EE WAS OPERATING A ROOF RANGER II ROOF BOLTER. THIS MACHINE WAS RECENTLY WORKED ON & THE HYDRAULIC HOSES WERE SWITCHED FOR THE UP & DOWN MOTION OF THE DRILL HEAD. EE WENT TO DROP THE HEAD & IT WENT UP INSTEAD & SPUN. THE TIGHTNER WRENCH HIT HIM ON HIS FOREARM. CAUSE OF THIS INJURY WAS KNOWLEDGE. MINER KNOWLEDGE A FACTOR, PERSONAL SAFETY EQUIP NOT A FACTOR, MINING/SYSTEM WAS NOT A F