Pit of rainfall

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Pit of rainfall
General information about the mine
Mining technology Partial pillar construction with offset
Funding / year 98,500 t
Information about the mining company
Operating company Erzgebirgische Fluss- und Schwerspatwerke GmbH
Employees 37
Start of operation 2013
End of operation open
Funded raw materials
Degradation of Fluorite , barite
Geographical location
Coordinates 50 ° 27 '23.8 "  N , 13 ° 1' 14.2"  E Coordinates: 50 ° 27 '23.8 "  N , 13 ° 1' 14.2"  E
Precipitation pit (Saxony)
Pit of rainfall
Location pit precipitation
local community Oberwiesenthal
District ( NUTS3 ) Erzgebirgskreis
country Free State of Saxony
Country Germany

The Precipitation Pit is a mine opened in 2013 on river and barite in Oberwiesenthal , Erzgebirgskreis ( Saxony ). To the west of the mine is the eponymous town of precipitation , which is now part of the Bärenstein community .

Deposit

The deposit is located on an approximately 35 km long fault system that extends from Kovářská (Schmiedeberg) on the Czech side via precipitation to Scheibenberg on the German side. Of this, however, only a 5.5 km long section between Kovářská and the Luxbach shows significant mineralization . In the near-surface area, which was the subject of uranium mining by Wismut AG , it is split into two passageways . With increasing depth gather them into a single composite fluorite barite mineral gear having an average thickness of from about three meters.

Around two thirds of the cross-border proven deposit is on the German side. In this area, the corridor strikes mainly 160–170 ° (SSE – NNW) and falls with 72–82 ° to the SW. According to the current exploration results, the economically viable filling of the Spat dike extends to a depth of at least 800 m.

During the mineralization of the subsurface Gangtrümer with their uranium mineralization during MgU- and BiCoNi formation was carried out, the deeper parts during been EBA formation ( chert , Rotbaryt ) and finally the fba formation ( quartz , fluorite, barytes) mineralized. The Spatgang has only low levels of copper, lead, zinc and iron sulfides. In the upper area it is interspersed with a marble warehouse .

history

Old mining

The name Berghäusel could provide the first reference to mining in the region . What is meant here is a silver mine that was probably destroyed in 1427/29. Another clue comes from 1477 when a silver mine was sold. In Weipert opposite, a wild hammer was newly awarded in 1506 , which is an indication of older iron ore mining. Around 1550 two mines built on tin and silver were mentioned in documents. Around 1650, after the end of the Thirty Years' War , intensive mining for iron , tin , copper and silver revived on the Stahlberg . Mining experienced its heyday when silver was found again around 1715. In the period from 1730 to 1870 mainly silver and cobalt ores were mined. Between 1913 and 1915 there was a small amount of uranium mining.

Bismuth mining

Wismut AG began exploring the Neu Unverhofft Glück mine in autumn 1946 . She overcame the old structures and opened up the deposit through numerous shafts , tunnels and pits. The objects were already in safe custody in 1954 . During this time, 132.7 tons of uranium were extracted.

Exploration work in the GDR

During the investigation work on uranium ore between 1950 and 1954, the mineral deposit was also discovered. Since the bismuth was aimed exclusively at the extraction of uranium, the reserves were offered to the nationally owned mining industry for investigation in 1955. From January 1, 1956, the Spatgang (Magistralnaja) was excavated and explored by the Wismut on behalf of the state- owned company "VEB Erzgebirgische Spatgruben" founded on April 1, 1955 . As of January 1, the company was incorporated into the VEB Zinnerz Ehrenfriedersdorf, which from this date traded as VEB Zinn- und Spatgruben Ehrenfriedersdorf. The mining investigation work was carried out in the central area in a depth interval of 260 m to 554 m above sea level by the Wismut and stopped in 1960. Since the processability of the fluvial spate was not clarified, all the stocks explored were classified as off-balance sheet stocks by the state stock commission. In 1959, VEB Geophysik Leipzig, on behalf of the State Geological Commission, carried out a geoelectrical investigation of the north-west continuation of the deposit in a 700 m wide and 2600 m long strip of territory. From November 7, 1972 to July 1977, the SDAG Wismut carried out extensive search and exploration work in the deposit by means of deep boreholes on behalf of the Ministry of Geology of the GDR. In addition to the central area, the north-west continuation and the north-west flank were also included in the investigations. In the central area, the drill exploration was carried out below the mine field developed by mining operations down to a depth of 0 m above sea level. 6,257 kt of raw spar with a content of 2,345 kt of CaF 2 were reported . Both the northwest continuation and the northwest flank were classified as not worth building . In the processing tests carried out in the laboratory using flotation, 80% of the iron content and 50% of the sulfide content remained in the concentrate. So the concentrate was not for sale. Between 1980 and 1988, the 8 km long Vykmanov adit was excavated, with the help of which it was possible to prove that the mineralization extends on the southeast continuation of the deposit to Kovářská. A revision in 1988 revealed a total of 3,338 kt of raw spar with a content of 1,413 kt of CaF 2 and 558 kt of BaSO 4 . Another 2.1 million tonnes of raw spar are added on the Czech side. The exploration and research work was ended for the time being in 1991 with the cessation of ore and spar mining in the Ore Mountains.

