Bismuth object 09
The object 09 was a retrieval object and as an independent structural unit within the Wismut AG / Wismut reports directly to the head office. The mine field of object 09 in the area Niederschlema- Aue - Alberoda had an area of about 22 km² and was developed through a total of 9 tunnels, 21 shafts and 30 blind shafts on 60 levels . The greatest depth in the pit field was reached at −1482.60 m above sea level at blind shaft 383 IIIbis . This corresponds to a total depth, based on the zero point of the Marx-Semler-Stollnsohle , of 1812.60 m. All depth information in + m or −m was based on the level of the Marx-Semler-Stolln. The 330 m above sea level The measuring point established for this purpose lies between the light holes 12a and 14a, directly below the Oberschlema train station. Up to 13,000 workers were employed in the building at the same time. The total production of uranium between 1949 and 1991 was 73,125 tons of uranium. It was thus the largest mining operation in the Wismut.
geology
The Niederschlema-Alberoda deposit is part of the Schneeberg-Schlema-Alberoda ore field. It is located at the intersection of the WSW-ENE running Lößnitz - Zwönitzer Zwischenmulde and the NW-SE- striking Gera - Jachymov fault zone. In the Lößnitz-Zwönitz intermediate hollow, Silurian - Devonian rocks are embedded in Ordovician slate . The dark schists, dark mica rocks, metadiabase and skarns that occur here form the so-called productive series, in which around 95 percent of the uranium reserves of the deposit are concentrated. The productive series is located within the approximately 1 km thick contact area of the Auer Granite intruded into the slate complex and has been changed by this contact metamorphic .
The Niederschlema-Alberoda deposit is delimited in the south by the granite from Gleesberg and Aue, in the north and east by the outer contour of the contact yard and in the west by the administrative border of the NW-trending fault Schwerin . In the depth, the rocks of the productive series wedge out at around 2200 m. Some of the veins continued into the granite, but became deaf here. The Niederschlema-Alberoda deposit is a hidden deposit, as a large part of the ore veins do not extend above ground. The outcropping veins are covered on the earth's surface by loose material up to 12 m thick. In the depths, blind ore veins increasingly appeared, which also do not reach the surface of the earth.
The main structures of Union, Erna, Sinaida , Inge and Gera, which coincide with the course of the Lößnitz-Zwönitzer Zwischenmulde, reach lengths of up to 6 km with a thickness of up to 10 m. The veins of the same name in these vein structures belong to the morning vein system . The dip in the corridors is between 45 ° and 65 °. Other important corridors of this system are the morning corridors Elbe , Egon, Elfriede, Leonid, Oderbruch , Regen , Ilm and Inn . Around 15 percent of the uranium content of the deposit was concentrated in these tunnels.
The duct structures occurring in the course of the north-west trending Gera-Jachymov fault zone reach lengths of up to 8 km with a thickness of up to 25 m. The incidence is between 50 ° and 90 °. Their main representatives belong to the flat corridors and are the structures Schwerin, Ruhmvoll, Seim , Nelson and Dürre Henne . Other important courses are Freital , Araqui, Babelsberg , Kamenz , Kosmos , Olivine , Beryl , Ferrite , Leucite , Crystal and Luppe . Around 35 percent of the uranium content of the deposit was concentrated in these tunnels.
In addition to the main strikes, there are also late strikes with a WNW strike. Their strike is several 100 m and the vertical extent 500 m. The dip is between 70 ° and 90 ° with a thickness of the corridors between 0.5 m and 1 m. Significant passages are Bad Elster , Borna , Freunde, Astra, Sophie, Bozen , Jatu, Tiber , Saar , Natascha and Valentina. Around 35 percent of the uranium content of the deposit was concentrated in these tunnels.
The corridor system of the NNW traversing corridors (flat corridors) was poorly developed and was mainly to be found on the southern flank on lower levels (from -990 m level). Their strike is up to 100 m and the vertical extent 500 m to 1000 m with a dip between 60 ° and 75 °. Important veins are Plauen , Oschatz , Cubanite , Kassiterite , Brookite , Hematite , Zinc , Brilliant , Tokyo , Quartz , Isar and Columbia . Around 15 percent of the uranium content of the deposit was concentrated in these tunnels.
Standing tunnels (strike direction NE) do not play a role in the deposit. They are usually of low thickness and short extension. Representatives are e.g. B. Congo and Coincidence. Mineralization of the veins was not proven here.
- Noble quartz formation eq
This formation was only encountered on the deep floors of the southern flank near the granite. The corridors are made of quartz. The mineralization with wolframite , scheelite and molybdenite found there was not worth building.
- Gravelly lead formation kb
This formation occurred on the NW and ENE trending corridors. The corridors are mainly made of quartz. The mineralization of these veins consists of chalcopyrite , sphalerite , arsenopyrite , galena , pyrite , bornite and tennantite and was in most cases not worth building. However, concentrations of lead, zinc and copper ores that were extracted were only found sporadically.
- Comb quartz calcite pitchblende formation kku
This formation was encountered on all veins of the deposit. The veins consist mainly of quartz, fluorite and calcite . The mineralization of these veins consists of pitchblende , coffinite , chalcopyrite, pyrite, galena, sphalerite, hematite, lepidocrocite and lollingite and was representative of the primary uranium mineralization of the deposit.
- Magnesium carbonate pitchblende formation mgu
This formation is a metasomatic transformation of the veins of the comb-quartz-calcite-pitchblende formation and was the primary uranium carrier of the deposit. The courses consist mainly of dolomite and black fluorite (stink spar). The mineralization consists of pitchblende, chalcopyrite, hematite, lepidocrocite, clausthalite , umangite, naumannite, tennantite, bornite, chalcosine and marcasite .
- BiCoNi formation
This formation is of secondary importance, but is spread over the entire deposit. The corridors consist of dolomite, quartz, fluorite, barite and calcite. The mineralization of the veins consists mainly of native bismuth , skutterudite , rammelsbergite , safflorite , native silver , nickel line , lollingite, chalcopyrite, pitchblende, sphalerite, bismuthinite , coffinite and native arsenic . Occasionally ore lenses up to an area of 100 m² also occurred.
- Silver-Sulphide-Arsenide-Formation ags
The mineralization in this formation is of minor importance. Often she appears as a younger education in the corridors of the BiCoNi formation. The mineralization consists of cullet cobalt (steamed arsenic), lollingite, proustite , argentite , native silver, pyrite, marcasite, chalcopyrite, pyrargyrite , argentopyrite , xanthocone and realgar . Gaits are calcite and barite.
With an explored reserve of around 100,000 tons of uranium, the Niederschlema-Alberoda deposit is one of the largest uranium ore deposits in the world.
The uranium ore thickness in the veins averaged 0.5 cm to 3 cm. In some corridors the thickness reached a few decimeters, in extreme cases even between 1 m and 4 m. The uranium ore lenses within the ore veins could extend up to 1000 m². The number of uranium-mineralized veins of the deposit is given as over 1000, with the mineralized area being about 5 percent of the exposed vein area. The ore output increased with the depth and reached its first peak at the −420 m level at 81.4 t / m, with the highest output on the −540 m level at 103.4 t / m has been. Below the –540 m level, the ore output decreased continuously to the level of the –940 m level, and then rose again and reached the final peak of 80.2 t / m depth on the –1080 m level . While below the −1080 m level the total output due to the further shrinking mine field as well as the decrease in the density and number of dykes continued to decrease, the output of 3 kg uranium per square meter of passage area remained almost the same up to the –1800 m level. 50 percent of the ore reserves in the deposit were between the −540 m level and the –1080 m level.
In addition to uranium, the "minor ores" found in the corridors were also extracted from time to time if they were suitable for construction. From 1957 to 1978, carried out extraction of these ores to the -990 m level.
The ores of the BiCoNi formation were mined . These are cobalt ores (main components skutterudite and safflorite), nickel ores (main components nickelline, rammelsbergite and nickel skutterudite ) and bismuth ores (main component native bismuth). From 1957 to 1978 a total of 137 tons of cobalt , 260 tons of nickel and 90 tons of bismuth were extracted.
The main distribution of these ores was between the −420 m level and the −855 m level. The corridors in Schwerin, Freital, Maiskaja, Rostock, Seim, Bad Elster, Ruhmvoll, Tiber, Bautzen, Sinaida, Dürre Henne and Nelson were mined.
