Report On Noisy, Salty Northern Nevada Ground, The GPZ And The SDC

[Reno Chris]

Many of the prospectors here sometimes prospect in Northern Nevada, and like a number of GPZ users prospecting in northern Nevada, I have been experiencing issues in certain places with the GPZ moaning and groaning over wet ground that is a little bit salty. The amount of salt in the ground at various places in northern Nevada ranges from not salty at all to fairly salty with all ranges in between. When fully dried out this ground is no problem, but when wet it is a whole different story. Some places the salt is no issue, while in others it is very noticeable. Salt, by itself, is not conductive and dry salt will not respond to a metal detector, but when dissolved in water the salty solution is conductive. The extreme of this is wet ocean beach sand. The salty placer areas of northern Nevada are not nearly as salty as ocean beach sand but they have proven to be salty enough to cause the GPZ to have difficulty with this ground. Here in Northern Nevada we have had an unusually wet period of about the last six weeks. Much ground is now saturated wet and in places there are even puddles of standing water. Even where the surface is dried out, an inch or two below the dry surface crust the ground is fairly damp.
I was camped recently in an RV park in the Pershing / Humboldt County gold areas of northern Nevada and was approached by GPZ owners also staying in the same park expressing their concerns about the GPZ ground balancing in these areas of salty wet ground. A good ground balance with a stable and quiet threshold cannot be achieved in these areas. A slow swing speed is the best way to deal with the groaning at present. Slowing way down does greatly reduce the groaning, but it does not totally eliminate it. The good news is that once this ground dries out fully, the GPZ will have no problem with the ground. The downside of this is that we have had so much rain in the last six weeks that it will likely take more than a month of dry weather before the ground dries out to the point where the salt will no longer be an issue.
So I wanted to make some tests to determine what level of problem the salty ground is really causing out here in northern Nevada. A while back, Steve found a nugget patch in northern Nevada. I will not say where or exactly when that occurred, but the ground is salty and does groan quite a bit with the GPZ when its wet. In some spots on this area the wet ground really does make quite a bit of noise. Steve gridded the spot very carefully with his GPZ, and I walked around on it afterward with my GPZ and did not find any additional gold – he cleaned it very well. However, we have had a lot of rain in the last two months and I consider this an excellent spot to try out an alternative to the GPZ to see if the salty ground would cause targets to be missed. I wondered if there might be very small bits that the GPZ had missed because the groaning ground overwhelmed the target response of small targets. I figured the SDC 2300 would be a great alternative to see what, if anything, the GPZ might have left behind. So I took my SDC 2300 to the spot to see what I could find. First, I will say that even in the non-salt mode, the SDC 2300 did not have nearly the same level of difficulty with the salt. In the salt mode, the SDC was nice and quiet. I have to admit that the nice quiet threshold of the SDC was a lot more pleasant to listen to than the moaning and groaning of the GPZ. I went over the spot fairly well with the SDC and found a number of very small pieces of trash, the vast majority of which were tiny pieces of steel window screen manufactured with a wire less than a quarter of a millimeter in diameter. I did find one small nugget which weighed 0.22 g on my very accurate scale.
Here is my conclusion after testing the SDC with its salt mode versus the GPZ on salty ground with comparatively shallow gold:
First, Steve didn't miss much. Even though his detector moaned and groaned (and my GPZ did too), he was hearing essentially all the targets in the ground. He may have missed one very small nugget, and the window screen wire bits were very small and near or possibly below the limit of what the GPZ could hear anyway (I think on these tiniest of targets, the SDC is a bit more sensitive). My conclusion about this testing was that if you know what to listen for and listen carefully on that salty Northern Nevada ground, you are not missing much of anything with your GPZ. The ground noise may be annoying to listen to, but if you're listening carefully you're not missing much. I now have more confidence in my GPZ going over these grounds – it will be nice however when the ground dries out and the groaning goes away.

[bado1]

Great report, Chris. Certainly shows why having more than one "arrow" in the quiver can be advantageous. Owning both of those machines I think would cover most prospecting situations. The addition of a good VLF for trashy areas would round out them out.

Did you notice much depth loss hunting in the salt mode on the SDC? Not that it would make much of a difference in that if the machine isn't stable you won't be effective at any depth. Thanks again!

 

Dean

[Norvic]

Reading this post and other posts in the 4Ms archives, it seems you folks have ground just the same as we have here in OZ. Most of the ground I prospect in NQ OZ is only slightly noisy. If wet even less noisy and more depth penetration. Certainly not like your salt areas, nor like some areas of WA or in particular some patches around Wedderburn in Victoria OZ.

Got me thinking and must ask you fellows that have experienced both US and OZ fields, is there really any difference, is it just a myth downunder that our ground is the worst to detect in?

[Reno Chris]

Got me thinking and must ask you fellows that have experienced both US and OZ fields, is there really any difference, is it just a myth downunder that our ground is the worst to detect in?

No Myth. Topographically places in northern Nevada look somewhat like WA, but geologically, its night and day different. We have some places in the Western US that are bad, some as bad as Australia, but overall, you are way worse. There are a few mild places in WA, and there are a few bad places in the US. We just have a lot less iron in the ground where most of our gold deposits are. Salt however, is totally different to ground balance as compared iron rich, magnetically reactive soils.

[Norvic]

Yeah I did some detecting in the salt lakes of WA back a bit, certainly difficult. We are probably fortunate in QLD OZ, we do have some "hot" areas, but overall tis quiet, well where I`ve been. But I get you the iron richness is what makes WA  gold deposits different to most of yours.

[1515Art]

Hi Chris, Thank you very much for the report and all the help and information you so freely give all of us. I'm really appreciative for the info and it will be a big help for me next month. thanks

 

with the GPZ, when encountering difficult salty ground, i imagine it is difficult to say exactly where you will encounter this problem other than by how the metal detector reacts. Or, do you tend to find the difficult salt ground to be in more low lying areas or pockets? Is there any relationship to heavy salt concentrations in higher areas that might indicate ancient low ground that may also have collected other heavy metals and by this could the GPZ's extreme sensitivity to salt be anyway advantageous?

[Reno Chris]

The conditions that cause salt in the ground have little to do with the conditions that cause gold to be present. Plenty of salty places with no gold,

[klunker]

Thanks  Chris for taking the time to do an excellent write up.

 

 That would have taken me all a day to write and I would have a blister on my finger.

[hawkeye]

Hey, I found some of that window screen wire with my 2300 in N Nevada too.   Must have been after Steve cleaned out the patch.     Thanks for nice write up Chris. 

[Reno Chris]

I've found that window screen in a bunch of places. For some reason the desert old timers liked it - it was cheaper than a real window. One window screen, once rusted can break up and the wind will contaminate dozens of acres with little wires a quarter to a half inch long.