2012 - A Student of Sand

[bigscoop]

This summer has been especially slow here on the East Coast, so.....like many others I was forced to become a student of deep sand. Given this, I just want to take some time to tell you what I learned in sand school this year.

A different way to look at things:

I just went through several gold and silver rings I have on hand, measuring and weighing each one. The biggest ring I have on hand is just over an inch in diameter, the smallest was right 5/8” in diameter. Of these, the widest band is just under ¾” and the smallest is about 3/16” wide. The heaviest ring is only about 11 grams and the lightest is 2.3 grams. However, even with these relatively small dimensions these are pretty dense metals with very little surface area to help slow their descent, they are certainly many times heavier then the soft and loose surface they are trying to penetrate. Jiggle or vibrate that surface just a bit and the task of sinking even becomes much easier, much faster. Such a tiny item, and miles and miles of deep sand. Well, you get the picture. But sometimes even great coverage isn't enough, and believe me, I spent hours upon hours with the deepest and most sensitive machines I could get my hands on, all the while making sure I never missed a single inch of sand. Sure, every great once in a while I'd find a nice recent drop but over all the results still proved dismal for the time and labors invested. So here's what all this labor and time taught me this year.

Try this, the next time you are walking on top of the wet sand take note of the water around your feet that gets squeezed out from under you with each stride, then watch that water get sucked back in as you raise your foot. In reality you just created a type of “sponge effect” everywhere you step, now imagine hundreds of feet passing all over this same section of beach. Think of all the minute vibrations that are taking place and acting to disturb this soft wet sand, even the crashing of the waves at the breaker line can be felt throughout this soft wet sand. You can’t always see it, but these very fine, soft wet sand particles are always shifting and moving, if ever so slightly. And as it continues to move, our heavier items with little surface area keep right on sinking. Raise your foot and stomp down on this wet sand, the effects of this constant vibration is now clearly magnified as you can easily see the vibration you created spread out from the point of impact. If we could take a tiny, very sensitive microphone and bury it several feet deep in this wet sand we would be amazed by the amount of constant vibration we would hear. We would hear the passing of every vehicle, the pounding of every wave, the passing of every footstep, etc. And each time we hear these things this soft wet sand is, even if only minutely, moving and shifting.

Gold prospectors and even diamond hunters have recognized this for centuries, that the heaviest and most dense items will always be found near, or on, some form of hard pack under these lighter and less dense surfaces. This same basic knowledge is even applied as they are actively panning or slucing or high-banking, etc. Shake all the collected material and then look for the heavier, more dense, pieces to be found at the bottom. This same concept is what makes our beaches so tough to hunt when there is a lot of soft wet sand over the harder packs, if you don’t get the recently lost items quickly they will get buried too swiftly and to deep for our detection And they will keep right on sinking until they reach a point where the substrate is as least as dense as they are. The more vibration and movement that takes place in these lighter surfaces the faster our denser items will pass through them. But take away all this soft wet sand and……well, I get excited just thinking about it! Yes the deep wet sand of this past summer has been a bummer, and while I have resigned to other pursuits for the time being, this sand has played this same trick on just every other hunter too, so, there must be "a lot" of goodies just out of our reach and prime for the picking when this deep wet sand gets removed.

 

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[MrNelson]

I agree... I noticed when i dig here on the low tide its at least 14" of soft mush untill i hit hard stuff. When does the mush go away?

 

[hamiddetecting]

Good luck!

 

[jim/wpb]

On the east coast of Florida, sand is a by-product of limestone and shells. It has a variety of sizes from the most miniscle 1/1000th of an inch on to about 2 mm by definition. The smaller particles of sand find their way to the deeper depths, compact nicely and become almost hard. This fine sand becomes the catcher's mitt for dense metals like gold and silver.

Think of a sanded in beach as Quick Sand as waves continually saturate it. It occurs almost anywhere if the conditions are right. Quick sand is basically an ordinary sand that has been so saturated with water that the friction between sand particles is reduced. Thus the resulting sand is a mushy mixture of sand and water that can no longer support any weight including its own. That is when Heavy Metals drop to the next layer. A better word for this is "hydraulics" which is when sand is moved or effected by liquid. "hydraulic erosion".

All items that are denser than sand will drop through it because of the hydraulics of the sand/water mix.

Please also keep in mind that when sand is saturated and bouyant it can easily be moved by wave action either in or out. Sand has a tendency of moving in if wave action is over a 4 second increment; and moves out if the action is under 4 seconds.

 

[smuggy]

I enjoy reading these posts on the technical side of detecting. Here in New Jersey where I hunt the beaches have also been badly sanded in this summer. Hunting is slow and the gold is few and far between. Can't wait for a good old coastal storm to shake things up. HH

 

[Crispin]

Conservation of Mass/Energy: Matter can neither be created nor destroyed. Heavy items have a tendancy to settle out but the same vibrations that send them down can also churn them back up. Albeit, gravitational potential energy pulls things down at a greater rate then random entropy brings them up...it still brings them up. The most movement of sand will take place where the most energy is exerted. On any beach, the most movement of sand takes place at and above where the waves break. Kinetic energy is applied at the point where the wave breaks and pushes up the beach but an equal amount of gravitational potential energy is applied as the water receeds; thus, providing a no sum gain or loss. In sanded in beaches the best chance of finding gold is:
A. Waist to chest deep water.
B. Knee to waist deep water.
C. Ankle to knee deep water.
D. Ankle deep water through the wet sand line.
I cannot answer this question with anything other then opinion. However, I would opine that the answer is D. As the previous posts point out the soft wet sand quickly claims most new drops. This weekend I had zero luck any deeper then ankle level. When I moved to the breakline and tideline I found old crusted coins, earrings, and a teenie tiny ring. I doubt you will find heavy rings in these areas because the amount of random energy needed to bring them to the top is too great; but, the lighter metal objects are constantly going from deeper to shallower levels in these areas.
Just one man's thoughts. Good luck.

 

[billinstuart]

Maybe in WPB, but north of there true beach sand comes out of the rivers from the mountains, is round and smooth, and very uniform in size. I did my undergraduate thesis on beach erosion at Daytona.

1) The steepness of the beach is proportional to the coarseness of the sand. fine sand, smooth hard beach.
2) Fine sand is more easily transported than coarse sand. Dunes are comprised of VERY fine wind blown sand. Coarse sand doesn't move easily!
3) On the treasure coast, because of all the CRAP! the corps of engineers has deposited on our beaches, we no longer have natural beaches
4) Soft sand (dirt) is probably recently deposited from wave action and doesn't contain much of anything valuable..metal is harder to transport.
5) The heavy stuff does indeed sink to the hardpan layer.
6) As the beaches erode, this hardpan layer becomes more readily accessible.

 

[bigscoop]

Was at 27th street this afternoon at low tide. I'm 5' 7" and I was head tall even with the furthest pole. This spring it was easily 3ft or more taller then I am. I took the Excal with 8 inch coil and planned on working the breaker line back and forth for a while but there was so much soft sand moving in the increased currents it kept trying to swallow my coil whenever I let the coil touch bottom. I finally resigned to the wet sand until the storms moved in about thirty minutes later. Hit a few recent coins, pull tabs, bottle caps, etc., all the lighter stuff one would expect. But, I do think the sand is starting to move a bit, especially in the troughs where the long currents have been working it over for quite a while now. Problem is, those currents are still too strong to hunt.