Here are a couple of posts from Goldprospectingforum.com (Goldhog's forum) of an actual user of this system. Since mostly only gold is caught at the various stages of screening no further panning is required.
CdnSilverback
Post subject: Re: clarifying micro gold
We made a bar mill using an old electric cement mixer. After the cons have been run on the table. we collect the blacks. Once the season is over, we run the collected blacks at a rate of about 2 pounds to an equal amount of water for about 7 minutes. Th gold "flattens out" and anything else powders down. We then run this through a series of screens... down to 400 sometimes... the gold is then caught by the screens. Works well for us!
CdnSilverback
Post subject: Re: clarifying micro gold
We started with a 8" inside diameter, 1/2" steel pipe. Welded a plate at one end and then welded a connector to that plate for the cement mixer shaft. The top end we put a plate with a half turn lock on it as a cover. The rods inside are varying sizes... 3/8", 1/2", 5/8" and 3/4"... each about 1/2" shorter than the inside of the mill so that they can not jam while turning.
We place about 2 pounds of black sand collected from the vibrating table along with about 2 cups of water in the mill and run the unit for about 7 minutes. This slurry is then poured through a 100 screen. The "flattened" gold stays on the screen. What goes through the screen is collected.
This collected material is put back into the mill and run for 3 minutes. Again, this milled material is then screened through a 200 screen to collect the gold.
This is done over again a third time... using a 300 screen.. then a 400... and if you like... even smaller screens.
The principle of the whole operation is that the hard materials will mill to smaller and smaller sizing... while the gold will "spread" due to its malleability. This spreading is what makes it larger than the screen being used... thereby being rescued from the sands.
We even get sands from the local gold shack that cleans other people's gold.
We seem to average about 1.5 grams per 2 pound run through.
Gavin and I talked a lot about this at the Geoconference in Whitehorse. From what I gather, there are a lot of those being made this year up here!
From these references and from the articles then I like this system much better than a blue bowl or miller table! I don't think my usual gold production would justify the expense though.
