I've been working with that foamy batch of the -70 magnetics today and let me tell ya guys, you want to talk about messy to work with? This stuff is almost as bad as that powdered graphite lock lube! You just touch it and your fingers are black as the ace of spades! It pretty much looks like black talcum powder. I did a dry cleanout with one of my magnets and got everything out I could and then slapped the remainder under the scope. Yup! There be some gold in there! There is no way that I'd catch it even with a 100 mesh screen though. I'll attempt to get some pics of it a bit later as a couple of the pieces are really nice looking even if they're almost invisible to the naked eye.
As this batch was all -70 magnetics, I didn't expect there to be very much gold in them and I was right. While the milling did free the gold up and flatten tit out, they're still very tiny. I feel sure that when I move up in size the I'll find more gold and it MIGHT even flatten out enough to be caught in a classifier. Though I had hoped to be able to get away from doing a Mercury amalgamation, if I want to get all the gold in that fine stuff out of the smaller mesh cons I'm going to have to keep doing it or spend forever panning it out.
While I was cleaning out that last batch, I ran another batch of -20/+50 magnetics so I can get an idea of what is in them. I only ran it for an hour ( I know the dadburn PDF said 15 minutes!) and I've yet to open the barrel. I used all the rods, a 1/2 cup of sands and a 1/2 cup of DiHydrogenMonOxide. I didn't have the same problems with the barrel that I had on the last batch and am kind of at a loss as to why that last one was so screwy on the drive. I suspect that it was more to do with the mesh size of the materials than anything else. They just didn't want to start flowing in the barrel or something like that. Tomorrow I'll dump it out, classify it down, and see how well it did. I've also got to finish running samples from two different sites that I'm testing to see if they might be worth filing a claim on so I'm going to be working harder than a one legged man in a butt kicking contest. Jan has started her internship (at the V.A.) so she's not going to be around to help OR hinder. This is the last step she has to complete to finish up her Masters Degree so needless to say I'm all for it. Kind of nice to be with a lady that are a college edumacated woman.
As long as you are experimenting and since you do not have classifiers smaller than 100 mesh you might want to try the method Goodguy offered up. See below.
"Quote Originally Posted by Goodyguy View Post
You guys may also want to try a process utilizing Oleophilic Adhesion. I learned this technique from a fellow prospector that I met at one of my favorite gold bearing creeks.
It's a very simple cheap, fast and fun way to recover fine and micro sized gold from your -30 and smaller concentrates.
Simply smear a thin smooth layer of petroleum jelly (Vaseline) onto a flat smooth slick plate.
Hold the slick plate under water in a tub or if in the creek with a safety pan underneath it and shake the slick plate back and forth while pouring your wet concentrate through a sieve above it.
The gangue will not stick to the petroleum jelly however the gold will stick due to its oleophilic nature.
To remove the gold imbedded jelly from the slick plate use a body filler spreader to swipe off the petroleum jelly and then swipe off the spreader into a small jar.
To recover the gold from the jelly just use charcoal lighter fluid in the jar and shake it to dissolve the petroleum jelly. Simple as that!
The prospector I met was using this technique at the creek and my curiosity got the best of me so I had to ask what he was doing. Turns out he is a contributing writer for ICMJ's Prospecting and Mining Journal along with other publications. His name is Alex Dolbeare and the ICMJ issue that this technique was featured in detail was Volume 83 Number 8 April 2014
Go for the Gold
GG~"
I did a crude test with some ocean beach concentrate, all minus 100 mesh and the gold down to much smaller. The cons were probably 80 to 90% magnetic black sand. It caught gold and shed virtually everything else. Might be an option to process your powdered material (I would dry it first to make feeding easier).
Congratulations to your wife and good luck to both of you.
someone else may benefit from seeing my trial and error with black sands. Plus it will keep me busy while I'm patiently waiting for spring
especially the S cal part....
It's OK, I like the game. 
