Crushed ore-microscope pictures-help please

[thesilverfox111]

I'm very new to hard rock prospecting and so far what I have been doing is just sending my samples in for assay but I would really like to get into trying to determine the gold values in my samples on my own if possible.

As I am waiting for my fire assay results to come back on the samples I sent in I decided to crush a sample up to look at under the microscope. The particle sizes in the pictures are from 50-400 minus mesh. I just did a rough crush with hammer.

After panning this one sample I didn't see any free gold but I'm curious about a couple of things..

1. From my microscope pictures which minerals can you guys identify? I realize there are pyrites there because of all of the cubic shapes but for me as a beginner it is very hard for me to tell the differences between chalcopyrite, iron pyrite, arsenopyrite etc. Any help you guys can give me would be great.

2. If there is gold value in the pyrite is it only possible to get it out by chemical or torch? Or can I crush it further into pulp to see if any gold that may be there will get freed up?

3. It seems that the finer the material gets like pulp the harder it is to pan it and if the gold is so tiny there can be more chance for floating out or gumming up with the other pulp and getting tossed out. If grinding it down to pulp is recommended then would the recovery process from there need to go to chemical leaching, torching, or table or jig separation?

4. Fire assays are of course a necessity but I have been keeping pieces from all of my samples I send in to practice my own gold recovery. Is this worth while or would a home built gold recovery set up never come close to getting as accurate of assay results as a professional laboratory can?

 

[thesilverfox111]

Here's a few more of the crushed ore microscope pictures

 

[rookieminer]

I'm far from an expert on mineral id, but the ones with the purplish color on them look like chalcopyrite to me. I would love to see what an expert has to say, just to see if I'm close.
There are also a couple that look like they could maybe be calaverite. You can do simple test for tellurides with sulfuric acid to see if you have any, it would be very good to know for assay and recovery purposes.

rookieminer

 

[Dr. Poe]

:mrgreen: Nickel, cobalt, iron arsenide, silver, gold, platinum group metals, they are all there. Definitely do fine grinding and fire assay. Dr. Poe 8)

 

[shaftsinkerawc]

Be sure your assay lab is aware that it is a sulphide (Refractory) ore.

 

[thesilverfox111]

Be sure your assay lab is aware that it is a sulphide (Refractory) ore.

Hey Shaftsinkerawc, thank you for the heads up. This stuff is so new to me so I have just recently been reading about the sulphides and how the ore has to be treated differently in order to get the gold from the sulphides.
The assay package the lab recommended to me was a GEO2 package which they describe as a group 1DX (aqua Regia/ICP-MS .5 grm) + Group 3B (fire geochem Au)
The assay's are getting done at ACME in Vancouver, BC. Their lab book description of this assay type says that this is a 36 element assay with Au and PGM's by fire Geochem..

So that is all french to me
Will the type of assay I am getting do a good job of getting the Au and PGM's from the sulphides or is a different type of assay needed? I don't think the lab has done the assays yet so I can call them on Monday morning to direct them to do a different assay type if needed.

Recommendations?

Thank you for your advice!

 

[shaftsinkerawc]

If you dealt with a good employee that knows what he's doing you should be fine. If you dealt with a new employee or someone that doesn't care, then they will let you pick the process and it may not be the right one. I would call and let them know that it is a sulphide/refractory ore and they will let you know if the process is right.

Do you have any pictures of your ore?
Is it a vein deposit crosscutting country rock or layered with it & How Big is it?
Crushing alone will not release Au from sulphides, an Autoclave is required. Have done professionally.
When you panned your crushed material, did you have a grey scum that floated on the water?
What's your magnification on the microscope?
Any weights on starting ore and final concentration sample?
What State are you in?
Use caution when crushing as the dust produced can be toxic.

Have fun and have a great day.

 

[thesilverfox111]

:mrgreen: Nickel, cobalt, iron arsenide, silver, gold, platinum group metals, they are all there. Definitely do fine grinding and fire assay. Dr. Poe 8)

Hey Dr. Poe nice to meet you and thank you very much for your comment on my post! I hope you are right!

