Perhaps WA in not 'technically closed' for all small scale powered mining equipment.
I was told that miner's in Washington State can still operate small mechanical portable mining equipment such as high-bankers, classifiers and trommels using gas engines or electric motors with a water pump...as long as the water used in the process remains fully contained (and reused) within the processing system.
An example might be a 2" high-banker with a small gas engine and water pump that operates within a large contractor's tub. Water must be contained within the entire system although the outflow of cobbles, rocks and gravel could be deposited onto the ground. Same goes for a small trommel such as a Gold Fox unit. Might need further clarification so suggest looking at the wording within latest (June 2020) version of the WDFW "Gold and Fish Book".
With obvious disappointment this would not include small-scale suction gold dredges.
LD