The silver ores mined in the same period (main components: silver, argentite, argentopyrite, proustite and pyrargyrite) yielded 2.3 tons of silver. Silver ores were common in the Bautzen , Nelson, Jubiläum, Seim, Löbau , Main , Freital and Brahmaputra corridors .
The buildable lead and zinc ores found in the kb formation (main components galena, sphalerite, chalcopyrite and bornite) produced 80 tons of lead , 50 tons of zinc and 9 tons of copper . These ores were mined in the Galenit, Union West, Erna West, Dürre Henne and Karl-Marx-Stadt corridors .
After the first discovery of selenium ores in the deposit in 1957, special investigations were undertaken in 1960 to find and mine these ores. The main components were clausthalite, umangite and naumannite. A newly discovered selenium mineral was named after its place of discovery, Schlemait. The selenium ores were mined between 1960 and 1965. 9 tons of selenium were extracted. The selenium ores were widespread and were mainly extracted from the Tiber, Brahmaputra, Nelson, Ruhmvoll, Babelsberg, Dürre Henne, Bad Elster, Alberoda, Gera, Halle , Seim, Bautzen and Egon corridors .
After a rich silver mineralization was encountered on the −1395 m level on the eastern flank of the deposit, this deposit was determined by a resolution of the Council of Ministers of the GDR on June 15, 1984, between the −1305 m level and the −1710 m- Thoroughly examined the sole. The main components of silver mineralization were not only native silver but also dyscrasite, pyrargyrite, stephanite and prostite. Mineralization occurred on the stephanite, dyscrasite and argentopyrite veins. 3.9 tons of silver were extracted here between 1984 and 1988.
After mining ceased in 1991, around 2080 tons of uranium, 137 tons of cobalt, 857 tons of nickel, 350 tons of bismuth, 252 tons of lead, 172 tons of zinc, 28 tons of copper, 420 tons of selenium and 122 tons of silver remained in the deposit.
The naming of the veins was obviously not subject to any uniform regulation. While in Oberschlema only numbers (e.g. 6, 16 or 25) were often assigned for veins on the upper levels, in Niederschlema on the upper levels it was mainly names of rivers and cities (e.g. Mulde , Rhine , or Peene and Pirna , Dresden or Saalfeld ). There were also exotic names in the deposit (e.g. Río Tinto , Limpopo , Borax , Torpedo , Urania, Komet , or Geologist). Occasionally, German and Russian women's names (e.g. Marta, Senta or Ruth or Wasilisa, Axinija or Olga) were used. On the deeper levels, the passages were mostly named after minerals (e.g. bravoite, arsenic or emerald ).
In other districts, corridors were also named according to months (Sentjabrskaja, Aprilskaja), the direction of strike (Parallelnaja, Diagonalnaja) or the condition of the corridors (e.g. "Der Nasse" (Mokraja) or "Bride without dowry" (Bespridanniza )):
Administrative development
The exploration object 21, founded in March 1947, carried out the exploration on the flanks of the districts Schneeberg ( object 03 ) and Oberschlema ( object 02 ) over an area of around 14 km². After positive results in the area of Niederschlema, the exploration object 21 was converted into the exploration and extraction object 09 (object 09) in autumn 1948. The seat of the administration of the object 09 was the Niederschlemaer Weg 49 in Aue. Some of the workforce ( Steiger , Hauer , Markscheider and Geological Service) were transferred from the exploration object 21 to the new object.
Until 1959, object 09 carried out the setting-up and dismantling work on the levels from Marx-Semler-Stolln to the −540 m level, while the shaft sinking and alignment work were carried out on object 11 during this period.
In order to have a raw material base immediately, the Niederschlema-Alberoda partial deposit was transferred from Object 02 to Object 09 in 1949. In this episode, the deposit areas Niederschlema (with the shaft management 13, 207 and 250) and Alberoda (with the shaft management 186) were created.
With the dissolution of object 03 in September 1950, the shaft administrations 3 and 10 that still existed there were taken over by object 09. In addition, in object 09 there was a department for auxiliary and ancillary operations as well as the geological exploration group to which the investigation areas of the disbanded object 21 were assigned.
Individual shafts were assigned to the shaft administrations. The assignment did not depend on geological conditions, but was based on the performance of the pits and the number of employees. The structure of object 09 was therefore subject to constant change, depending on the status of the dismantling work and the capacity of the pits. In January 1950, the geological exploration group was spun off from object 09.
With the dissolution of object 02 on April 1, 1958, object 09 also took over shaft management 12 as the last still working unit of object 02. With the dissolution of object 11 in 1959, this object was also integrated into object 09.
Property 09 was restructured in 1960. It now comprised the storage parts NW / SW, the central part and NE / SE as structural units. The shaft administrations 38, 207 and 366 for the levels from the –390 m level to the –630 m level were assigned to these three parts of the deposit. The shaft administration 66 was responsible for the floors from the −270 m level to the −360 m level and the shaft administration 371 for the levels below the −630 m level throughout the district. In 1963 the shaft administration 207 was dissolved. The remaining stocks of the shaft field were allocated to shaft administrations 38 and 366.
When the exploration work carried out by the Saxon Geological Exploration Group in the area of Pöhla -Hämmerlein and Pöhla- Tellerhäuser since the beginning of the sixties brought positive results, the Pöhla exploration area was founded in 1967.
Also the Pöhla- Globenstein partial deposit with dig 24 and tunnel 19, which was first created by object 01 and after its dissolution on January 1, 1958 by shaft combine 235 and after its dissolution from April 1, 1959 by the Saxon search and prospecting expedition (SSSE) was assigned to this exploration area in 1967.
The Saxon search and prospecting expedition was converted into the Saxon Geological Exploration Group on November 1, 1960 and placed under Object 09.
By order of the general management of SDAG Wismut on September 18, 1963, the Dresden geological exploration expedition was founded by the object 09. Their task was to accelerate the exploration of the Königstein deposit, carried out since 1958 by the Saxon search and prospecting expedition and its successor, the Saxon Geological Exploration Group.
With the formation of a Central Geological Operation on April 1, 1966, the Saxon Geological Exploration Group and the Dresden Geological Exploration Expedition were spun off from Object 09 and placed under the Central Geological Operation.
In the course of the reorganization of the administrative structure of SDAG Wismut in 1968, all properties were closed. The Aue mining operation emerged from property 09. Similarly, the shaft administrations were also dissolved and the pit areas 1 to 7 and an alignment pit area were created. The last remaining pit areas 1 and 3 were merged in July 1990.
The more in-depth mining of the deposit and the impoverishment of the ores in the Ronneburg deposit led to constantly rising costs. From 1984 these began to exceed the price of 65.97 rubles per kg uranium in concentrate agreed between the GDR and the USSR . Analogously, the world market price fell to 38 rubles / kg in 1985. Thereupon the USSR urged the GDR to restrict uranium mining and to re-evaluate the stocks. As a result, the deep parts of the deposit and the remaining stocks in the peripheral areas were written off. However, the Soviet Union obviously did not consider a reduction in uranium production planned by 1997 by 5 to 10 years, proposed by the GDR in 1985, to be sensible. However, the Soviet Union wanted to contribute significantly less to the costs of uranium mining. According to a resolution of the government of the GDR on April 27, 1989, the number of employees in the Aue mining company was to be reduced from 5700 (April 1989) to 2400 employees (by 1993). However, the political developments from October 1989 onwards destroyed all of these plans. In 1990 the GDR and the USSR agreed to stop uranium mining on January 1, 1991.
After the end of active mining on April 1, 1991, the Aue mining operation was converted into the Aue renovation operation on January 1, 1992.
Study areas
For the investigation of radioactive anomalies in the edge area of the Niederschlemaer deposit , the area was divided into several investigation areas. Already in 1947, which were areas Waschleithe , Bockau and Weidauer (in the local situation of Lauter examined) by the object 23rd After its dissolution in November 1948, the geological exploration group from Object 09 took over these investigation areas. From 1949 the investigation of radioactive anomalies was extended to the districts of May 1st, outdoor swimming pool, Klosterberg , Brünlasberg , Wildbach , Langenbach , Dittersdorf and Affalter . In 1950, the geological exploration groups of objects 02, 03, 09 and the Zwickau and Chemnitz groups formed object 29. Object 29 took over the work in the investigation areas in 1950/51. After the relocation of object 29 to Neustadt / Orla , object 09 took over the remaining work in the still existing areas of Neu Alberoda , Zeller Berg, Freibad, Lauter and Henneberg from 1952 and completed this work in the course of 1953. In the period 1947 to 1953 of the study area were a total of 17 wells and 80 geteuft Schurfschächte or in the 15 districts aufgewältigt and 27 Stolln ascended . It has been proven that 9.1 tons of uranium were mined. However, none of the districts has proven to be worth building.
