Placer Claim Mined Out?

[desertgolddigger]

I belong to a local club that owns a claim. This club has had this claim for many years, and acquired it after the old timers had mined it previously, and others after they commercial outfits closed up.
I walked quite a bit of the 160 acre claim, and noted that just about every wash had been worked. Most of the surface nuggets has also been detected by those with gold detectors. In other words, this place has been picked over and over and over.
But I m a stubborn type of person, and I figured, just watching how people ram their puffer and blower drywashers, that some gold was just being blown through them. maybe not much, but some small stuff that never got a chance to settle behind the riffles.
I know many of you would never go to the effort of digging for three to four hours through the tailings in these washes. Again, I'm a bit stubborn, and anyway, I just wanted to have some fun locally, instead of driving 300 miles roundtrip to something that gives a little more for less effort.
I've spent the last three weeks, digging a few times a week along about 30 yards of wash, and have recovered just about a gram of gold. That might not seem like much, but I have only dug up 5 grams, not counting this one gram in almost 20 years out here drywashing in the desert of southern California.
As you would know, things always seem to go wrong. My gas powered blower motor decided it was time for the repair shop, and haven't heard from the shop in two weeks. So I purchased a WORX WG521 corded electric leaf blower to use with my Royal Large drywasher. I'm using a portable generator to provide the power. And it actually is working better than with my old gas powered blower. I have to run the blower on the lowest speed, or I just blow everything through the riffles. Results are very good, as I am getting gold specks so small that I will have to use the Blue bowl in order to recover them.
I'm not only getting a little gold, I'm having some fun, and I am getting a good workout. I've lost 10 pounds since I started. So things are going well.
I'm still digging test holes around the old time hard rock mines in the hope I will find where the gold has drifted downhill below these mines. So far just a couple specks here and there. I figure I just have to move laterally one way or the other before I get something better Of course, I' don't really know if the old timers stripped the hillsides. Even if they have, they apparently aren't as thorough as I am. I hope that I may be lucky and find a larger piece of gold that the old timers, previous placer miners, and detectorists have missed.
Hope everyone is having as much fun as I have been having.

 

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[southfork]

yes I agree on the retort's op. but "could" minuscule amounts of Mercury escape with the steam when heated ? and when cooled by the atmosphere would drop to the ground. I'm not sure if it will BUT if some greenie would come along and see what your doing and "assume" you were doing something illegal and assume you were on a claim and wanted to start trouble with these miners (which I believe is possible) then you would keep the BLM/ Forest Service or some other from ruining the day! It may not be a problem but I just thought it may stop any problems before it got rolling ! Rather be safe than sorry ! BUT then again this is just my way ! I'm not tring to ruffle anyone's feather's !

It's not cooled by the atmosphere it's cooled by water enclosed by the body of the retort and the capture jar is water filled. More mercury in the food you eat lol. I have a recirculating pump on my setup for extra cooling you can add ice but works as is.

 

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[russau]

southfork , thanks for the info ! Now I know !

 

[N-Lionberger]

Don’t mess with that potato method.

 

[desertgolddigger]

Hey All. Sorry to be a stranger. it is summer here, and has been miserably hot. I manage a couple hours puttering around the property each morning, either doing work on the grounds, or sluicing the the remains of 800 pounds of material that I put through the chain mill and sifters.

The sluicing has been very slow, as I have to keep the flows almost as low as you would see on a Miller Table. This allows me to capture gold as small as 800 mesh.

Today I finally finished my sluicing through the big and cleanup sluices. Total amalgam is 2.85 grams. The gold is mostly 500- mesh, but I did get some larger than 100 mesh.

I won't know how much gold is in that amalgam ball until I retort it. Since it is super fine gold, I'm guessing it takes more mercury, and I am hoping for a gram of gold. I know that it'll probably be less, and once I melt things, probably even less because of the impurities.

