METHOD FOR ASSESSMENT OF ROCKS DANGER BY FRICTION INFLAMMATION OF AIR-METHANE MIXTURE Russian patent published in 2009 - IPC E21F5/02 

FIELD: mining.

SUBSTANCE: invention is related to the field of mining, in particular, to safety issues in coal mines, namely to explosions of methane caused by friction spark created as a result of mine machines picks friction against hard rocks. Method is suggested to assess danger of rocks regarding friction inflammation of air-methane mixture, which consists in the fact that rock samples are taken, their strength and content of silicon dioxide are determined, and then tests are carried out at test bench danger of friction sparking. In order to perform test, explosive mixture is formed in test bench, and nominal cutting speed is increased 1.5 times. If at hardness of rocks f from 3 and content of silicon dioxide up to 30% no inflammations were observed and no friction sparks were produced, then rock is considered safe. If at hardness of rock from 3 to 5 and silicon dioxide content from 30 to 50% with availability of friction sparks with temperature of up to 300°C and absence of inflammations, rock is considered as spark-hazardous of the 1^st extent, and if their temperature is more than 300°C - to spark-hazardous of the 2^nd extent. If at least one inflammation occurred from friction sparks, rock is considered highly explosive. Use of suggested method makes it possible to increase safety of cleaning and preparatory works.

EFFECT: development of fundamentals for rock classification procedure by danger of friction inflammation in case of their damage with account of their physical-mechanical properties.