Mining operation
Alignment, fixture and removal
Object 09, founded at the end of 1948, took over shafts 38 and 66, which were already being mined, from object 02, as well as shafts 186, 207 and 208 that were in the depths. The Marx-Semler-sole and the -30 and -60 levels were unlocked . In mid-1949, the shafts 13 and 13 bis , which were still being mined, and tunnels 128 and 129 were assigned to object 09 . In the same year the devastation began for shafts 250 and 276 and light hole 9 of the Marx-Semler-Stolln was put into operation as shaft 237. The dismantling was on the levels of Marx-Semler, −30 and −60. The first 12.9 tons of uranium were mined. Due to the lack of powerful hoisting machines, the existing day shafts were not able to reach greater depths. The deposit was therefore gradually developed via blind shafts. The term “cascades” was used for this in the language used within the property.
The first cascade reached from the turf hanging bank to the −240 m level, which was reached by shaft 38 in 1950. From this level, the deepening of blind shaft 38 to the −380 m level began. Shaft 276 (Teufbeginn in 1949) went into operation when it reached the Marx-Semler bottom. Shaft 250, started in 1949, was the first shaft to penetrate to the −240 m level. In 1950, the digging of shafts 296, 312 and blind shaft 331 began. Mining began at the −90 m level and 65.4 tons of uranium were extracted.
After the dissolution of object 03 (Schneeberg) in September 1950, object 09 took over the remaining shaft administrations 3 and 10 with a total of 13 shafts (3, 9, 10, 11, 24, 25, 43, 50, 72, 83, 130, 150, 200), 3 blind shafts (24 bis , 25 bis , 90) and a dig (18).
In 1951, blind shaft 38 c was sunk from the −240 m level to the −300 m level and the blind shaft 340 from the −120 m level to the −240 m level. Shafts 186, 207 and 208 went into operation when they reached the −240 m level and the blind shaft 331 when they reached the −180 m level. The dismantling followed the device without any time delay and was extended to the levels −120 and −150. In Schneeberg, shafts 11 and 150 were further sunk or excavated from the −30 m level to the −120 m level. Shafts 11 and 150 have been written off.
In 1952, mining reached the −180 m level, which, with a length of 140,733 m, became the largest level of the I. Cascade. In comparison, the length of the Marx-Semler-sole was only 12,147 m. The production of uranium had risen to 321.3 tons in 1952. In order to create an exploratory advance, in 1952 from the −240 m level with the depth of the blind shafts 186 bis , 186 c , 207 bis , 208 bis and 312 to the outcrop of the 2nd cascade up to the −540 m Sole started. The blind shaft 340 was put into operation. The time lag between removal and installation and dismantling increased and reached three years on the −540 m level. In 1952, parts of the mine field of shaft 64 belonging to object 02 were assigned to object 09 to expand the supply base. In Schneeberg, shafts 9, 24, 24 bis , 25, 25 bis and 90 and dig 18 were dropped.
When soles −270 and −300 were reached in 1953, dismantling began at the same time as the device. Shaft 66 was reconstructed and deepened from the −60 m level to the −300 m level. Shaft 38 c reached their final depth with the −480 m level and shafts 38 to and 312 down to the −540 m level. Shafts 296 and 312 went into operation. In Schneeberg, the shaft of the Resurrection of Christ treasure trove was opened up to explore the edge areas of the deposit . At the same time, shaft 43 was dropped
In 1954, blind shafts 186 bis , 207 bis and 208 bis reached their final depths when the −540 m level and shafts 186 c on the –420 m level and 66 on the −300 m level were attached . In order to solve the problem of the missing central shaft up to this level, shaft 38 was reconstructed. The shaft tube was expanded and the shaft sunk to the −540 m level. In addition, the depth of shaft 186 a and blind shaft 296 bis began . The soles −210, −240 and −330 were included in the dismantling. With 1138 tons of uranium, object 09 took over the top position in uranium mining in the SDAG Wismut in 1954. In Schneeberg, shafts 3, 10, 50 and 72 were closed.
In order to do justice to the increasing amounts of production, the sinking of shaft 366 to the −540 m level was started in 1955. It is the first round shaft with brick walls, the SDAG Wismut. In the same year, the depth of shaft 365 to the −240 m level began. The −540 m level became the central level in the entire mine building. The levels −360, −390 and −420 were brought into dismantling. Shafts 130 and 200 were dropped in Schneeberg.
In August 1956, when production of shaft 83 ( Türkschacht ) ceased, mining in Schneeberg was ended. In order to ensure a sufficient increase in stocks, the development of the III. Cascade started from −540 m level to −990 m level. The sole distance has been increased from 30 m to 45 m. The blind shaft 38 IIbis was sunk from the −540 m level to the −990 m level and the blind shaft 207 IIbis from the −540 m level to the −765 m level. At the same time, the depth for the future central shaft 371, a circular shaft with concrete lining, and the weather shafts 208 W , 372 and 373 began. The shaft 186 a reached its final depth at the −240 m level. Shafts 296 bis and 366 went into operation when the −540 m level was reached. Dismantling was started on levels −450 and −480 and mining was discontinued on the Marx-Semler level as well as levels −30 and −60. The shaft 276 was dropped. In 1956, the production reached 2263 tons of uranium.
In 1957, with the depth of blind shafts 366 bis and 371 bis from the −540 m level to the −990 m level, the III. Cascade forced. Shafts 365 and 38 IIbis went into operation and mining began on the −510 m level.
On April 1, 1958, the object 02 (Oberschlema) was dissolved and the last production shaft management 12 with a total of 18 shafts (5, 5 bis , 6, 6 bis , 7, 7 bis , 14 bis , 27, 27a, 64, 67, 125, 127, 259, 280, 309, 310, 311) and 8 blind shafts (I, IV, V, 27 bis , 271, 339, WI and W III) assigned to object 09. The mining here was on the Marx-Semler levels up to −150, as well as on the levels −240 to −540. The −585 m level was still in the jig. In the same year, the shafts 5 and 6 bis and the blind shafts I and W III were written off. In Niederschlema, the depth of blind shaft 296 IIbis began from the −540 m level to the −990 m level. The 208 W weather shaft went into operation when it reached the −720 m level. Mining on the −540 m level was started and stopped on levels −90 and −120. For the first time, with a production of 3153 tons of uranium, which was around 50 percent of the annual production of SDAG Wismut, the 3000-tonne mark was exceeded.
In 1959, shafts 371, 372 and 373 went into operation when they reached the −990 m level and the blind shaft 207 IIbis when they reached the −765 m level. In order to improve the fresh weather situation on the deeper levels, the depths of the weather shafts 382 and 383 began. With the start of mining on the −585 m level, the first level of the III. Cascade in production. The mining on the levels −150, −180 and −210 was stopped in 1959. The shafts 13, 237 and the blind shaft 340 were discarded. In Oberschlema, the −630 m level was driven and mining above the −480 m level was stopped at the end of the year. Shafts 5 bis , 7, 14 bis , 27a, 64, 67 and 125 as well as blind shafts IV, 271 and 339 have been written off.
In 1960 mining was stopped in Oberschlema and shafts 127, 311 and blind shafts V, 27 bis and WI were dropped. In Niederschlema, mining was started on the –630 m level and stopped on levels –270, −300, −330 and −360. When the −990 m level was reached, blind shafts 296 IIbis , 366 bis and 371 bis went into operation. Shaft 208 was reconstructed, the shaft tube expanded to a round shaft and deepened from the −240 m level to the −816 m level.
When mining on the −240 m level was stopped in 1961, mining on the I. Cascade ended. A total of 4968 t of uranium was mined on the first cascade at a depth of 270 m. In the same year, mining began on soles –675 and −720 and stopped on soles −390 and −420. In the Oberschlema, shafts 27, 280 and 309 were written off.
