GPZ7000 Tech White Paper

Thank you very much Bruce Candy for this invaluable resource to our better understanding of the GPZ and how to get the most from it.

http://www.minelab.com/__files/f/266297/KBA_24-1%20ZVT%20Technology.pdf

Thanks alchemist for posting this, Interesting reading.

Cheers
Ashley

Ash100456 wrote:Thanks alchemist for posting this, Interesting reading.

Cheers
Ashley

G'day Ashley,
                     I think Bruce has cleared up some important misconceptions with this document.
Among the technical points there are some important operational points.
A couple that really hit me were these.

Cheers
(I hope they don't mind me reproducing it here)

Ground Balancing ‑ VERY IMPORTANT
The best way to ground balance initially after switch on
with the Quick‑Trak trigger depressed, is to sweep the
coil in a typical side‑to‑side search mode at the expected operating
height above the soil surface, e.g. 2–3 cm or whatever the soil
saturation or terrain will allow, but at the same time move forward
at slightly faster than normal walking speed, so as to cover as much
different ground as possible in the first 10 to 12 seconds. The idea
during this initial period after turn on, is to expose the detector to
as much different soil data as reasonably possible to improve the
initial calibration.
IMPORTANT! DO NOT ground balance using a coil up and down
motion (like one would do using a PI detector) initially after turn
on with the Quick‑Trak trigger depressed. This does not give the
initial calibration enough different soil information to calibrate
optimally. If ground balance is required again sometime later (but
without turning the detector off), ONLY THEN is the usual (PI type
of) ground balancing up‑and‑down coil motion OK.

Ground Balance Reset
If you think the detector is producing an
unexpected level of soil signals, switch the
detector off, then on again, and re‑ground balance. Usually
this time your detector will be correctly calibrated from the
restart.
If your detector is still producing an unexpected level of
soil signals, select Quick Start on the Detect page, and then
select Reset Audio and Detector settings when prompted.
The guide will then prompt you to perform a ground
balance again.

Thanks for the link, it's a good document.

A big thankyou to Bruce Candy and Minelab for putting this info onto paper and getting it out for us all to read, I very much appreciate it.

This is some of the info that is needed to get a better understanding of this new machine and how to operate it better and in the way it was designed to be used, instead of trying to use it like a GPX 5000/4500 model.

Thanks again.

cheers dave

The White Paper is part of the reason I've been holding off on posting too much, it gives clear guides on how to get the best outcome for GPZ from the man who invented it. Up till this point I've been a little unsure how much I can say and how much Minelab want me to say when educating their GPZ customers, like I've said elsewhere the GPZ 7000 has been developed to be as simple to use as possible but it is a very complex beast under the hood, having a good grounding in some of that information helps immensely in getting good outcomes for GPZ.

Bruce's paper is superb, it explains things in simple terms and gives very good advice on getting the best out of the detector, I strongly recommend people print the paper out and familiarise themselves with the material.

Lastly, the GPZ is not complicated to use, follow the suggested method of Ground Balancing at the start of each session and your good to go, none of us really need to know everything about how the detector manages itself, just learn and follow the simple procedures required to allow it to do its job.

JP

Thanks JP.

Jonathan Porter wrote: Bruce's paper is superb, it explains things in simple terms and gives very good advice on getting the best out of the detector, I strongly recommend people print the paper out and familiarise themselves with the material. JP

Thanks JP, good advice, I've read it, printed it and attached it into manual that I've also printed out and Veronica nicely bound into a booklet for easy use.

cheers dave

Thank you JP.

Can I ask if you will have a DVD out for the 7000 soon?

Robert

alchemist wrote:
Thank you very much Bruce Candy for this invaluable resource to our better understanding of the GPZ and how to get the most from it.

http://www.minelab.com/__files/f/266297/KBA_24-1%20ZVT%20Technology.pdf

Very helpful +1.
Cheers

goldnomad wrote:Thank you JP.

Can I ask if you will have a DVD out for the 7000 soon?

