Potash works unions Orlas and Nebra
| Orlas and Nebra potash mines | |||
|---|---|---|---|
| General information about the mine | |||
 |
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| other names | Potash works "Union Orlas" and "Union Nebra" | ||
| Mining technology | Chamber construction | ||
| Information about the mining company | |||
| Operating company | Orlas and Nebra unions | ||
| Employees | up to 200 | ||
| Start of operation | 1911 | ||
| End of operation | 1921 | ||
| Funded raw materials | |||
| Degradation of | Carnallitite u. Hard salt | ||
| Greatest depth | 529.4 m | ||
| Geographical location | |||
| Coordinates | 51 ° 14 '42 " N , 11 ° 32' 18" E | ||
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| Location | Wippach | ||
| local community | Bad Bibra | ||
| District ( NUTS3 ) | Burgenland district | ||
| country | State of Saxony-Anhalt | ||
| Country | Germany | ||
| District | South Harz | ||
The shafts and pits of the potash works unions Orlas and Nebra belong to the deposit area of the Roßlebener saddle. The general painting runs in the direction of NNW to SSE; the stratification varies between 5 and 12 degrees to the east. The salt deposit shows strong disturbances due to folds and displacements . Mined here were hard salt , carnallite and to a lesser extent, kainite and sylvite . Orlas shaft is located approx. 2 km west of the Wippach locality on the site of a former brickworks; Nebra shaft is located approx. 1.1 km north of the Orlas shaft in a wooded area. The mine workings of the "Orlas and Nebra unions" extend over a length of approx. 2.5 km in strike direction and a width of approx. 700 m. Both mines are on the 467-m sole interconnected. The level -180 m above sea level was set as the upper limit of degradation . The conveyed goods were ground up for days and brought to the loading facility in Kleinwangen by cable car. From there, the salts went by rail and axle for further processing in the factory of the Roßleben mine . As Versatzgut rock salt was the Abteuf halde used. The promotion was stopped in 1921. Up to then around 53,000 tons of K 2 O had been sold. All surface facilities were demolished in 1934. Only a small remnant of the abyssal dump is left on the site near the Nebra shaft.
Geological and hydrogeological conditions
The geological conditions
The Orlas and Nebra shafts were set up on the northeast flank of the Roßlebener saddle in the middle red sandstone . The profiles inserted on both sides provide information about the penetrated layers . The sequence of layers in both shafts is characterized by the lack of Aller rock salt (Na 4). This fell victim to the leaching from the salt level. The horizontal distance to the leaching limit of the Staßfurt potash seam is approx. 600 m estimated. The shortest distance between the mine workings of the Orlas-Nebra mine and those of the closest Georg / Unstrut mine (see map above) is around 1,400 m.
In the Orlas-Nebra mine, hard salt and carnallitite from the Staßfurt potash seam were extracted. The potash deposit was found at a depth of 455.50 m from the Nebra shaft and at 458.50 m from the Orlas shaft. The collapse of the deposit is around 6 degrees with a general strike of 147 degrees. The deposit has been explored by striking stretches , plains, and quarries, as well as drilling above and below ground. The area covered by the route outcrop is approx. 700 m in the collapse and approx. 2,500 m in the strike. Two relatively extensive hard salt fields, which are connected with great certainty, have been identified in the vicinity of both shafts. The hard salt deposits are irregularly limited but elongated in the direction of strike of the deposit. A continuation in both southerly and northerly directions is likely. Intense folds at the hard salt-carnallite border (as found in the shafts) simulate a double bearing. The intensity of the folds is greater than that on the Roßleben mine. However, it appears to be limited to the salt distribution limit. The carnallitite is reddish to silver-gray and almost everywhere kieseritic. Hard salt is available in different varieties with often very high sylvene contents. It occurs kieseritisch, anhydritisch and langbeinitisch. Kainite is said to be enriched in the main area of the Nebra Well. Noteworthy are the often low hard salt thicknesses, which, similar to the area around the Roßleben mine, are to be understood as a consequence of the Zechstein Age leaching at the top of the potash deposit and were particularly effective here.
The hydrogeological conditions
The quaternary and tertiary deposits are very water-bearing due to the relatively high proportion of sand , gravel and clay till. The water table is in the Unstrut-Aue at a depth of 1–2 m; its general level is about 10 m below ground. According to the petrographic formation and the tectonic location of the Upper Buntsandstein in the area of the mine fields, it is hardly water-bearing. In contrast, the middle red sandstone is a very good aquifer ( drinking water fountain horizon). According to previous investigations, the medium to coarse sandstone deposits in the middle and lower red sandstone have the greatest abundance of water.
