australian electronic gold prospecting forum.com

Common interest forum. => General chat and discussion forum => Topic started by: Huego on Friday January 16 2015 17:14:47 AEDT PM



Title: Detecting Larger Nuggets
Post by: Huego on Friday January 16 2015 17:14:47 AEDT PM

There is a general perception that larger nuggets are (or should be) more easily detected (ie detected deeper). 
That is, the bigger the target, the easier it is, or should be, to detect at depth.

     - What factors, that we can control as prospectors, maximise detection depth?
     - Can it be explained in largely not technical terms to readers?
     - Are any new detectors (even prototypes) showing promise in achieving greater detection depths?

Allan says larger nuggets “have LONG TIME CONSTANTS” … OK, but what does that mean to a detectorist in selecting tools (eg detectors, coils), optimising settings or selecting ideal conditions for searching for them? …. from a prospectors, not designers, point of view. 

How can one maximise the detection or detection depth for large nuggets (1 oz + say)? 
Does one seek or avoid certain geology shallow or deep ground or soil type, always use largest coil, which detector settings? Generalities, not detail.

Perhaps Alluvium can do this from a successful (big nugget finder’s) point of view? If he were looking for a big nuggets (1+ oz) what tools would he want need to find them at depths over 30 cm? 

Huego  ::62::


Title: Re: Detecting Larger Nuggets
Post by: moodz on Friday January 16 2015 21:33:50 AEDT PM
  

There is a general perception that larger nuggets are (or should be) more easily detected (ie detected deeper). 
That is, the bigger the target, the easier it is, or should be, to detect at depth.

     - What factors, that we can control as prospectors, maximise detection depth?
     - Can it be explained in largely not technical terms to readers?
     - Are any new detectors (even prototypes) showing promise in achieving greater detection depths?

Allan says larger nuggets “have LONG TIME CONSTANTS” … OK, but what does that mean to a detectorist in selecting tools (eg detectors, coils), optimising settings or selecting ideal conditions for searching for them? …. from a prospectors, not designers, point of view. 

How can one maximise the detection or detection depth for large nuggets (1 oz + say)? 
Does one seek or avoid certain geology shallow or deep ground or soil type, always use largest coil, which detector settings? Generalities, not detail.

Perhaps Alluvium can do this from a successful (big nugget finder’s) point of view? If he were looking for a big nuggets (1+ oz) what tools would he want need to find them at depths over 30 cm? 

Huego  ::62::


Any detector with a ground balance cct whether auto or manual is old hat ...its gonna ignore some nugg sizes at depth. The ground does not need to be balanced it needs to be ignored ... the wanna be's are trying to improve old methods ...the new tech like cc ferinstance ignores ground without balancing ccts. Time constants dont matter only signal to noise ratio.


Title: Re: Detecting Larger Nuggets
Post by: Doug on Friday January 16 2015 22:22:33 AEDT PM
  
... the wanna be's are trying to improve old methods ...the new tech like cc ferinstance ignores ground without balancing ccts. Time constants dont matter only signal to noise ratio.

Can this be achieved by methods other than sampling during CC periods?
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: moodz on Friday January 16 2015 22:31:49 AEDT PM
  
  
... the wanna be's are trying to improve old methods ...the new tech like cc ferinstance ignores ground without balancing ccts. Time constants dont matter only signal to noise ratio.

Can this be achieved by methods other than sampling during CC periods?
doug ::419::

Its the addition \ subtraction of samples filtering the ground but also filtering some targets that matters otherwise you can sample all the time for better snr ..one of the patents states this in similiar words.


Title: Re: Detecting Larger Nuggets
Post by: Prospector_Al on Saturday January 17 2015 05:56:27 AEDT AM
  
  

There is a general perception that larger nuggets are (or should be) more easily detected (ie detected deeper).  
That is, the bigger the target, the easier it is, or should be, to detect at depth.

     - What factors, that we can control as prospectors, maximise detection depth?
     - Can it be explained in largely not technical terms to readers?
     - Are any new detectors (even prototypes) showing promise in achieving greater detection depths?