Robert

Thank you Jonathan for the heads up.

I too am curious about a potential DVD.
I'm a better visual learner than a reader, I find it easier remembering moving pictures than words.

I'm especially interested in this scenario. You locate a target within the first 20 seconds of switch on. You recover the target and then are ready to proceed, how should you go about obtaining an optimal GB, since the initial ground data capture will have been biased by the target?

This is a genuine question, no tricks, no stirring, no moaning. It seemed that in the White Paper, Bruce arrived at this scenario but didn't quite clarify how best to proceed i.e.

Bruce Candy wrote:
if you happen to initially ground balance on an atypical location
(e.g. too close to a metal target or over an unusual patch of soil),
the initial calibration may end up being inaccurate, and this will
cause extra audio signals when detecting. This is because the slowly
updating calibration is taking a longer time to become more
accurate to the typical conditions (rather than the initial atypical
conditions).

Would simply doing a sweeping quick track balance be sufficient, or would a tector reset be better, and then ensuring the first ground grab is over ground previously detected and now known to be devoid of targets?

I realise this is a very rare occasion but if that first target was gold and you're on a run, you need to have confidence that you're GB is optimal.
I get highly suspicious if the tector is dead quiet more so than if it gives a little feedback.

If the answer is in the DVD I'm quite happy to wait

Cheers

This is a great document, especially the graph on page 3 showing depth advantages over the 5000 for different nugget sizes. Shame the nugget size is 0 to 30 (0 20 oz, 30 0.13) and not actual nugget size. Would be nice to know where a 1 oz and a 5 gram fit in. It is important to know when to cut from high yield to general for greater depth.

Thanks again minelab.

kevwr wrote:This is a great document, especially the graph on page 3 showing depth advantages over the 5000 for different nugget sizes.  Shame the nugget size is 0 to 30 (0 20 oz, 30 0.13) and not actual nugget size.  Would be nice to know where a 1 oz and a 5 gram fit in.  It is important to know when to cut from high yield to general for greater depth.

Thanks again  minelab.

Personally I think the secret is in this statement from Bruce

"Shallow Soils
When searching in previously well-detected shallow
soils that have been previously detected with a
GPX 5000, it is likely all of the larger gold nuggets have been found
because it is easily detectable at shallow depths, and only the
smaller pieces remain. Hence in these locations, only operate the
GPZ 7000 using High Yield, and do not use Extra Deep because this
does not detect small gold well.
To find deeper larger nuggets, you need to seek out deeper soils.
Generally, many of the most well known gold fields that have
often been detected with the GPX 5000 tend to be shallow (but
by no means all), whereas the deeper fields are generally not so
well‑known because overall fewer nuggets (mostly fewer small/
medium nuggets) have been found in these fields."

So don't operate the Zed like a 5000, and take it to deeper ground.

Shame the nugget size is 0 to 30 (0 20 oz, 30 0.13) and not actual nugget size. Would be nice to know where a 1 oz and a 5 gram fit in.

The problem is that not all nuggets of the same weight are the same. the response of a gold nugget has not just to do with the weight, but the shape and density also, and these can have a significant impact. You could have a collection of 5 g Nuggets where all of them weigh about the same, and plot them on a graph such as the one in the white paper and they would have different responses. I have a specimen of mossy, porous gold which weighs about 5 g and my 5000 will hardly see it, yet on a piece of solid gold weighing 5 g, the 5000 will scream like a banshee. The response of the GPZ is also affected by shape and nature of the gold, although less than the 5000. It is a common assumption that a metal detector will respond in the same way on all nuggets which weigh about the same, but it is just not true. Gold nuggets are not like coins where all coins of the same denomination are the same weight, size and nature.

alchemist wrote:
Thank you Jonathan for the heads up.

I too am curious about a potential DVD.
I'm a better visual learner than a reader, I find it easier remembering moving pictures than words.

I'm especially interested in this scenario. You locate a target within the first 20 seconds of switch on. You recover the target and then are ready to proceed, how should you go about obtaining an optimal GB, since the initial ground data capture will have been biased by the target?

