A hand held shovel and you can only move 2,000 yards of dirt per day,for causal use.

GPAA claims are classified for casual use to avoid the process and expense of Notice of Intent and Plan of Operation with BLM.  You are good to go with gas or battery powered dredges,power sluices,  dry washers, recovery wheels, etc., (where and when legal) for processing material  The auger might be pushing the limits as most digging is limited to hand powered tools.

anything that is considered earth-moving equipment is considered to be beyond casual in the mining law as amended. This is interpreted usually as anything that digs or pushes dirt or material. This could even include a quad with a blade or rototiller to soften dirt or a mechanical hammer device. Not all jurisdictions or agents apply it the same and warnings are not a demand before being sited. So be careful out there both with use of equipment and health.