We have the NEW Sierra Blaster rock breaking system. Demolish boulders, break open bedrock cracks, stope or drifting. Safe, cheap, effective and fun. $670 for a single head blaster, multi head units, too. Can rig up to 8 blasters on one shot, electrically fired, reliable in the field, 2 1/2 years in development, No permits, or licenses, magazines. Portable, light weight for field use. If you had only had Sierra Blaster in the past, imagine how much more gold you'd have now! Use with mini generator of inverter and batteries, 110 volt or 12 volt batteries. Recommend Harbor Freight hammer drill. You can drill, charge and shoot a round in only 5 minutes!