Microscope mineralogy (Help)

[dkbinco]

Greetings to all, I have a fairly good Idea of the process I have been working on for a good while to leach with AR, I have studied Holks book and some chemistry. Thanks to all of you. Thank you. I respect all of you who are knowledgeable and help us all. I believe I have enough equipment and supplies to work with now. (funny) I bought a digital microscope to be more selective of ore I am going to crush, and mill down to 80um and spend chemicals on to process. HA! I am a backyard miner in central Co. and have several kinds of ore I am trying to pick out the best, but I have decided I don't know how to use this thing yet. I wanted to put a couple pics on here to see if anyone could maybe help me at all with what resolution or magnification that makes it best to identify raw ores or 80-100 um particles. No pickers or much free gold in this stuff. Well AU is what I am looking for. It is 1080P has 3 lens 18-720X, 1650-2040X, and 2760-4080X and 3X digital zoom. If anyone can help I appreciate it. I don't have a very good turn around on assay's 6-8 weeks, but a friend has a mine up here that helps me out with their lab and equip sometimes, I haven't found much worth while yet, but I am not going to die trying. anyhow I am trying to use this thing to pick out AU and I know there is pyrite, Iron, copper, not 100% if the chalcopyrite is encapsulating AU or if it's all a waste. This is mostly double refractory stuff I have, sulfide ores I guess. Up here is several telluride ores, calaverite and sylvanite mostly, there is fluorite in a lot of the rock but not seeing a large concentration of what I am looking for in it. Still and I know I have to roast at 600 C. and I have that covered too, someone told me to add a little silicon sand in the beginning cool and add some charcoal after to take cyanide out??? I will also put a pic of a couple of the raw ores, one I think is iron sulphide, and another that shows fluorite and what I think is pyrite. Help. This other rock I thought was fluorite, but now looks like maybe sodalite, but after I finally split it I am not sure. Its a 6-7 hard it weighs 48 oz. it shows a lot of microscopic metals in it, and it does not glow under UV light. Help, Sodalite is not supposed to have metals in it not even pyrite. Thanks to all, I know I ask a lot, I really am just a humble little student.

 

[goldshark]

The videos show what I believe to be either Chalcopyrite, or Bornite. The last 2 pictures look like typical CC ores, Phonolites with Fluorite . The metallic fleck looks like it could be Calaverite. Calaverite doesn't have the typical cubic or hexagonal shape of Iron pyrite. But pyrite cubes will break conchoidally, so the only way to really test is with an assay.
AR is great for metals reduced from sulfides, but should not be used on raw ore or rock.
Usually, you will not see very much Au on the surface of any rock, it is locked up in too many ways, chemically and in the matrix of the host rock. A technique of sawing the rock with either a lapidary saw, or a tile saw, will smear the Au a little, also leaving a smoother surface which the microscope can more readily focus on. Especially at higher resolutions. A rule of thumb is that if a sample has any easily visible Au, it will assay at least 1T oz. per ton. Tellurides take a while to get some experience with, as there are some sulfides associated with the unoxidized rock.
Pictures never photograph well, except for some of the good mineral specimen photographers out there, with the proper equipment, knowledge, and lighting. A skill unto its own.
Since security is tight at these mines, I doubt you are obtaining ore off the heap leach pile. So cyanide should not be present.
Roasting should be done in a calcining ( Oxygen present ) atmosphere. Carbon may help reduce the Calaverite to metal. This is done in a crucible after you have crushed the rock to a fine powder, and collected the free Calaverite crystals, mixed with the proper fluxes, etc.. To roast a piece of ore or rock in a bunch of carbon powder will not work very well. Probably the best way to roast ore, would be to do it in an old coal fired forge. This will allow the Carbon and Oxygen to reduce the Calaverite to metal beads on the ore sample. Have fun!

