Gold Coin Cache Hunting--Technical Question

mbryant01

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Aug 23, 2009
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I've got a site where they may be a cache of gold coins. It would be 2-4 feet deep in a clay jug. It's buried in red clay, which is very mineralized soil. I'm trying to figure out which type of equipment to use, such as a large PI loop, GPR, magnetometer or maybe a Electromagnetic (EM) antenna, like OKM makes. I've been told that a cache of gold coins will not show any bigger (surface-area-wise) than a single coin, even though they are touching each other, but a solid a gold bar would show a bigger surface area, because it's solid. I was wondering if this is true, and if anyone could recommend what equipment would work best in these conditions. Per the Lorenz site, (a German company that makes very good PI units) their 1 meter loop is too big to pick up on a single coins and their double-d coil (the one the can differentiate between ferrous and non-ferrous) doesn't go much past 15 inches on a coin. I was also told by a GPR manufacturer that GPR does not work well in mineralized soil. Not sure what to do.
 

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Terry Soloman

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I've got a site where they may be a cache of gold coins. It would be 2-4 feet deep in a clay jug. It's buried in red clay, which is very mineralized soil. I'm trying to figure out which type of equipment to use, such as a large PI loop, GPR, magnetometer or maybe a Electromagnetic (EM) antenna, like OKM makes. I've been told that a cache of gold coins will not show any bigger (surface-area-wise) than a single coin, even though they are touching each other, but a solid a gold bar would show a bigger surface area, because it's solid. I was wondering if this is true, and if anyone could recommend what equipment would work best in these conditions. Per the Lorenz site, (a German company that makes very good PI units) their 1 meter loop is too big to pick up on a single coins and their double-d coil (the one the can differentiate between ferrous and non-ferrous) doesn't go much past 15 inches on a coin. I was also told by a GPR manufacturer that GPR does not work well in mineralized soil. Not sure what to do.

The FIRST thing to do is slow down before you throw your money away on a machine that is not going to work for you. If you are serious, about recovering this "possible" cache, and it is in fact within 40" from the surface, a Minelab GPX 5000 with a 20" coil will find it easily. I said EASILY. I'm a gold prospector and I have personally and personally witnessed single gold nugget recoveries at 30"+ on 2-4oz nuggets.

Don't fall for cock-n-bull advertising copy, pretty little underground multi-colored graphics and technology mumbo-jumbo. You did exactly the right thing by doing your due diligence and checking it out yourself before purchasing. Good Luck!
 

Tom_in_CA

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Get a two-box unit, if the stat's you're talking about are really true. Something lunch-box sized like that, is perfect for a two-box (and you'll simply not hear the pesky individual coins, nails, tabs, etc....).

But let me tell you, cache stories are a dime-a-dozen. I wish I had a dime for every "sure fired" treasure lead I've heard from convinced friends, relatives, and passerbys, in my 35+ yrs. of this :)
 

Ism

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While it is true that each coin will give an individual response, a mass of coins will give a larger response than a single coin. The percentage increase is difficult to determine but I would say 25-40%. Partially because of the area of the mass and partially because of the combined response of each coin. I have buried caches and can detect them from a much greater distance than a single coin. Look at it this way, ring a single small bell and you may only hear it from 50ft away but ring a dozen small bells and you will likely perceive the combined ringing from a much greater distance. Good luck with your search.
 

signal_line

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The question is will an 18 inch coil on a pulse induction machine find it? The answer is yes if the ground is not extreme. In the 20 inch deep range, no problem. In the 40 inch deep range, you might need a one-meter square coil. In moderately hot ground the 18 coil will work even at 40 inches on a handful of coins.
 

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mbryant01

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Aug 23, 2009
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That's interesting. A guy at KellyCo told me, unless I misunderstood him, that a gold coin cache will not register, surface area wise, more than a single coin even if the coins are touching each other. So your saying that it will register like a larger object would.
 

Frankn

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Here's how a detector works. It transmitts out a signal at a fixed strength. It then measures the strength of the return signal. SO, the larger the metal object, the further away it will be picked up. If you have a pot of gold coins, it will pick up that mass of coins. I would try a 2 Box detector. Most will go over 6' for a pot of gold coins. You can probably pick one up on E Bay for around $300. The old Transistor models are as good as the new ones. Don't get an old tube model. I use the Hays, but most are good if in good working condition. The Lorenz PI is a good unit, but pricy, as I recall, it is in 4digit territory. In clay, you could just use a rod to probe if you have a good location. I also go along with the member that said those stories are a dime a dozen or words to that effect.

hand print-2_edited-3.jpg
 

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Dixiegal

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A clay pot if its full of coins will register approx the size of the diameter of the pot or container. At 2-4 ft we just use our White 808 two box. We work in highly mineralized soil and the 808 can be dialed down to pretty much ignore the mineralization. Hope you find your cache.
 

Terry Soloman

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Has anyone here used a Minelab GPX 5000 with a big coil besides me? Where are my GPX people? Soil does not get any more mineralized than that found in the goldfields of Arizona and Australia. If it is a cache of coins in a clay pot, the Minelab will hit it at 40-inches like it was a truck bumper.
 

