Something interesting witht he 7

Was out today and thought id take along a test bit to muck around with settings and see what would happen.
The test bit is a 5 gram bit that was found with a 5000 and 12" coil, recovered from a depth of around 14". It wasn't dug from the side of the hole and I thought it was at the bottom, it was from the bottom as there was a rock sitting on top of it. Its one of those bits you know exactly how deep it was which is why I took it out with me.
I was surprised I could only get it at 11" with the 7000, regardless of if I used High Yield or General. Nothing special about the nugget either.
Thing is I got a 4.2 g bit deeper than that with the 7000 the other week.
Im beginning to think that although the 7 does go deeper, it doesn't on all gold and that on some it goes shallower. Or, that for some it doesn't see that well. But yeah, I know, all detectors have blind spots/windows.
If I had not brought a 7 and tested it out using this bit I would have thought for sure the 7 is junk. But its not.
ps.. I found the test bit in worse ground than I tried it in today.

Canned Heat wrote:Was out today and thought id take along a test bit to muck around with settings and see what would happen.
The test bit is a 5 gram bit that was found with a 5000 and 12" coil, recovered from a depth of around 14". It wasn't dug from the side of the hole and I thought it was at the bottom, it was from the bottom as there was a rock sitting on top of it. Its one of those bits you know exactly how deep it was which is why I took it out with me.
I was surprised I could only get it at 11" with the 7000, regardless of if I used High Yield or General. Nothing special about the nugget either.
Thing is I got a 4.2 g bit deeper than that with the 7000 the other week.
Im beginning to think that although the 7 does go deeper, it doesn't on all gold and that on some it goes shallower. Or, that for some it doesn't see that well. But yeah, I know, all detectors have blind spots/windows.
If I had not brought a 7 and tested it out using this bit I would have thought for sure the 7 is junk. But its not.
ps.. I found the test bit in worse ground than I tried it in today.

G'day Canned Heat

Yes but now it is only an air test with the 5 gram bit, what you must remember is that on undug targets mostly you get better depth than once its out.

You need to rebury the 5 grammer and leave it the ground for quite a few million years and then you may get a better result.

cheers dave

Then the same could be said about the video with Bruce Candy at Jupiter Creek! Or the tests done by other forum members.
So are you saying that a nugget that can be heard with a 5000 at 14" buried but can only be heard by a 7000 at 11" will be heard deeper if it was undug by the 7000, say 16"? It was first heard at 14 with the 5 undug and still at 14 when all the ground was removed, with the rock. It can still be heard at 14.
So if an undug target gets better depth then why do targets signals increase as we remove the dirt and gravels? Shouldn't they diminish!?
To the point that when we have removed the bulk of it all, say 90%, the signal is greatly weaker.
You get a faint signal, remove some dirt, it gets louder, remove some more (adding more air to the mix) yet its louder still or at least the same and still well and truly there. Why isn't it decreasing?
True, some targets seem to move as we dig with the effect of removing the ground and some do, not very many though, get a tiny bit weaker but the number of the weaker I could count on my hand.
How many times have we heard a faint signal and thought "hmm, maybe" and as we dig and remove ground, adding air to the mix, it gets louder and we go "yep that's a target"?

Canned Heat, when you are digging a target, normally you dip the coil into the hole or along the contour of your scraping so your coil is getting closer to the target, hence it gets louder. I think and I emphasise the think part of it, if you dig a hole over a target and wave your coil at ground level without dipping the coil into the hole, the target may stay the same if not get a bit weaker, but this all depends on the composition of the soil, ie mineralisation, clay content etc.

G'day Canned Heat,

What Dave is getting at, is Air tests are not the Same as a true test on an undisturbed buried target. As you said I have dug many faint iffy targets and the more dirt removed the better the response is. This is true, but once you have removed that target and you bury the same target at the same depth, but everything has changed the ground is not the same as it was, once it has been disturbed. Hope this makes sense.

Cheers.

Mike.

G'day Canned heat,

What Dave & Mike are saying is true, when the nugget was still in the ground under the rock the halo surrounding the nugget gives it a better magnetic field to be detected, Halo caused but the leaching of silver,copper, etc from the nugget into surrounding soil over a long period of time.
Some detectors will pick up a freshly buried target better than they will after 12 months time, as I've found out with earlier VLF detector (Midas).
but the target has not been their longer enough to create a halo of such.


Cheers Mick

Thanks Canned Heat for sharing your observation.

At first I thought the Bipolar Constant Current Pulse system may not have detection holes, but the scatter graph in Dr Candy's white paper clearly shows that the 7 does indeed posses holes, wherein some nuggets have a weaker than expected response.

Your test nugget is likely one such, but as you noted you have another smaller nugget found deeper that was clearly not in any detection hole.

