The 300G copper nugget i found it dredging with the same sluice box.. Found it in the gold pan.
But we ran a test running the nugget first then dredging as usual but when we went to the sluice box it was gone. .
A sluice box need to be made to trap everything that is metal. Specially heavy items atleast..
Ima test these taller riffles to see if i could get it to work properly.