Looking for Sulfides

GoldReport

Jr. Member
Oct 6, 2024
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Hello esteemed members of the board.

In my local area there are no commercial gold mines and never really have been. Through research, I came across an old State Geologist Report from the late 1800s. In it they mention that some gold was found alongside pyrite. At the time it was not of a high enough concentration that they were interested in it, but it has got me searching for this elusive deposit. I am located in the Northeast US where there is virtually no lode gold deposits to speak of. ( hardly any placer either :BangHead:)

I went out searching today to see if I could find this pyrite, I used a combination of the report I found with geologic maps to identify the units in question. The report describes the pyrite found at the contact of two distinct geologic units which only crop out in a few places that I have so far found. My first instinct is to locate places where streams have cut through this geologic contact and pan samples downstream of that. I would have done that today but underestimated how big of a drop I was facing and ran out of sunlight before I could find a good place in the stream where any material could build up. I was at the top of a series of short but steep water falls and only made it down about halfway before dusk started to set in.

The question I have for you all today: is there is a good way to locate sulfides/pyrite in the ground other than just visual examination?


The rock around here is quite mossy and full of lichen. I suppose I could take my wire brush and clean off any outcrops I suspect would be good but that seems inefficient and time consuming. While hiking today I saw samples on the ground with good iron staining (in a shale rock which doesn't seem quite normal to me) but seeing iron staining around here doesn't make me feel any better as there is considerable magnetite all over, I live within 5 miles of a handful of old workings.

Any tips?

I plan to keep searching but am not extremely confident for a couple reasons: around the time of this geologist report there were many scams of people finding gold so the information is unreliable at best, and if there was any decent gold to be found I think someone would have already done so given the lack of other gold deposits. I don't have a metal detector and it's not in the budget to buy one at the moment.

Will update as the hunt continues...
Thanks!
 

Upvote 1
If you don't find any free gold what do you do? Just roast your crushed material for a couple hours? I imagine I will be in the same boat
If they have any sulfides, I’ve been keeping them in a jar until I am motivated enough to learn to smelt.
I have no real experience with hard rock stuff. I just enjoy a good excuse to climb up mountains and bring home rocks 🤓
 

around the time of this geologist report there were many scams of people finding gold so the information is unreliable at best, and if there was any decent gold to be found I think someone would have already done so given the lack of other gold deposits.
I saw a very similar trend around here (Washington state) where the report from the 1800’s were boasting of insane values. But then you find the more recent reports and read the vein actually contained about 10% of that. Plus the fact that no one else reopened them after the Revoked Order L-208 that banned gold mining.

But aren’t those old reports so fascinating to read? I get so excited when I find a new one to read
 

I saw a very similar trend around here (Washington state) where the report from the 1800’s were boasting of insane values. But then you find the more recent reports and read the vein actually contained about 10% of that. Plus the fact that no one else reopened them after the Revoked Order L-208 that banned gold mining.

But aren’t those old reports so fascinating to read? I get so excited when I find a new one to read
Yes I love reading the old reports and seeing what rocks people were interested in back in the day. They were certainly very thorough. Industry was much different back then, small mining operations were fairly commonplace across the region. One thing I find interesting is seeing how drastically the industrial revolution changed the landscape. Operations went from a couple hundred tons per year to tens of thousands in the span of a decade!

That and being in the mining industry is what got me interested in prospecting in the first place!
 

Yes I love reading the old reports and seeing what rocks people were interested in back in the day. They were certainly very thorough. Industry was much different back then, small mining operations were fairly commonplace across the region. One thing I find interesting is seeing how drastically the industrial revolution changed the landscape. Operations went from a couple hundred tons per year to tens of thousands in the span of a decade!

That and being in the mining industry is what got me interested in prospecting in the first place!
right? Went from making tunnels to making craters. The old stuff seemed like more of an art.

If you don’t mind me asking, what do you do in the industry?
 

right? Went from making tunnels to making craters. The old stuff seemed like more of an art.

If you don’t mind me asking, what do you do in the industry?
Former quarry manager, currently a mining engineer/project manager for an aggregates company. Not the most exciting side of the industry but at the end of the day mining is just moving dirt and rock!
 

Do you have some photos of the conglomerate formation that is next to bedrock?
Here's a couple pics at different points in the formation. Finding an outcrop at the actual contact has been challenging.

This is the underlying shale:
20241116_113318.jpg


This is what the conglomerate looks like:
20241013_140317.jpg


The conglomerate has lots of exposures since its quite erosionally resistant and forms a long ridge line. The base of it is quite hard to locate directly.
 

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Here's a couple pics at different points in the formation. Finding an outcrop at the actual contact has been challenging.

This is the underlying shale:
View attachment 2180323

This is what the conglomerate looks like:
View attachment 2180324

The conglomerate has lots of exposures since its quite erosionally resistant and forms a long ridge line. The base of it is quite hard to locate directly.
It will be quite a job to find either color or pyrites from what I see in the photos. Your idea of checking the near by streams for pyrites and colors may have a better outcome.
 