I need to get all the equipment ready for retorting it. I get to use the full face mask I purchased that has filters to protect me from any mercury vapors. First thing tomorrow morning I need to move my propane tank over to where I usually pound my gold ore into submission. That'll provide a three sided windbreak so the flame isn't dancing around, and can properly heat the retort metal pipe cap. Not sure how long this retorting process takes. Hopefully I can manage in a couple hours. Oh, and that three sided block wall, with dirtcrete base should contain an explosion, if I do something incorrectly. Hopefully, following the instructions that came with the retort will prevent such an occurrence.

Anyway, if all goes will with this small amalgam ball, I will follow it up with my 17 gram amalgam ball.

 

[N-Lionberger]

I’m not sure how you would create an actual explosion in a retort but I have heard of hell breaking loose by having the end actually go under water. Never seen it happen just have heard stories of water getting sucked up. I was taught to use a tube of cloth on the output that sits in the water . When my mining claim partner was a kid his dad ran a retort on the kitchen table. Use a piece of fine buckskin or a syringe with a cotton ball in it to squeeze the excess mercury out of your amalgam, it will speed up the retorting. The retorted amalgam makes this interesting spongey mass of the fines it’s pretty cool looking.

 

[southfork]

With the cloth vapor brake, you add a measure of safety. I have a recirculating pump on my setup I doubt the cooling chamber would get hot enough to thermosyphon but why take a chance. I polished the inside of the pipe cap chamber a little to ease up on the sponge sticking because of impurities and rough casting. I spray rattle can graphite in the cap to help seal and it lets the sponge pop out with the help of a screwdriver blade. Be careful of what you seal the chamber with, or it might be a problem to open. Let your retort get good and hot the mercury vapor stops and starts just watch the collection jar. After it cools tip the retort and tap it a little sometimes a little mercury gets trapped you might see a little drop into the collection jar. Have fun it's easy and effective my first run to test I just added water to the pipe cap chamber. And just watched the steam to test the welding it looked a little rough but was ok.

 

[desertgolddigger]

I have a retort with recirculating cooling. I'm going to try graphite powder to seal the pipe cap threads, as suggested by a forum member.

I guess you're saying that even though the retort removed mercury from the amalgam ball, some may still be trapped. I'll keep the gold sponge in a small jar with water until I decided to try melting it in my mini furnace.

 

[southfork]

I have a retort with recirculating cooling. I'm going to try graphite powder to seal the pipe cap threads, as suggested by a forum member.

I guess you're saying that even though the retort removed mercury from the amalgam ball, some may still be trapped. I'll keep the gold sponge in a small jar with water until I decided to try melting it in my mini furnace.

The mercury gets trapped in the retort and a little in the sponge sometimes.

 

[desertgolddigger]

I just about goofed on determining what amount of gold I would get from 800 pounds of low grade ore from my clubs claim old timer vertical shaft waste pile.

I'd forgotten to rerun the cleanup sluice tailings. Those tailings amounted to 0.7 grams when added to the current amalgam ball. The ball weighed in at 3.45 grams.

I went ahead and squeezed the heck out of that ball through a shammy until all I had left was a crumbly mass. Weight is now 2.968 grams.

Now I need to set up the retort, and recover the mercury. I'm hoping to do this early in the morning. Need to move everything needed to my rock pounding pad tomorrow morning, and try setting things up for a test.

 

[desertgolddigger]

I finally got my retorting Paraphernalia out and discovered I don't have a 120 volt water pump. So I will need to order a small one before I can so any retorting.

I've been concerned with the gold sponge sticking to my metal pipe cap, so I read a little online. It seems you can prepare your pipe cap by melting borax to coat the inside, which apparently helps prevent gold from sticking. I'll get that done while waiting on my water pump.

I need to do a bit more reading before I attempt my first retort, but it shouldn't be too difficult once I get everything set up and in order inside my pea brain. :-)

 

[southfork]

I finally got my retorting Paraphernalia out and discovered I don't have a 120 volt water pump. So I will need to order a small one before I can so any retorting.

