Underground mines me khuni gas kaise banti hai? | How khuni gas is made in underground mines?

·    Sabse Jayda khuni gas after explosion(CH₄ )ke      baad banti hai.

   ·    Coal me spontaneous heating hone se.

   ·    Coal me aag lagne se.

   ·   Baaarud purn-roop(puri tarah) se nhi jalne se.

   ·  Mines me diesel , locomotive, diesel shuttle , & air  compresser chalne se.