Just wanted to give a quick update to this thread. The samples I took didn't yield anything interesting after crushing and panning. So I decided to roast them over a campfire. When I did this I saw some red embers come and go, I roasted for about an hour until I didn't see any more red or glowing bits. I took that and panned it down. I found some black bits which I assume are residue steel from my crushing equipment. I also found some yellow flakes but I'm not convinced it's gold which makes me think it definitely isn't but curious if anyone has any other thoughts. Apologies in advance for the poor picture quality, its tough to get pictures through a loupe. I really don't want to spend the money on an assay, any other ways of identifying if gold is present?
20241201_214101.jpg
20241201_214055.jpg
20241201_214017.jpg
 

Just wanted to give a quick update to this thread. The samples I took didn't yield anything interesting after crushing and panning. So I decided to roast them over a campfire. When I did this I saw some red embers come and go, I roasted for about an hour until I didn't see any more red or glowing bits. I took that and panned it down. I found some black bits which I assume are residue steel from my crushing equipment. I also found some yellow flakes but I'm not convinced it's gold which makes me think it definitely isn't but curious if anyone has any other thoughts. Apologies in advance for the poor picture quality, its tough to get pictures through a loupe. I really don't want to spend the money on an assay, any other ways of identifying if gold is present? View attachment 2181511View attachment 2181513View attachment 2181514
The flakes are small. Maybe a hammer to flatten out?
 

They are very tiny, not sure how I should go about doing something like that
The black sands will shatter and the yellow will flatten out on the hammer surface (likely stick to the hammer or metal surface).
 

I'm guessing you have already tried some of this, but my process would be this.
Pick up all the little pieces of metal from the crushing process with a magnet.
Normally I would try grabbing it with some tweezers and give it a squeeze. If it's pyrite, it'll shatter. But it looks like your pieces are too small for that.
If I couldn't figure it out from that and I really wanted to know, I'd hit it with chemicals. I'd assume it's chalcopyrite based on the color, and try to use some nitric acid. If it dissolves, it's not gold. (disclaimer: I've never tried this before)
 

I'm guessing you have already tried some of this, but my process would be this.
Pick up all the little pieces of metal from the crushing process with a magnet.
Normally I would try grabbing it with some tweezers and give it a squeeze. If it's pyrite, it'll shatter. But it looks like your pieces are too small for that.
If I couldn't figure it out from that and I really wanted to know, I'd hit it with chemicals. I'd assume it's chalcopyrite based on the color, and try to use some nitric acid. If it dissolves, it's not gold. (disclaimer: I've never tried this before)
What you said about chalcopyrite sounds about right to me. Guess I didn't quite oxidize all the sulfides when I roasted. It also didn't quite behave how I would expect gold to, but it is quite small in size so I somewhat expected some weirdness. Cleaned it up a bit and let it dry. Here's another picture through my loupe, what I really need is a better way to take close ups haha.
20241202_221051.jpg
 

Can see it a lot better in that new photo.
So what's next? Going to take more samples of the same spot or a new one?
Both, when I have the time. I want to get a lot more material from that spot, I'm thinking 30 to 50 lbs. There's another area to check out that has some outcrops, only reason I haven't gone yet is the hike is longer and I need a full-ish day to do. I guess I will just dream about it for the next month or so :BangHead:
 

Both, when I have the time. I want to get a lot more material from that spot, I'm thinking 30 to 50 lbs. There's another area to check out that has some outcrops, only reason I haven't gone yet is the hike is longer and I need a full-ish day to do. I guess I will just dream about it for the next month or so :BangHead:
Sounds like a lot of work! especially carrying that 30-50lbs on a long hike. Wish you luck there. What are you using to crush that much? I'm only working with a tiny little guy that you could barely call a crusher. I can't do more than small hand samples.

1733346297314.png


The places I have been searching are all covered in snow, so I have to wait until July to get back at it.
 

Sounds like a lot of work! especially carrying that 30-50lbs on a long hike. Wish you luck there. What are you using to crush that much? I'm only working with a tiny little guy that you could barely call a crusher. I can't do more than small hand samples.

View attachment 2181913

The places I have been searching are all covered in snow, so I have to wait until July to get back at it.
So my crushing setup is super crude and homemade. First I break my rock down with a hammer/chisel to about 3 inch minus. From there I put my rocks into a coffee can and break them down to about 3/4 minus using a piece of rebar and a hammer. After that I throw whats left into my chain mill I built out of scrap wood, a pot, a cookie sheet, my angle grinder and whatever else I had sitting around. Processing 50 lbs will probably take me a couple hours but that's fine for me, I don't feel like buying something when I am yet to actually find any decent gold in the ground. 😂 I found the chain mill really speeds things up since most of the time I spent crushing was getting the fine stuff ground down.
 

So my crushing setup is super crude and homemade. First I break my rock down with a hammer/chisel to about 3 inch minus. From there I put my rocks into a coffee can and break them down to about 3/4 minus using a piece of rebar and a hammer. After that I throw whats left into my chain mill I built out of scrap wood, a pot, a cookie sheet, my angle grinder and whatever else I had sitting around. Processing 50 lbs will probably take me a couple hours but that's fine for me, I don't feel like buying something when I am yet to actually find any decent gold in the ground. 😂 I found the chain mill really speeds things up since most of the time I spent crushing was getting the fine stuff ground down.
Thats awesome!! You really MacGyver'd yourself a crusher! hahaha
I would love to do something like that, but I also know that after $200 in random materials, some bloody knuckles, and hours of frustration, it would result in me giving up and just purchasing a new unit.

But I agree, wait until ya find something worth it before spending the money.
 

Roasting the ore will make it a lot easier to crush. I heat the rock in a crucible placed in a furnace for about ten minutes. When it starts turning red let it cool then give it a whack if it's not already in bits. I'm still experimenting with small samples heat and time but so far it simplifies the testing cool crush and pan good luck.
 

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