The lower red sandstone is also very water-bearing in certain areas, especially in the Rogenstein zones . The inflow volumes are strongly influenced by the tectonic situation. So were z. For example, in the Thuringia I / II pits closest to the “Bottendorfer Fault”, inflows of up to 4 m 3 / min were found during the sinking of these pits . During the devastation in the Lower Buntsandstein (between 119.5 and 166.3 m depth ), freshwater inflows with approx. 0.5 m 3 / min and between 250.0 m and 279.8 m with approx. 1.5 occurred in the Nebra shaft m 3 / min. Only the clayey lowest 40m - 50m of the red sandstone can be regarded as completely water-free.
The Orlas and Nebra shafts are approximately 600 m away from the leaching edge of the Staßfurt potash seam. The Aller rock salt was not drilled through by either of the shafts, as it had already been leached. The Leine rock salt was encountered with a thickness of 43 m or 46 m and should not be affected by the leaching. The lower part of the main anhydrite turned out to be very fissured. In it took place at approx. At 425 m depth, a saline solution ingress, accompanied by gases, through which about 60,000 m 3 should have flowed out with a discharge of approx. 0.7 m 3 / min . Orlas shaft, which is in the same position as the Nebra shaft, facing the salt surface, has been sunk dry in contrast to this in Zechstein. There were no inflows into either the gray salt clay or the main anhydrite , although the latter is said to have been severely fissured . Small amounts of saline solution ingress in connection with gases from areas of the gray salt clay have become known. In the braking mountains I to III, which rose from the main floor to the west in the camp horizon, only weak moisture penetration is said to have occurred in places.
Search and exploration work
A number of deep boreholes were carried out in the vicinity of the former Orlas-Nebra mine. Some of these deep boreholes were only drilled as so-called “ mutation boreholes ”.
These boreholes are compiled in the following table according to location and depth as well as the possibility of a geological statement for the pit fields of these shafts:
| Name of the hole: | Orlas II | Orlas III | Thuringia IV | Thuringia VII | Thuringia IX | Victory of truth | Nebra XII | Large-
cheeks |
Nebra II | Nebra V | Large-
cheeks I |
Bucha I | Bucha II | Bucha IV | Bucha V | Cold bunny | Bergwinkel 1E / 61 | Thuringia III | Bad Bibra 1 | Bad Bibra 2 | Bad Bibra 4 | Bad Bibra 6 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Final depth (in meters) | 364.20 | 357.70 | 448.60 | 386.70 | 406.20 | 567.50 | 276.80 | 267.35 | 266.60 | 289.90 | 412.20 | 309.30 | 319.80 | 478.10 | 345.00 | 558.00 | 744.20 | 505.30 | 1,023.00 | 695.20 | 784.10 | 701.00 |
| Deepest stratigraphic horizon reached | Leine rock salt | Leine rock salt | Leine rock salt | Leine rock salt | Leine rock salt | Aller rock salt | Leine rock salt | Leine rock salt | _ | _ | _ | _ | _ | _ | _ | _ | _ | _ | _ | _ | _ | _ |
| Result of the Kaliflöz search | _ | _ | _ | _ | _ | _ | _ | _ | Potash seam drained | Carnallitite and hard salt | Potash seam drained | Potash seam drained | Potash seam drained | Carnallitite | Potash seam drained | Carnallitite | Hard salt | Carnallitite | Deadening
zone encountered |
Deadening
zone encountered |
Hard salt | Hard salt |
The operation of the potash plant
The company formation
The "Orlas Union" was founded as a union under Prussian mining law *) through the associations of the individual unions Orlas, Orlas II, Orlas III, Wennungen, "Der Kalte Hase", Bucha II, Bucha IV, Thuringia IV, V, VI, VII, IX, “Victory of Truth” (all founded in Frankfurt am Main ) as well as the Bucha salt mine belonging to the businessman Hermann Mommsen (Frankfurt / Main). The founding charter is dated August 26, 1909. The large number of “unions” listed here may be astonishing today, at the time it was “an extremely simple process. In part, this is because a mining company was once considered a highly personal endeavor. Two People just need the application for "ceremony" a union to provide, by presumption insert due to their discoveries at mining authority, and they get their union without further notice. "
The new Gerechtsame originally had a total size of 3,0645.5927 hectares in the districts of Wippach , Nebra , Altenroda , Birkigt , Orlasheide, Großwangen, Wennungen , Bad Bibra , Bucha , Saubach , Steinbach, Pleißmar, Wallroda, Kalbitz and Memleben . Of this, 133.9405 hectares were diverted to form the “Nebra Salt Mine” (through the founding of the “Nebra Union”), leaving Orlas 293.06522 hectares. This complex was divided into three independent mines in March 1911 after approval by the Halle Oberbergamt: Mine “Victor” (445,108 m 2 ), “Der Kalte Hase” (9,434,348 m 2 ) and “Consolidated Orlas” with 19,427,066 m 2 . The latter are in the districts of Wippach, Großwangen, Altenroda, Bibra, Orlasheide and Saubach.
