GP 3000 settings?

[Digger Bob]

I had something odd happen this last weekend. Maybe someone out there can enlighten me as to what caused this.

While testing a new machine in the field, we buried a large nugget (about 1/4 oz.) about 8 inches deep. Normally this is a no brainer as far as the signal strength from my 3000. But this time when I went over it, there was virtually no signal. Going slower and scrubbing the ground produced a weak low signal like deep iron. I usually hunt in Deep and Sensitive to pick up the small ones. I now started fooling with the controls to try to figure out what was wrong. As soon as I switched to Normal from sensitive, the signal boomed through, even several inches above the ground. The same thing happened in salt mode.

So, my question is what does that say about the ground? Highly mineralised or low. Why such a pronounced difference on a relatively shallow target? The ground was damp mud and the nugget setting on hard pan bedrock, bluish-grey in color. Up on the bank where we usually hunt, it's red and fairly hot ground. I was using the stock 11" DD loop and all the usual settings that have produced many deep nuggets over the years. It's shaken my confidence a bit and may have to go back over some ground I thought was cleaned out.

Digger Bob

 

[DOC]

Digger. if I remember correctly, senstive should never be used unless you are looking for small surface targets. You should normally always hunt in normal.

I know for a long time I hunted in sensitive thinking it would be more sensitive to targets, and then I went back to the manual and learned that you lose depth in sensitve because it is designed to help you find small very shallow targets.

You can call Gus at my office, 1-800-477-3211 and talk to him, he knows all of the machines inside and out.

Take care!

DOC

 

[Digger Bob]

First of all, thanks to all who responded. I've gotten a wide range of opinions on the various forums from many respected sources. Let me see if I can summerize and expand on what happened.

The area has two distinct gold bearing "fields". The first is brick hard clay ranging up to 12 inches deep with decomposing granite bedrock under it. "Large" nuggets up to 6 dwt have been found on the bedrock with nothing but trash in the overburden. The over burden is fairly warm and the bedrock mild. This is where I hunted first and got no good signals deep. And it is here where I suspect I may be missing something using these settings. I'll now have to go back after some rain softens things up and try some different settings to test these theorys. I find it hard to believe that I just happened to hit on the right size, shape, and depth of nugget to be undetectable at the usual settings. I'm hoping that is the case, since I know there are more there. But that brings up even more questions.

The second area is the same bedrock covered by only an inch of dirt. Nothing large has ever been found there, but there are lots of .1 and .2 dwt pieces imbedded in it. Working in Sensitive makes these little ones pop even with a 11" loop. I've had these little ones "disapear" when hunting in Normal.

I've found large and small, shallow and deep, using the Sensitive and Deep and the ground usually doesn't cause an instability problem. That's why I was so mystified with the response this time.

I ground balanced each time after changing settings. I even changed to fixed before going over it.

One of the problems of course, is that in a new area you don't know what size gold is there or how deep until you start finding something (if there even is anything) So, hunting the same ground twice or even three times with different settings becomes time consuming when there is more ground to check out.

My favorite loop is the DD Wallaby but was using the stock loop this trip. I'll now have to play with other loops and nuggets and see if I can duplicate this with monos and well as the pro coils. The nugget was solid, not porous nor quartzy. A 3 ozer buried 12 inches boomed as did a 1 ozer in the same ground with the same settings.

Strange... well, back to the drawing board

Digger Bob


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"In Gold We Trust"