If you dealt with a good employee that knows what he's doing you should be fine. If you dealt with a new employee or someone that doesn't care, then they will let you pick the process and it may not be the right one. I would call and let them know that it is a sulphide/refractory ore and they will let you know if the process is right.

Do you have any pictures of your ore?
Is it a vein deposit crosscutting country rock or layered with it & How Big is it?
Crushing alone will not release Au from sulphides, an Autoclave is required. Have done professionally.
When you panned your crushed material, did you have a grey scum that floated on the water?
What's your magnification on the microscope?
Any weights on starting ore and final concentration sample?
What State are you in?
Use caution when crushing as the dust produced can be toxic.

Have fun and have a great day.

Hey Shaftsinkerawc,
Yes I have lot's of pics of the ore. I'll post some up on this thread. I have sent in 22 samples from 3 different veins, in 3 different areas, not at all related to each other. I took several samples from each vein in different places along the exposed vein. One of the veins I uncovered a lot of overburden from it to follow it for a ways then took more samples from it farther along the vein.
One of the veins is very decomposed with lots and lots of sulphides colored orange, green, brown, black etc. The next one is a very plain milky white quartz vein with not much if any visible sulphides or minerals showing on the surface or on broken chip pieces to the naked eye. I haven't crushed the milky white quartz yet though to look at it under the microscope. Then the last vein I have sampled is more of a sedimentary looking and feeling ore. It is very brittle but in a different way than the first sulphide vein. It kind of turns to powder rock just by breaking with the hands. Like a sand like sedimentary ore with a lot of sulphide staining through it. It is the one that I crushed up and have the microscope pics of on this thread. The first vein I mentioned and the milky white one are both cross cutting country rock. The other more sedimentary one I mentioned I believe looks to me more like it is layered with the country rock because when I break off sections and chunks of it from the country rock it looks very layered. Not like a very defined quartz vein cross section but definitely layered looking.

Can you explain what those differences mean and the significance of either a cross cutting vein, or a layered vein? Sorry be patient with me I'm trying to learn this stuff. I have lots of patients and determination when it comes to prospecting and hiking/exploring through the mountains but I lack the scientific knowledge of how all of this works. But I think I'm learning

The first vein with lots of sulphides is approx 2 meters wide in some places that are exposed and it goes from approx 1 meter to 3 meters in a few places. It goes in to the mountain so I have no idea how long the vein runs for or if other stringers come in and out of it because the land where it is is quite hard to navigate in some places and because of it going into the mountain.
The milky white vein is much smaller. The biggest section I uncovered is around 12-14" thick and it has tons of little stringers of 1 to 4" running into or out of the other bigger one. This is the vein I had to uncover a lot of overburden from. It is in a creek canyon and runs across the creek along the bedrock then up the other side. One side of the canyon is solid country rock and the other is a shorter country rock to the creek level and is covered with soil, trees, etc. as the vein comes out of the creek, up the country rock and into the hill. Hope you get what I am describing..
Then the third one is near a lake. It is the sedimentary looking/feeling one. It runs right down from the mountain and into the lake. In the summer I snorkeled in the lake to look at the vein as it enters the lake. It goes down farther than I could swim down to see. And it travels up the rock along the lake then into the mountain. There has been a recent discovery of high value minerals very close to where this vein is. By very close I mean around 10 km's.

I crushed this ore sample on a concrete floor with a hammer and a towel covering the ore as I crushed it. Then I swept up the crushed material and panned it. In some of my micro pics there is about -50 mesh material that still has some quartz chunks in the the pics because I only rough panned it out. Then I later crushed a bit further and panned it more thoroughly removing almost all of the lighter weight quartz pieces and leaving just the sulphide, pyrite material in the pan. The further crushed material after panning passes through a 400 mesh screen. The pictures I took with the usb microscope of the panned material all range from around 500 to 720 x

Today I spent more time isolating smaller sections of the panned material to look at with the microscope and it amazes me how many mineral colors are in the pyrites. I see gold colors, brass colors, very shiny whitish silver colors, purples, blues, and blacks.
There are a lot of pieces that are so bright whitish silver that it reflects the light of the microscope like a mirror. Any idea what that mineral could be? I'm hoping a PGM but who knows? The fire assay will tell but the wait is nerve racking lol.
I can post more pics of the isolated silver minerals if you think it would help.