Daytime facilities : shaft building , mill system with two complete grinding systems, electric hoist, power transmission line, administration building, four civil servants 'houses, workers' colony. Property size: 22 ha 56 ar 50 m 2 .
Potash indicator: the distribution office granted the plant a provisional quota in autumn 1911. Since January 1, 1913, the plant had a definitive quota, which at the end of 1935 was 4.9402 thousandths.
Last ordinary trade union meeting: on May 17, 1935.
Here are some excerpts from statistical yearbooks (1910–1914):
1910: Representative: Bergassessor Mehl in Roßleben. Sinking of the shaft began in September 1909.
1911: Board of Directors: Bergrat Ebeling in Hanover . Technical director : Bergassessor H. Lohmann in Nebra. Commercial director: Ebeling in Nebra. Operations manager: Graduate mining engineer Herrmann in Wippach. The sinking is in full swing. Depth about 300 m. Average number of workers: 120 men.
1912: Board of Directors: Bergrat Ebeling in Hanover. Technical director: Bergassessor H. Lohmann in Nebra. Commercial director: Ebeling in Nebra. Mining inspector: Dipl.-Bergingenieur Herrmann in Wippach. Operator: Obersteiger Löttel in Wippach. The production or alignment of the deposit has started. Cable car after the loading station at Klein-Wangen. Average number of workers: 120 men. The Nebra shaft is in the process of being sunk; the average workforce is also 120 men.
1913: Board of Directors: Bergrat Ebeling in Hanover, chairman. Technical Director: Bergassessor Dr. H. Lohmann in Nebra. Commercial director: Ebeling in Nebra. Mining inspector: Dipl.-Bergingenieur Herrmann in Wippach. Operator: Obersteiger Löttel in Wippach. The production or alignment of the deposit has started. Cable car over Nebra shaft to the Klein-Wangen loading station, salt mill. Average number of workers: 160 men. The Nebra shaft is still being sunk, an average of 120 workers.
1914: Board of Directors: Bergrat Ebeling in Hanover, chairman. Technical director: Mine director, qualified mining engineer Pfister in Roßleben. Commercial director: Ebeling in Nebra. Mining inspector: Wiedenbeck. Operator: Obersteiger Löttel in Wippach. Cable car over Nebra shaft to the Klein-Wangen loading station, salt mill. Average number of workers: 160 men. At the Nebra shaft, the final conveyor system will be completed by the end of the year. Workforce: 120 men.
*) The right of the union was regulated by state law. The Prussian mining law it was enough when two people represented only a request for "ceremony" a union by presumption men casting due to their discoveries at Mining Authority. This explains the extremely large number of “unions”.
The shaft construction
On December 10, 1909, the sinking of the "Orlas" shaft began on the site of a former brickworks and this work was successfully completed in autumn 1911. The height of the hanging lawn bench is + 275.25 m above sea level. The diameter of the shaft is 5.25 m.
The Orlas shaft is constructed as follows:
From 0 to 80 m in masonry , from 80 to 195.3 m in cast iron tubbing and from 195.3 to 529.4 m (final depth) in masonry.
During the devastation , water inflows in the zone from 80 m to 195.3 m up to 0.5 m 3 / min. These inflows could be kept short by using appropriate pumps. The inflows were finally closed by installing German segments.
The bottom was raised : at 435.35 m the weather bottom and at 475.6 m the first underground level. The eaves water inflow after sinking was approx. 3 l / min.
The Nebra shaft is constructed as follows:
0.0 to 119.5 m in masonry, 119.5 to 166.3 m in cast iron tubbings, 166.3 to 250.0 m in masonry, 250.0 to 279.8 m in cast iron tubbings, 279.8 to 407 .0 m in masonry. 407.0 to 439.0 m in cast iron segments and from 439.0 to 490.0 m (final depth) in masonry.
The Nebra shaft was started in 1911 and completed in 1913. The shaft diameter is 5.25 m. The height of the hanging lawn bench is + 267.74 m above sea level. Level I at - 199.28 m above sea level = 467.02 m depth, shaft sump = 22.98 m, total depth = 490.00 m.
