I use a medium size shop vac that is 110 volt, powered by a 12 volt inverter, hooked up to the trucks battery when I can drive up close to the spot being worked, using a 100 foot extension cord,  when working in the desert. ( I keep the truck running )  

     Also use a small generator that can be packed in if needed when I can't get the truck in close enough.  

     It is always a good idea to do a bedrock clean up and a shop vac will do a good job getting the gold your other tools could not pick up.  Sometimes the shop vac has more gold in it than the other 18 five gallon buckets that have been screened down to 1/4 inch minus and ran through the wash plant.

     When there is water in the wash I use hand held suction devises to clean up the exposed bedrock.              Ron 

Thanks Ron.  That was one of my thoughts; to use an inverter for a 120v vacuum.  I think it would have more suction than any battery powered or 12volt vacuum.  Ditto on more gold in the vacuum cause it's going to get the most from the deep and hard to get at gold.  Reviews of battery powered vacs say they might get only 10 to 15 minutes before the battery dies.  Not good enough, if you ask me.  Still would like to hear about any other vacs out there.

     There are gasoline powered vacs out there that are more a commercial type vac and they have a  larger diameter hose than the homeowner style vac.  The larger hose clogs less often than the smaller hose.  A few years back on one of the digs I was at, a guy had what I think was a Dewalt gasoline vac and it had lots of power and did a great job.

     I make smaller diameter size adapters that fit on the store bought hose that can get down into the smaller crevices, you may want to do this also.            Ron