I am surprised at how heavy these sulphide minerals are. When panned even at 400 mesh they really hug the bottom and the riffle edges on the pan. I was thinking that the specific gravity of the pyrites should be from 4 to 6 somewhere from what I read so being that compared to the specific gravity of gold of 19 I would think the pyrite would want to leave the pan more readily. Hopefully this is a good sign that there are some heavier more valuable elements locked up in these pyrites.

There wasn't any grey floating scum on the water when I panned the material at all. What is the significance of a grey scum forming on the water surface?

I didn't weight the sample before and after crushing and panning it. I crushed it more to have a look at it under microscope; not thinking about doing it to find an assay value on the sample but I will do that next time for sure when I try to refine the sample further.

I'm in BC Canada.
I'll be sure to be careful with the fumes from the crushing. There has to be a significant amount of arsenopyrite in this sample I crushed because both when I heated it up in a pan to burn of the water from panning there was a smell of garlic and even more noticeable is the smell of garlic on my fingers after playing with the crushed material. I was reading about it and can't find where it says the crushed mineral will smell like garlic; only that the heated gas off will smell like garlic but I can say for 100% I haven't touched any garlic and my fingers smell very strong like it.
I hope this isn't a big health issue. I washed my hands very well now and won't be heating any more of it up in the house :shock:

I'll post up some pics of the ore I have now on my computer and I'll take some new ones of the chip samples from this one sample I crushed up also and post them up too.

 

[thesilverfox111]

Here's some pics of the ore's from the largest vein with the large amounts of sulphides

 

[thesilverfox111]

Please note: the ore samples I showed pics of in the post right above this one are not of the vein that I crushed and showed the microscope pics of and neither are these ore pics I'm showing in this post. These pics are from the other vein with the milky white quartz.

The next post will be pics of the actual ore that I crushed up and showed the microscope pics of..the third "sedimentary type" vein. Now I really confused things :roll:

 

[thesilverfox111]

Here's pics of the ore I crushed and the microscope pics are of.

 

[shaftsinkerawc]

Should # your photo's during photography to help with discussing them or post one series at a time or have individual thread for different ores.

I'm just sharing some observations, I'm not an expert.

Anyway the rusty/quartz (Largest Vein) looks well worth some investigation. Did you have any of the country rock surrounding this one assayed? Also if this shows no or low values currently it may still interest a Junior Exploration Co. that has access to a drill rig as veins pinch in & out and values vary along the vein and at depth. Lots of interest in VMS deposits. (Volcanogenic Massive Sulphide) If I understand it, you haven't taken any micro pictures of this ore?

Dark rock with qtz. laminations & cross-cut veins looks like a sedimentary rock that has been metamorphosed with squeezing and folding and also has the potential for VMS deposits. During metamorphosis the minerals can remobilize allowing the qtz. to layer out. Look for areas that may have been near the top of the fold during metamorphosis, also check the country rock to both sides. Check all juctions of veins with others. Looks like folding to me but it could be a shear zone as well and worth checking out. If this is a known gold producing area, where this one crosses the creek has the potential of a natural riffle for placer deposition and should be sampled on both sides. Is both sides of the creek the same looking country rock?

The sedimentary rocks you show could be part of a supergene secondary enrichment.

"There has been a recent discovery of high value minerals very close" Do you have any info that you are comfortable sharing about this? What mineral, what type deposit?

"pieces that are so bright whitish silver that it reflects the light of the microscope like a mirror" Make sure it's not just a crystal face/plane reflecting back at you.

The grey scum I mentioned is just something I seem to come up with when I crush sulphide ore. Do you pan into a container or running water?

Arsenic is poisonous so use PPE and don't do anything with it in the house or without ventilation.

 

[thesilverfox111]

Should # your photo's during photography to help with discussing them or post one series at a time or have individual thread for different ores.

I'm just sharing some observations, I'm not an expert.

Anyway the rusty/quartz (Largest Vein) looks well worth some investigation. Did you have any of the country rock surrounding this one assayed? Also if this shows no or low values currently it may still interest a Junior Exploration Co. that has access to a drill rig as veins pinch in & out and values vary along the vein and at depth. Lots of interest in VMS deposits. (Volcanogenic Massive Sulphide) If I understand it, you haven't taken any micro pictures of this ore?