During the devastation, the water inflows from the areas from 119.5 m to 166.3 m and 250.0 to 279.8 m were approx. 0.5 m 3 / min and 1.5 m 3 / min. When passing through the anhydrite (at a depth of around 425 m), the inflows were 0.7 m 3 / min. When starting a pump on the well bottom is a serious occurred methane gas explosion , the eight miners were victims.
The potash store was approached at a depth of 455.5 m in the Nebra shaft and at 458.5 m in the Orlass shaft. After a rock salt compound, a carnallite deposit was also drilled. After sinking, the inflows were 3.5 l / min. The first underground excavation level was set at a depth of 467 m. It connects both shafts. The distance between the shafts is 1.1 km. The "Orlas" shaft served as a delivery shaft and an extending weather shaft ; "Nebra" shaft, also known as the " forest shaft" , as a material and cableway shaft as well as a retracting weather shaft.
Removal and installation, dismantling and relocation processes
The dismantling was carried out using the chamber construction method. Due to the storage conditions, the extracted salt was transported over brake mountains to the main production floor. The mining parameters are the same in the two mining fields Orlas and Nebra. There is only an indication of the dismantling heights . Accordingly, the dismantles that were not moved were at a sales height of 2.5 m. No information is available on the amount of the staggered mining operations.
The deposit was developed by driving the 467 m level. The hard salt was extracted from the ridge construction on both sides of the inclined routes. The chamber width for hard salt was 15 m, the pillar thickness was 7.5 m. Mining took place in the years 1914 to 1917. Carnallitite was initially mined in 15 m wide chambers, the pillar thickness here was 10.0 m. From 1918 the width of the chamber and the thickness of the piers were uniformly set at 10 m.
In the east section of the Orlas mine, several horizontal boreholes were drilled to explore the deposit.
The offset:
As can be seen from the existing floor plans of the Orlas-Nebra pits, around 50% of the excavated chambers were relocated. The documents in the Staßfurt archive show that flushing was planned in connection with the pillar dismantling. The backfill material was initially intended to be the mining dump and later mild sandy layers of the red sandstone. Certainly it can be assumed that only the Teufhalde and possibly rock salt from Roadway drivages used as backfill. There are no indications of the offset technology used. This means that no statements can be made about the density of the offset introduction. The following information can be found in an " Expert report on hydraulic displacement " of August 27, 1926 about the cavities created :
In carnallite: workings 39,716 m 3 , lines 46 757 m 3 .
In the hard salt: excavations 70,965 m 3 , stretches 66,600 m 3 .
In rock salt: 7,946 m 3 stretches .
In anhydrite: stretches 1,120 m 3 .
Total : 110,681 m 3 dismantled . Lengths 122,423 m 3 .
As can be seen from a letter to the Prussian Mining Authority, the cavities of the unmoved and scattered mining sites in the Orlas field amount to 44,000 m 3 and in the Nebra field 5,000 m 3 , so a total of 49,000 m 3 .
From the above The figures show that only approx. 62,000 m 3 of the excavation cavity were moved and around 171,000 m 3 of cavities on the routes and excavations remained unmoved.
Special occurrences
In the Orlas-Nebra mine, gas leaks from the main anhydrite, the gray salt clay and the potash store are documented. In 1912, when the Nebra shaft was being deepened, the main anhydrite was accompanied by an ingress of saline solution, causing strong emissions of combustible gases, the quantity of which decreased over time.
They had the following composition: methane 28%, heavy hydrocarbons 8% and nitrogen 64%.
When the Orlas shaft was being deepened, several gas eruptions of varying strength occurred in the gray salt clay . One of these occurred in connection with an ingress of solution and lasted for several months. When the mine workings were driven, gases appeared almost exclusively in the hanging part of the deposit and in the vicinity of the hard salt-carnallite boundary. Particularly violent gas leaks occurred when driving the cross passage from the Orlas shaft in the area of the gray salt clay.
The manufacturing processing of the crude salts
The extracted salts were ground for days and then transported to the potash factory in Roßleben for further processing into fertilizer salts . Around 53,000 t of K 2 O had been sold by the time production was discontinued.
The closure of the potash works
In 1921 the pits were shut down. In 1927 the Nebra shaft was filled and covered with rock salt and Latvians from the abyssal dump (together approx. 5,000 m 3 ) to a depth of 293 m . In the Orlass shaft, plumbing of the bottom of the shaft led to the assumption that major breaches of the shaft lining must have occurred. After 1921 the Orlas shaft was also partially filled and covered with a cover.
