Rain soaked ground and the effect on metal detecting?

Aside from just making digging easier, I am curious about if rain soaked ground increases any detectors ability to detect deeper targets, and has anyone done objective testing in rain soaked vs. dry conditions ??

Tri

In my ground I see silver and copper that are deeper targets when we get a few days of rain and for sure in the winter. Just yesterday in the Gold Country where it has been raining off and on the last week I found a deep 9" 1917 wheat in an area that I find coins from the 1940s. I find more siver dimes also at this park in the winter.

LowBoy

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Read Tom's article on this. He mentions improved depth, but also that it is very site specific, meaning if your site is heavily contaminated with iron, the iron will give stronger signals and mask the good targets more when the ground is socked. Dry ground is the opposite. I think this is what he says if I remember it correctly, but I read this article 3 years ago so not even sure which one it is.

Hi,, I agree that the signal on nails iron etc. does increase with more moisture in the ground...Tin foil is another culprit that will be more prevalent when detecting....With enough moisture I don't think the detectors discriminator will function nearly as good with heavy moisture (you will dig more junk targets)....So over all I believe that just about everything in the ground becomes more conductive....I also believe that you could detect deeper coin targets if there was no junk targets around to hinder the detector...JJ

Unfortunately if it accentuates the good targets it does the same for junk so its a two headed sword kind of thing...

Years ago read an interesting article where a gentleman swore his 1266 did better in dry ground but like the rest of us got some real deepies in rain soaked ground using various units and it had merit but can't confirm as the snap-crackle and pop is not my cup of tea...

Yep to a degree it helps the recovery process but too much and its a muddy mess situation...

The more a target oxidizes............the more 'activated' the target becomes when water is added. Iron will become highly activated with rainwater. Silver and Gold do not oxidize......and water will provide some.....but minimal extra detection depth.

Tri…I have not done any documented testing on targets between dry and moist dirt conditions. I agree with the posts above generally but will emphasize that metal detector responses to whatever ground minerals with variable soil moisture levels can be site specific. Some examples…

My ground is a brown clay based material that is at least partially dominated by magnetite. That is to say the F75 and stock 11” DD combo yield a ground phase of GB84 and a magnetic susceptibility that varies between 0.1 and 0.3%…a kitchen magnet run through loose soil for a few seconds comes up literally covered in magnetite ‘filings’ (for lack of a better word).

My best depth readings on coin targets occur when this ground is dry. When the soil moisture content exceeds ‘damp’ into wet conditions target detection depth suffers…not greatly but definitely noticeable. It’s the difference between acquiring a weak but sure response on a real copper penny at 10” or losing the signal altogether in wet conditions.

A favorite 100+ year old park has rich dark soils, markedly less clay content than surrounding areas. I’ve hunted it for 25 years off and on…and came to believe that soil moisture to the point of “damp or compactible” soil yielded best depth results…despite a higher phase readout and similar magnetic readings to here at home.

Here’s an excerpt from an essay I wrote recently that describes a separate example that has much wider geographical application…

"Some soils become more reactive as soil moisture increases. This phenomenon can reduce EMF penetration and play havoc with target ID. Some experts attribute this condition to enhanced soil mineral ionization resulting from increased soil moisture content. Soil moisture beyond “compactive” soil conditions slightly decreases detection depth in my area, a brown clay-based soil that happens to be marginally dominated by magnetite. Let’s look at a documented soil sample that is representative of soils commonly encountered throughout many southeastern states.

I have a soil sample lab report from a major manufacturer. It provides an analysis of a “reddish” soil sample submitted by a friend residing in a southeastern state. It concludes the soil in a dry state qualifies as “bad ground” but well within the ground rejection range of their current detector models. The engineer recommended that soil type should only be searched when in a dry state. Below is a direct quote about that same red soil in a wet state.

“When wet the sample becomes very had ground, difficult to reject and or penetrate. This type of iron oxide, because of its consistency, achieves a solidity or connection between iron particles making it much harder to reject when wet.”

The report does not specify the iron mineral, but the culprit is undoubtedly maghemite. We can see why the relic hunters in parts of Alabama, Georgia, Tennessee, North Carolina and Virginia have such a difficult time searching these red soils with VLF units. Target depth is reduced, and target ID is practically useless in some areas especially when the soil is wet.”

To summarize, generally some soil moisture does not hurt and I believe it helps with detection depth to coins as an example. In other areas, soil moisture beyond “compactive soil”… particularly ‘wet’ conditions… may very well inhibit EMF penetration, depending on the actual soil minerals present…as in the example above… red or red-brown soils dominated by maghemite.

Jim.

CHARACTERIZATION OF A NANO-MAGHEMITE BEARING, VOLCANICLASTIC FORMATION FROM IDAHO'S EASTERN SNAKE RIVER PLAIN

Samples taken from an iron-rich, weathered basalt formation in Box Canyon in Idaho's volcanic eastern Snake River Plain were analyzed for mineral content and crystal structure; pore size and surface area; iron concentration; and proportion of magnetic material, as an analog to Martian sediments. Using magnetic separation, the sample was found to be comprised of at least 89% magnetic materials. Through quantitative analyses, this material was concluded to be Fe-bearing smectite and nano-crystals of maghemite, a cubic mineral (P4332) that has a structure very similar to that of magnetite (Fd3m). Analysis of total iron concentration using citrate-bicarbonate-dithionite extraction yielded a mean weight percent Fe(II) of 2.86%. X-ray diffraction (XRD) and X-ray energy dispersive spectroscopy (EDS) data indicate that the sample also contains quartz, phillipsite (a potassium-rich zeolite), and nontronite (an Fe(III)-rich smectite).

No wonder the E-Tracs reign supreme around here..........lol

Although........believe it.......or not..........my 20yr old White's Silver Eagle with auto-ground balance, no less.......can detect a freshly buried pre-1982 penny at 8" in this stuff. I did the test this past Saturday in a park. Hope when my T2 gets back from service, it can match/exceed this.



Edited 1 time(s). Last edit at 06/07/2011 12:04PM by TerraDigger.

And that gentlemen, is why I like the Explorers/Etracs!! (and G2)----I'm right next door to you TerraDigger--(OR gold country).----------Del

Thanks



Edited 1 time(s). Last edit at 06/18/2011 02:54PM by Tri.

The analysis was done by a professor...et al...... at the University of Wisconsin.



Edited 1 time(s). Last edit at 06/07/2011 09:15PM by TerraDigger.

Thanks again.



Edited 1 time(s). Last edit at 06/19/2011 02:22PM by Tri.

Jim.............whilst answering SO many PM's from this forum......I answered one specific PM (a couple of days ago) from a forum member with nearly the exact same answer....to the exact same question. Thanks for 'covering me' (in my Private Message saturated) absence.......and my inability to keep up with this forum.

Yes...........rain-water 'saturated' LOW mineral dirt....can somewhat 'enhance' detection depth.
Rain-water 'saturated' HI mineralization dirt can 'activate' the iron-component of the dirt.......and reduce detection depth AND cripple ID capabilities.

A 'controlled-environment' test-garden will dictate what type(s) of conditions you have in your location.