Terry Soloman

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That's interesting. A guy at KellyCo told me, unless I misunderstood him, that a gold coin cache will not register, surface area wise, more than a single coin even if the coins are touching each other. So your saying that it will register like a larger object would.

Gosh, a salesman talking out of his belly-button.. Who would have thunk it? :laughing7:
 

signal_line

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That's interesting. A guy at KellyCo told me, unless I misunderstood him, that a gold coin cache will not register, surface area wise, more than a single coin even if the coins are touching each other. So your saying that it will register like a larger object would.

You might have misunderstood. Sure, loose coins are not going to hit as hard (or discriminate as well) as a solid object of the same weight.

Just an example I dug a 36 inch deep hole and poured a hundred copper pennies in it. So that's about a handful of coins spread out over the six inch diameter. The 18 inch coil detected them. Now I am fairly certain one penny would not have been detected.
 

gleaner1

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It's the enigma of metal detecting. You can find a cache so easy, it's so simple a caveman could do it. But you have trash. Now you cant do it. Now two to four feet, no way, unless it is trash free. A two box would make this almost easy enough for even a cave man to find. Two to four feet deep, you cant miss it and you wont dig shallow trash.
 

signal_line

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I owned a two-box. Like that one thread about which detector do you dislike, the two-box is on the top of my dislike list. I sent mine into to the factory for re-tuning. They said it was "good as new". Maybe they are okay in no mineralization, but what I found was it was worthless as a cache machine for my area. A garbage can lid at three feet? Probably, but you can't depend on that if there are any factors involved like mineralization or power lines within a couple hundred feet. They work good in air test. The two-bow were originally never advertised as a treasure hunter. They always were classified as an "industrial locator" meaning things like septic tanks, etc. I chuckled what one guy said about finding a car body at four feet. He said a VW only two and a half feet.
 

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mbryant01

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Aug 23, 2009
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I get it now. Thanks for the info. I'm going to check out the Golden Sense detector made by Nokta or a PI unit.
 

signal_line

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I don't know much about the Golden sense but it is a VLF and VLF's do not work that well in mineralized ground. I read somewhere they only go that extreme depth if you adjust the ground balance so far over. But I've never used one and don't know. You might want to do some research on that one. The post I read said the guy only got nine inches until he tweaked it way out. That doesn't mean it will work in the real world or in mineralized ground. Again, I don't know. I do know pulse with a big coil will work in mineralized ground.
 

gleaner1

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I get it now. Thanks for the info. I'm going to check out the Golden Sense detector made by Nokta or a PI unit.


Get a cheap two box and find that cache. A pulse machine will not work on your quest if there is any trash involved, unless you hire a bunch of digger dudes and quit your job. Dont worry about mineralization, metal detectors have a ground balance feature to adjust to mineralization. Even two box machines. A deep cache, 2 to 4 feet, is two box work. To find something that deep with a pulse, you would need a least a twenty inch coil, and if there is any trash it will raise cob with your project, it will be almost impossible. Your chances are a hundred times better with a two box.
 

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U.K. Brian

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Ground balance doesn't do away with the effects of mineralisation it just allows the target to be heard better against what would be a load of background noise. A two box also will not cope well with mineralised red clay.
While Lorenz are being very honest about single coin detection thats not what you say your after. If its really in a fired clay pot then that will add to the P.I.'s performance. Pay attention to what Signal Line has said. I've used the Discovery two box, the Whites and the C-Scope. Prefered the Discovery but they all had trouble in bad ground.

The coil size is no worry. Most P.I. hoard machines come with a square 40" x 40" coil as standard and this will have more depth than you need but isn't a weight problem as you wear them on straps over the shoulders. For covering large areas you can get coils up to eight feet wide that cover ground in no time but you do need someone at each end. Large coils can have the advantage of being insensitive to all small items so no problem with near surface rubbish. Large iron need not be a problem as they can use the decay rate of large iron if you want to ignore fist size and above iron.
 

jmoller99

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channelonline.tv - News, Weather & Information for the Channel Islands - Treasure island - this looks like what you want to find - It's obvious that there are more out there like it (This find is somewhere in the UK). Caches can be anywhere. Odds are good if you are not digging everything, your experance (and your detectors VDI) might suggest something like this is junk.

I would agree that a PI detector (like the high end Minelabs) is the way to go if you are looking for something deep.
 

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gleaner1

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Very interesting post. I have been influenced by the videos of guys using two box units to find ww2 helmets four feet deep. Two box units have their place in treasure hunting, and as with all other tools, has a set of pros and cons. Certainly a two box unit will find a crock of gold at three or four feet deep and ignore shallow trash. Right? Or is that a myth?
 

U.K. Brian

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Right and wrong. I've had a few gold hoards/caches both fairly modern and going on 3000 years old and silver hoards and silver bars, cannons etc. As I tend to travel abroad and detect areas with bad ground and wet salt sites a hoard (not gold hunting) P.I. is my choice. The two box machines work fairly well within their limitations but positive salt areas, high mineralisation etc can really knock the performance. There is an old test report on line somewhere I'll try and find it. Trouble with pulse hoard hunter in the U.S. is they never seemed to make any except the Pulse 2000 which was fairly cheap but not up in the Pulse Star/Lorenz league.
 

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