Detecting seam diggins, vein deposits, and free gold ores

[UncleMatt]

Detecting seam diggin's, vein deposits, and free gold ores

I am just curious if anyone has ever actually found a vein, or seam, or even a free gold ore deposit, with a metal detector (of any kind)? If you have, I would love to hear your story. Of course, no need for details on location.

What I would really like to hear about is what kind of signal a piece of free gold rich ore would give off to a VLF detector! (note: not talking about tellurides, etc) If the detector is signaling off of hundreds of very small gold particles in the host body at once, what does that sound like? What magnitude of signal should be expected under those circumstances at shallow depth, a whisper, or a howl?

Anyone have any personal experiences to share on this? Or better yet, maybe an audio file we could all listen to?

This may belong in the metal detector section, but I am focused on hard rock situations with this question.

 

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[Terry Soloman]

Forget about getting gold ore to sound off with a metal detector. I have used metal detectors inside old gold mines to find larger pieces of gold (.5-gram +), but the machine will only
"see" individual targets, not hundreds of small particles. Same thing with a gold chain, it only reads the individual link, not the entire chain.

 

[UncleMatt]

I understand Terry, but I was under the impression the proper metal detector could detect gold ore with free gold particles. That each particle would sound off as a tiny hit, or maybe a chorus signal of some kind. I guess it depends if the particle size in the ore meets or exceeds the threshold of the detectors resolution.

But you are saying metal detectors are pretty much useless when it comes to hard rock prospecting for ore with dust size free gold in host gangue/ore? Even the VLF machines? Interesting.

 

[bug]

If the gold gets too disseminated you will loose any signal. Luckily many seams are pockety and throw big gold which could be the tip you off you are looking for.

 

[UncleMatt]

If the gold gets too disseminated you will loose any signal. Luckily many seams are pockety and throw big gold which could be the tip you off you are looking for.

Well, I guess that is better than nothing!

 

[Terry Soloman]

I understand Terry, but I was under the impression the proper metal detector could detect gold ore with free gold particles. That each particle would sound off as a tiny hit, or maybe a chorus signal of some kind. I guess it depends if the particle size in the ore meets or exceeds the threshold of the detectors resolution.

But you are saying metal detectors are pretty much useless when it comes to hard rock prospecting for ore with dust size free gold in host gangue/ore? Even the VLF machines? Interesting.

Yep, that is exactly what I am saying. Micro-gold locked up in host rock will not make any metal detector respond.

 

[Fullpan]

Classic case of using MD's to find gold in a hard rock mine was the Original 16-to-1 mine in Allegheny, Ca. In about 1990, for about 10 years, they found
1,000's of ounces beeping the quartz veins, BUT that mine had been famous for jewellry ore, that is, solid free gold lumps and stringers that made their
detectors scream. I think they still have a website, but regulations and enviros eventually forced them to shut down with thousands of ozs of proven reserves
left. Lets here it one more time for the beaurocrats and tree-huggers

 

[kuger]

I specifically of three different mine dumps that have each produced 200+ oz of gold all found with detectors......that being said thats out of hundreds of tailing dumps.

 

[UncleMatt]

Problem is, I am not talking about scouting tailings, I am looking for deposits still in the ground that have not been touched yet. In the San Juans you find ore with small particles of free gold and tellurides. I am trying to figure out the best way to go about scouting with a metal detector for those seams, veins, and ore on hillsides that have not been prospected or mined.

 

[kuger]

...I think Terry,and the rest above covered that pretty well.....

 

[UncleMatt]

So when it comes to hard rock prospecting in the San Juans, there really aren't any new tools other than what the old prospectors had: A pan, a sluice, your eyes, perhaps a map, and experience. Now there is a lot more information about gold formation available to the public than was available 100 years ago, as well as better geological maps, satellite imagery, etc. But no new technology that can be used on the ground seems to have come along. Please feel free to correct me if I am wrong. When you are dealing with ores that have micro-gold and that consist primarily of tellurides, is anyone aware of any primary detection methods other than what the old prospectors used?

 

[Fullpan]

Drilling core samples is the way large mining companies do it. First, their paid geologists have outcroppings assayed, then the drilling programs start.

 

[UncleMatt]

True enough, I missed that one. There are also magnetometers.

My goal was to detect seams of ore just below the surface that had been missed by the old prospectors. Soil and silt moves around a lot up in that high country, and one year an outcropping can be exposed, and the next nowhere in sight. And if there was no consistent outcropping, and no placers substantial enough to detect through panning or sluicing, that seam would have been overlooked. Those were my targets.

I may still get lucky and find enough detectable gold to signal the seams I am after. Time will tell.

 

[Fullpan]

Don't feel too frustrated, even the big boys get it wrong. Alta Gold Corp. had a brochure in about 2003, that stated their Olinghouse property just east of
Reno was full of "bonanza" ore according to numerous drill core samples. A couple years later they were bankrupt.

 

[Oakview2]

Good article this month in the ICMJ about beeping in the 16-1 mine.

Classic case of using MD's to find gold in a hard rock mine was the Original 16-to-1 mine in Allegheny, Ca. In about 1990, for about 10 years, they found
1,000's of ounces beeping the quartz veins, BUT that mine had been famous for jewellry ore, that is, solid free gold lumps and stringers that made their
detectors scream. I think they still have a website, but regulations and enviros eventually forced them to shut down with thousands of ozs of proven reserves
left. Lets here it one more time for the beaurocrats and tree-huggers

 

[UncleMatt]

I also read the article on icmj.com, but the 16-to-1 mine has a different kind of gold deposits than what I am dealing with in the San Juans, and is different than what I started this thread to talk about. What works with load gold in that mine will not work when it comes to detecting tellurides or micro-gold ores in Colorado. I wish more people who were hard rock prospecting in CO were posting online so we could get their input from their experiences, but they tend to be a very secretive bunch....

 

[Oakview2]

Sorry to hijack the thread, just got my copy of ICMJ and wanted to give Fullpan a heads up about the article on beepin in the 16-1 mine...

 

[UncleMatt]

No biggie, it was a good article

 

[Fullpan]

I apologize too, UnckleMatt - I know what you are seeking, and it seems technology will catch up soon to enable modern day prospecting of outcrops.

 

[UncleMatt]

Wow, did the finishing school just let out around the corner? lol You nice young men are so polite!

If I came across as irritated, I'm not, just frustrated that there isn't an off the shelf technology to take advantage of. Prospectors have crawled pretty much all over the San Juans back in the day, and I am fearful I will not have much luck up in the high country without a technological edge. The visible outcrops have all been examined, though there might be a few exceptions, and perhaps a few new outcrops in the past 50-100 years. Most of the placers have been worked out too. Southwest CO is not known for producing large gold nuggets, otherwise I would just focus on nugget shooting in the area. Hard rock is the name of the game here, I will just have to spend more time studying what I need to be successful.