I would think it would get plugged up .But as is said you never know until someone has tried it .If you do let us know how it works .

I have a hopper with a 12 volt vibrator on it. I works real good with dry but may have issues with wet. Having the addition of a spray bar would do the trick though.

My preferred way in a good strong running area... Shovel straight in. 

  

If you curious how well it catches the gold then:

 

 

A buddy made me a screen that fits over the top of the flare of my sluice. He picked up angled aluminum from home depot and made a frame that fits just inside the flare with the angle part going over top of the edge of the flare. He then made a second frame and laid it over top of the first one. Then he put wire mesh in between the frames and used screws and nuts to hold it all together. At the same time the screws and nuts hold onto the outside edge of the flare and hold it in place. So I just shovel directly onto the screen and it classifies for me. Just a thought. Cost about $10 he said and 30 minutes to build.

I used my drywasher classifier a little to fill buckets. It works great on the river bank. I didn't try it with water though. I think it would work if I didn't overfill it and shoveled water to splash it down. I like the Idea of retrofitting a built in classifying system! You got the wheels turning in my head now!