Allan says larger nuggets “have LONG TIME CONSTANTS” … OK, but what does that mean to a detectorist in selecting tools (eg detectors, coils), optimising settings or selecting ideal conditions for searching for them? …. from a prospectors, not designers, point of view.  

How can one maximise the detection or detection depth for large nuggets (1 oz + say)?  
Does one seek or avoid certain geology shallow or deep ground or soil type, always use largest coil, which detector settings? Generalities, not detail.

Perhaps Alluvium can do this from a successful (big nugget finder’s) point of view? If he were looking for a big nuggets (1+ oz) what tools would he want need to find them at depths over 30 cm?  

Huego  ::62::


Any detector with a ground balance cct whether auto or manual is old hat ...its gonna ignore some nugg sizes at depth. The ground does not need to be balanced it needs to be ignored ... the wanna be's are trying to improve old methods ...the new tech like cc ferinstance ignores ground without balancing ccts. Time constants dont matter only signal to noise ratio.

Hi Paul,

Candy's Constant Current patent does not include the means to ignore the ground.  Even if it had been included, the Patent Office would have required a restriction, since the method isn't
specific to the CC circuit.  Without the means to ignore the ground and hot rocks, the modest
depth increase of the CC method does not outweigh the drawback of the icreased current
consumption

It's my guess that ????? has filed another patent that will fix the CC detector, and Minelab will have to hire him back..

My Crystal Ball also shows that the new "Flagship" release will be further delayed..

Clairvoyant Al



Title: Re: Detecting Larger Nuggets
Post by: Prospector_Al on Saturday January 17 2015 06:09:47 AEDT AM
  

There is a general perception that larger nuggets are (or should be) more easily detected (ie detected deeper). 
That is, the bigger the target, the easier it is, or should be, to detect at depth.

     - What factors, that we can control as prospectors, maximise detection depth?
     - Can it be explained in largely not technical terms to readers?
     - Are any new detectors (even prototypes) showing promise in achieving greater detection depths?

Allan says larger nuggets “have LONG TIME CONSTANTS” … OK, but what does that mean to a detectorist in selecting tools (eg detectors, coils), optimising settings or selecting ideal conditions for searching for them? …. from a prospectors, not designers, point of view. 

How can one maximise the detection or detection depth for large nuggets (1 oz + say)? 
Does one seek or avoid certain geology shallow or deep ground or soil type, always use largest coil, which detector settings? Generalities, not detail.

Perhaps Alluvium can do this from a successful (big nugget finder’s) point of view? If he were looking for a big nuggets (1+ oz) what tools would he want need to find them at depths over 30 cm? 

Huego  ::62::


Hi Huego,

In my opinion there's nothing a detectorist can do at this time to improve her chances of finding
large nuggets other than waiting for the Ship to come in.  For all we know, it may be sailing under a different Flag than expected.  All I know for sure is that ships are on the way..

Crystal Ball Al


Title: Re: Detecting Larger Nuggets
Post by: moodz on Saturday January 17 2015 11:41:19 AEDT AM
  
  
  

There is a general perception that larger nuggets are (or should be) more easily detected (ie detected deeper).  
That is, the bigger the target, the easier it is, or should be, to detect at depth.

     - What factors, that we can control as prospectors, maximise detection depth?
     - Can it be explained in largely not technical terms to readers?
     - Are any new detectors (even prototypes) showing promise in achieving greater detection depths?

Allan says larger nuggets “have LONG TIME CONSTANTS” … OK, but what does that mean to a detectorist in selecting tools (eg detectors, coils), optimising settings or selecting ideal conditions for searching for them? …. from a prospectors, not designers, point of view.  

How can one maximise the detection or detection depth for large nuggets (1 oz + say)?  
Does one seek or avoid certain geology shallow or deep ground or soil type, always use largest coil, which detector settings? Generalities, not detail.

Perhaps Alluvium can do this from a successful (big nugget finder’s) point of view? If he were looking for a big nuggets (1+ oz) what tools would he want need to find them at depths over 30 cm?  