Dark rock with qtz. laminations & cross-cut veins looks like a sedimentary rock that has been metamorphosed with squeezing and folding and also has the potential for VMS deposits. During metamorphosis the minerals can remobilize allowing the qtz. to layer out. Look for areas that may have been near the top of the fold during metamorphosis, also check the country rock to both sides. Check all juctions of veins with others. Looks like folding to me but it could be a shear zone as well and worth checking out. If this is a known gold producing area, where this one crosses the creek has the potential of a natural riffle for placer deposition and should be sampled on both sides. Is both sides of the creek the same looking country rock?

The sedimentary rocks you show could be part of a supergene secondary enrichment.

"There has been a recent discovery of high value minerals very close" Do you have any info that you are comfortable sharing about this? What mineral, what type deposit?

"pieces that are so bright whitish silver that it reflects the light of the microscope like a mirror" Make sure it's not just a crystal face/plane reflecting back at you.

The grey scum I mentioned is just something I seem to come up with when I crush sulphide ore. Do you pan into a container or running water?

Arsenic is poisonous so use PPE and don't do anything with it in the house or without ventilation.

Thank you very much for your replies Shaftsinkerawc. Sorry ya I realized that afterwards about not putting numbers on the photo's so we could reference them afterwards.

Yes I did take micro pics of the massive sulphide ore (largest vein) and actually my first post on this forum was asking for advice of knowledge of what kind of ore people thought it was and what minerals people could identify in the ore. But it wasn't crushed micro pics of the ore. I broke up a larger piece of the ore into smaller pieces then took micro pics of the surfaces of the broken pics. Here is the link to my first post about that ore of the bigger vein: http://goldrefiningforum.com/phpBB3/viewtopic.php?f=44&t=12123&p=119241#p119241
I have sent in samples of all of my ore from these veins for assay. I should have the results this week hopefully. I should crush up that ore from the first vein and take micro pics of the panned minerals in it also.
The reason I chose to crush the other ore from the sedimentary vein and take the micro pics of it is because it broke up very easily and the cracked surface looked so mineralized with all the pyrites etc. But you and a few others have told me that it's the other ore that looks promising so I will crush that up tomorrow and get some pics of it and update the other post of mine with the micro pics of the crushed material.

Great info on the layering/sedimentary deposits thank you!

The milky white quartz veins that cross the creek do come from an area that has both very small flour placer gold that I have found and in past history in the early 1900's has had a few hard rock mines which produced gold, silver, copper, etc.
I'm not prospecting that same creek but a tributary to it higher up in the mountain; but still in the same general area. I have also found a few pickers of placer gold in the creek as well while sniping the bedrock but mostly its very small flour gold. The placer pickers have quartz attached to them that I could only see when I looked at the pieces under microscope. So from what I understand that should mean is that those pickers didn't travel too far away from where the came off the hard rock. I took some samples out of this vein last year and sent them in for assay but that was my first attempt at taking a hard rock sample so I think I may have messed up and given in too much of the host country rock in with my sample of the quartz to get an actual good assay representation of the value of the minerals in the quartz vein itself. I have the assay results from that sample last year. It showed very small amounts of gold, silver, copper, zinc, etc..so I have sent another sample in of just the quartz itself with no country rock to see if I get a different assay result but the other issue is that the sample I sent in recently is from a different stringer vein than the first sample I sent in because the other one had a slide covering it when I went back this year to get another sample so I don't know how this will affect the assay. I will go back this spring to clear out some of the slide material (if possible) that is covering the original spot I got the sample from so that I know I will have the same vein spot to take a new sample with to compare assays with the original one.

