Detecting at old mines....

[Desert Gypsy]

Yesterday while detecting around some old long forgotten mines, I ran across an area where my Garrett AT Pro went off. Pinpointed it down to an small area and got out my Garrett Pro Pointer. Dug down around the area and nothing. Then I realized it was the soil in the area of about a 3 feet. Never could find anything substantial, just the soil. Had me stumped. Has anyone ever ran into this? It would only go off in this certain area. From the hole I dug, it would go off beneath it and all around the sides, and the dirt that was dug up. Has my curiosity up. I have just started hunting around some of the old mines and dump sites. I find them very interesting and quite alluring and yes, quite dangerous as well. I would very much appreciate anyone's input on this.

Thanks Much!

 

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[Clay Diggins]

Often mines are in the business of extracting raw metal ores from the ground. Many of these ores contain enough metal to set off your metal detector.

Please be careful around old mines. If you don't know what a winze is you shouldn't be investigating old mine properties.

 

[gollum]

Clay,

A lot more than just winzes. Stopes, bad air, histoplasmosis, snakes, mountain lions, cave-ins, etc are all good reasons for ill equipped and untrained people to stay out of old mines.

1. Winzes and Stopes are just ways mines were dug to get at the ore. They undercut each other and leave things dangerous (especially if they are old) to walk on.

2. Bad Air has killed more people in caves/mines than any other danger. If you descend into an old shaft, all it takes is one deep breath of CO, CO2, or HCN (Hydrogen Cyanide Gas) for you to drop like a rock, and be dead before you know it. See, all the bad gasses are heavier than air, and since there is no airflow, they pool in deeper places in caves and mines. So, you are just walking along in an old mine, then everything goes black (like the end of The Sopranos). Hydrogen Cyanide Gas is in old mines because the old miners used "cyanide leaching" to get the silver/gold from the ore. Over a hundred years or so, the old cyanide has leached into all the surrounding ground and water tables. It also outgasses into the old mines themselves. Hydrogen Cyanide Gas is what they use in Gas Chambers for executions.

3. Histoplasmosis is basically a fungus that grows inside old caves/mines in the droppings of birds/bats. As you walk through kicking up dirt, you inhale the fungus, and it starts to grow in your lungs. When it gets into your bloodstream (from your lungs), it runs through your entire body. At first it seems like a bad cold/flu. If left untreated it has a VERY high kill rate.

4. You know what rattlesnakes and mountain lions are I am sure. Snakes den up in the nice cool subterranean places, while mountain lions like to live there (especially if they have cubs).

5. I am also sure you know what cave-ins are.

If you don't own a personal gas detector (for mine work), either stay out of old mines, or at least be tied off to someone no closer than ten feet behind. That way, if they see you drop, they can haul you back into better air.

Best - Mike

 

[luvsdux]

I've detected around a few old mines - surface, not inside. All I ever found was old iron junk and nails from the buildings that had deteriorated. I guess once in a while someone will find a bit of gold or whatever in the tailings, but that didin't happen to me.
luvdux

 

[BDinutah]

I am by no means an expert on this phenomena but here in the desert I've experienced this several times & in my case it appears to have come from having had tin deteriorate over time to where it has become powder and has mixed into the soil to where the ground looks like brown dirt, but the metal signal is still there.

 

[AU_Solitude]

Bad air is a huge one! I've been in a few but anything beyond a hundred feet from the entrance and it's stupid not to wear an SCBA. And winzes are crazy - it can be easy to be staring at the walls and the ceiling of a mine shaft and not notice the pit of death in front of you - the few I've seen had to have been near 100' deep in Nevada. Crazy what they used to do.

 

[Lanny in AB]

"Yesterday while detecting around some old long forgotten mines, I ran across an area where my Garrett AT Pro went off. Pinpointed it down to an small area and got out my Garrett Pro Pointer. Dug down around the area and nothing. Then I realized it was the soil in the area of about a 3 feet. Never could find anything substantial, just the soil. Had me stumped. Has anyone ever ran into this? It would only go off in this certain area. From the hole I dug, it would go off beneath it and all around the sides, and the dirt that was dug up. Has my curiosity up. I have just started hunting around some of the old mines and dump sites. I find them very interesting and quite alluring and yes, quite dangerous as well. I would very much appreciate anyone's input on this."

Lots of times around areas that produce gold (whether hard rock or placer) there are serious concentrations of minerals in the ground. As Clay says, they are in concentrations heavy enough to set off your metal detector, but after you disturb the material (dig through it, scrape around in it with your pick), the signal may or may not continue.

If you are going to work around old mine sites, please be careful as everyone has advised, and please get yourself a super-magnet (either on a wand, or held in place by a bracket on the end of your pick). The magnet will quickly pull out tiny bits of rusted metal or iron wire, etc.; it's the kind of trash that's always around old mine sites. It will save you a lot of detecting time as well.

People do find specimen gold around mine dumps where the ore was hand sorted, but unless you're used to hunting gold with a detector, it can be a very steep learning curve.

By the way, sometimes the color of the soil will tell you if you're working on a signal emanating from ground noise (highly mineralized dirt). Sometimes all you have to do is disturb it and the signal will get weaker or stop all together.

All the best, and be safe,

Lanny

 

[Tom_in_CA]

Desert Gypsy, I won't chime in on the part of your question about false signals, machine settings, minerals, etc... But do want to point out that as "alluring" and intesting that old mine entrances are, those are not the places you want to detect. If coins and personal effects are your goal, that is. Because think of it: the mine (or stamp mill, or processing stations, etc...) are where they WORKED. Hence it will have the most industrial iron junk around it. And yes, the most lasting visible vestages of the mining era. But no, not the place at an old mining district that will necessarily have the coins you want to find.

Instead, you want to detect where they LIVED. You know: ate, slept, played, drank, sat around, dressed and undressed, etc... And that was NOT where they worked. You want to find out where their tent-cities where, where they LIVED. And that won't necessarily be right there at the diggins and processing industrial type areas. Often time their tent cities (since they were "tents" afterall, and board-&-batton at best) will be long gone, with no trace. So don't make the mistake of rushing right up to the visible ruins of these area (mine entrances, sluices, etc...), but instead try to find out where the miners set up to sleep, and have their little tent cities. Would be close-by, is a safe guess. At a nearby bluff or meadow, etc....