Huego  ::62::


Any detector with a ground balance cct whether auto or manual is old hat ...its gonna ignore some nugg sizes at depth. The ground does not need to be balanced it needs to be ignored ... the wanna be's are trying to improve old methods ...the new tech like cc ferinstance ignores ground without balancing ccts. Time constants dont matter only signal to noise ratio.

Hi Paul,

?????'s Constant Current patent does not include the means to ignore the ground.  Even if it had been included, the Patent Office would have required a restriction, since the method isn't
specific to the CC circuit.  Without the means to ignore the ground and hot rocks, the modest
depth increase of the CC method does not outweigh the drawback of the icreased current
consumption

It's my guess that ????? has filed another patent that will fix the CC detector, and Minelab will have to hire him back..

My Crystal Ball also shows that the new "Flagship" release will be further delayed..

Clairvoyant Al



Hi Al ....

the relevant claim is this one ...

Apparatus comprising a metal detector having an energizing coil, a capacitor charged by a high voltage source and discharged into the energizing coil and for rapidly energizing the coil, a low voltage source connected to the coil for establishing and maintaining constant current in the energizing of the coil magnetic field in an adjacent substance that allows eddy current target objects to charge up according to their own time constant and sustaining the established constant current and having a receive coil detecting change of the magnetic field current target objects to charge up according to their own time constant and sustaining the established constant current and having a receive coil detecting change of the magnetic field during that time and amplitude during that time that characterizes the eddy current object while permeability mineralization is ignored.


This claim does not explain how it works though ....however there is a well known device in a certain industry that utilises this method as its primary money spinner ... and its not a metal detector.

You may find that a boarding party has been prepared for that ship and there will be great difficulty in offloading any stores in OZ.


Title: Re: Detecting Larger Nuggets
Post by: Doug on Saturday January 17 2015 11:44:34 AEDT AM
  
You may find that a boarding party has been prepared for that ship and there will be great difficulty in offloading any stores in OZ.

????
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: authere on Saturday January 17 2015 11:53:43 AEDT AM
Hi Moodz,

If the ship's sailing I wanna be on it, what's goin on/////

Is it time/// ::10 ::

Ron


Title: Re: Detecting Larger Nuggets
Post by: Doug on Saturday January 17 2015 12:17:14 AEDT PM
  
This claim does not explain how it works though ....however there is a well known device in a certain industry that utilises this method as its primary money spinner ... and its not a metal detector.
Moodz,what are you inferring by this statement?
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: moodz on Saturday January 17 2015 13:10:32 AEDT PM
...well the vested interests are not interested in any competition ... by boat or any other means  ::620:: ::620::


Title: Re: Detecting Larger Nuggets
Post by: Doug on Saturday January 17 2015 16:48:51 AEDT PM
  
  

There is a general perception that larger nuggets are (or should be) more easily detected (ie detected deeper). 
That is, the bigger the target, the easier it is, or should be, to detect at depth.

     - What factors, that we can control as prospectors, maximise detection depth?
     - Can it be explained in largely not technical terms to readers?
     - Are any new detectors (even prototypes) showing promise in achieving greater detection depths?

Allan says larger nuggets “have LONG TIME CONSTANTS” … OK, but what does that mean to a detectorist in selecting tools (eg detectors, coils), optimising settings or selecting ideal conditions for searching for them? …. from a prospectors, not designers, point of view. 

How can one maximise the detection or detection depth for large nuggets (1 oz + say)? 
Does one seek or avoid certain geology shallow or deep ground or soil type, always use largest coil, which detector settings? Generalities, not detail.

Perhaps Alluvium can do this from a successful (big nugget finder’s) point of view? If he were looking for a big nuggets (1+ oz) what tools would he want need to find them at depths over 30 cm? 

Huego  ::62::


Any detector with a ground balance cct whether auto or manual is old hat ...its gonna ignore some nugg sizes at depth. The ground does not need to be balanced it needs to be ignored ... the wanna be's are trying to improve old methods ...the new tech like cc ferinstance ignores ground without balancing ccts. Time constants dont matter only signal to noise ratio.