In 1962, the depth of the blind shaft 208 IIbis began in Niederschlema from the −810 m level to the −990 m level. The reconstructed shaft 208 went into operation as a fresh-weather shaft. The shafts 13 bis , 365 and the blind shaft 312 bis have been discarded. While mining was started on the −765 m level, it was stopped on the −450 m level. With the production of 4230 tonnes of uranium, which was around 60 percent of the annual production of SDAG Wismut, the 4000 t mark was exceeded for the first time. Shaft 259 was dropped in Oberschlema.
In 1963, the fourth cascade began to explode with the depth of blind shafts 366 IIbis and 371 IIbis from the −990 m level to the −1350 m level. The shafts 186 a and 312, as well as the blind shafts 186 c and 296 bis , were discarded. With the start of production at levels -810 and -855, mining moved further down. Mining on the −480 m level was stopped. Uranium production peaked at 4,553 tons. After that, a steady, increasingly faster decline in the output began.
In 1964, the depth of the weather blind shaft 208 IIW began from the −720 m level to the −1170 m level. The weather shafts 382 and 383 went into operation when the −1305 m level was reached. The blind shaft 208 IIbis went into operation when it reached the −990 m level. The shaft 250 was dropped. Production started on the −900 and −945 levels, but stopped on the –510 m level. In Oberschlema, shaft 6, which had previously served as a pumping station for the water drainage, was dropped.
With over 8000 tonnes of uranium, 4228 tonnes of which from object 09, uranium production at SDAG Wismut reached its peak in 1965. With the beginning of the depth of the weather blind shaft 372 up to the −990 m level to the −1620 m level, the opening of the 5th cascade was prepared. The blind shaft 371 IIbis went into operation. With the −990 m level, the last level of the III. Cascade in operation. The blind shaft 38 c and the shaft 207 were discarded. On the −540 m level, mining on the second cascade ended for the time being with the cessation of mining. Until the final end of operation in 1988, a total of 19,065 t of uranium had been mined on the second cascade at a depth of 300 m. In Oberschlema, shaft 310, which last served as a weather shaft for Niederschlema, was thrown off.
In 1966 the weather blind shaft 208 IIW and the blind shaft 366 IIbis went into operation. The shaft 186 and the blind shafts 38 bis , 186 bis and 208 bis were discarded. The fourth cascade went into operation with the start of production on the levels −1035 and −1080. Mining was stopped on the −585 m level. The total production of Object 09 was well below the 4,000 ton mark.
Due to the very rich stocks on the soles in production, further development in the depths took place very slowly. In 1967, mining on the −630 m level was stopped.
In 1968 the −1125 m level was put into operation and mining on the −675 m level was stopped. The annual production of Object 09 fell below the 3000 ton mark. In Oberschlema, revision work was carried out for the last time in the area of the blue color factory.
In 1969 the weather shaft 372 went into operation until it reached the −1620 m level.
The −1170 m level, which was put into production in 1970, was the largest level of the IV cascade with a driveway length of 116,597 m. Here it became clear that the mining area shrank with increasing depth. In the same year, production on the −720 m level was stopped. The shaft 66 and the blind shaft 207 bis were discarded. In Oberschlema, shaft 7 bis , which had previously served as a pumping station for the water drainage, was dropped.
The uranium production of the mining company fell below the 2000-tonne mark in 1971 and thus only reached 24 percent of the total production of SDAG Wismut.
In 1972 production began on the −1215 m level and after 10 years mining ended on the −765 m level. In comparison, the production period on the levels of the second cascade was only 6.5 years on average.
The year began with the depth of the weather blind shaft 373 bis (from the −990 m level to the −1170 m level) and the blind shaft 383 bis (from the −1305 m level to the −1710 m level) 1973 the organization of the 5th cascade. In the same year the soles −1260 and −1305 went into operation. The −810 m level was thrown off. The last shaft on Schlemaer Flur was dropped with shaft 38.
In 1974, the −1350 m level, the last level of the fourth cascade, went into production. Mining at the −855 m level was stopped. The depth of the weather blind shaft 373 IIbis from the −1170 m level to the −1350 m level began and the weather blind shaft 373 bis was put into operation.
The buildable mineralization found on the southern flank of the deposit was mined from the −900 m level. As a result, the number of soles produced increased steadily. While there were eight soles in 1961/62, in 1975 there were already 11 producing soles. The weather blind shaft 373 IIbis went into operation in 1975.
With the −1395 m level, the first level of the 5th cascade went into operation in 1976. In the same year, the 373 IIIbis weather blind shaft was sunk from the −1350 m level to the −1440 m level and was also put into operation at the end of the year. The total annual production falls below 1000 tons of uranium. The mining company only took 5th place out of 7 manufacturing companies within the SDAG Wismut.
In 1977 the depth of the weather blind shaft 373 IVbis began from the −1440 m level to the −1530 m level and the −1440 m level went into operation.
The weather blind shaft 373 IVbis and the blind shaft 383 bis went into operation in 1978. As a result of the promising mining results on the southern flank of the deposit, the −855 m level was taken back into operation. At the same time, the −1485 m level also went into operation.
Due to the expansion of the mining industry, the number of soles in production rose to 15 in 1979 and their depth increased to 675 m.
In 1980, mining reached the −1530 m level.
Mining on the −540 m level was resumed in 1981 and simultaneously stopped on levels −855 and −900. The depth of the weather blind shafts 373 Vbis (from the −1530 m level to the −1620 m level) and 373 VIbis (from the −1620 m level to the −1710 m level) began. The weather blind shaft 373 Vbis went into operation in the same year.
In 1982, mining began on the −1575 m level and the 373 VIbis weather blind shaft went into operation. Mining on the −945 m level was stopped.
When mining on the −990 m level was stopped in 1983, operations on one of the most important levels of the mining operation also ended. Mining began on the −1620 m level. With the beginning of the depth of the 383 IIIbis blind shaft from the −1620 m level to the −1890 m level, the VI. Cascade started.
In 1984 mining was resumed on levels −720 and −765. On the −1035 m level, operations were stopped.
In 1985, mining began on the -1665-m level and was resumed on the -675 and -810 levels. This increased the number of soles in production to 18. Mining was stopped at the −1080 m level. The depth of the weather blind shaft 208 IVW from the −1350 m level to the −1530 m level has started.
In 1986, mining was resumed on the −630 m level and stopped on the −1125 m level. The weather blind shaft 208 IVW went into operation when the −1530 m level was reached. From the −1170 m level to the −1350 m level, the depth of the weather blind shaft 208 IIIW began. The depth of the weather blind shaft 373 VIIbis from the −1710 m level to the −1800 m level was started, but was canceled in the same year for economic policy considerations. The depth of the blind shaft 383 IIIbis was set 26 m below the –1800 m level, also for economic policy considerations, and thus the opening of the VI. Cascade canceled. The planned blind shaft 383 IIbis from the −1620 m level to the −2070 m level was no longer implemented. The lowest point of the mine was reached here at −1482.60 m above sea level. Calculated from the turf hanging bank of the main shaft 371, the total depth of the pit building was 1837.6 m.
With the start of production on the −1710 m level, the last level of the 5th cascade went into production in 1987. Mining on the −585 m level was resumed and mining on levels −1170 and −1215 was discontinued. The weather blind shaft 208 IIIW went into operation when the −1350 m level was reached.
With the start of mining on the levels −1755 and −1800, the VI. Cascade in operation. Mining on the −540 m level was stopped.
After the mining of 2.7 tons of uranium on the −1800 m level, the mining on the deepest level of the district ended in 1989. In the same year, the mining was also started on the levels of −585, −630, −675, - 1260, −1305 and −1350 are set. With the mining cessation on the −1350 m level, mining ended on the 4th cascade, on which a total of 14,841 t of uranium was mined over a depth of 360 m.
In 1990, mining on the levels −720, −765, −810, −1395, −1440, −1485, −1575, −1620, −1665 and −1755 was also ended. The dismantling on the III. Kaskade ended with mining stopped at the −810 m level. With a depth of 450 m, a total of 36,495 t of uranium was mined. When mining on the −1755 m level was stopped, mining on VI ended. Cascade. A total of 34.2 tons of uranium were mined on it. Due to economic policy considerations, the front and rear alignment of the two levels (−1755 and −1800) of the VI. Cascade as far as possible. The reserves calculated in 1985 of 4277 tons of uranium up to the planned −2070 m level were also corrected downwards in 1991 to 1048.8 tons of uranium and written off.
