Bad weather

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Bad weather is harmful gas mixtures in mining . These are caused by the mixing of the breathing air with gases that are harmful to humans either due to their toxic properties or due to the displacement of oxygen. After a business interruption, miners are only allowed to re-enter the mine workings , in which bad weather cannot be ruled out, until the weather has been measured.

History

The term bad weather joined the miners in the early mining with the idea that this is a dragon IN QUESTION, of his fire-breathing breath into the tunnel blew. Agricola wrote of these ghostly animals:

“ These animals that are terrible to look at and very hostile to the workers. There is such an animal in the pit near Annaberg, called the Rosary, which killed twelve people with the breath of its throat. It sprayed its breath of flame every time it opened its throat and usually appeared in the form of a horse. In the St. Georgs pit in Schneeberg there was one with black fur, which workers blew into the air, not without great danger to his body. "

Only later did it become known that this breath of flame was an explosion and that the bad breath was the subsequent poisonous vapor.

Composition and origin

The composition of the bad or poisonous weather is very different depending on the mine. The formation of the bad weather takes place through combustion, putrefaction processes, through oxidation, through the use of explosives, through the escape of gas deposits in the rock or through creeping currents from the old man . Consumption of oxygen creates carbon dioxide , which miners call carbonic acid . Carbon dioxide has the property of accumulating in the area of ​​the floor or in depressions such as the sump during sinking work . Such strong carbon dioxide weather is called severe weather or plume. In the Harz mining industry these plumes were called cold steam . Another type of nasty weather are the smoldering weather. This gas mixture occurs as a result of fires in coal mines. When the coal burns, gases such as carbon monoxide and carbon dioxide are produced. As a result of the formation of carbon dioxide, carbonic acid is formed with mine water. Since in almost every seam proportions of sulfur and gravels are present, is formed by the combination with moisture sulfur dioxide . This gas mixture has a peculiar, disgusting smell. The fire-setting used earlier in ore mining released poisons such as arsenic as fumes. In this way, arsenic acids were formed in the tin ore pits, which were mixed with the soot particles that formed when the wood was burned and were often in the current for days in the current. In silted mine workings , the decomposition of the pyrites forms the toxic gas hydrogen sulfide . In mercury mines, volatilization of the mercury , which is mixed with the breath, can occur. The decomposition of animal excrement produces the toxic gas ammonia . These putrefaction gases produced by faeces can mix with the air we breathe in connection with putrefaction particles. These mixtures are called miasms .

Effects

Since the toxic effects of the individual types of gas are quite different, it depends on their concentration in the air we breathe. For gases such as hydrogen sulfide or carbon monoxide, certain maximum limits are prescribed in mining. Although carbon dioxide itself is not poisonous, inhaling carbonated air with a volume fraction of five percent is already harmful. In contrast to carbon dioxide itself, carbon monoxide is toxic. The tricky thing about this odorless gas is that the presence of carbon monoxide is only noticed after poisoning has already occurred. As little as 200 ppm lead to fainting after 1–1.5 hours and death if there is a longer stay. In the case of carbon monoxide poisoning, death from suffocation occurs very quickly. After mining accidents, miners poisoned by carbon monoxide were found whose bodies were still in their previous working posture and who were found with a smile on their faces. Arsenic-containing vapors lead to unconsciousness, the affected miners look as pale as if they were already dead. Hydrogen sulfide is even more toxic than carbon monoxide. Even with a volume fraction of 0.1 percent hydrogen sulphide in the air, a person quickly loses consciousness and dies when inhaling this air. A horse dies at a concentration of 0.25 percent. However, air containing hydrogen sulfide can be recognized by a strong odor of rotten eggs. Miasms are dangerous to health, people can get cramps when inhaling. These substances can be fatal at higher concentrations.