As for the recent discovery of high value minerals in the area of both the larger massive sulphide vein and the sedimentary vein (the two veins are in different areas but still in the same "relative" area as the discovery but the larger vein is much closer than the sedimentary one.
When I read your question about what kinds of minerals were found I went back looking for the info I found on the discovery and spent a bunch more time looking for more info on any discoveries in the area. I found that there were actually three discoveries in the general area. Here is some of the text from a geologist report on one of the discoveries: (note that I have taken out some of the text for privacy) "...deposits in the ___ area have been classified as
volcanogenic massive sulphide deposits of the ___ type.
....mineral values are silver, gold, lead, copper and zinc. Mineral
zones are stratabound and somewhat distorted and disrupted by folding
and faulting and are commonly enclosed in distinctive alteration envelopes
of pyritization, sericitization and dolomitization. The ____ deposit
is essentially quartz-hosted, possibly including parts of a stockwork
feeder, ______ from massive to disseminated
sulphides in barite and/or silica gangue..."

Your descriptions of the ore/vein types sounds similar to some of the terminology the geologist used in their description of that discovery but who knows I know there can be a big difference from one vein to another even if they are in the same general area.

I have read reports of geologist doing surveys very close to where I am prospecting with some assay reports but they didn't have any high value reports to mention in their reports but I have speculation as to what means those geologist went to in order to gather their samples. Did they hike for hours and days around the mountains? Did they have gps back then when they did the reports or just compasses and contour maps? Did they break trails with chainsaws, machetes, and atv's? Or did they just hike the animal trails and get around in a 4 x 4 truck?
Those are the kind of thoughts that keep me going lol :idea: Gotta try and check things out or we will die wondering right?

As for the shiny/whitish mineral in the crushed material; I was thinking the same thing. Is it a reflection, or the light from the camera causing so much shine, etc. so I took pics at different angles, I shaded the material, I pushed it around on the plate so it caught different amounts of light etc. and the results were the same; very silver/white shiny material. And there are a lot of pieces of it in the sample crush.
The assay will tell me what elements are in my samples but will it tell me what sulphides are present that the elements were locked up in? If so that could help me learn a lot about identifying sulphides in the future and which ones can produce good or bad assay results.

I panned this sample into a container under running water so I caught everything that came out of the pan in case I want to look at it or crush it more after. There was a lot of gummy white/grey pulpy material that came out of the pan quickly but it wasn't floating.

Sorry about the long reply. I'm passionate about it and I can ramble.. :roll:

 

[shaftsinkerawc]

We should all be learning and I know I am, this is one way we learn. Discuss and listen and hopefully if we have it wrong someone will come along and inform us better.

"placer pickers have quartz attached" - Check for glacial activity in the area. They can move things a long ways.

The discussion on country rock was to have seperate assays of the country rock on each side and of the vein. Most do a channel sample first with small samples across a large area and then if it shows value will go back and sample individually to differentiate where the value is coming from.


I hope you have this area claimed up so you may be able to recoup your expenses if you have to sell to a Junior Exploration Co.
If a large area is open to staking having samples from around it are better to give a regional setting, keep good records(personal) of where each sample came from and if possible map it.

Old timers sampled surface and possibly some Adit samples(time consumptive). Newer Exploration likely has a core drill and sampling large areas.

I don't know how well funded you are but VMS is generally thought of as Big Boy Stuff. Might be worth you staking and then try and option to the guys near you.

Sounds like you're having fun so continue and be careful what you do.

 

[shaftsinkerawc]

Just read the other thread and you're doing the right thing. If the values are large then you can look at a rock and tell if it has value, but when it gets microscopic the best way is to get assays done and don't be afraid to have multiple assays of the same crushed rock to compare against each other. Just because an assay says you have high values does not mean it will be economical to recover, but well worth the hunt. Something else you can try is find a tile saw/rock saw and cut some slabs for viewing under your microscope.

 

[thesilverfox111]

We should all be learning and I know I am, this is one way we learn. Discuss and listen and hopefully if we have it wrong someone will come along and inform us better.

"placer pickers have quartz attached" - Check for glacial activity in the area. They can move things a long ways.

The discussion on country rock was to have seperate assays of the country rock on each side and of the vein. Most do a channel sample first with small samples across a large area and then if it shows value will go back and sample individually to differentiate where the value is coming from.


I hope you have this area claimed up so you may be able to recoup your expenses if you have to sell to a Junior Exploration Co.
If a large area is open to staking having samples from around it are better to give a regional setting, keep good records(personal) of where each sample came from and if possible map it.

