Frozen lower left alternator bolt

Hello everyone. The bolt is out without being broken off, etc. Process that was used was to drill a hole large enough to insert the plastic nozzle of the penetrating spray. The engine stand caused the engine to lean forward so a 2x4 was placed under the front of oil pan and on the trolly jack so as to tilt the engine nose up. When time permitted the penetrating spray was added and a few taps from a heavy hammer were applied. The bolt was not rusted at the threads but rather around the shaft of the bolt for one half inch at the face of the engine. Today light pressure from an impact gun was all that was required to free it up after several reverse and forward light impact gun trigger pulls were used. If you are not in a rush this process is fantastic. Thank you all for your input.