ABOUT COIN DEPTHS

Detectordan/MXT

One must also take into consideration such activities as rottotilage or farming.:cool:
 
Mindreader..

Thats interesting what you say about how things like a bottle cap can sink so far down while something else can be almost right at the top. This makes me think about some of these articals I have read about how SO and SO finds Roman coin buried deep in American soil. Proof that Romans were here before Columbus? I don't think so now, after considering these posts.
RR
 
Sorry, this is a long reply.

For years, decades, a common topic among hobbysists is the subject of "Coin Depth." For those who know me from other forums, you know I can get a bit lengthy at times, and I apologize if this and other replies I post here turn out that way. Still it might take a few to give some examples to qualify my beliefs about this.

First, CarolK, this is not intended to be an argument with your post. Anytime someone puts in the effort to learn and try to understand some aspects of the hobby it is beneficial for them and those they share it with. However, I do think your are references related to Specific Gravity, and there's a little difference between that and 'Density', at least in the way many would interpret the terms.



Why are some older coins very shallow when newer coins are deep at the same sites? How can a new coin sink deeper in a few years than an old one in over 80 years?
As some have noted, I am not a big fan of the 'sinking' theory. In this case I prefer the term 'displacement' which might be caused by a specific gravity event, but is often caused by ground disturbance such as digging, tilling, placement of fill material, grass cutting buildup and leaf droppage, erosion, etc.

In 1981 I opened a shop in Kaysville Utah and the old stone library and city hall were across the street. I could find silver and other older coins as well as modern change co-located from just sub-surface to about 7". It was explained to me by city workers that during some renovation in recent years they had tilled the ground to smooth it out and plant new grass. No 'sinking' was involved.




The density of inorganic soil is from 2.6 to 2.8 and any object of greater density, including coins, would eventually sink until the density of the soil equaled the density of the object.
Yes, there might be some displacement, if there is sufficient water and soil activity such that the site would be in a fluid state.



The sink rate is determined by the difference in density, the greater the density the faster the sink rate. Contributing factors are vibration, rain, frozen soil, grass buildup, leaves and a few others.
Grass buildup and leaf deposition are the kids of effects not associated with any natural 'sinking' or 'displacement' activity. The only real determining factors for a specific gravity event assisting a coin or other target to relocate to a deeper position are 1.. Water Saturation and 2.. Sufficient Ground Movement.

Example: You take four identical gold pans and fill them ? full with the same dry material and set them along side each other on a table.

The 1st gold pan is left dry and you place a gold nugget on top of the material in the center.

The 2nd gold pan is filled with water, even to the top of the pan (to allow for evaporation) and an identical size and shape gold nugget is placed on top of the material in the center.

With the 3rd gold pan you match the water level and identical nugget placement of the 2nd pan.

The 4th pan is set up identical to pan s #2 & #3, but each day you actually pick the pan up, give it a good 15 seconds of shaking and put it down.

You leave all four pans sitting on the table for one year. Allow for this example that they are indoors, out of the elements, and there are no earthquakes or other jarring events other than the following:

Each day for one year you bump the side of pan #3 one time so that only it gets jarred and it doesn't affect the first two. At the end of the year, the gold nugget will most likely still be on the top of the 1st and 2nd pans, but due to jarring in the early days when it was water saturated, the gold nugget will be out of site in pan #3, and quite probably the nugget will have experienced ample displacement that it will be on or near the bottom of pan #4




How often the ground gets saturated can be a much bigger driver of coin depth than any minor differences in soil density. Until the ground directly beneath the coin becomes saturated to the point where the dirt becomes suspended in the water, and can move to the sides of the coin due to the coin weight, then little depth due to sinking can occur.
Quite correct, it must be totally saturated ... AND be in a fluid (moving) state or have the room to do so. That's the part of this statement that makes it tough for coins to displace even if the soil is saturated. The ground (soil) doesn't have the opportunity to "move to the sides" so as to allow a coin (or other target) to move downward!

A simple example would be a beach situation. High on the beach in the dry sand, if you eliminated any high tide effects, any moisture, and any foot traffic, the dropped coin/target isn't going anywhere per-se. But head on out to where the water action both saturates AND agitates and moves the sand, then you can experience the effects o displacement due to specific gravity .... as well as the erosion effects that leave coins exposed or near the surface after a storm in a 'cut' or possibly not associated with an obvious cut in the sand.