 

[dkbinco]

The videos show what I believe to be either Chalcopyrite, or Bornite. The last 2 pictures look like typical CC ores, Phonolites with Fluorite . The metallic fleck looks like it could be Calaverite. Calaverite doesn't have the typical cubic or hexagonal shape of Iron pyrite. But pyrite cubes will break conchoidally, so the only way to really test is with an assay.
AR is great for metals reduced from sulfides, but should not be used on raw ore or rock.
Usually, you will not see very much Au on the surface of any rock, it is locked up in too many ways, chemically and in the matrix of the host rock. A technique of sawing the rock with either a lapidary saw, or a tile saw, will smear the Au a little, also leaving a smoother surface which the microscope can more readily focus on. Especially at higher resolutions. A rule of thumb is that if a sample has any easily visible Au, it will assay at least 1T oz. per ton. Tellurides take a while to get some experience with, as there are some sulfides associated with the unoxidized rock.
Pictures never photograph well, except for some of the good mineral specimen photographers out there, with the proper equipment, knowledge, and lighting. A skill unto its own.
Since security is tight at these mines, I doubt you are obtaining ore off the heap leach pile. So cyanide should not be present.
Roasting should be done in a calcining ( Oxygen present ) atmosphere. Carbon may help reduce the Calaverite to metal. This is done in a crucible after you have crushed the rock to a fine powder, and collected the free Calaverite crystals, mixed with the proper fluxes, etc.. To roast a piece of ore or rock in a bunch of carbon powder will not work very well. Probably the best way to roast ore, would be to do it in an old coal fired forge. This will allow the Carbon and Oxygen to reduce the Calaverite to metal beads on the ore sample. Have fun!

Thanks G, I am still trying to take pics, when I do, this microscope jumps to videos and dosn't save pic. I will get better. I will slice samples and try on smooth surface, thank you. I crush samples to 100 um, but still not level on the microscope stage, by the way the only way I can roast is the crushed ore in a skillet with a 40,000 BTU stove with air blowing over it, I have a lazer that shows up to 2,300 C, I show at least 600 C, after blue smoke stops, cool down add 5% carbon and fire back up to burn it out. I cannot roast or do any calcining. I do not collect tailings or anything that might have cyanide, toxic enough as it is. HA! My process is leach the AU with AR and precipitate with SMB, or sulfamic acid, maybe detox nitric with urea or boil. I have done a couple small samples, Made some stannous with HCL and tin shot, It shows pregnant, but not strong (light brown), I hope I am doing the right things. No need to test these yet. I don't even want to waste an assay so far. I will work on the images, hope to talk again.
Thanks again

 

[goldshark]

Just wondering what the reference to cyanide is about. Mixing 5% carbon will help reduce the sulfides to metal. Most people will either have a sheet of steel, or a frying pan, with lots of surface area to the atmosphere. Heating is done from below, so you don't blow the fine concentrates away, by directing a torch, or other hot heat source over the top, such as you describe you are doing. Mix the Carbon in, heat from below, and stir or rake frequently. You should read Ms. Hoke, and assaying book in library, to better understand what you are trying to accomplish. There is much more then simple (relatively) refining to what you are doing. No no on Urea, read many posts why (every other refining question here is," why not use Urea ?" ). Don't mean to be snarky, but either spell check, or your lack of proper vocabulary sometimes turns your, and others into a comedic read.
As in DETOX nitric, in lieu of DENOX nitric. Its all good though.

 

[dkbinco]

Greetings again, Yes G thanks, I meant denox, and I probably watch too many U-Tube people. I will go back to Hokes book again. In CC they heap leach with cyanide and some stuff around there is contaminated. I tried a couple slices and some crushed rock with the microscope, still having trouble taking pics, but videos keep saving. Not sure what to call any of these anymore, I think you are right G, bornite looking, I lowered magnification way down and labeled a couple of those quartz and phonolite??? Look way different. I have a bunch of brass looking metals in a lot of ore, but I was curious about some of this stuff looking a little more yellow and not flashing when the light moves like mica and pyrite does. Still trying to find out about AU being encapsulated by anything in this stuff that I will be able to separate later (sorry I forgot the proper term) .The slices are cut from the previous rock I split. The image is a little better since it is a flat surface to look at and playing with the light. Thank you G...Well any comments will be appreciated.

 

[goldshark]

Actually, that is pretty good looking stuff. I hope you have a mountain of it.