I've been concerned with the gold sponge sticking to my metal pipe cap, so I read a little online. It seems you can prepare your pipe cap by melting borax to coat the inside, which apparently helps prevent gold from sticking. I'll get that done while waiting on my water pump.

I need to do a bit more reading before I attempt my first retort, but it shouldn't be too difficult once I get everything set up and in order inside my pea brain. :-)

I said it before that the cap most likely needs a little grinding inside to remove casting ridges. Before coating with Borax or Graphite.

 

[desertgolddigger]

I said it before that the cap most likely needs a little grinding inside to remove casting ridges. Before coating with Borax or Graphite.

I don't have an tool for grinding in small spaces. I'll just need to ensure I do Things carefully. I do have a tiny crucible that will fit inside the cap. Maybe I just need to coat that with borax.

 

[southfork]

I don't have an tool for grinding in small spaces. I'll just need to ensure I do Things carefully. I do have a tiny crucible that will fit inside the cap. Maybe I just need to coat that with borax.

That will work but will take a little longer to get up to temperature.

 

[ConceptualizedNetherlandr]

I don't have an tool for grinding in small spaces. I'll just need to ensure I do Things carefully. I do have a tiny crucible that will fit inside the cap. Maybe I just need to coat that with borax.

Dremel is your friend

 

[ConceptualizedNetherlandr]

I have never retorted. So bear with me.

If you weigh your Hg first when it is pure, then you can weigh it later to know how much is added.

If we know what the limiting concentration is we will also know when out ball is 'full' or nearly so, right?

Besides Au, what else would the Hg absorb? Could it pull plated gold off items?

 

[desertgolddigger]

I have never retorted. So bear with me.

If you weigh your Hg first when it is pure, then you can weigh it later to know how much is added.

If we know what the limiting concentration is we will also know when out ball is 'full' or nearly so, right?

Besides Au, what else would the Hg absorb? Could it pull plated gold off items?

Yes, I did do that this week. Weighed out 1 gram of mercury, and then added the gold I sluiced until the amalgam ball started failing to pick up the 500 minus mesh gold. The one gram ball was 1.2 grams. so I'm guessing that I'll only get 1/5th of the weight in gold. Kind of disappointing for all the work I've been through collecting 300 minus mesh gold this summer. Well, it's better than I was getting several years ago when I first started.

 

[ConceptualizedNetherlandr]

Yes, I did do that this week. Weighed out 1 gram of mercury, and then added the gold I sluiced until the amalgam ball started failing to pick up the 500 minus mesh gold. The one gram ball was 1.2 grams. so I'm guessing that I'll only get 1/5th of the weight in gold. Kind of disappointing for all the work I've been through collecting 300 minus mesh gold this summer. Well, it's better than I was getting several years ago when I first started.

By your numbers you should get 0.2g Au, being 1/6th...

 

[desertgolddigger]

By your numbers you should get 0.2g Au, being 1/6th...

Yeah, I know I goofed on the math yesterday. Just figured it's close enough for government work.

 

[N-Lionberger]

From what I remember of retorting you line the cup with paper and the resulting ash layer prevents sticking. In my foundry work we put cardboard under the crucible so it doesn’t get stuck to the furnace floor. I looked at my literature it says to use a couple layers of newspaper, or to paint the interior with a graphite/water or chalk/ water solution and allow it to air dry before firing. I wouldn’t use Borax, sounds like trouble concerning it’s fluxing nature when heated.

 

[desertgolddigger]

From what I remember of retorting you line the cup with paper and the resulting ash layer prevents sticking. In my foundry work we put cardboard under the crucible so it doesn’t get stuck to the furnace floor. I looked at my literature it says to use a couple layers of newspaper, or to paint the interior with a graphite/water or chalk/ water solution and allow it to air dry before firing. I wouldn’t use Borax, sounds like trouble concerning it’s fluxing nature when heated.

Thanks for the great suggestion. I'll definitely give that a try. The worst that could happen is I will need to pry the gold out of the pipe cap.