You could join me on a late summer hunt to one of my favorite desert ghost towns of Oregon or Nevada to experience some head scratching events. The ground around the sage brush and in most of the open spaces between lets us hunt for coins and relics with ease of recovery. Most of the time you can wear a pair of boots and simply toe-scuff the desert dirt to the side to expose the target. I've done this to recover old Chinese cash coins and US coins and trade tokens and good relics such as buttons, bullets, buckles, cartridges, etc., down to 4' or 5", and even 7" and a couple at 8" or 9". This qualifies as being loose, not hard-packed, ground.

Many times, since I started hunting one of the towns on May 4th, 1969, I have eyeballed a coin, token, button or other desired target right on top of the ground, and most of the targets are just a gentle scuff away at maybe ?" to 1?".

Now, I said a late summer hunt because it's not uncommon during a good August or July hunt to have a serious thunderstorm show up ... frequently! You can be walking on and scuffing to a depth of many inches (or dig a foot or two or three deep if you're screening) and have nothing by dry sand and dirt when one of these storms rolls in.

You retreat to your rig and drive up onto some higher ground, such as an old railroad grade, and watch the splendor of mother nature. :D I've sat in a vehicle alone or when accompanied by friends as we wait out the storm and watch the black and billowing white clouds roll in. Thunder, sheet and streak lightning, and rain by the buckets full! It will sometime hail so hard it leaves a good half-inch of hail on the ground for a while. Often, very often, the rain is just an absolute drenching event and you can see pool/puddles of water in every low spot.

These storms can be brief or lengthy. I've been there when, after an hour and a half of miserable weather there's no break in sight so we've headed into a nearby town for some grub and to wait it out. On one of my first visits there during a thunder storm had passed, I gave it about 10 minutes and then drove back to where I was hunting and got out. I only had to walk about 30' to the spot where I was searching, but before I got halfway there each foot weighed about 10-15 pounds heavier from all the mud that was caked around my boots! It was one gooey, gumbo mess.

I've amused myself on subsequent visits during a nasty storm as I sit there nice and dry and watch others get out with hunting on their minds! :lol: The secret is to wait about 30 minutes to an hour or so, then you can get out and hunt it.

I've worked one old town site so much and have experienced many a storm to know that the ground is quite loose, and that water will quickly drain through it. Sometimes I can hunt an hour or so later and the surface is dry to about 1?'-2" and then it gets damp, and sometimes it appears a little wet on the surface yet usually not enough to stick to your foot, and I can scuff down 2"-3" or m ore and it is dry.

These storms occur frequently, and can unload a lot of rain! On top of that they do get some regular rain and winter snows that I have experienced there almost knee deep. Yet, even last month's trip still turned up Seated Liberty dimes and metal buttons and bullets and cartridge cases from shallower depths. Why? Because they just don't sink.



That's why many coins seem to end up in the 6-8 inch range - it takes a real soaker to move them deeper. So maybe the discrepancies in coin depth can be attributed to minor differences in the local drainage. The finer the soil particles, the easier they get suspended and the faster the sink rate.
Suspended particles in a fluid state of an ample amount to allow displacement is seldom going to ocur in most of the sites we hunt, unless it is a beach site with a lot of water and wave action.

In many, most, commonly searched areas, an honest 5" to 8" coin IS a deep coin. More often than not, buildup contributes to "coin depth" more than any sinking effect, and erosion can both deposit material on top of a desired target or remove some material.




Looking at the chart below, the dime should sink a lot farther than the penny, because the gravity is twice as high on silver as copper is? I know I've found silver just under the grass and then dug 6" or 7" for a clad penny. Nothing worse than getting a deep signal, dig it and it's a clad penny!
Actually, using your chart, a silver dime would only have about a 16?% higher specific gravity than would a copper penny.

I am with you, however, on the frustrations of finding newer coins at deeper depths than anticipated. Root structures and other underground things can add the some differences in old Vs new target placement. A few years back at an old park in Portland, Oregon I was popping modern change from 1" to about 5?" with five friends. As I worked in under an evergreen tree I got another penny/dime response at about 2"-2?" and up popped a nice 1884 Seated Liberty dime!

The tree was about 75 years old and this took place on April 24th, 1999. So the tre had only been around since it got started about 1924. Most of the coins had been a bit deeper due to the obvious build-up of the grassy area from lawn mowing, leafage, and perhaps some erosion since we were hunting on a sloped area.




The good stuff is sinking faster than the trash. No wonder not many gold coins are being found!
After ample years of detecting I'll hold to my belief that coins (targets) don't 'sink' as such unless all the factors are in place to assist in their displacement. They just don't naturally 'sink.'