 

[Yggdrasil]

Thanks G, I am still trying to take pics, when I do, this microscope jumps to videos and dosn't save pic. I will get better. I will slice samples and try on smooth surface, thank you. I crush samples to 100 um, but still not level on the microscope stage, by the way the only way I can roast is the crushed ore in a skillet with a 40,000 BTU stove with air blowing over it, I have a lazer that shows up to 2,300 C, I show at least 600 C, after blue smoke stops, cool down add 5% carbon and fire back up to burn it out. I cannot roast or do any calcining. I do not collect tailings or anything that might have cyanide, toxic enough as it is. HA! My process is leach the AU with AR and precipitate with SMB, or sulfamic acid, maybe detox nitric with urea or boil.
I hope you have made sure there are no toxic elements as Arsenic, Cadmium or Mercury before putting it into acid.
Sulfamic will convert excess Nitric and NOx to Sulfuric and such deNOx the acid, Urea almost the same with less effect and with possibility of creating explosive compounds.
I have done a couple small samples, Made some stannous with HCL and tin shot, It shows pregnant, but not strong (light brown),
Positive is purple in some shade all brown shades are some kind of contaminant, not positive, often called false positive.
I hope I am doing the right things. No need to test these yet. I don't even want to waste an assay so far.
Assays are cheap and will make sure you don't waste your time and money on a barren ore, it will also tell you if there are toxic elements as Arsenic Cadmium or Mercury in there.
I will work on the images, hope to talk again.
Thanks again

Comments in bold.

 

[stella polaris]

Looks like Chalcopyrite in my eyes.
You have at least some copper. Au often follows that in minor quantities.

Au "flash" even without direct light

 

[dkbinco]

Thanks to all, I am waiting on some insulation to use on this stove to keep heat directly on skillet from stove flames, too much flame is wrapping around outside of skillet. I will get another assay if this stuff looks like its AU positive, HA! This looks better to me than the last I sent, I have all the PPE and follow the advice here. Thank you, I am just sure that I need to roast anything I am getting here. I am learning and want to do things right. I tried the roasting and panning to see if any free gold would be released, but too small if any that I could see so if the ore I am finding has any AU I believe it will have to be leached,chlorinated out. I hope I do not sound ignorant, I have tried to study Hokes info and tried to research chemistry and methods. My stannous test did show a dark purple to darker in the past, but Some brown and some turns clear after a couple seconds. I have to do something. I have to do things outdoors and wind is still cold and blowing here, so if I am hearing right I will crush up 100 g or so of this rock I started slicing and the better looking phonolite stuff I have seperated here and send off for an assay to see all elements to be sure and safe. I have different ores from different places. I have researched rocks and ways they came about, the areas I am going to, and still learning. I do not think it is worthwhile for me to process ore that has a OPT of .05 or something, but I want to pick out the better stuff with microscope and assay's. I will ask my friend, but he double checks his lab at another place with a week turnaround for $35 so Better for me than others. Thanks for any help.

 

[dkbinco]

Actually, that is pretty good looking stuff. I hope you have a mountain of it.

Thanks G, I am still playing with microscope. Hope your not playing. I am going to send some for an assay so we will see. I have a better option now. I hope your right. Have a good day.

 

[goldshark]

After roasting, the Au will have a coating of either Iron Oxide or possibly some other compound. So it will not show up in a pan, all nice and Gold like. Now you have to put it in either a ball mill, or rock tumbler, to remove the outer coating. Try this technique next time, and see if the Au shows up. Probably so fine, most will float.

 

[goldshark]

