" Traipsing the tunnels alone, the boys depended on the ponies for companionship; if their lamps went out, as they frequently did, a pony could guide them home. 'The ponies knew their way around their own district of the pit and could always find their way back to the pit bottom. They did this by travelling against the air which was being fed down the shaft,' Jim remembered. 'If you got caught in the dark, you grasped your pony's tail and tried to get your head just below the level of his back while he walked slowly - never offering to kick you - straight back to the pit bottom. "

― , Black Diamonds: The Rise and Fall of an English Dynasty