CC  Pi technology  may not" ignore the ground" if the ground is strongly conductive eg moist and salt  effected.
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: moodz on Saturday January 17 2015 17:50:40 AEDT PM
  
  
  

There is a general perception that larger nuggets are (or should be) more easily detected (ie detected deeper). 
That is, the bigger the target, the easier it is, or should be, to detect at depth.

     - What factors, that we can control as prospectors, maximise detection depth?
     - Can it be explained in largely not technical terms to readers?
     - Are any new detectors (even prototypes) showing promise in achieving greater detection depths?

Allan says larger nuggets “have LONG TIME CONSTANTS” … OK, but what does that mean to a detectorist in selecting tools (eg detectors, coils), optimising settings or selecting ideal conditions for searching for them? …. from a prospectors, not designers, point of view. 

How can one maximise the detection or detection depth for large nuggets (1 oz + say)? 
Does one seek or avoid certain geology shallow or deep ground or soil type, always use largest coil, which detector settings? Generalities, not detail.

Perhaps Alluvium can do this from a successful (big nugget finder’s) point of view? If he were looking for a big nuggets (1+ oz) what tools would he want need to find them at depths over 30 cm? 

Huego  ::62::


Any detector with a ground balance cct whether auto or manual is old hat ...its gonna ignore some nugg sizes at depth. The ground does not need to be balanced it needs to be ignored ... the wanna be's are trying to improve old methods ...the new tech like cc ferinstance ignores ground without balancing ccts. Time constants dont matter only signal to noise ratio.

CC  Pi technology  may not" ignore the ground" if the ground is strongly conductive eg moist and salt  effected.
doug ::419::

Its all basic physics when di/dt =0 the coil is a short circuit. Conductivities of metals like gold ferinstance far exceed any clays or salt water. Targets are not homgenous like clay or water.


Title: Re: Detecting Larger Nuggets
Post by: Aziz on Saturday January 17 2015 21:11:16 AEDT PM
  
Hi Al ....

the relevant claim is this one ...

Apparatus comprising a metal detector having an energizing coil, a capacitor charged by a high voltage source and discharged into the energizing coil and for rapidly energizing the coil, a low voltage source connected to the coil for establishing and maintaining constant current in the energizing of the coil magnetic field in an adjacent substance that allows eddy current target objects to charge up according to their own time constant and sustaining the established constant current and having a receive coil detecting change of the magnetic field current target objects to charge up according to their own time constant and sustaining the established constant current and having a receive coil detecting change of the magnetic field during that time and amplitude during that time that characterizes the eddy current object while permeability mineralization is ignored.


This claim does not explain how it works though ....however there is a well known device in a certain industry that utilises this method as its primary money spinner ... and its not a metal detector.

You may find that a boarding party has been prepared for that ship and there will be great difficulty in offloading any stores in OZ.


Hi moodz,

which patent are you referring to?

And what device are you refferring to too?

BTW, it is an interesting topic.
Cheers,
Aziz


Title: Re: Detecting Larger Nuggets
Post by: Aziz on Saturday January 17 2015 21:48:06 AEDT PM
Ok, I have found it.

It's the White's CC patent moodz was referring to.
http://www.uspto.gov/web/patents/patog/week44/OG/html/1408-1/US08878515-20141104.html

^sif


Title: Re: Detecting Larger Nuggets
Post by: Alluvium on Sunday January 18 2015 12:45:43 AEDT PM
Hi Huego & Al, Members.

Thank you both for resurrecting this subject, after all it is what really matters if you want to make some dollars out of this pastime, most have not seen the good old days of big nuggets, but it will happen again.

Huego, your questions below.

Quote:    1 - What factors, that we can control as prospectors, maximise detection depth?
             2 - Can it be explained in largely not technical terms to readers?
           3 - Are any new detectors (even prototypes) showing promise in achieving greater detection depths?