Thanks to all, I am waiting on some insulation to use on this stove to keep heat directly on skillet from stove flames, too much flame is wrapping around outside of skillet. I will get another assay if this stuff looks like its AU positive, HA! This looks better to me than the last I sent, I have all the PPE and follow the advice here. Thank you, I am just sure that I need to roast anything I am getting here. I am learning and want to do things right. I tried the roasting and panning to see if any free gold would be released, but too small if any that I could see so if the ore I am finding has any AU I believe it will have to be leached,chlorinated out. I hope I do not sound ignorant, I have tried to study Hokes info and tried to research chemistry and methods. My stannous test did show a dark purple to darker in the past, but Some brown and some turns clear after a couple seconds. I have to do something. I have to do things outdoors and wind is still cold and blowing here, so if I am hearing right I will crush up 100 g or so of this rock I started slicing and the better looking phonolite stuff I have seperated here and send off for an assay to see all elements to be sure and safe. I have different ores from different places. I have researched rocks and ways they came about, the areas I am going to, and still learning. I do not think it is worthwhile for me to process ore that has a OPT of .05 or something, but I want to pick out the better stuff with microscope and assay's. I will ask my friend, but he double checks his lab at another place with a week turnaround for $35 so Better for me than others. Thanks for any help.

Maybe try turning the flame down a little. Don't restrict the air circulation while roasting.

 

[dkbinco]

Maybe try turning the flame down a little. Don't restrict the air circulation while roasting.

Thanks G, I have been looking at a couple little DIY milling tools on U-Tube that would be good for sampling. I am low budget at present, but I am still gathering Tools and such, I want to cover as many aspects as I can along the way. Do you think 100 um is ground small enough to roast like this or mill before? And then mill or stick in polisher. I know you knowledgeable of sizing and measurements, There is a windows measuring app. that I can install on my laptop for microscope that is supposed to be able to measure sizes of particles I see, but I am not sure if that would be useful to me at this time. I will eventually have the right ore and get the best process to finally use some of this lab equipment and supplies I have been gathering. Looking at a little rock crusher a jaw crusher that I can put a motor on as well for later. Thanks for the direction....

 

[goldshark]

I don't know what type of eye piece is on your microscope, but something called a reticle can be added to most scopes, or a graduated glass slide can be used. 100um should be small enough, but will depend on your tailing assays. Quite a bit of testing goes into the logistics of optimal recovery to grind size. Grind to optimal size , roast, regrind for gravity or amalgamation recovery, or smelt to reduce by fire. Mechanical crushing/pulverizing is many times faster then hand crushing, even for small amounts.

 

[user 69385]

Greetings to all, I have a fairly good Idea of the process I have been working on for a good while to leach with AR, I have studied Holks book and some chemistry. Thanks to all of you. Thank you. I respect all of you who are knowledgeable and help us all. I believe I have enough equipment and supplies to work with now. (funny) I bought a digital microscope to be more selective of ore I am going to crush, and mill down to 80um and spend chemicals on to process. HA! I am a backyard miner in central Co. and have several kinds of ore I am trying to pick out the best, but I have decided I don't know how to use this thing yet. I wanted to put a couple pics on here to see if anyone could maybe help me at all with what resolution or magnification that makes it best to identify raw ores or 80-100 um particles. No pickers or much free gold in this stuff. Well AU is what I am looking for. It is 1080P has 3 lens 18-720X, 1650-2040X, and 2760-4080X and 3X digital zoom. If anyone can help I appreciate it. I don't have a very good turn around on assay's 6-8 weeks, but a friend has a mine up here that helps me out with their lab and equip sometimes, I haven't found much worth while yet, but I am not going to die trying. anyhow I am trying to use this thing to pick out AU and I know there is pyrite, Iron, copper, not 100% if the chalcopyrite is encapsulating AU or if it's all a waste. This is mostly double refractory stuff I have, sulfide ores I guess. Up here is several telluride ores, calaverite and sylvanite mostly, there is fluorite in a lot of the rock but not seeing a large concentration of what I am looking for in it. Still and I know I have to roast at 600 C. and I have that covered too, someone told me to add a little silicon sand in the beginning cool and add some charcoal after to take cyanide out??? I will also put a pic of a couple of the raw ores, one I think is iron sulphide, and another that shows fluorite and what I think is pyrite. Help. This other rock I thought was fluorite, but now looks like maybe sodalite, but after I finally split it I am not sure. Its a 6-7 hard it weighs 48 oz. it shows a lot of microscopic metals in it, and it does not glow under UV light. Help, Sodalite is not supposed to have metals in it not even pyrite. Thanks to all, I know I ask a lot, I really am just a humble little student.

