After they scrape the bed rock,there seems to be material left behind .Their excavator buckets can't get it all.they move somewhere else to run more volume through their plant.what if they flood the cut with enough water to run a 8inch dredge. It would be interesting to know how much gold would be there. 2 guys small scale dredging alot of claims might return enough to make good money.it most likely would have more gold than what they are loosing from there sluice.yukon gold had a guy called hero add a fine gold trap to their wash plant.They recovered 10oz or so of fines every cleanup.most of them run the easiest most productive gravel to keep their business operating.sure there is more gold there,but they aren't going to go bankrupt chasing 7-12% when they can recover 88-93% with ease. With bedrock not being flat i would like to see recovery figures of the bottom of the cut.i am willing to go over there if anyone has a lazy hundred grand laying around.Big scale mining has big scale running costs.Adjustable diffusers or mudflaps can create low pressure spots along a sluice causing gold to drop out as well as riffles.They also flatten out turbulence and help fine gold recovery.
. also wanted to add that all the owners of dredges are waiting to see if mr beets has good returns,as every tom dick and harry will be copying him.once a guy comes up with a good idea that no one else would try.The copycats will follow.better to be an innovator than a imitator.