I think anyone serious about detecting all possible gold on a NEWLY discoverd patch, actually needs to use both the GPZ and GPX, to cover all bases.

Cheers.
Kev.

P.S. these holes appear to be an interaction between the timings ground exclusion function, the actual soil composition, the ground balance algorithm and the nuggets inherent characteristics, all very complex.

This emphasizes what others above have said about replicating and comparing recoveries, way too many variables at play. I still believe you have located a hole though. If you were able to use Normal that would've been interesting. I have been gobsmacked by what I have seen.....more later. Adieu.

Mike54 wrote:
This is true, but once you have removed that target and you bury the same target at the same depth, but everything has changed the ground is not the same as it was, once it has been disturbed.  

Are you really burying it at the same depth though?
You must also take into account in such a situation the mechanics of digging out your target! To remove one from depth it requires you to dig past the target to lever it out in the dirt. Thus making the finished holes bottom deeper than where the target rested! Put a target back in such a hole, one that was faint, and you probably wont hear it for that simple reason, not because the ground did anything. Also what often happens is the target was not directly below where one thinks it is and excavating the hole deeper and wider causes one that is actually in the side to fall deeper into the hole. This I have noticed often and would explain how many think it was the ground that gave them the response. Hence some claims by some I have met that say they recovered a target from ridiculous depths for the size. A nugget that was only 10" deep but a hole that was dug that was 18" for example.
Whilst I have had the rare target, and I say rare, slightly diminish on the first dig, I have not had one that I believe disappeared due to the removal of the ground. I have had them seem to move from where I first thought they were and that was for sure the ground, but not otherwise.
An no with any of my experiences has it been the target getting louder from dipping my coil into the hole.

Canned Heat wrote:

Mike54 wrote:
This is true, but once you have removed that target and you bury the same target at the same depth, but everything has changed the ground is not the same as it was, once it has been disturbed.  

Are you really burying it at the same depth though?
You must also take into account in such a situation the mechanics of digging out your target! To remove one from depth it requires you to dig past the target to lever it out in the dirt. Thus making the finished holes bottom deeper than where the target rested! Put a target back in such a hole, one that was faint, and you probably wont hear it for that simple reason, not because the ground did anything. Also what often happens is the target was not directly below where one thinks it is and excavating the hole deeper and wider causes one that is actually in the side to fall deeper into the hole. This I have noticed often and would explain how many think it was the ground that gave them the response. Hence some claims by some I have met that say they recovered a target from ridiculous depths for the size. A nugget that was only 10" deep but a hole that was dug that was 18" for example.
Whilst I have had the rare target, and I say rare, slightly diminish on the first dig, I have not had one that I believe disappeared due to the removal of the ground. I have had them seem to move from where I first thought they were and that was for sure the ground, but not otherwise.
An no with any of my experiences has it been the target getting louder from dipping my coil into the hole.

Well you must not have been detecting for very long or you must have not been to a lot of different areas.
I've dug many many nuggets that once removed from the ground were undetectable at the depth that they were recovered from.
Even got a few on video.
I know what depth they came from for sure as I found them cemented in the bottom of my hole.
This is very pronounced in some ground types, we call this ground penetrating ground.
It has to do with the conductive property's of the ground, some ground carries the signal much deeper/further, and some ground reduces the depth.
In one place we go to when the ground is moist we have got 2x the air depth on nuggets in this area.

Well I agree with much of what you said Canned Heat although I have only been detecting for 25 years.

G'day Canned Heat,

Yes I can see where you are coming from, but in my 30+ years experience of detecting I am pretty sure I have enough experience to know how to pinpoint a target in the ground. Yes there is one particular Nugget (1/2oz) in Cap rock over in WA where we had the same thing happen to me, each time we chiseled a bit more rock out of the hole the Target seemed to change positions in the hole.     This one was a weird one indeed.  Many times I have dug a deep nugget and have bottomed right on top of the nugget, with the last scoop of dirt leaving the nugget sitting in its resting place staring at me as I look into the hole.  As for the reburying a nugget, as  I said once you have dug/disturbed the dirt/soil you have changed its properties ie loosened/caused air rated, mixed its original status, there is so many variables it is not funny.  Anyway I have waffled on a bit here, but I don't mean to come across as a smart@ss I am just trying to share my experiences with everyone.  

Cheers.

Mike.

