IF a cloud of dry dust is suddenly raised by a current of air and projected against an insulated conductor, the latter becomes charged with electricity to such a potential that sparks several centimetres in length may be obtained. It does not matter much—save in respect to the sign of the charge—what the nature of the dust is, for sand, coal dust, flour, or iron filings all give rise, to strong charges.
Sand gives a positive charge and coal dust a negative one. It therefore appeared possible that a cloud of dust raised by a sudden fall, or other means, in a mine might charge up an insulated conductor to such an extent that a spark could pass to an earthed conductor near it, and thus fire an explosive mixture of gases if this was present.
You can also search for this author in PubMed Google Scholar. Reprints and Permissions. Nature 92, Facebook Twitter LinkedIn Syndicate. Friday, December 9, Coal dust explosion blast wave exiting mine portal. How Big is the Problem? From to , there were 10 multiple fatality explosions in underground coal mines in the U.
These explosions increased the fatality rate from The worst disaster caused by a coal mine explosion in the U. Links with this icon indicate that you are leaving the CDC website. Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
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Tools you can use Related projects Related contracts All explosion prevention content. Mine explosion. Links with this icon indicate that you are leaving the CDC website. Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
You will be subject to the destination website's privacy policy when you follow the link. CDC is not responsible for Section compliance accessibility on other federal or private website. When air contains approximately 9. This produces water, carbon dioxide and a lot of amount of heat. The heat generated by this process raises the temperature of the air within the mine, which causes it to expand in volume. Since hot air cannot expand easily underground, pressure builds in the mine.
If this pressure is high enough, it can cause the air ahead of the combustion zone to compress and cause a shock wave, Luo explained. Ventilation is the most common method to avoid such methane explosions in coal mines.
Large fans are used to blow air out or draw air into mines, but Luo stated that mine ventilation is still a complicated science.
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