Old timers sampled surface and possibly some Adit samples(time consumptive). Newer Exploration likely has a core drill and sampling large areas.

I don't know how well funded you are but VMS is generally thought of as Big Boy Stuff. Might be worth you staking and then try and option to the guys near you.

Sounds like you're having fun so continue and be careful what you do.

Just read the other thread and you're doing the right thing. If the values are large then you can look at a rock and tell if it has value, but when it gets microscopic the best way is to get assays done and don't be afraid to have multiple assays of the same crushed rock to compare against each other. Just because an assay says you have high values does not mean it will be economical to recover, but well worth the hunt. Something else you can try is find a tile saw/rock saw and cut some slabs for viewing under your microscope.

Thank you very much for your words of encouragement and all of the great information you took the time to share with me. It means a lot to me and has opened my eyes about a lot of things I didn't think about.

I called the assay lab this morning to make sure the assay I was getting would really concentrate on the sulphides in the ore and the guy at the lab said there was a "group 7" assay package choice that is a lot more sulphide specific so I got him to email me the info which I'm going to look at right now and if I get them to do that they are going to take longer with my samples (they already started assaying them he said) but at least it will be the exact kind of assay I need.

I'll update the threads when I get the assay results back.

All the best to you!

 

[Dr. Poe]

Your's isn't the only gold mine in your area, but it just might be the richest. If you don't get an assay of three digits per metric ton, send me a fifty gram or more sample and I'll do the assay right. Your ore isn't viable for gravity separation methods until you first crush it and leach the enormous amount of gold sulfides and minute particles of gold from it. Then and only then can you concentrate the residuals by gravity methods. Try first sodium ammonium thiosulfate with aeration @25C for 12.5 hours.
De-aerate before cementing the gold back onto steel wool pads. If you can't procure this chemical, then add flowers of sulfur to a solution of hot caustic soda and cook it into it for an hour @ 80C. This is yellow sodium poly-sulfide and will dissolve your sulfides of precious metals as well as the not so precious. Burn your pregnant steel wool pads prior to any more processing.
Then thank God for your good fortune. Dr. Poe

 

[AztekShine]

If your finding placer deposits with quarts attached .... You doing really good... Follow the yellow brick road!

 

[thesilverfox111]

Your's isn't the only gold mine in your area, but it just might be the richest. If you don't get an assay of three digits per metric ton, send me a fifty gram or more sample and I'll do the assay right. Your ore isn't viable for gravity separation methods until you first crush it and leach the enormous amount of gold sulfides and minute particles of gold from it. Then and only then can you concentrate the residuals by gravity methods. Try first sodium ammonium thiosulfate with aeration @25C for 12.5 hours.
De-aerate before cementing the gold back onto steel wool pads. If you can't procure this chemical, then add flowers of sulfur to a solution of hot caustic soda and cook it into it for an hour @ 80C. This is yellow sodium poly-sulfide and will dissolve your sulfides of precious metals as well as the not so precious. Burn your pregnant steel wool pads prior to any more processing.
Then thank God for your good fortune. Dr. Poe

Hey Dr. Poe thank you for taking the time to post your info on my thread! Well I have my assay reports back. I'm going to post them up here so please tell me what you think and everyone else please give me your opinions and advice on what you see in my assays. One group of samples in particular have decent values of silver, zinc, lead, and a bit of gold as well. Not sure if it would be an economical venture but let me know what you guys think please!

If your finding placer deposits with quarts attached .... You doing really good... Follow the yellow brick road!

Hi AztekShine nice to meet you! Well if you knew how bad the access was to the creek canyon drainage system where I have found a few pickers and some small flake gold when prospecting there you probably wouldn't be as excited for me as you are :lol: I have spent so much time in that canyon and not come out with very much placer gold to make it too worth while. I like the hard rock prospecting much better. After all with hard rock there is more opportunity to discover many different valuable elements than just gold. Rock hunting is more my cup of tea. A big issue though is the trouble that comes with getting injured while prospecting in remote areas. I had a close call with that this past year and it was very eye opening for me. I digress..

Here's my assay's please let me know what you all think. Thank you!

 

[thesilverfox111]

A couple more reports with the assay