When mining on the levels −1530 and −1710 ceased in April 1991, mining on the 5th cascade also ended. A total of 7092 t uranium was mined over a depth of 360 m. After 43 years, active mining in the Niederschlema-Alberoda deposit was ended in April 1991.
Used conveyor technology
The first shafts taken over from Object 02 and sunk in the period from 1947 to 1949 were rectangular shafts built according to a uniform type with timber construction and a clear cross-section of 8.5 m² (e.g. shafts 13 bis , 38, 66, 186 and 208 ). The pits, which were also sunk in the investigation area in 1949 and which in some cases also reached the −240 m level, had a clear cross-section of 5.0 m². The wooden winding towers erected over the shafts during this time and the TM 23 hoisting machines used allowed a maximum depth of 300 m and a maximum conveying speed of 5 m / s with a hunt in the conveyor frame .
As early as the end of 1949 the sunk shafts had a clear cross-section of 12.0 m². They were rectangular shafts with timber construction, with which 4 rubble could be conveyed with 2 hoisting machines. Although more stable round or oval shafts with brickwork have been common for centuries, Wismut AG continues to rely on the quick and inexpensive to build rectangular shafts with wooden headframes due to ignorance of the dimensions and depth of the deposit.
Hunte in the form of front tippers and side tippers were used for horizontal conveyance. This hunt had a volume of 0.44 m³ and a track width of 600 mm. In the first few years, the filling of the hunt and the transport through the mine were largely done with pure muscle power. The driveways had a cross-section of 3.5 m² to 5 m² up to the −330 m level. The battery locomotive EGS Karlik , which was built from 1947 by the Bleichert transport plant of the AG “Transmasch” Leipzig , has been used as a traction device . The battery locomotive weighed 2.2 tons and had a pulling force of 2 kN at a top speed of 5.9 km / h.
From 1949, manual filling of the hunt was gradually replaced by the use of the first PML 3 throwing shovel loader. Probably also from 1949 the first battery locomotives of the Metallist type from the BBA Aue were used. This battery locomotive weighed 2.9 tons and had a pulling force of 2.1 kN at a top speed of 6 km / h. It was used as a "universal locomotive" until the end of the seventies, as its small width (780 mm) and a negotiable curve radius of 5 m made it ideal for small track cross-sections and tight curve radii.
In the same way, larger dogs with a volume of 0.60 m³ were used, which resulted in a rapid increase in production. This increase led to problems with the existing shaft systems, as they were underdimensioned for the pumping volume. For the time being, however, the depths of new shafts were shied away from and therefore, from March 1953, shaft 66 was expanded to a clear cross-section of 16.75 m² and its depth to the −300 m level. In addition, shaft 66 was the first Wismut AG shaft to receive a steel head frame (two-storey solid wall double bracing frame ) and the first shaft in object 09 to receive a ski lift. Funding was provided through 4 skip and 2 rack pieces. 3 drum winders were probably used for conveying . From April 1, 1954, the shaft tube of shaft 38 was also enlarged to a clear cross-section of 20.41 m² and deepened to the −540 m level. It received a two-storey full-wall double-headed frame and 2 Koepe machines for conveyance . This enabled the conveying speed to be increased to 16 m / s. Was funded over 4 ruins. The conveyor racks had space for 2 hunts on two floors, which means that 8 hunts could be conveyed at the same time.
The blind shafts sunk to the −540 m level in the early 1950s also had a rectangular cross-section with standardized dimensions and were lined with wood. The shafts 38 bis and 38 c had the dimensions of 4.02 m × 3.20 m and a clear cross-section of 12.86 m². They had 2 conveyor fragments and were designed for one-day rack conveyance with two hunts. The shafts 186 bis , 186 c , 207 bis , 208 bis , 296 bis and 312 bis had the dimensions of 6.67 m × 2.00 m and a clear cross section of 13.34 m². They had 4 conveyor fragments and were designed for one-day rack conveyance with a hunt. Drum winding machines of the type TM 23 were used for conveying.
Due to the emerging depth of the deposit, larger shafts became necessary from the mid-1950s. Shaft 366, which was sunk from March 1955, was the first circular shaft of the SDAG Wismut. The cross-section was 23.75 m² and the extension was done with bricks. Shaft 366 received a two-storey full wall double bracing frame and was equipped with 2 Koepe machines. Funded was over 2 skip trumps and 2 rack trunks. The weather shafts 208 W (clear cross-section 23.20 m²) and 372 (clear cross-section 38.46 m²) were also built in brickwork and as round shafts . Shaft 371, which was sunk from April 1, 1956, with a cross-section of 38.46 m², was the first circular shaft with concrete lining. It had a two-storey full walled longwall frame and was equipped with 2 Koepe machines. As in the case of shaft 366, funding was provided via 2 ski sections and 2 rack sections each. The clear cross-section of blind shafts 38 IIb , 207 IIbis , 208 IIbis , 296 IIbis , 366 bis and 371 bis sunk in 1955 and 1956 reached 20 m². Due to the larger cross-section, it was now possible to convey 2 hunts per floor with 4 conveyor towers. Two-tier conveyor racks and conveying machines of the type TM 300 were used.
With the introduction of the new charging and transport technology (e.g. throwing shovel loader PM 17 or PML 63 and the Akkulok Metallist) underground, larger profiles became necessary when driving the routes. In 1954 they reached 7.5 m² on the −540 m level.
Since the scope of funding was constantly increasing, more powerful locomotives were also needed on the branch lines. For this reason, the Akkulok EL 61 was developed in 1961 from 2 battery tenders and a driver's cab suspended between them.
With the 4 weather shafts 372 (round shaft in brick construction), 373, 382 and 383 (round shafts with concrete construction), the sinking of day shafts was completed. While shafts 372, 373 and 382 for emergency access and shaft control received a drum winder, a reel was set up on shaft 383 . The blind shafts 366 IIbis and 371 IIbis, which were sunk between 1963 and 1965 , had a clear cross-section of 26 m² and were equipped with 4 conveyor columns and a two-tier rack conveyor for two hunted each.
From the mid-1960s, shaft 371 became the main shaft with the closure of all other production shafts of the property. It had a conveying capacity of 410 t / h. From then on, shaft 366 served as an emergency and material shaft. The main lift level became the −990 m level after the conversion of the conveyor system.
The first EL 6 catenary locomotives were probably used from 1967 onwards , as they could now be brought underground via the excavated shafts. The EL 6 contact wire locomotive was built in the LEW Hennigsdorf from 1951 , weighed eight tons and had a pulling force of 21 kN at a top speed of 25 km / h. With a length of 4450 mm and a smallest negotiable curve radius of 8 m, it could only be used on the main routes.
Due to the increasingly longer conveyor routes, the main lines were expanded to double-track and battery locomotives of the types EL 61 and EL 71 were increasingly used. Depending on the type of expansion, new main routes with a cross-section between 8.1 m² and 10.5 m² were excavated.
From 1973 the first EL 30 catenary locomotives from the BBA Aue were used. In contrast to the EL 6, the EL 30 could also be used in smaller distances due to its smaller dimensions.
From the end of the seventies, the battery locomotive B 360 was used as a further development of the Metallist. Similar to the battery locomotive EL 61, the battery locomotive B 660 built in the BBA Aue was used.
From 1985, 20 EL 6/01 built at VEB Inducal Göllingen were used. It largely corresponded to EL 6. Since the EL 6 / EL 6/01 catenary locomotives used were not suitable for all applications, a total of 9 EL 30 T tandem locomotives were built in the shaft's own workshop . While the locomotives of the types B 360 and EL 30 managed train lengths of up to 18 full hunts, the corresponding tandem variants were able to pull double the number of full hunts. The locomotives of the types EL 6 and EL 6/01 were even able to pull trains with up to 50 full hunts.
Weather management
In addition to the on-site fresh air supply, the aim of the ventilation is to remove the dusts and aerosols generated in the mine and, in uranium mining, to reduce radon pollution for the miners. Especially in the Niederschlema, the cooling of the temperature on site was achieved through the ventilation, as the rock temperature reached 65 ° C on the lowest levels. When it comes to ventilation, a distinction is made between main weather management via stationary main pit ventilators on the shafts and special ventilation with the aid of portable ventilators for ventilating the drive-up and work locations.