Mining started again

With the rise in raw material prices, the extraction of raw materials became economically interesting again. When creating a catalog of raw materials in the Free State of Saxony in 2008, this deposit also became interesting.

On March 4, 2008, the Saxon Mining Authority granted the “Erzgebirgische Fluss- und Schwerspatwerke GmbH” a license in accordance with Section 8 of the Federal Mining Act (BBergG) for the extraction of fluorspar and heavy spar.

On November 8, 2013, the mine was officially opened after a two-week trial run. A total of around 25 million euros, mostly from private sources, were invested in the development and construction of the processing plants.

The mine has been in regular operation since 2015. In the first year, 98,500 tons of raw spar were obtained, which after processing resulted in 20,650 tons of acid spar with a purity of at least 98 percent.

In December 2015, the mine ownership was awarded according to §13 BBergG.

With the announcement of the Saxon Mining Authority on December 16, 2016, the mining law permit of March 4, 2008 expired.

At the end of 2018, 63 employees were already working in the Precipitation mine and processing in Aue.

Training and device

The orientation of the mine began on 28 October 2010 with a symbolic blow. The bismuth tunnel 215 is torn to 20 m 2 and should open up the mine. From the bottom of the tunnel, 780 m above sea level, a ramp "Neu Straßburger Glück", named after a nearby old pit, is driven down to the first level at 734 m above sea level. The entire mine field of the Wismut with a north-south extension of 4 km drains via the tunnel 111 located at 733.5 m above sea level. Below the tunnel sole, the entire deposit stood down to the 5th level at 494  m above sea level. NN in the pit of the shaft 34 completely under water. The deepest pit in the central area is the 5th level at 554  m above sea level. NN The former bismuth shaft 281, which extends to the 4th level, was selected for the swamping of the mine workings .

processing

The preparation takes place in two stages. Even underground , pre-shredding and pre-separation takes place with the help of sensor-based sorting using X-rays and strong air currents. The concentrate is then further enriched in a specially designed processing plant in the Aue nickel smelter by grinding, floating and finally dewatering.

Others

The development work was followed for two years by a camera team from the MDR . This resulted in the eight-part documentary Die Männer vom Berg , which was broadcast from September 2012. During the entire time there was a strong media response, which, in connection with exploration work on other raw materials, based on the great time of mining in the Ore Mountains, led to the striking formulation of new mountain screams .

literature

  • Ewald Kuschka: The uranium ore-barite-fluorite deposit at Bärenstein and neighboring ore deposits . In: Sächsisches Landesamt für Umwelt, Landwirtschaft und Geologie / Sächsisches Oberbergamt (Hrsg.): Mining in Saxony . Mining monograph. tape 6 . Freiberg 2002 ( qucosa.de [PDF; 60.3 MB ; accessed on May 23, 2014] as well as attachments).
  • Wolfgang Schilka: Approval procedure for water discharge into the Grenzbach . In: Proceedings of the DGFZ eV Dresden Groundwater Days 2013. Issue 49. Dresden 2013, p. 121–129 ( gwz-dresden.de [PDF; 474 kB ; accessed on July 18, 2014]).
  • Gottfried Schlegel, Walter Bergner: 550 years of mining in and around Bärenstein in the Ore Mountains . Part 1: The historical mining industry. Part 2: Uranium ore mining. Bärenstein 2011.

Web links

Individual evidence

  1. ↑ Werner Runge: Chronicle of the bismuth . Ed .: WISMUT GmbH. Self-published, Chemnitz 1999, p. 1652 (CD).
  2. ↑ Geokompetenzzentrum Freiberg e. V .: Revaluation of spar and ore deposits in the Free State of Saxony. (PDF; 12.64 MB) Profile catalog. Saxon State Ministry for Economic Affairs and Labor, 2008, p. 11 , accessed on July 19, 2014 .
  3. ↑ Extraction in ore and spar deposits within the scope of permits in accordance with Section 8 of the Federal Mining Act (BBergG), status: July 9, 2014 ( memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.bergbau.sachsen.de
  4. ^ The treasure of Oberwiesenthal (n-tv). Retrieved July 20, 2014 .
  5. ↑ Toothpaste from the mountain (Der Tagesspiegel). Retrieved July 20, 2014 .
  6. ↑ New mine opened in Oberwiesenthal health resort . In: Official and information sheet of the city of Kurort Oberwiesenthal . Volume 2013, December 2, 2013, p. 5–6 ( oberwiesenthal.de [PDF; 818 kB ; accessed on May 15, 2018]).
  7. ↑ Mining in Saxony - Report of the Saxon Mining Office and the State Office for Environment, Agriculture and Geology for 2015, p. 8 (PDF; 7.9 MB)
  8. ↑ a b Mining Today - EFS. In: efs-nha.de. January 5, 2017, accessed January 5, 2017 .
  9. ↑ Announcement by the Saxon Mining Authority on the cancellation of the “Precipitation” permit under mining law (City of Kurort Oberwiesenthal, municipalities of Bärenstein and Sehmatal) dated December 16, 2016 ( SächsABl. 2017 p. 39 , PDF, 931 KB)
  10. ↑ Lucrative deposits in the Ore Mountains. Retrieved July 20, 2014 .
  11. ↑ Plot “The Men from the Mountain”. Retrieved July 20, 2014 .