                                                                                                                                                                                

Questions # 1 + 2. There are a few factors within our control presently to achieve finding large nuggets at depth. I would say the main one is to have the best detector currently available for this purpose. Obviously in Australia a P.I. unit is going to give your best chance.                                                                                                                            

Knowing how to use it to the maximum advantage in this quest is next, this will only come with experience out in the field, and dedicated persistence in learning all of the foibles that come with it.

Then it is best to use the right size and shape Coil for the job in finding those deeper nuggets, this as you all know is by swinging a big loop of at least 18”inches, one can use coils much larger than this, but these have to be physically managed properly to do the work needed.

The most challenging one is by knowing most things about the finding of gold in nugget form, and where it might be found. The dedication in learning what’s required in this to put it mildly is huge. Sure a newcomer can go out on his or her first trip and find a large nugget, this has happened many times over many years.
 
But being realistic to consistently find larger gold it is best to study up over a long period. Learning how to prospect successfully is an art in itself.
===========================================================================

Question # 3. As always there are new detectors being designed to do a better job than the last model. Some are successful, but most others are just more bells and whistles, or a few different Timings to move the existing hole in detection to another position.

This allows a new class, type, shape or texture etc; of nuggets to be found that were missed before-hand. Realistically thinking outside the existing boundaries of restrictions posed by old methods is what is needed.
===============================================================================

Coils will make a big difference.


Having tested coils for manufactures through the years, I can tell you there is a big advancement to come yet, this will give your existing detectors new life, and speaking of depth on large nuggets this will happen.  The results I have seen in the last 2 years have amazed me, and to use these new style coils over hot soils in Normal timing, and staying quiet, yet actually punching deeper is another dream come true.

Yes there are detectors out there being tested and perfected, and they have been over some time. Unfortunately a certain large Company has put a dampener on this, as many manufactures have found out to their detriment over the years. If anyone looks like coming up with a better machine they are hit with threatening letters, law suites, you name it.

I have seen it first hand over many years, what most of you do not realise, is that these actions are what is holding back the detecting industry. I have been lucky enough to have tested and used some of these new style detectors and they do the job admirably, they are the new breed of advanced digital technology.

There have been exciting leaps in this tech that most of you have only dreamed of, but while one company has a strangle-hold over this matter, we all sit and wait. A select few will enjoy the spoils of this new tech, but as always the majority will miss out.  

That is sad, it’s Criminal Really!  

Cheers Alluvium.

Edited For Grammar correction. Alluvium.




Title: Re: Detecting Larger Nuggets
Post by: Huego on Monday January 19 2015 12:13:00 AEDT PM
Thanks for your understandable and well considered response Alluvium. The lesson is, as always, learn to know your tools better, understand the local geology and gold history and that should maximise your chances ... until a new and major advance in technology is available which may double or treble our chances.

When I return to prospecting, maybe I should consider uprgrading my coils to larger lighter ones and continue to use to old 2200D? I have never pursued prospecting for $, its always been a hobby for me.  I have never found a "big one", and if I did I would probably never turn it into dollars, its just another collectable item for me.

".....but while one company has a strangle-hold over this matter, we all sit and wait. A select few will enjoy the spoils of this new tech, but as always the majority will miss out."  

Lets hope this situation wil change soon and justice will return to the goldfields.
Prospectors have a sense of JUSTICE, one forged in Eureka, one that is even greater their their loyalty to the designers of tools, makers or sellers.

Thanks to other members for their comments.

Huego  ::62::


Title: Re: Detecting Larger Nuggets
Post by: Aziz on Monday January 19 2015 22:29:25 AEDT PM
Hi all.

Pity, that the technical aspects of detecting larger nuggets and how to overcome the issues haven't been really discussed.
I presume, that it won't be possible due to vested interest.

How can we overcome the vested interest and kill that evil greed to make some real progress together? I'll be willing to contribute to that interesting discussion.
::10 ::
Cheers,
^sif


Title: Re: Detecting Larger Nuggets
Post by: GARY on Tuesday January 20 2015 09:53:35 AEDT AM
Huego’s thread here got me thinking after some in-ground tests that showed it could be easy to miss a response from a nugget, be it a large or a small one at its depth. While trying to locate a response in-ground I found it easy to miss on the first couple of swings until a couple more swings over the same spot which massaged the response just enough to verify. How often would you swing the coil 4 or more times over the exact same spot while out detecting on the goldfield unless you got a sniff of a response on your first couple of swings.