In the early years of uranium mining, the mine workings could hardly be ventilated in a targeted manner. The natural flow of weather due to temperature differences was mainly used. The existing compressed air was used to ventilate the workplaces after the blasting. The legal basis at this time was the general mountain police regulations for the state of Saxony of September 27, 1929 and the resulting safety regulations for weather management and firedamp as well as light and lamp management from 1932.
From 1949 onwards, the Wismut AG issued the first safety regulations, in which a fresh weather quantity of 3 m 3 / min fresh weather was required for every worker working on the most busy shift at the same time . This regulation also applied to the horses used, for which 6 m 3 / min were required. In order to meet these regulations, the establishment of a weather service was started in 1949. To ensure the Sonderbewetterung spot was Lutten made of cardboard with a diameter of 20 to 30 cm and blowing fans used with a power of 3 kW.
The first statutory regulations of the GDR on technical safety and occupational health and safety in ore mining, which also regulated the requirements for ventilation, were issued on December 30, 1952. However, a general rethinking of the necessary construction of a central ventilation system did not take place until after the mine fire on July 16, 1955 on the −480 m level in the filling location area of blind shaft 208 bis . 33 miners were killed.
From the mid-fifties onwards, sheet metal ducts with diameters of 40, 50 and 60 cm were increasingly used in special ventilation because of their longer durability.
From 1955, Soviet personnel from the geophysical service carried out measurements of radon exposure. However, these measurement results were not published. At that time there were no statutory regulations on radiation protection.
In 1956, the depths of 5 weather shafts (208 W , 372, 373, 382 and 383) began. With the commissioning of the weather shafts 208 W (December 1958), 372 (May 1959), 373 (March 1960) and shaft 208 (November 1961), reconstructed as a round shaft and sunk to the −816 m level, the main ventilation was gradually improved. The ventilation took place with suction via the main pit ventilators installed in shafts 372 and 373. The amount of weather leaving was around 75,000 m 3 / min. The shafts 38, 66, 207, 366, 371, 382 and 383 acted as the pull-in shafts.
In 1957, systematic radon monitoring began by taking air samples. This monitoring was carried out by the “ Dosimetry group ” consisting of 15 people . Depending on the extent to which the limit value was exceeded, warnings were issued, but workplaces were also blocked. Every year around 10 percent of the occupied locations were blocked.
When the −990 m level was reached in 1959, the weather had to be cooled. The rock temperature on this floor was 40.6 ° C. Since mining was planned to a depth of 1400 to 1500 m at that time, the use of cooling units underground was necessary.
On June 10, 1964, the first Radiation Protection Ordinance came into force (Journal of Laws of II No. 76, pp. 655–678). Amendments followed on November 26, 1969 and October 11, 1984. As a result, legal stipulations of limit values for radioactive contamination and thus also new guidelines for the “Dosimetric Group” came into force.
From 1965, measurements of the concentration of radon-progeny products were started at all permanently occupied underground workplaces.
As a result of the measures introduced to improve ventilation, the amount of weather available per worker and minute increased from 12 m³ to 36 m³ between 1960 and 1965.
In order to enable even more effective ventilation with the large area of the soles, the excavation of special weather soles began in 1958. These were 6 m below the corresponding main floors and were used to quickly evacuate the weather. The soles −486, −546, −636, −726, −816, −906, −996, −1086, −1176, −1266, −1356 and −1626 were used. In order to be able to provide a sufficient amount of weather, from a depth of 1000 m a special weather bed would have been necessary for each of the main levels. As this effort would have been specifically from the V. cascade with the decrease in the payability too high, Abwetterblindschächte (z. B. 373 were geteuft outside the productive range up to 373 VIIbis ), which were then connected to the main weather shafts of the upper cascade.
In the special ventilation on the V. and VI. Cascade only used ducts with a diameter of 600 mm and provided with interposed weather coolers for longer drives.
The penetration into ever greater depths led not only to the constantly rising rock temperature but also to ever wider weather paths. In order to guarantee a sufficient amount of weather, fans were installed above days on the weather shafts 382 and 383 for additional blowing ventilation . These went into operation in July 1964 at shaft 382 and in February 1965 at shaft 383.
In 1975 the amount of weather available per worker and minute was 50 m³ and thus more than four times the amount of weather available in 1960.
In order to reach the workplace temperatures of 25 ° C to 30 ° C required in the work and fire protection arrangement 120 (ABAO 120), the incoming weather had to be cooled. This task was solved in several stages with the help of the Institute of Thermal Engineering of the Academy of Sciences of Ukraine . At the shafts 382 and 383 additional cooling systems for weather cooling were installed, which went into operation in April 1964 and April 1965 respectively. This enabled the fresh weather to be cooled in the summer months. However, the mobile cooling units, which cooled the incoming weather stream directly on site, were soon no longer sufficient. To cool the main weather stream, additional stationary weather coolers were therefore installed on the levels −765, −855, −945, −1035 and −1305. The necessary cooling of the cooling water of the movable mine weather cooler was done by heat exchangers on the levels −945, −990 and −1305. The cold water required for this was generated in the cooling systems in shafts 382 and 383. After the expansion of the cooling systems at shaft 383, the flow temperature of the cooling water was 5 ° C. The cooling water was made available to the heat exchangers underground via a heat-insulated high-pressure system in a closed circuit.
The large spatial expansion of the mine meanwhile made it necessary to separate the weather system and the weather cooling into an east and a west part. This created two independent weather cycles. In 1976, a system with turbo chillers was built on the −1485 m level to weather the levels below the −1485 m level, and in 1986 a system with screw chillers was built on the −1620 m level .
To keep the dust pollution of the fresh weather small and little used mines within fresh weather stream by sprinkling MgCl were very long 2 flakes or washing the collisions with MgCl 2 - lye kept moist and thus binds the dust. From 1972 two corresponding washing trains were constantly in use.
Although the cessation of mining in object 09 was foreseeable from 1984 onwards, the work to reconstruct and increase the performance of the main pit ventilators of the weather shaft 273 was still being completed. This increased the available amount of weather again to 74.2 m³ per worker and minute.
The planned weather cascade of shafts 366 IIIbis to 366 VbIII up to the −1800 m level and the continuation of the weather cascade of shaft 373 with shafts 373 VIIbis and 373 VIIIbis up to the −1890 m level were no longer implemented.
In June 1989, the 208 W shaft was the first weather shaft to go out of service. This was followed by the shutdown of the fan shaft 382 in October 1989. The cooling systems of the shafts 382 and 383 were switched off in November 1989 and November 1990 and the ventilation shafts 383 and 372 went out of operation in May 1990 and November 1990, respectively.
After the main pit ventilator at shaft 208 was switched off in April 1994, shaft 373, the last weather shaft, went out of service in November 1997 after the highest impacted floor (−540 m) had been flooded.
In order to continue to ensure ventilation of the remaining parts of the pit, the former fresh weather shaft 382 was converted into a weather shaft. It went into operation on September 27, 1997. The excavation workings were the shaft 15 IIbis , the light hole 15a in Oberschlema and the shaft 208 and the light hole 9 in Niederschlema. In order to guarantee the weather management until the pit was completely flooded, extensive work had to be carried out on the floors of Marx-Semler, −60 and −240. 47.1 km of discarded mine workings had to be reopened and 31.5 km of them had to be cleared.
After the underground mine workings were completely flooded in January 2009, the Marx-Semler-Stollnsohle, the deepest anhydrous floor, plays an important role in the continued ventilation of the permanently anhydrous mine areas in Schlema and Schneeberg.
Drainage
The water inflow into the mine building took place via crevices and fissures in the mountain range, whereby geological deep waters played no role. The water inflow was very different depending on the depth and the spatial extension of the deposit. While being obtained on the cascade I. hour 500 to 800 m³ of water, there were on the V. cascade only 25 to 30 m 3 / h. Despite the increasing depth of 820 m 3 / h in 1953 , the amount of water only increased to 860 m 3 / h per year (average 1965 to 1990).
With increasing depth, the meteorological influences on the pit water also decreased. On the −240 m level, these influences were only detectable after a time lag of 14 days. From the −360 m level onwards, these influences were difficult to detect and occurred with a delay of about three months.