No problems people. I have not disputed the fact that there does exist the halo effect on some nuggets but I don't believe it is encountered as often as people think. Yes for sure on those moving targets but even then I don't feel its always attributed to the halo effect and is sometimes just the ground or the structure of the gold. The other day I had a small 1.5 g bit move about on me but given its prickly nature and the fact that even when dug out and the coil was raised well above it, it still warbled. With this bit I believe it was the structure of the gold that caused it. There are a lot of variables to take into account. Such as did the nugget get to its final resting spot in a relative short amount of time allowing for the leaching process to take place mostly there? Or did it do some travelling and have it leached out on several occasions or over the course of its travels leaving it with most of it done elsewhere and little if any where it lay? The possibilities are endless. What about tiny bits that seem to move, do they really have a significant halo created around them to cause the effect? But again, I never disputed the halo effect.
I wonder how many people factor into the account of telling others how deep a target was the fact that they also levered out a few to several inches of dirt below the target to get it out? The hole being 15 inches deep but the nugget was really only 11. Not too many is my guess from experience. The hole I dug for the 1.5 g in the end was about 8 inches but Id call 5 inches for actual depth. Unless I see it in the bottom of the hole still embedded I generally subtract 3 inches, sometimes a bit more depending.
The cigar goes to Alchemist for picking up on the intent of the original post, well spotted mate.

G'day CannedHeat,

That is why in my first post of the 50+ gram that we found the very first nugget we found with the 7000. I quoted it was 20-24" as it came out in the last hand full of dirt in the bottom of our hole and still incased in clay/dirt, the hole was 24" deep, but I allowed the extra and said it was a good 20".
Yes you are right there is many variables and we know for a fact that a lot of the ground here in Vic does hide the Gold.

Cheers.

Mike.

Canned Heat wrote:  No problems people. I have not disputed the fact that there does exist the halo effect on some nuggets but I don't believe it is encountered as often as people think. Yes for sure on those moving targets but even then I don't feel its always attributed to the halo effect and is sometimes just the ground or the structure of the gold. The other day I had a small 1.5 g bit move about on me but given its prickly nature and the fact that even when dug out and the coil was raised well above it, it still warbled. With this bit I believe it was the structure of the gold that caused it. There are a lot of variables to take into account. Such as did the nugget get to its final resting spot in a relative short amount of time allowing for the leaching process to take place mostly there? Or did it do some travelling and have it leached out on several occasions or over the course of its travels leaving it with most of it done elsewhere and little if any where it lay? The possibilities are endless. What about tiny bits that seem to move, do they really have a significant halo created around them to cause the effect? But again, I never disputed the halo effect.
I wonder how many people factor into the account of telling others how deep a target was the fact that they also levered out a few to several inches of dirt below the target to get it out? The hole being 15 inches deep but the nugget was really only 11. Not too many is my guess from experience. The hole I dug for the 1.5 g in the end was about 8 inches but Id call 5 inches for actual depth. Unless I see it in the bottom of the hole still embedded I generally subtract 3 inches, sometimes a bit more depending.
The cigar goes to Alchemist for picking up on the intent of the original post, well spotted mate.

I don't think the halo effect has any real effect on gold as it is nearly totaly inert, and if you get silver oxide or copper oxide or other salts of these minerals they are un detectable and the concentration of these mobile mineral salts would be only ppm.
I think it has more to do with the conductive properties of the undisturbed ground.
I have done a fair bit of experimental work with rocks and minerals for use in semiconductor's and altering magnetic fields.
And I have seen some surprising results on how certain rocks and mineral's conduct and alter electric or magnetic energy.

Good on you Mike for factoring that in.
On the halo effect, im going to try an experiment in the coming weeks. Ill let you all know about it when im done.

l can't explain why but I've had numerous smaller nuggets that gave a nice clear signal in the ground but once dug gives only a faint signal making it hard to locate and then the opposite with kinder surprises that scream out and get you thinking you have a reasonable nugget that when cracked open has you wondering how such a small nugget can make such a loud noise

Interesting concept Canned Heat, I'd never really thought about that before. One could make the supposition that Halos are more likely to form in primary, residual, or near source elluvial deposits, where ground chemistry supports base metal leaching over long undisturbed periods. Once the gold meets the alluvial environment it usually already has an enriched pure gold rim and is recycled too frequently to allow any remaining impurities to develop Halos.

A number of people in the industry refute the possibility of Halos existing, mostly due to the lack of any reliable experimental data to support it. I believe in halos since I've seen the phenomena enough times in the field to know something is going on. I believe it has to do with metal oxides, especially cuprous oxide, forming dendritic pathways or nano-chains allowing conduction of Voltaic or magnetic forces from the surrounding rock strata.

These oxides have a semiconducting like effect when our detectors field hits them, they rectify the energy, in effect amplifying the response to the field. Hence the extreme depth or sensitivity to small or deep targets way beyond what we would normally expect. It appears from Zed reports that the ZVT method may in fact take advantage of the "Halo effect" Whereas traditional PI tech, such as the GPX, hits better on consolidated nuggets at extreme depths, and is better suited to eddy currents formed deep within the nugget and not only in the skin.