Stay in bad weather

Since staying and driving in bad weather is very dangerous for humans, various breathing devices have been developed that allow staying in bad weather for a certain period of time. There are different variants, from simple face masks to hose devices to knapsack devices. Face masks can, depending on the structure of the filters and the composition of the chemicals used, absorb carbonic acid or carbon monoxide gas and enable driving in breathing air mixed with these gases. Respiratory protection devices , the filter self-rescuers , have been developed for the coal mining industry , which miners use as escape devices in the event of a mine fire with the development of carbon monoxide. In salt mining, gas outbreaks with carbon dioxide sometimes occur ; special breathing apparatus has been developed for these events. Special escape chambers are also used for longer stays in bad weather.

early detection

Since even a short stay in bad weather can be fatal for the miner, effective early detection of bad weather is very important. To do this, the miners initially used canaries after a mine fire or a firedamp explosion . The birds were carried in a special portable cage in order to detect any carbon monoxide that was still present. In ore mining, the miners took their canaries with them into the pit during the normal shift. If the bird suddenly stopped singing, the miners interpreted this as a warning signal and left the tunnel . In individual cases, mice were also used underground for the early detection of carbon monoxide. Since mice succumb to the effects of carbon monoxide ten times faster, the animals were kept in individual cages in the suspicious pits. However, since the animals were not at hand everywhere and the method was cumbersome, it could not prevail. In modern mining, special measuring devices tailored to the respective gas are used for early detection. There are measuring devices with test tubes for hand measurements by supervisors . Electronic gas measuring devices are used in certain mines for continuous measurement.

See also

literature

  • The pit fire and the bad weather in the mines of the Upper Harz . Schweiger Buchhandlung Verlag, Clausthal 1848

Individual evidence

  1. ^ A b Gustav Köhler: Textbook of mining history. 6th improved edition, published by Wilhelm Engelmann, Leipzig 1903.
  2. ↑ General Mountain Police Ordinance Online ( Memento from June 7, 2012 in the Internet Archive ). January 13, 2015; PDF; 233 kB.
  3. ↑ Explanatory dictionary of the technical art and foreign words that occur in the mining industry, in metallurgy and in salt works . Falkenberg'schen Buchhandlung publishing house, Burgsteinfurt 1869.
  4. ^ A b c d e Emil Stöhr, Emil Treptow: Basics of mining science including processing. Spielhagen & Schurich publishing house, Vienna 1892.
  5. ^ A b c d Carl von Schauroth: Die Grubenwetter . at JCB Mohr, Heidelberg 1840.
  6. ^ Carl Hartmann: Handbuch der Bergbaukunst . Second volume, Verlag Bernhard Friedrich Voigt, Weimar 1845.
  7. ↑ a b Georg Agricola: Twelve books on mining and metallurgy . In commission VDI-Verlag GmbH, Berlin.
  8. ↑ Albert Serlo: Guide to mining science. Second volume, 4th improved edition, published by Julius Springer, Berlin 1884.
  9. ↑ a b c d Fritz Heise, Fritz Herbst: Textbook of mining science with special consideration of hard coal mining. First volume, fifth improved edition, published by Julius Springer, Berlin 1923.
  10. ^ A b c d Walter Bischoff , Heinz Bramann, Westfälische Berggewerkschaftskasse Bochum: The small mining encyclopedia . 7th edition, Verlag Glückauf GmbH, Essen 1988, ISBN 3-7739-0501-7 .
  11. ↑ Franz Ritter von Rziha: Schlagende Wetter . Lecture from February 10, 1886.
  12. ↑ Dräger Review 384: Protection for the City Underground . February 2010 Online  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (accessed on May 16, 2012; PDF; 3.2 MB).@1@ 2Template: Dead Link / www.draeger.com  
  13. ^ A b Carl Hellmut Fritzsche: Textbook of mining science. First volume, 10th edition, Springer Verlag, Berlin / Göttingen / Heidelberg 1961.
  14. ↑ Canaries in Mining - Birdcage Safety in Mining (accessed May 10, 2012).
  15. ^ The History of Canaries (accessed May 10, 2012).