Gold coins were not carried as commonly as other money, thus their loss rate was less. Moneychangers who were in a position to be carrying and spending gold coins also toted them in a coin pouch or draw-string bag, etc.

As for silver coins, other old coins and modern money. I know that a bulk of the older coins that were lost in public access areas have been found. For those of us who took an avid, active approach to detecting in the 1960's and 70's and into the early/mid 1980's, we got to enjoy the glory days of the hobby! :spin: :tumble:

Today, and for the last decade or so, I only hunt out-of-the way locations, many researched sites, private property (with access), renovation sites, old picnic and recreation sites, homesteads, ghost towns and similar sites if I want to get silver and older coins.

If I plan to hunt city parks and open areas for silver, I take a different approach and get more selective of the detector I use (I'd pick a Minelab Explorer 1st and a White's XL Pro 2nd) and the techniques, such as only going after higher-conductive targets that are in the over 3" depth range.

Again , I apologize for my long reply, and while your post had statements related to what might take place, I felt many would over-read it and errantly believe that all old stuff is deep, and all newer stuff is shallow Outside activity/events more than natural forces can be the cause for coin depths and the baffling questions it creates.

Happy Hunting!

Monte

PS I could have put in two hours of hunting instead of typing this, if only it would have been daylight. :lol:
 
ive hunted hard to reach places where it would seem no one has set sight on the place for decades and always thought it was odd most finds in these locations where very shallow 4" and under yet i could hunt a park and if i made an old coin find it would be double if not triple that depth,your post monte shed a bit of light on that. thanks.
 
Keep in mind what happens to the soil as you dig

There are so many factors when it comes to coin depth. I have found colonials sitting on the surface, yet dug clad coins 6 inches and more.

One thing I have found is that in my immediate area in an open field where the soil is clay peat , coins rarely will sink more than 5-7 inches. As I dig beyond this depth, the soil becomes much denser. It is my opinion that most coins will not sink beyond this level due to the compactness of the soil.

If I walk a mere 100 yards into the upland forest coins can be much deeper. This is due to the fact that that years and years of decaying leaves and vegetation will add layers to the soil. Many times I will dig down 8 or 9 inches to find a Wheat cent, or even an occasional Lincoln zinc. I work an area like this much slower and methodically, digging more of the "iffy" signals.

Another mile down the road from me is the Northwestern edge of the famous New Jersey Pine Barrens. Here the soil is known as "sugar sand". Sugar sand is even finer than most beach sand. It is very unpredictable as far as coin depth. Sometimes coins remain near the surface, other times they will sink very deep. Even the deepest coins found in these conditions like the 1836 cent pictured in my avatar are in remarkably good condition. This is due to the excellent soil drainage.

Another factor on how deep a coin sinks can be caused by it's position in the soil. A coin lying flat may stay near the surface, however a coin that lands leaning, on edge in grass or other similar conditions most likely will end up sinking deeper. (Picture trying to stick a butter knife into the soil on it's flat side as opposed to it's edge).

So how deep??? There is only one sure answer...; it depends!
 

Attachments

  • 2007_0803Image0015.JPG
    2007_0803Image0015.JPG
    42.8 KB · Views: 5,814
Certainly coin depths are intriquing-As has been said the water and soil factors are the #1 factors/Mainly water. Find a real wet spot it seems and there deep. Dry spot and there shallow. At our town common if you hunt where the ice hut area is for parking the coins are deep/having found zinc pennies and nickels without corrosion at a true 7" deep with a 11" coil on the machine. I actually cut the plug with a knife which will dig down to say 5"/pop the plug and then nothing but my bare hand digging at the dirt in the hole and 1" at a swipe i scan the handfull of dirt over the coil and repeat if it's deeper. Now like most have said the other coins away from this wet area in the common run about 3-4" max. depth for all coin types.

I always have one of those 3' tapes in my pocket that you can buy for a $1 at wal-mart and measure the deep coins if i happen to remove enough dirt with my hand but can still see the coin in the hole.

Some of the tricks the guys that have been in it for a while use is to move your coil less then 1/2 it's width and sweep again=Stay away from those full coil length swings when your in an area that has a potential for older coins/Even coins on edge or Diamond ring(like i found 2 years ago at a park that had the bejeezum hammered out of it) I barely got the signal and had to sweep the spot a couple of more time so that i could find the exact spot on it as the signal barely came in. Found an Indian head penny in the same park this year at 6 1/2" the same way.