The horizontal distribution of the water inlets was also not uniform. When driving a cross passage to shaft 365 on the −240 m level, water inflows of 219 m 3 / h occurred . The shaft 365 itself was the most water-rich shaft of the property with inflows of up to 61 m 3 / h. Also on the southern flank at the granite contact there was still considerable water inflow even on deeper levels. In contrast, there were no water inflows on the levels −1395, −1440 and −1480 on the eastern flank of the deposit.
The mineralization of the mine water in property 09 was low, while the radon content could reach considerable values. In a study carried out in 1959, the highest value of 120,150 Becquerel was found on the −420 m level at shaft 38. This corresponded to about 66 percent of the value measured at the famous Hindenburg spring in Oberschlema with 182,250 Becquerel.
In order to lift the water from the pit, an elaborate system of pipes, pump systems and storage basins was necessary.
The first pumping stations for the main drainage system were set up on the −240 m level at shafts 38, 186 and 207. As the mining industry penetrated into the depths, further pumping stations were built on the −540 m level at blind shafts 38 bis and 186 bis and on shaft 371. More pumping stations followed later on the −720 m level at blind shafts 207 IIbis and 366 bis as well as at Gesenk 2/585. By 1960 pumping stations were added on the −810 m level (at the weather shaft 1 and at the blind shaft 371 bis ) and on the −990 m level (at the blind shaft 371 bis ). The total delivery rate was 6210 m 3 / h.
With the cessation of mining in Oberschlema in 1960, it became necessary to raise the pit water that had previously been released by the pumping stations there. For this purpose, a powerful pumping station with a capacity of 750 m 3 / h was built on the −546 m level at shaft 38 . Quarter 1960 was put into operation. This enabled all pumping stations in the Oberschlema district to be gradually taken out of operation.
With the cessation of mining on the I. Cascade in 1961 and the opening of the IV. Cascade from 1963, the dewatering had to be adapted to the changing mine field also in Niederschlema. The three pumping stations on the −240 m level were shut down. The new plant at the shaft 38 on the -546 m level promotes the resulting mine water from the upper area and the Schlemaer zusitzenden waters of the blind shafts 38 to and 207 up through the shaft 208 in the settling tank Borbach. The pumping station at Blindschacht 186 bis with a capacity of 236 m 3 / h also pumps the pit water through the shaft 208 into the Borbach basin, which in turn drains into the Zwickauer Mulde. The pumping station installed on the −540 m level at shaft 371 pumped the mine water into the Zwickau Mulde via a wastewater treatment system. The maximum flow rate was 300 m 3 / h. The pumping station built on the −996 m level at the blind shaft 296 IIbis with a capacity of 600 m 3 / h conveyed the mine water from the deeper parts of the reservoir to the pumping stations of shafts 38 and 371.
The pumping station built on the −1312 m level at blind shaft 372 bis had a conveying capacity of 750 m 3 / h . This pumping station pumped the falling water between the −990 m level and the −1305 m level, as well as the pit water from the lower lying parts of the reservoir to the pumping station at shaft 296 IIbis . Three more pumping stations at Blind Shaft I on the −1485 m level, at Blind Shaft 383 up to the −1710 m level and at Blind Shaft 383 IIIbis on the −1800 m level, pumped the pit water in stages to the pumping station on the −1305 m level. Due to the large delivery heads, axial piston pumps were mainly used. A system of underground storage tanks with a total volume of 58,000 m³ completed the mine water management system.
With the cessation of mining, the planned flooding of the mine began. The flooding level reached the −1485 m level at the end of 1991. The amount of water to be lifted decreased from 1989 to 1993 to around 50 percent. In 1993, the -1035 m level was also flooded. Due to the greater expansion of the mine area to the upper levels, the rate of flooding slowed down continuously. At the end of 1997 the water level reached the −540 m level. When it reached the −90 m level in 2001, the flooding was stopped. After the completion of the renovation work on the upper levels, the −60 m level was also flooded by 2008. The final discharge level in the area of the Marx-Semler-Stollnsohle will only be established with the completion of the tunnel pavement in 2013. Starting at light hole 14, this is to bypass the deformation area in a southerly direction and in the area of the King David shaft it is to be integrated into the already existing bypass from 1822. In the future, the pit water that falls below the Marx-Semler-sole will escape via the 0.60 m below the level of the mouth of the Marx-Semler-Stolln on the right bank of the Mulden river from the water treatment plant in Niederschlema. The water treatment plant is located between the Niederschlema train station and the 371 shaft. The pit water from the Schlemaer mine construction above the Marx-Semler sole and the Schneeberger mine field flows directly and without water treatment via the Marx-Semler-Stolln into the Zwickauer Mulde.
At the beginning of September 2011, the 5 submersible pumps responsible for the drainage of the Schlema - Alberoda mine were expanded in shaft 208. 2 submersible pumps in a die in the area of the water treatment plant took over their work. Shaft 208 will be kept until 2014.
Dump management
The tailings accumulating during excavation, alignment and excavation was deposited on heaps (pointed cone heaps and shallow heaps ) outside the mine building . At a total of 18 shaft locations there were more or less large heaps, some of which were used by several shafts. In total, around 39 million m³ of dump material was deposited in the area of property 09 on an area of around 230 hectares .
The composition of the dump material varied greatly. On the heaps of the weather shafts 208 W , 372 and 373 only the mountain masses from the depth of the shafts and the device of the filling location areas are stored. As a result, it is predominantly secondary rocks (e.g. phyllites , quartzites , diabase , fruit and knot slate ). The heaps of the production shafts 38, 66, 296, 312, 366 and 371, on the other hand, contain up to 15 percent dike material in addition to the secondary rocks, since the rock masses from the tunneling and mining were extracted through these shafts. This gangue material consists mainly of carbonates , fluorite, barite and quartz. The ore minerals hardly play a role. The arsenic content, the highest metal content, is between 0.01 percent and 0.03 percent and the uranium content between 0.002 percent and 0.0035 percent.
Most of the dump was poured in via terraced areas. This led to the pointed cone heaps typical of the Ore Mountains (e.g. the three heaps of shaft 366). In order to prevent the risk of landslides, the heaps were subsequently converted into truncated cones by flattening the tips of the heaps accordingly.
In addition to the pointed cone heaps, the mountain masses were also deposited on so-called flat heaps. The piles of shaft 382 are a typical example of shallow heaps. Around 4.2 million m³ of pile material from various shafts, mainly from Oberschlema, were deposited here, since the storage capacities in the narrow Schlematal were exhausted. The landfill was carried out with the help of a dump railway operated by steam locomotives.
Shaft 371, which developed into the main shaft from the mid-1960s, used a valley adjacent to the company premises to tilt the mountain masses. The mountain mass conveyed via a terraconic was temporarily stored at a transfer station in a mass bunker, then loaded onto trucks and transported to the dump and tipped there. Around 13.1 million m³ of dump material from the entire mine building was deposited on this heap alone. A water sprinkler system was used in the summer to combat dust in the area where the mountain mass was loaded and on its transport routes. In winter, this task was carried out by spray vehicles with magnesium chloride lye.
From the 1950s onwards, heaps were only allowed to be created with the approval of the mining authority of the Karl-Marx-Stadt district and the backfilling of the heaps was monitored. In order to ensure compliance with the official regulations, a monthly check was carried out by the main mine separator and the responsible division manager (division manager of mine cutting service until 1964, then division manager processing and from 1983 division manager extraction) of the mining company. The last valid dump ordinance (legal gazette of the GDR, Part I, No. 31) dates from 1980. In this ordinance, specifications were made for the creation of dumps (removal of the cultivated soil before creation of the dump and storage for later covering) and the Stability (e.g. slope angle and the distance between the berms ) met. In 1960, the first crushing plant was built at shaft 366 to meet the company's own needs for ballast. Since this facility was unable to sort out any uranium ores that were still present in the dump, the facility was shut down in 1970. A new crusher system with the appropriate sorting facility and a capacity of 430,000 tons per year was built in 1975 on the dump of shaft 371. In a cooperation agreement concluded between SDAG Wismut and VEB Hartsteinwerke Oelsnitz, Hartsteinwerke took over this facility and its staff for use. As early as the mid-1960s, dump material was processed into ballast and sold within the GDR (e.g. for the construction of the Rostock overseas port). The dump of shaft 65 was removed for this purpose. From 1975 onwards, the dump material from shafts 127 and 311 was also processed into ballast in a crushing system at shaft 127.