Btw it’s always good when Alluvium joints a discussion either by request or not and adds his wealth of knowledge from years of experience and success at detecting / prospecting. He shares that knowledge in an easy to understand way through his writings without being too technical. Actually I’ve had the good fortune to meet him and he is a true gentleman or as us Aussies would say, a top bloke.

Since this thread is about detecting large nuggets my friend and I travelled to Wedderburn on two occasions. Both trips were for 2 weeks of continuous detecting to find that elusive big one that we all hope and read about found by the old-timers. Using both of our 5000’s our two best pieces were a 14 gram at 13” my friend detected with an 11” mono and a 9.5 gram at 14” that I detected with a 25” mono. Boy compared to swinging my normal coil of choice an 18” then trying to swing a large 25” coil of that size it sure can be awkward as well to pinpoint along with having to dig a large diameter hole.

Also the nasty ground had its part to play with no thought of using any other timings on offer other than what this detector offered for this type of ground.

Another observation from these trips that caught my attention was the amount diggings and potholes dug by the old-timers. As you swing your coil near, around or over them I had that nagging feeling going by the depths some were dug down too, then I would have little hope of detecting a large nugget if one came from those depths, even with a large 25” coil attached to your detector of choice.

Now from where I come from nuggets found are tiny in comparison to the Golden Triangle's history of large nuggets.


Title: Re: Detecting Larger Nuggets
Post by: Alluvium on Tuesday January 20 2015 13:41:07 AEDT PM
Hi Huego, Aziz & Gary.

Thanks for keeping this topic going boys, firstly Huego, I kept my comments simple without going into great detail, re; what are the actual best Detectors, Coils etc, that will do a much better job at finding larger nuggets at depth.                                                                                                                        

Plus explaining about the material and guidance necessary to learn the art of prospecting which is huge, not to mention the books, reports, photos and maps, CD’s with all info etc, that is needed to research the best places to have your greatest chance of finding the size of gold we seek.

Maybe at a later date, perhaps a series??                                                    

Your posted Quote: until a new and major advance in technology is available, which may double or treble our chances?

Huego these advances in tech are available now, but they are and have been suppressed, and will be until the time where someone bites the bullet and dares challenge Goliath. These are the bigger companies like Whites, First Texas, Garrett etc, they have the clout and $$ necessary for this.                              

Not those poor individuals working World-wide, trying to make ends meet on a shoe-string budget at home in their workshops. As you know I have been detecting since 1980, and have seen the various developments throughout those years, but I can tell you these haven’t traveled very far at all, re real new tech.

When you look at say the old green SD 2200, this detector with the right set-up, can still find big nuggets at depth, and just as well as the latest models, yet most likely deeper, and better.
Yes these latter detectors can find shallow tiny gold in extremely hot mineralised ground, but like I have always said, ---

“(It takes myriad number of small specks to make up for a 5 or 10 ounce nugget)”

Personally, I would stick with your 2200 Huego, with the right big coil it can find those deep nuggets, I can advise you about the coil to use.

Mate money helps pay the bills, fuel costs to name one, so we must look on detecting as not only just a hobby, but to at least pay our way until that big mother comes along.
===========================================================
 
Aziz.

Your. Quote: Pity, that the technical aspects of detecting larger nuggets and how to overcome the issues haven't been really discussed.
I presume that it won't be possible due to vested interest.

Yes I have not put any detail into this, on what we can do and use to find deep large nuggets. – As of yet.

I certainly cannot discuss the new tech I have seen and used in the field, but  maybe I can hint a little occasionally,  I can assure you there are exciting advancements and not far away either.

