Mähring uranium mining

from Wikipedia, the free encyclopedia

The uranium mining Mähring was an investigation of the two shafts, the mine Wäldel and the height stone pit existing mining projects for the investigation of a uranium deposit in the district of Tirschenreuth in the Upper Palatinate in the state of Bavaria .

location

The uranium deposit in the Upper Palatinate lies in the border area between the Moldanubic and the Saxothuringic ( Variscan orogeny ). The uranium mineralization in the Wäldel pit is bound to a quartz vein and a vein-shaped structure. Uranium occurs in association with other metals and as uranium enrichment with primary uranium minerals associated with carbon, phosphorus and molybdenum. The shafts are in the Tirschenreuth district

history

Actually, with the Control Council Act No. 25, research into uranium deposits in Germany was largely prohibited, but immense amounts of uranium were required for the ambitious nuclear weapons programs, so uranium prospection was tacitly tolerated. The uranium deposits in the Upper Palatinate were known for a long time and in 1958 a more intensive exploration of the deposits began . 1967 mandated the union Brunhilde the company balance with the sinking of an inspection pit in the quarry Wäldel , this exploration shaft reached a depth of 170 m. In 1972 the work was temporarily stopped and only resumed in 1978. An exploration shaft has now also been sunk in Höhenstein parallel to the Wäldel pit . This shaft was named Höhenstein shaft . For economic reasons, work in the two shafts was stopped in 1982.

The rich ore (uranium content> 0.1%) was transported to the Ellweiler uranium ore processing plant for further processing . In total, around 8,000 t of poor waste with a uranium content of <0.1% were produced during the exploration , which had been subjected to dump leaching since 1972. The heap material was treated with sulfuric acid and the uranium (V, VI) oxide was eluted with nitric acid via an ion exchanger and precipitated with sodium hydroxide . The concentrate from the stockpile leaching was then transported to the Ellweiler uranium ore processing plant for further processing. The process water was neutralized with milk of lime and seeped into a sludge pond . The dump leaching lasted until 1989. As early as 1987 it was examined whether the dump leaching and waste water disposal had effects on the groundwater. The analysis showed increased values ​​for

Decommissioning and renovation

The shafts were a cohesive concrete column closed . The dump material from mining was mechanically and chemically changed and had to be completely encapsulated for reasons of water management and radiation protection. Therefore, a class I landfill was set up on the site of the Wäldel mine. 8000 m³ of dump material, 1300 m³ of sediment from the sludge pond and 1700 m³ of contaminated rubble were stored in this landfill. The dump material was neutralized with sodium hydroxide solution before storage . The material from the sludge pond was thixotropic and had to be mixed with 650 t of lime before storage . Any wastewater was collected and, after clearing, it was fed into the Lohbach. In November 1994 the landfill was completed. In order to guarantee the surface sealing of the landfill, it is necessary that deep-rooted plants are removed regularly.

Contaminated sites

The poor dump consists of around 8,000 t of leached poor ore (<0.1% U) with a direct radiation of 2.3 μSv / h (20 mSv / a).

Web links

Individual evidence

  1. ↑ Harald G. Dill: Genetic studies of deposits in the area of ​​the uranium ore structure Wäldel / Mähring (NE Bavaria) . 83rd edition. Geologische Rundschau, Bonn 1983, p. 1 .
  2. ↑ RESERVES AND FUNDING OPPORTUNITIES FROM URANIUM TO 2050. (PDF) BMU: Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, p. 340 , accessed on June 5, 2020 .
  3. ↑ J. Schmitz, A. Olkis, H. Klenk, K. Bächmann: Radio-ecological studies in the Mähring / Poppenreuth area . Nuclear Research Center Karlsruhe, Karlsruhe 1985, p. 1 .
  4. ↑ 4th MARKETEDWITZER SOIL PROTECTION DAYS. (PDF) Bavarian State Ministry for the Environment, Health and Consumer Protection, 2006, p. 225 , accessed on June 10, 2020 .
  5. ↑ 4th MARKETEDWITZER SOIL PROTECTION DAYS. (PDF) Bavarian State Ministry for the Environment, Health and Consumer Protection, 2006, p. 225 , accessed on June 10, 2020 .
  6. ↑ Further methodological development of the guideline for radiological examination and assessment of mining contaminated sites and expansion of the scope (Report I). (PDF) BMU: Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, 2007, accessed on June 5, 2020 (page 80).