I've found probably 40,000+ coins and 90+% were under 4" deep and the silver is there right along with them if your the first one to hit the lucky spot. About 3 weeks ago when i found the Autori Plebis token it was only 2 1/2" deep and reading in the quarter range but a couple of # lower then a newer Qtr so i really though i had a new quarter to dig up/Much to my surprise i found out different. It was in a high and dry soil. My brother Seated Half Dime that day was the same thing only 3" deep...If i remember right my First colonial was only like 3-4" and doing the same thing on the meter and i though a new Qtr.

Kevin
 
Very interesting and helps explain my 14 inch deep Merc found in Floridas sugar sand where we get thunderstorms almost daily four months of the year.
 
Many people overestimate the depth of their finds.

If you use a pinpointer with a long rod, you can use a magic marker to turn it into a ruler - just put it next to a ruler and mark off each inch, starting at the tip - and now you can easily discern the depth of your finds at the moment you unearth them.
 
I just had an experience today that relates to coins sinking. I normally find zinc pennies within one or two inches of the surface, and old coins not much deeper. However, today I found a zincoln about 6 inches down. The reason - ants had built a nest, loosening the soil significantly.
 
Great info

This is great information. The secret is soil density. It can change dramaticly even in the same general area. As stated by many here a gravel road centuries old will have a much greater density than a sandy soil ground. The density of the coin will never change.
 
I recently found an Indian head cent (in really rough shape,thin,brittle and date undiscernable)8-9 inches down on the banks of a long dried up creek bed. It didn't even look like a coin till I put a little water to it. Not 15 ft along the banking away the MXT sounded off again at about the same depth,this time it was a round lead musket ball.The musket shot was easily 5x heavier than the coin but sunk to almost identical depths as the coin,makes me wonder just how much weight of the object fiugures into the final depth it will reach. My feeling is the that the lead shot had been in the ground longer than the coin was.
 
There's another angle that could have an effect on the depth of coins. Living in New England, we are constantly dealing with a natural movement of the soil in the winter that causes "frost heaves". As I understand this, the hard frost in the winter can make the soil and rocks (and buried coins, I guess) push up toward the surface and that causes the pavement in the winter to become very bumpy in spots. Now, it seems to me that if all this dirt and soil is being pressed upward, then deeply buried coins and other parapenalia would also be pushed upward. This is just my theory and, sometimes I admit, my wife gives me way too much time to think.:lol: Steve
 
Even though it's been a couple of years since you posted this thread and I'm
just now reading it,it was very interesting and informative,almost to the point
of scientific :wow: I knew that it had to do alot with how wet the ground is and all that but would have never knew all the density's of different metals.
Thanks Carol..HH...Bobby
 
There's another angle that could have an effect on the depth of coins. Living in New England, we are constantly dealing with a natural movement of the soil in the winter that causes "frost heaves". As I understand this, the hard frost in the winter can make the soil and rocks (and buried coins, I guess) push up toward the surface and that causes the pavement in the winter to become very bumpy in spots. Now, it seems to me that if all this dirt and soil is being pressed upward, then deeply buried coins and other parapenalia would also be pushed upward. This is just my theory and, sometimes I admit, my wife gives me way too much time to think.:lol: Steve

We also have that alot here in Tennessee during the winter,on real cold mornings when you walk outside the ground has the "ice/frost" crystals pushing upwards out of the ground,sometimes a few inches high.I imagine thats the same thing you are talking about...HH...Bobby
 
OH !! and the point of me even quoting your reply was that i totally agree with the theory of it pushing stuff closer to the surface.I guess my better half
gives me way to much time to think too :wow:...C-ya...HH...Bobby
 
About Coin Depths

Here in the Midwest (Ohio) we have earhtworms in our soil. I was always told these earthworms brought up new soil each year and made items on the top of the soil sink. Also we have yearly freezing and thawing. My two cents worth. Hey maybe three cents.
 
Thanks for the interesting info...I know we've discussed this topic in depth before on the forum..seems like we came up with over 50 variables ...probably are a good many more...Roadrunner
 
I've always had a problem with "sink rates". Maybe they sink a little, but I'm more inclined to believe that annual vegetation decay, dropping pine needles and tree leaves, dust & dirt accumulation, etc.has more to do with it. Every time the lawn gets cut with a mulching blade (or simply not bagged & removed) we're adding depth to the soil and covering up what's there with more and more top soil over time...
 
Back
Top Bottom