Whoa john,i,m gettin depressed when i see the beautyful sites you guys have overthere and then look out of my window,all i see is concrete and autumn is there,i have to stop diving because i have no hws ,not allowed cause that would involve a motor,also my best sites are 5 hours away with the car,so even a weekend trip becomes problematic with the days getting shorter and shorter.I could go to nearer places but the more gold theres is the more the laws are designed to keep the goldseekers away.Often pushed by fish and hunting departments,they want the sandbox for themselfs .But also from the communities.For example in switzerland all the communities can make their own rules about mining.The rule is ;the more gold there is to be found the moore restriction there are;for example,no motors, no mechanical,no ropes ,no winches,no sluice box over 4 feet or 6 feet,depending on communitie,not even goldpanning on sundays ,bank holydays and from sept.to may.These are worst areas,but with the biggest gold to be found.Also in these communities Ther are areas there where -with enviromental pretences-they forbidd also goldpanning now-but the same communities are evaluating to give permission to a big company for underground mining,involving mooving thousands of tons of material that would be brought to italy where with cyanide and stuff they would get the gold,where the cyanide waste goes after i don,t want to know.Immagine a comparison ,co,2 footprint or heavy metal/poisons usage study between a goldpanner or even dredger and a operation like this,like you said we remove the heavy metals from fishermen and hunters(,by the way i like to fishing too and would like hunting for shure).It shows what is happening all over the world-precautionally principle,dreamed up by some ecologists,maybe with a good intention.But to what does it lead?Big companys who can afford to make a enviromental impact study can avoid that "precautionally principles "are applyed to them,and for the small scalers...sorry.But enough of that negativ stuff-i thinked about over -under too,but having no throttle i,m afraid to not have enough water when working in places with just enough drop to run,so i applyed your KEEP IT SIMPLE AND STUPID rule.But-i made the sluice so its easyly convertable to a over and under or double classification if i should find a site with much gold and plenty of drop someday.For over and under a aluminum sheet on top of last section of classifiers over expanded,and a set of riffles above,for double classification a aluminum sheet on top of last section classifiers ,some half inch high riffles on the sheet and a half inch openings classifier on top of all. But really i don,t know if i will do it as it adds much weight to a already bulky set up.I did not test the sluice in a fine/flower gold (2000-3000 specs for a gram)creek i know yet,if it turns out to not hold the small stuff maybe i try it.One thing i do,nt know about over -under,should the under section be sealed airtight from classifier entry on,so it works like a gravity dredge hose sucking material from flow above? Thanks for the AU blessings john,wish also to you and some rain too.
I Like my 4" as ez to setup and for sampling absolutely great. Mine is a over/under classification to get the micro pieces as I AM greedy and want it all. Picture is the trinity river by Douglas City up here in extreme northern california,about 20' deep as pounds of lead from fishermen every 15 minutes so had to clean off the top layer sic sic sic-Hope ya have a grand time and find tons a au 2-John
