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OK - Do Coins Sink or Not?
Posted by: berryman
Date: June 10, 2013 02:20PM
After they're dropped, do coins sink or are they simply covered over by new surface materials (e.g., dirt, grass, etc.)? I've heard both arguments but don't know if anyone has ever put either theory to the test.

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Re: OK - Do Coins Sink or Not?
Posted by: Larry (IL)
Date: June 10, 2013 02:37PM
I have read about the tests that have been done and they don't sink by gravity as some think because gravity is constant on all matter, but they can sink by other means such as freeze and thaw movement, rodents and bugs in the ground, people walking on them and many more reasons. Most of the older coins deep in the ground are covered up over time with airborne dust and decomposition of leaves, grass and the like.



Bells and whistles are nice, but nothing will substitute for the basic understanding of the hobby.

:minelab: CTX 3030, :whites: V3i



Edited 1 time(s). Last edit at 06/10/2013 02:38PM by Larry (IL).

Re: OK - Do Coins Sink or Not?
Posted by: BarberBill
Date: June 10, 2013 03:04PM
I think Larry hits it right on the head. There are lots of variables as to why and how deep a coin may end up, but with the exception of sloppy mud or water I don't think coins "sink" in the normal sense of the word.
BB



North Idaho - A bunch of Tesoros, 3 Whites, Gray Ghosts, Sunray probe
If you don't dig it, you'll never know!

Re: OK - Do Coins Sink or Not?
Posted by: dan93
Date: June 10, 2013 03:56PM
Here is a link on soil forensics
Centre for Australian Forensic Soil Science
there are books on soil science as well that might help answer question, one of the oldest coins I found was after winter and it was only 1" under the ground
maybe coins rise too after freeze thaw.

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Re: OK - Do Coins Sink or Not?
Posted by: MarkCZ
Date: June 10, 2013 03:59PM
Hey I like the one about rain beats them into the ground!
Soft muddy spots they will sink,
beach sand all the time moving they may sink,

But places like yards, parks, and soccer fields and the grass clippings are not collected its "Soil Growth" Often times wooded area hunts coins will not be as deep over the same time span as coins lost in a park.
I'm with Larry!

Mark

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Re: OK - Do Coins Sink or Not?
Posted by: Larry (IL)
Date: June 10, 2013 04:50PM
It's a whole new subject on density and hydrology issues when water gets involved. The coin sinks :biggrin:



Bells and whistles are nice, but nothing will substitute for the basic understanding of the hobby.

:minelab: CTX 3030, :whites: V3i

Re: OK - Do Coins Sink or Not?
Posted by: Hobo lobo
Date: June 10, 2013 05:32PM
Larry is mostly right. Lay a coin on the bare ground and place a 50 year 2' x 2' box over it. In 50 years remove the box and see how far it has sunk. my bet is it will still be on or very near the surface

Re: OK - Do Coins Sink or Not?
Posted by: GroundScanner
Date: June 10, 2013 06:23PM
I heard that a untouched surface a coin sinks 1 inch every 50 years.

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Re: OK - Do Coins Sink or Not?
Posted by: bootyhoundpa
Date: June 10, 2013 06:25PM
incredible number of variables on this subject and to be quite honest there couldnt any simple answer.....a lot will depend on soil conditions ,long term weather,density of the root system,interference by man such as adding fill or moving soil in any fashion ,etc,etc ..... i know in my area the grass roots seem to hold the coins above the root line for a least a year or two...... i hunted a field across from an elementary school and all the pennies were between 5 and 6 inches deep and all were only about 20 years old,this soil was soft and stone free..... the shallowest silver coin i ever found was in my backyard..it was only 1/2 inch deep in a relatively grass free area near trees..... i remember asking the guy i bought my first detector from this same question twenty some years ago..... he simply said most will sunk a few inches but some will rise with frost heave... then he said not all objects in the soil can keep sinking otherwise all of your finds would be found at the top of the clay layer and nowhere else....kinda made sense to me.....

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Re: OK - Do Coins Sink or Not?
Posted by: KinTN
Date: June 10, 2013 06:26PM
I predict this will be a loooooong thread.

Don't forget ground vibrations and its effect (think earthquake liquefaction in the extreme sense). More obvious on the beach with the constant wave poundings.

Frost heave is real and will move objects towards the surface. But it also opens up the soil, changes the density as water freezes and thaws, + things can move down that way too. The greater the depth of frost, the deeper things can go. Go out some cold winter morning and note how the upper soil has moved. Whether or not coins go up or down, I haven't a clue tho. Probably both depending on how much blue wavelength the Sun is emitting that winter or how the metal detectorist is holding his/her mouth.



Minelab Safari
Minelab Excalibur II

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Re: OK - Do Coins Sink or Not?
Posted by: Rob (IL)
Date: June 10, 2013 07:40PM
This topic has been going on forever. Bottom line, it doesn't help me find coins whether they sink or not. When the post is ended there will be people still thinking both ways. :heh: Did someone say Halo?



"Everyone has an opinion, but mine is free":devil:
"You might very well think that; I couldn't possibly comment..."

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Re: OK - Do Coins Sink or Not?
Posted by: GunnarMN
Date: June 10, 2013 09:15PM
Ants push lots of dirt to the surface i figure hear in minnesota 1/4th " per year or better



ITS BEST TO TRAVLE THE BUMPY ROAD BEFOR THE SMOOTH ONE- curently own a blisstool & tesoro outlaw,

Re: OK - Do Coins Sink or Not?
Posted by: richbat
Date: June 11, 2013 06:28PM
The only time i think coins will sink is in softer soil say like near creek banks,swamps ect. where the soil is more moist.As far as parks and such i think that vegatation plays a bigger roll then anything and not by the coin sinking but new growth over the coin or whatever may be laying there.

Re: OK - Do Coins Sink or Not?
Posted by: Hobo lobo
Date: June 11, 2013 10:24PM
If coins sink, then why? Is it because their heavier,? If so then why do pulltabs sink, since they are about the same specific gravity as soil? IMO coins do not sink nearly as much as they get covered, pushed down and buried. Freezing and thaying may also play a role. In my part of the world things (coins) do not "sink" in undistrubed areas. I have found coins, gold nuggets, meteorites and other objects on the surface that have bee there many many years. Metorites and gold are heavier than dirt and rock.:smile:

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Re: OK - Do Coins Sink or Not?
Posted by: togamac
Date: June 12, 2013 05:13AM
I was flabbergasted to learn as a young man in EOD school that bombs that are dropped from aircraft and fail to explode can be found about 5 feet deep in sand and over 100 feet deep in clay. We learned to sink a shaft in the clay and the digging was TOUGH!
Once they've reached these depths, they do not sink further. It's their initial velocity and of course weight that gets them sunk.
Bottom line: coins are going to stay where they've been dropped unless the critters, frost, etc. disturb them and of course they'll slowly get covered over with leaves, grass, dust, etc.

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