This is a genuine question, no tricks, no stirring, no moaning. It seemed that in the White Paper, Bruce arrived at this scenario but didn't quite clarify how best to proceed i.e.

Bruce Candy wrote:
if you happen to initially ground balance on an atypical location
(e.g. too close to a metal target or over an unusual patch of soil),
the initial calibration may end up being inaccurate, and this will
cause extra audio signals when detecting. This is because the slowly
updating calibration is taking a longer time to become more
accurate to the typical conditions (rather than the initial atypical
conditions).

The GB of the GPZ 7000 is extremely refined, generally if a target is sensed the GB will automatically pause to prevent tracking it out, if after digging it out your not confident the GB is correct then just power cycle the detector and start again using the method described.

No plans for a DVD at this stage, a massive amount of work, not enough return and too many people either recycling them on ebay or worse copying them and handing them to mates.

JP

Jonathan Porter wrote:
No plans for a DVD at this stage, a massive amount of work, not enough return and too many people either recycling them on ebay or worse copying them and handing them to mates.

JP

Fair enough JP. Thank you for the reply.

Robert

So what i am reading about the 7000 here going over where the 5000 has been, does that mean that if there is an area where there is gold and it is just out of reach of the 4500 or 5000 then basically the 7000 will not find it either? I am talking gold from .3 to 2gram gold. We know it is there as have found plenty but if you scrap 2" of soil off the top then there is a lot more to be found. Or am i not understanding what chris reno and bruce candy have written in there writeup. Looking forward to a hopefully positive response.
 Yes JP, i understand you not doing a dvd, pity really as picture explains so much more than words when trying to learn a new machine.
 Thanks TG

No,it doesn't mean that at all Travelergold. Through my testing of the GPZ 7000,solid slugs of gold within the 0.3g to 2 gram you describe of,will be picked up by the 7000 at approx 20 to 25% above what the GPX 5000 can achieve with say a 12x7 or 8 inch round mono.These are my findings only,both over air tests and on the finding of 0.1gm to 0.4gm solid little slugs of gold,found in their natural undisturbed state.Although of the same weight,different types of gold can produce different results,some for the better,some for the worst,so my results,must not be taken for gospel. Now if that 0.3 gold were to be finely interwoven,within a mixture of highly mineralized ironstone/quartz,the % achievable on this difficult to pick up gold can,easily exceed the 250%+  jump,over that of the 5000 using a smaller coil.

Cheers Kon.

250% !!!!!

They're looking for a new Marketing Manager but you may have to change your name to 'Doc'.





Swinger

[quote="Reno Chris"]

You could have a collection of 5 g Nuggets where all of them weigh about the same   , and plot them on a graph such as the one in the white paper and they would have different responses.

Just wanting to check if this is a fact or an opinion? (Or an opinion about to become a fact)

Swinger

Thats fair enough swinger,cause I'm not here to debate what you can't grasp. The ones that have found the difficult to pick up gold(such that of fine thin sponge gold,or the fine gold found in such specimens,as I refer to above,) with their 7000s,gold that is quite transparent and difficult to pick up even with the GPXs and small mono coil combinations,understand exactly what I'm referring to.

Cheers Kon.

Jonathan Porter wrote:

The GB of the GPZ 7000 is extremely refined, generally if a target is sensed the GB will automatically pause to prevent tracking it out, if after digging it out your not confident the GB is correct then just power cycle the detector and start again using the method described.

No plans for a DVD at this stage, a massive amount of work, not enough return and too many people either recycling them on ebay or worse copying them and handing them to mates.

JP

Thanks JP for the reply.
I fully understand your predicament with the DVDs
It's a pity Minelab hadn't previously arranged for your productions to go in the box with each unit. You'd then be sure of a decent return on your time. After all, with each new release you must be one of just a very few that intimately know the infield behavior of that product and perhaps the only one in the world in a position to relay that understanding in a readily acceptable form to others.

Good hunting.
Kev.