-3-7392-7612-0 , pp. 255-256.
↑ ^a ^b ^c ^d ^e ^f ^g ^h Heinrich Otto Buja: Handbook of subsoil recognition. Devices and procedures, 1st edition, Vieweg + Teubner Verlag, Wiesbaden 2009, ISBN 978-3-8348-0544-7 , pp. 88, 89.
↑ ^a ^b ^c Kurt Thomanek: Fascination Salt Worlds. Salzburg - Hallstatt - Altaussee, pp. 24-27.
↑ Hans-Jürgen Holtmeier (Ed.): Significance of sodium and chloride for humans. Analytics - Physiology - Pathophysiology - Toxicology and Clinic, Symposium of the Society for Minerals and Trace Elements e. V. at the University of Hohenheim, Springer Verlag, Berlin / Heidelberg 1992, ISBN 978-3-642-77341-9 , p. 74.
↑ ^a ^b ^c ^d ^e ^f ^g ^h Friedrich Köthe, Daniela Schetar: Reise Know-How Chiemgau, Berchtesgadener Land. 2nd revised and completely updated edition, Reise Know-How Verlag Peter Rump, Bielefeld 2017, ISBN 978-3-8317-4226-4 , p. 188.
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Technical University Bergakademie Freiberg, Faculty for Geosciences, Geotechnics and Mining (Ed.): Joint excursion of the Institute for Mining and the Institute for Geotechnics from 07-11. October 2002 to Bavaria, Tyrol and Thuringia. Freiberg 2002, pp. 8-10.
^ ^A ^b ^c ^d ^e ^f Südwestdeutsche Salzwerke AG (ed.): Salt building block of life. Heilbronn 2011, pp. 18, 19.
^ Solveig Böhl: The salt from the depths of the Alps. In: Endress + Hauser Messtechnik GmbH (Ed.): Sommerkurier , Edition 2017, pp. 14, 15.
↑ Agnes Zeiner: In the realm of white gold. In: Reporter: The magazine of Leica Geosystems, pp. 3–5.

Remarks

↑ There are also drilling and flushing works in which, depending on the local conditions, an initial cavity of up to 10,000 cubic meters is exposed. (Source: Friedrich Köthe, Daniela Schetar: Reise Know-How Chiemgau, Berchtesgadener Land. )

[Quelle_1-1] 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 .

[Quelle_2-2] ↑ ^a ^b ^c ^d ^e ^f Heinrich Otto Buja: Germany's mineral treasures. Geology-Exploration-Extraction, 2nd edition, Verlag Cornelius GmbH, Norderstedt 2010, ISBN 978-3-7392-7612-0 , pp. 255-256.

[Quelle_6-3] ↑ ^a ^b ^c ^d ^e ^f ^g ^h Heinrich Otto Buja: Handbook of subsoil recognition. Devices and procedures, 1st edition, Vieweg + Teubner Verlag, Wiesbaden 2009, ISBN 978-3-8348-0544-7 , pp. 88, 89.

[Quelle_3-4] Kurt Thomanek: Fascination Salt Worlds. Salzburg - Hallstatt - Altaussee, pp. 24-27.

[Quelle_4-5] Hans-Jürgen Holtmeier (Ed.): Significance of sodium and chloride for humans. Analytics - Physiology - Pathophysiology - Toxicology and Clinic, Symposium of the Society for Minerals and Trace Elements e. V. at the University of Hohenheim, Springer Verlag, Berlin / Heidelberg 1992, ISBN 978-3-642-77341-9 , p. 74.

[Quelle_5-6] ↑ ^a ^b ^c ^d ^e ^f ^g ^h Friedrich Köthe, Daniela Schetar: Reise Know-How Chiemgau, Berchtesgadener Land. 2nd revised and completely updated edition, Reise Know-How Verlag Peter Rump, Bielefeld 2017, ISBN 978-3-8317-4226-4 , p. 188.

[Quelle_8-7] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ Technical University Bergakademie Freiberg, Faculty for Geosciences, Geotechnics and Mining (Ed.): Joint excursion of the Institute for Mining and the Institute for Geotechnics from 07-11. October 2002 to Bavaria, Tyrol and Thuringia. Freiberg 2002, pp. 8-10.

[Quelle_7-8] A ^b ^c ^d ^e ^f Südwestdeutsche Salzwerke AG (ed.): Salt building block of life. Heilbronn 2011, pp. 18, 19.

[Quelle_9-10] Solveig Böhl: The salt from the depths of the Alps. In: Endress + Hauser Messtechnik GmbH (Ed.): Sommerkurier , Edition 2017, pp. 14, 15.

[Quelle_10-11] Agnes Zeiner: In the realm of white gold. In: Reporter: The magazine of Leica Geosystems, pp. 3–5.

[Anm._Köthe.-9] There are also drilling and flushing works in which, depending on the local conditions, an initial cavity of up to 10,000 cubic meters is exposed. (Source: Friedrich Köthe, Daniela Schetar: Reise Know-How Chiemgau, Berchtesgadener Land. )