I was under the impression that Canned Heat had a nugget that was detected by a GPX at 14" depth. Even with the soil removed the GPX still gave a depth of 14". One would expect that the GPZ should have given a similar depth of 14" or more, but no it was 11".
Nothing to do with Halos since the GPX depth didn’t diminish after exhumation. Clearly a detection hole in the Zed for that nugget/timing/GB combination.

If it is correct that ZVT favours nuggets undergoing the process of secondary accretion and chemical enrichment, as reports seem to indicate, then it might be advantageous to focus on such areas.

I'll have that Havana now thanks.

Yeah Alchemist, I reckon its one of those nuggets that the 7 doesn't get well. I believe the same happens to most detectors.
I know an old guy from Dunolly who once found a nugget, 20 something grams (27 or 29g in that weight range roughly) with his 2100 or it might have been his 22, I cant recall which it was right now, but it could only be detected from about 8 or 9 inches deep. There was nothing remarkable about it and it wasn't spongy or prickly or anything like that just a typical nuggety looking bit. But it had a lot of people talking at the time. Most didn't believe it till he let them have a go at it with their detectors. Had a lot of people scratching their heads. What I noticed too with that bit of mine is how quickly the cut off point was for the 7 hearing it. No real fade out, just you could hear it well and raise the coil a touch and it was gone. A real abrupt loss of signal. Gold, it does my head in at times.

Clearly a detection hole in the Zed for that nugget/timing/GB combination.

Much too early to be jumping to conclusions after just one test, I should think. Maybe other factors are influencing the outcome, like ground conditions or human factors. Most of us are comfortable with the GPX but still pretty new to the zed. Lets wait and see if others are also getting similar results or if Canned Heat can reproduce his. Even if there were a detection hole, would it really matter? No-one seemed to notice the holes in the GPX until only recently.

BTW how's the new zed handling, alchemist? Anything to report back.

Sorry Canned Heat, going a bit off topic here, but still Zed relevant.

No shame in holes Nebuchadnezzar, all PIs have them. I like to think the Zed covers more than it leaves though.

I've not had enough time on the machine to make any solid contributions other than I believe the Zed is the most powerful detector I've ever seen and it will take quite a bit of skill and patience on the part of the operator to fully utilise this power.

From what I've experienced and from what others have reported, especially very early on, I believe people are pushing it way too much and then having to dumb it down to stabilise it. For instance, Sensitivity/Gain; 10 on the Zed is not equivalent to 10 on a GPX. I think that previous GPX users, who for argument sake consistently ran their GPX at a gain of 12, may feel that they have to run the Zed at 12 or they'll miss too much. Not so, the Zed is way different. Here's a little example, I can run my GPX in my living room only if I use cancel and set the Gain below 5, even then she warbles like the proverbial Fat Lady. I can comfortably run the Zed in my living, but I need to also turn the Sensitivity below 5 to get a usable threshold. Here's the point, even setting the Zed to a gain of 1, a 5c piece gives a very clear consistently repeatable signal at 17 to 18 inches. One and a half feet for a coin on the lowest Gain setting. This illustrates the difference between the machines Gain function, and not EMI immunity alone.

People are effectively hobbling some of the Zeds available power. To stabilize the machine they  apply extra Audio Smoothing, which subtracts target information from the audio stream, they are using a higher level of Ground Mode/Exclusion, which subtracts target information from the input summation circuits, in an attempt to lower ground noise. Before extending these and throwing away target information it would be best to consider lowering the Sensitivity/Gain and/or Target/Volume, and working with a little instability, after all it’s not a GPX.

I'd be interested to see if you come to similar conclusions Nebuchadnezzar, either way the Zed at first appears simple, but there is a balancing point in there, and finding it is the key, since with digitally processed detectors, the point is reached where the target signal is binary, either there or not, no grey areas in between like analogue that a signal enhancer can highlight. A few too many clicks here or there will either inhibit a signal completely, or switch it on.

Anyway I'll have more at a later on.              
Cheers.

alchemist wrote:Sorry Canned Heat, going a bit off topic here, but still Zed relevant.

Not a problem at all, what conversation in real life doesn't deviate a bit here and there? Normal communication mate, all good.
I agree with that, that the 7 appears simple. But you really have to drive it huh! Im often changing or fiddling with things to keep it on song.
The quick start could give one the impression its a set and forget, though I have never used it apart from using it to reset the 7 one day when it didn't want to play (a couple of settings wouldn't budge), you gotta drive it.

Thanks for some very good info alchemist. Although I'm talking about a GPX here, I've always thought some people were way overstretching the gain on their machines. I'll keep in mind to only use Audio Smoothing on the zed as a last resort, although this might be hard on very hot ground. Wait and see, I guess.

When I get out in the field in a few weeks time I'll do some testing of my own. I'll first hit my old patches as well as some well known patches that produced deep nuggets and see how I go. If I don't get too excited in the process I"ll also do some comparative testing with my 5k.