You can make a ore crusher for small quantities using a threaded iron nipple with end caps and tungsten balls (or steel ones if you want) and a electric paint mixer. You will want to modify the cradle of the paint mixer to hold the pipe securely (tie wraps will not hold) and create a dust that way that you can pan out or run over a miller table. It will not show any tellurides or sulfides and those will need separate treatment specific to each. In powder form it will be easier to roast without exploding rocks. When using a microscope and visible particles of metal are seen, get a hardness point for measuring rock hardness and see if it smears. Gold, silver, copper, etc will smear.

 

[goldshark]

Thanks G, I have been looking at a couple little DIY milling tools on U-Tube that would be good for sampling. I am low budget at present, but I am still gathering Tools and such, I want to cover as many aspects as I can along the way. Do you think 100 um is ground small enough to roast like this or mill before? And then mill or stick in polisher. I know you knowledgeable of sizing and measurements, There is a windows measuring app. that I can install on my laptop for microscope that is supposed to be able to measure sizes of particles I see, but I am not sure if that would be useful to me at this time. I will eventually have the right ore and get the best process to finally use some of this lab equipment and supplies I have been gathering. Looking at a little rock crusher a jaw crusher that I can put a motor on as well for later. Thanks for the direction....

Most people wanting to run production, will get a jaw crusher, hammer/impact mill, classifier, and fine grinder such as a ball or rod mill. Each is specific to a particular size particle, and its ability to break most efficiently for that particle size. Lots of ways to recover values, again specific to the. mineralization, and particle size relative to the ore.

 

[jobinyt]

For SAMPLING - not small batch production, but sampling, I've found that a hammer drill I had for other purposes serves very well to produce fine powders for testing.

Also, For microscopic inspection, I have a "USB microscope" . They are cheap. It looks like a fat pen with a cord on it. The cord plugs into a PC USB port. There's a button on the cord that takes a picture although a screen shot should work too. If I was shopping for a new one I'd be looking for one with greater than average depth of field/focus.

 

[dkbinco]

For SAMPLING - not small batch production, but sampling, I've found that a hammer drill I had for other purposes serves very well to produce fine powders for testing.

Also, For microscopic inspection, I have a "USB microscope" . They are cheap. It looks like a fat pen with a cord on it. The cord plugs into a PC USB port. There's a button on the cord that takes a picture although a screen shot should work too. If I was shopping for a new one I'd be looking for one with greater than average depth of field/focus.

Thanks for the hammer drill suggestion, might be cool for sample. I tried a portable USB microscope, shaky so I have an Andonstar 246S-P at Amazon, The plastic stand is more stable and supposed to receive a metal replacement stand for doing a review, but who knows. It has a wide range of magnification.

 

[dkbinco]

Most people wanting to run production, will get a jaw crusher, hammer/impact mill, classifier, and fine grinder such as a ball or rod mill. Each is specific to a particular size particle, and its ability to break most efficiently for that particle size. Lots of ways to recover values, again specific to the. mineralization, and particle size relative to the ore.

Thanks G, I hope I will be investing in something this summer after getting organized here a little more and it warms up. I am using a 3 in. Frit Piston and mortar and pestle to test and sample at present. These lenses are supposed to accept a reticle, I can play with that too it also has extra 20.2 mm threaded ports for additional lenses, but 1080P does not display from HDMI connection to TV digital zoom does not help the focus so I am going to try laptop and see what resolution it will display. I am checking on it.
Thanks again.

 

[dkbinco]

Greetings guys, I went on a tour with a friend who has a 500 acre mine about 250 miles of tunnel in Cripple Creek, and he does all of the assays. I helped do 13 assays, we shot my ores with the XRF and happy to say no cadmium, arsenic or mercury in any of them, but AU is running at 15 to 20 PPM. I believe I am going to have to concentrate, cannot buy a shaker table right now, I am crushing and panning some samples, maybe a blue bowl. I didn't get a print out, but AU, AG, TE, FE, MO, for the most part. I did grab a couple samples where they just blasted and it is about 135 PPM, I will have something to compare with. I just thought I would respond, I am going to start a thread on mining and ore to see if anyone knows about concentrating. Thanks Guys