The dump area in Oberschlema was rehabilitated for the first time in the mid-1960s. In the Niederschlema area, too, work began in the early 1970s to flatten the heaps of shafts 38, 66, 207 and 296 and to plant them accordingly. The huge plateau at Shaft 382, which was heaped up by the Haldenbahn, was also rehabilitated. The removal of the heaps of shafts 13 to and 250, which were in the area of Niederschlema, did not take place for cost reasons. This was only carried out in 1991/92.
In the course of the renovation work by WISMUT GmbH, almost all of the dumps have been renovated to date. With the exception of arsenic, the metal content of the seepage water discharged from the heaps is below the current legal limit values. Since the limit value for arsenic is only partially and slightly exceeded, there is currently no need for additional water treatment. A test facility in the form of Constructed Wetlands with swamp plants and algae for water purification was set up at the Halde Schacht 371 on behalf of WISMUT GmbH , which is currently in trial operation. In the course of the redevelopment, the heaps were re-profiled, covered radon-safe and sustainably greened. This reduced both the dust pollution and the leakage of seepage water. As one of the last large heaps, the heap of shaft 296 (952,000 m³) was rehabilitated in 2010.
Renovation company
With the conversion of the Aue mining company into the Aue renovation facility on January 1, 1992, the legal basis for the renovation of the surface and underground facilities and the areas used was created.
The underground rehabilitation began immediately after the active mining operations were completed in 1991. The area of the mine field, together with the Oberschlema construction site acquired in 1958, comprised a total of 32 km². 176.3 km of the original 4,200 km of track-bound mine workings, which had been excavated before the cessation of operations, were still accessible in 1990, and of the 51 day and 50 blind shafts that were available, 9 day and 4 blind shafts had to be kept open depending on the flooding of the mine workings.
Underground renovation
At the beginning of the underground renovation, all technical pollutants (oils, fats, acids, explosives, ammonia , freons and technical gases) were removed from the mine building and these substances were properly disposed of. Furthermore, all rolling material had to be removed from the pit to ensure smooth flooding. After a corresponding radiometric check, it was recycled. For cost reasons, the stationary underground systems were only dismantled where it was necessary for proper storage.
To ensure the dismantling and disposal on the individual levels, the flooding of the mine was controlled from June 1992 to November 3, 1997. For this purpose, around 9,000 m³ of pit water was lifted every day and pumped into the Borbachtal sedimentation basin. In November 1997 the last dewatering was also taken out of service. However, in order to be able to continue to control the flooding if necessary, 5 submersible pumps were installed in shaft 208. For the planned flooding of the mine, 7.5 km of mine structures hermetically sealed by brickwork were opened in order to prevent uncontrolled flooding of these areas.
In order to be able to carry out the further safekeeping of the pit, the fresh weather shaft 383 had to be converted into a weather shaft and the weather shaft 208 into a crew and cable car shaft before the −540 m level was flooded. For this purpose, mobile connections on the floors of Marx Semler, −60 and −240 were removed or newly created. During this work, a total of 47.1 km of pit length was reconstructed.
In order to prevent the occurrence of mountain damage in the future, mine structures close to the day had to be backfilled to a depth of up to 50 m. Since there was often no longer any connection to these pits, they were approached via dies. In order to be able to carry out this mountain safety work, the flooding of the pit was stopped in 2001 when it reached the −90 m level. After this work was completed, the pit was flooded as planned and the water level reached the −60 m level in 2008.
A water treatment plant was built on the right bank of the Mulde in 1997 to clean the contaminated pit water. In it, all mine water is cleaned for a period of at least 30 years. In order to ensure an even supply of pit water to the water treatment system, the pit space between the Marx-Semler level and the −60 m level with a volume of 1.5 million m³ serves as a buffer storage. Only after the water quality within the legal limits has been reached, the water treatment system is taken out of operation and the remaining pit area is flooded.
When storing the day and blind manholes, the blind manholes could be flooded without any further pre-treatment. The day shafts in the Niederschlema district were filled (66, 186, 186 a , 250, 275, 372, 365) or secured with a concrete seal (38, 207, 208 W , 296, 366). The planning for the safekeeping of the day shafts was carried out by the former Institute for Mining Safety in Leipzig. In addition to the safekeeping of these day and blind shafts, post-safekeeping work was carried out on various shafts in the Oberschlema. In 1989 this affected shafts 6 bis , 15 bis and 64, in 1990 shafts 8 and 127 and in 1991 shafts 14 and 14 bis . Shaft 12 was reopened in 1992 and made mobile in order to create further access to the Marx-Semler-sole.
Remediation above ground
In addition to the buildings and systems of the various shaft locations and auxiliary operations, the renovation of the surface systems also included the heaped dumps and the Borbachtal sedimentation basin.
In 1991/92 the heaps of shafts 13 to and 250 were removed and moved to the Oberschlema deformation area. After applying a cover and cultivation soil, the spa gardens of Oberschlema were created here.
Part of the heap of shaft 366 was relocated for the construction of the motorway feeder. All other heaps were left in place and rehabilitated there. The slopes of the heap were flattened and provided with a layer of clay to curb radon exhalation. After the cultivation soil was applied, the heap areas were greened. Dumps that were leveled and afforested in the seventies and eighties were also rehabilitated, as these apparently did not comply with the current regulations. For this it was necessary to remove the grown forest.
After the water treatment plant was commissioned in 1998, the Borbachtal sedimentation basin was also renovated. About 250,000 m³ of contaminated sludge was stored here on an area of 3.5 ha. As a renovation variant, the decision was made to use dry “in situ” storage. The required mass for the cover was obtained by flattening the embankments and partially relocating the adjoining pile of shaft 382.
All buildings and facilities at the various sites that were contaminated by processing or transporting uranium ores and tailings were demolished and the remains disposed of accordingly. The radioactive scrap that arose during the surface and underground remediation was disposed of underground with official approval by December 31, 1994. From 1995 the radioactive scrap and the contaminated building rubble were moved to designated areas of the shaft dumps 366 and 371.
The remaining company buildings had to be demolished over long distances due to their poor state of construction. After the renovation of these areas, they were handed over to the municipalities. The colliery building in shaft 371 has been renovated and has been the head office of the renovation company since 1994.
In addition to monitoring the dewatering and ventilation, the deposit is also monitored seismically. This was necessary because the flooding led to vertical and horizontal ground movements and these tectonic movements can still occur.
A subsurface trough with a maximum subsidence of 80 cm (lowest level in 1996) in the area of the Niederschlema paper mill was created above the deposit. With the cessation of mining in 1991, the subsidence subsided. With the increase in the flooding level, the surface began to rise slowly from 1998 onwards. In October 2008 the total amount raised reached 96 mm. It is assumed that a total elevation of 150 mm is not significantly exceeded until the subsoil has settled. The greatest elevation is between the train station and the Niederschlema sewage treatment plant, in the outcrop area of the Ruhmvoll , Bitterfeld and Halle corridor system .
literature
- Axel Hiller, Werner Schuppan: Geology and uranium mining in the Schlema-Alberoda district (= mining monograph. Volume 14 ). LfUG, Freiberg 2008, ISBN 978-3-9811421-3-6 .
- WISMUT GmbH magazine: Dialog . Self-published, Chemnitz 2011 (first edition: 1993).
- Werner Runge among other things: Chronicle of the bismuth . Ed .: WISMUT GmbH. Self-published, Chemnitz 1999 (CD).
- Oliver Titzmann: Uranium mining versus radium bath . Self-published, Schlema 2003.
- Bergbauverein Schneeberg eV (Ed.): Fifth conference volume on the occasion of fifty years of cessation of uranium ore mining in Schneeberg…. Mining Association, Schneeberg July 2007, OCLC 316096077 .
- Holger Neumann, Sven Kästner: Narrow-gauge industrial locomotives of the GDR . Wolfgang Herdam Fotoverlag, Gernrode 2008, ISBN 978-3-933178-22-0 .
Web links
Individual evidence
- ^ The main department XVIII: Economics (MfS manual). (PDF) (No longer available online.) Archived from the original on May 29, 2014 ; Retrieved May 29, 2014 . 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.
