Sulphide Question

[Goldwasher]

Say you had a bunch of sulphides. Like literally sulphides only. With a mix of oxides (hematite)

No Gangue. Just cubes of pyrite and lumps of hematite. A lot of them and I have read local reports of rich sulfide ore.

I can bring a pound home a day or more if I want. Like I said not in ore. Segregated free minerals.

I'm not really interested in roasting. I know of the patio method but have only read a brief description of it. I need help with what to do after.
Though considering what I have is essentially "free milling" I don't know if that's even the right way to go about it.

I'm interested in what Mad Machinist and Clay have to say.

I DO NOT WANT TO HEAR ABOUT SURVEYS

It's dark I will post some pics of the pieces I have actually kept tomorrow. I got a couple today that are oxidized differently than the ones I get most of the time, silvery and rough on the outside. I grab the unique ones when I see them in the pan while chasing the heavy line in the creek.
When I'm sluicing the run gets loaded with them.
I met a geologist lady who likes the cool cube on cube pieces and I hold on to the big hematite nuggets cause their cool.

I've thought about crushing and sending some samples in for assay but, I figure I'll just get several different results and still be a guy who has pounds of sulphides.

 

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[Mad Machinist]

Some of those are probably worth more as specimens that they are for gold.

I'll need to refresh my memory on the patio method.

 

[Mad Machinist]

If your thinking of using the mercury method, I won't recommend it.

 

[Goldwasher]

Patio method is a Spanish method of letting bio bugs do the job of conversion...kiddie pool+H2O+some fertilizer +your ore

I get it about the specemins...though there are local reports of very rich sulfide ore. LIKE RICH I don't how much secondary enrichment came into play.

I am in pocket and shear zone country. Yet, deeper mines are not as common as they are in the Mother Lode south of me.

I will try to find links to reference but, I have read on paper reports of gold in sulfides per pound that you wouldn't believe with out reading yourself.

 

[Assembler]

Hello
Assaying:
Iron in the form of nails and wire is used in the assay of sulphide ores. It forms iron sulphide with the sulphur, which is dissolved by the slag, if only a moderate quantity is present. A large quantity will form a separate layer of matte.

 

[Clay Diggins]

Patio process is for Silver. It has nothing to do with bio bugs. Patio process uses water, salt, Mercury and copper sulfate. It won't do a thing to gold sulfides. Gold bound in sulfides is not free milling so grinding or amalgamation alone won't recover the gold values. If there is free gold in your ore grinding and Mercury amalgamation might work although it's rarely so straightforward as that.

Generally for small batch processing roasting the ground ore is most efficient. With a bunch of pyrite you are going to be dealing with large quantities of free sulfur so roasting in your neighborhood or near humans is pretty much not going to happen. There are other alternatives but those will still have some pretty interesting slime disposal and chemical recovery problems themselves. In any process you use you will need to reduce the ore to a fine grind (-100).

All this is putting the cart before the horse. If there are gold values locked up in the sulfides you need to first determine if it's even worth processing. Get a fire assay, XRF is worthless for ore assays. If the results are encouraging (greater than 1 oz per ton) you next need to get a grip on the sulfide chemistry. A fire assay will tell you a lot about what is in the ore but it won't tell you what type of chemical associations are involved. The assayer themself might be able to give you some clues too. A lot of minerals get boiled off in an assay and sometimes an experienced assayer can tell you a lot about the nature of your ore.

Try a small batch cyanide process on a few pounds of grind. Try a Chlorine, Iodine or other halide process on the same. Compare the results to the total gold found in the fire assay. If you are getting 80% or better recovery you might have found a process you can do on your own. If it's anything less you have the typical mining complex reaction problems to sort out.

Here's a good article explaining some of the issues you will find with small batch processing. Another possibility is to research for articles on how similar ores were processed in your area. Often that research will lead you to a good explanation why the ore is still there.

I hope that helps.

Heavy Pans

 

[Goldwasher]

Hmmm thanks very much Clay

The reason I thought it worked for gold is because Chris Ralph mentions it in Fists Full of Gold.
Chrushed ore some wetness and a booster of fertilizer from what I remember the book isn't in front of me right now.

Also when its crystals or lumps is it still considered ore?

 

[Goldwasher]

Obviously several lumps of hematite.

But, I there are just thousands of crystals of the pyrite too.

I probably end up with several pounds a day when I'm sluicing

 

[SaltwaterServr]

Obviously several lumps of hematite.

But, I there are just thousands of crystals of the pyrite too.

I probably end up with several pounds a day when I'm sluicing

Some of that, especially the large piece on the left, looks like iron slag from previous smelting. The piece to the upper left with the crystal in it looks more like a limonite pseudomorph after pyrite.

Hmmm thanks very much Clay

The reason I thought it worked for gold is because Chris Ralph mentions it in Fists Full of Gold.
Chrushed ore some wetness and a booster of fertilizer from what I remember the book isn't in front of me right now.

Also when its crystals or lumps is it still considered ore?

Any rock with values in it is considered ore. Any barren rock is gangue. Pretty simple.

Clay is on the mark, patio process is designed to pull silver out alone. I've come across it on several texts that discussed the historical developments of mining in the Americas. Where some authors get confused is that you had old reports going back to Spain about gold being pulled out during the patio process. Since there was mercury involved, it too would pull gold out of the crushed ore that the mine management was not aware of.