This design of a manhole cover (see figure above right: Manhole closure system "Orlass") had generally established itself as a means of securing disused manhole tubes in potash mining. On August 2, 1945 and July 21, 1949, the cover of the Orlas shaft was destroyed by explosions of mine gas . These explosions were triggered by throwing in burning cigarette remains through the solder pipe. The manhole cover was then rebuilt. A letter from Salzdetfurth AG to Professor Hans Stille dated April 17, 1939, states that approx. 4,500 m 3 of rock salt and 500 m 3 of Latvians from the Abteufhalde were dumped in the Nebra shaft and that the eaves water in the Orlas shaft was 4 - 5 l / min cheat.
During research work in 1978, both manholes were found filled with air. The bottom plumbed in the Orlas shaft was at a height of −126.16 m above sea level, that in the Nebra shaft at −120.34 m asl. In addition, soil samples were taken from the plumbing areas (Orlas shaft at 529.4 m, Nebra shaft at 490.4 m depth). While the soil sample from the Orlas shaft soaked with water from the eaves could be described as a so-called filling, the sample composition from the Nebra shaft indicated collapse mountains due to defects in the shaft wall. When the shaft tubes were shut down, a total of 7 l / min was recorded in these eaves water inflows. With around 171,000 m 3 total void volume of the two interconnected mine fields, if there had been no drainage, the mine workings would have been drowned after approx. 46.5 years. Experience has shown that such eaves water inflows tend to increase rather than decrease in their pouring, especially since the water productivity of the Rogenstein zones was very high here. It was therefore assumed at the time that the mine workings were drowned up to the level of the main anhydrite, which was found to be fissured. The added water is therefore more or less unsaturated by the main anhydrite, possibly also by the gray salt clay.
Current condition
The plants belonged to the Salzdetfurth-Westeregeln Group from 1917 to 1945 . After 1945 they became “the property of the people”. From January 1, 1953, they became the legal entity of VEB Kaliwerk "Heinrich Rau".
Since the GDR's safekeeping order of October 10, 1971 (GDR GBl. II No. 73), the council of the Halle district has been responsible for a large number of old potash pits, so-called “pits of old mining without legal successors”. With the accession of the GDR to the area of application of the Basic Law , these closed mines Orlas and Nebra were also regarded as "closed down facilities of a mining operation for which a legal successor is no longer available or can no longer be determined". In place of the councils of the districts, the respective state governments acted until the relevant regulatory authority regulations were issued (for the state of Saxony-Anhalt: Law on Public Safety and Order of the State of Saxony-Anhalt (SOG LSA) in the version published on 23 September 2003 ( GVBl. LSA p. 214), last amended on May 18, 2010 (GVBl. LSA p. 340)). This ensures that these mines are to date regulatory law of respect. Duty of care in order to security in the jurisdiction of the municipality .
In order to guarantee public safety , the shafts have now been stored and secured by a cover (see photos above). The manhole safeguards are secured against unauthorized entry by means of a chain link fence .
Bibliography
- Lobert, Schwarzer, Nagel: Mining damage analysis of the “Orlas / Nebra” mine near Wippach . Roßleben 1970. Archive of the LAGB Saxony-Anhalt, archive no. 922.3A.
- J. Mossner (Hrsg.): Handbook of the potash mines, salt pans and deep drilling companies . Finanz-Verlag, Berlin 1936.
- H. Messenbrink, H. Richter: Selection and assessment of decommissioned or decommissioned mines with regard to their suitability as cavity storage for natural gas, brine, town gas and liquid gas . Expert opinion, German Fuel Institute Freiberg, 1971 (unpublished).
- G. Pinzke: Expert opinion on the assessment of the mining and public safety of selected potash pits without legal successors on the territory of the Halle district . Council of the District of Schwerin, Dept. Geology 1979, Archives of the LAGB Saxony-Anhalt.
- oV: Yearbooks of the German lignite, hard coal and potash industries. Wilhelm Knapp publisher in Halle / Saale.
Individual evidence
- ↑ digitalis.uni-koeln.de (PDF).
- ↑ gesetze-im-internet.de (PDF).
- ↑ Law on Public Safety and Order of the State of Saxony-Anhalt (SOG LSA)
literature
- J. Löffler: The potash and rock salt deposits of the Zechstein in the GDR. Part III: Saxony-Anhalt . Freiberg research books C 97 / III, Akademie-Verlag, Berlin 1962.
- E. Loock: Disused shafts - a problem for the potash industry . Freiberg research books, A 136 series, Akademie-Verlag, Berlin 1960.
- E. v. Hoyningen-Huene: Salt tectonics and leaching in the area of the Mansfeld Lakes. Freiberg research booklet C 56, Akademie-Verlag, Berlin 1959.
