While burning bolts off the Bunker Belt Head Roller at U/G Prod. Shaft Pocket (with torch), sparks from metal that was being cut ignited methane on top of the coal that was located in pocket. Ignition lasted 20 to 30 seconds & flame was extinguished with water. There was only 0.1% methane found prior to & during burning of the bolts. No property damage or injuries were incurred.