 

[Twobrothers]

Hmmm thanks very much Clay

The reason I thought it worked for gold is because Chris Ralph mentions it in Fists Full of Gold.
Chrushed ore some wetness and a booster of fertilizer from what I remember the book isn't in front of me right now.

Also when its crystals or lumps is it still considered ore?

The right bacteria, moisture, warmth, and a little nitrate will speed up the natural oxidation process. Looks like the material in your picture is already oxidized. Have to grind it up to see if it's oxidized all the way through.

You've basically got three options for dealing with sulfides:
Work with natural oxidative processes (atmospheric and bacterial oxidation)
Roast (heat)
Chemical (Hydrogen peroxide or other chemical oxidizer)

Gotta do the research and figure out what works from a personal experience/ safety and ore standpoint.

 

[Assembler]

If all the sulphur has been burned out ("dead" roasted), and the iron is oxidized to sesquioxide, it needs the reducing agent prescribed (can vary). If not all the sulphur is burned out, the ore may still have a reducing power; and the addition of a reducing agent may bring down too large a button.
When the percentage of sulphur is very high, add an equal weight of silica to the ore before roasting, which will help to prevent the ore from agglomerating. Take the amount of silica added into consideration in fluxing the ore (cost / time).

 

[Assembler]

If all the sulphur has been burned out ("dead" roasted), and the iron is oxidized to sesquioxide, it needs the reducing agent prescribed (can vary). If not all the sulphur is burned out, the ore may still have a reducing power; and the addition of a reducing agent may bring down too large a button.
When the percentage of sulphur is very high, add an equal weight of silica to the ore before roasting, which will help to prevent the ore from agglomerating. Take the amount of silica added into consideration in fluxing the ore (cost / time).

Potassium Cyanide, KCN, is a strong reducing and desulphurizing agent. It combines with oxygen, forming cyanate. Potassium cyanide is extremely poisonous.

 

[Goldwasher]

Not slag machinist I promise.

None of it is oxidized in the interior. If I crush any of the pyrite pieces they are brassy or silvery on the inside. Some more than others. Any oxidization is from being in the stream bed. These are all found while placering.

I've done all the tests to verify what they are.

Is it considered Limonite if it is only surface oxidization?

 

[Assembler]

Slags

Slags are usually made silicates, which are made up of a basic oxide, as sodium oxide, lead oxide, lime, or baryta, combined with silica, which is acid in character.
The fusibility of a slag depends on the character of the bases, and on the percentage of silica it contains. The silicates of lime and alumina are the least fusible.

 

[Goldwasher]

Some seems to be Ilmenite as well

 

[Twobrothers]

Not slag machinist I promise.

None of it is oxidized in the interior. If I crush any of the pyrite pieces they are brassy or silvery on the inside. Some more than others. Any oxidization is from being in the stream bed. These are all found while placering.

I've done all the tests to verify what they are.

Is it considered Limonite if it is only surface oxidization?

Limonite is a group of hydrated iron minerals that are often left over after the natural oxidation of the sulfur in iron pyrites. In my experience the minerals after pyrites are a spectrum. Local geologic and environmental factors influence what forms. Minerals morph and change over time w exposure. You got your limonites: hydrates and hydroxides of iron oxides. Usually yellowish spectrum/ crumbly friable. You got your straight oxides reddish sometimes hard layer forming, sometimes chalky. Then you get your "bog" irons form after prolonged exposure and leaching. Geothite. Just cause it's called big iron doesn't mean it formed in a swamp. Just lots of it found in those kinds of places historically. Suspect that's what's forming on the outer layers of the "slaggy" pieces.

 

[Assembler]

Fusible silicates that form Slags.

The most fusible silicates are those of lead, potassium, and sodium, after which come iron and copper.

 

[Goldwasher]

fellas...I really do appreciate the info.

Promise I'm not trying to discount any of the help.

Though some comments are not helpful at all!! We know who I am referring to.

I think I have some Ilmenite: An ore of titanium | Uses and Properties

and Limonite Limonite: an iron oxide used as pigment and iron ore

plus hemetite

I agree with Madmachinist that they seem to be Limonite pseudomorph after pyrite. Though the streak and Hardness are more pyrite-ish and the spec. gravity seems higher. Also the interior hasn't fully converted if at all.

I'm right on top of a contact of the Mariposa formation and the Calveras formation with exposures and there fore contacts with Diabase & Hornblende porphyrite ,serpentine-pyroxenite-peridote , amphiabolite schist.

Probably other intrusive igneous rock

The high res geo maps shows them all locally, my feet and eyes on the ground have found them all in the drainage.

Silver and platinum have been reported locally in reports. I have a few multi grain platinum pieces I have recovered sluicing and sniping.

Clay knows where I am working

I am not in the mood to start a new tract of recovery though I am going to start stockpiling all the heavy minerals end up with in my sluices and will have some assays done.

General season starts Saturday this spot is a water source for critters right now, once I drop my buck I'll be running a pump. Until then I don't want to make too much noise in this spot plus I'm pulling enough color and have enough rocks to move and cracks to clean at the moment.

Again Mad, Clay, Two brothers thanks for the help and tagging along.

 

[Goldwasher]

I'm after other chunkies right now...and have rock to move.
Heading out soon.

Notice the Black pieces.....I don't think it's manganese oxide coating. I'll hit it with a torch and acid later and see if the color goes away

 

[Goldwasher]

Hers some slag I have found though it was from a silver mining area in the Inyo Mountains. They did much more smelting there than was ever done in this area.