Aziz, you well know from your work over the years, that what we are using now is quite old technology, and continually this is as always, just old tech dressed up with Lipstick.                                                                                

I can tell you there are going to be a lot of disappointed people soon, that have been talking it up lately, anticipating big changes on this next detector to be released in late March.                                                                            

(It's just more Bells and Whistles I'm afraid) and so heavy too.
==================================================================

Gary.

Thank you for your kind comments, I will help anyone that has a question, just ask.

Your. Quote: How often would you swing the coil 4 or more times over the exact same spot while out detecting on the goldfield unless you got a sniff of a response on your first couple of swings.

In your post you referred to the chances on missing a small target response easily, this is quite true. As most operators know, you can’t ever get them all, but then again you can certainly maximize your chances with a bit of thought.

When looking for the big deep stuff, you should target specific ground, which means, being in an area that you know of where some deeper gold has already been found, either by yourself or another person etc.

This will give you a better chance of finding these sorts of nuggets that we all crave, so when detecting over your selected areas, you have to really knuckle down, slow right down, concentrate, overlap your swings, and listen very carefully, it won’t be a screaming signal. Use a grid pattern if you like; there are many ways to do this.

On the experiences you had detecting at Wedderburn, firstly with using the 18”in round mono coil as your standard weapon of choice, on this goldfield it gave your best chance of getting deeper missed nuggets, we all have to use the right tool for this quest.

Those operators that use small or tiny coils limit their chances immediately, meaning they have restricted themselves to detecting shallow ground and if they spend any time on the deeper areas, really they might as well be p!ssing into the wind.

Gary swinging a 25”in round mono is extremely hard work, especially combating the extra EMI that comes along with it, these and larger coils are not for prospecting, unless you have an arm like” Popeye”. They are to be used on known patches in deep soil areas, really it’s used as a clean-up coil.

With Pin-Pointing, we all need to have a small coil to do that task when you have a big hole opened out, either a small DD Joey coil on a stem, or a dedicated old Coiltek Hand-Grenade on a stick type, like I use. The nasty ground at Wedderburn and some other fields here in Victoria, do certainly pose a big problem with the detectors on offer today, this is where knowing your detector inside out is your only hope at times, either you dumb it down or go home.

Observing the old boys diggings shows an operator a wealth of knowledge, I advise to take some time before you start, (half an hour at least), have a walk up and down the sides of those gullies, see what the old boys were chasing and from where, those shallow side feeder runs on either side that you find joining the main run, have a detect in the deeper ground of to their sides, and on the lower end of these, they do hold some surprises.

Gary with having smaller gold where you reside, it is really a case of “When in Rome, -------------- “.

What else can you do?   That is unless you move interstate.

Cheers from Alluvium.

Edited for corrections Alluvium.


Title: Re: Detecting Larger Nuggets
Post by: authere on Tuesday January 20 2015 14:20:17 AEDT PM
Hi All,

I know of a guy that regularly chases large nuggets,his coil of choice is only a 16" mono he does a double swing on every swing and certainly produces the goods,he also uses an 18" but not often

A lot of it boils down to getting to know your equipment and what to actually listen for, I've had a specie that gave a proper signal from the length of my pick handle deep that had 2oz's of gold mostly fines and a 1oz solid nugget that only gave a warble from 100mm depth others are just ground noises that get bloody loud the deeper you dig

So how many signals do we miss or misinterpret, the mind boggles

Ron


Title: Re: Detecting Larger Nuggets
Post by: GARY on Wednesday January 21 2015 10:57:50 AEDT AM
I thought I would add some colour to this thread with some pics in regards to my 2 trips to Wedderburn.

The first two below were taken when my friend snagged this 14 gram piece with his 11” mono during our 1st trip and him standing in its hole. This piece ended up being the largest found.

(http://members.optusnet.com.au/~quarman1/14 gram Nugget.jpg)

(http://members.optusnet.com.au/~quarman1/14 gram nugget hole.jpg)


The pic below is our combined nugget haul over the 10 days we spent detecting for the 1st trip.

(http://members.optusnet.com.au/~quarman1/Nugget haul from 1st trip.jpg)




The next two pics below is the 9.5 gram piece I found with the 25” mono on our 2nd trip with me sitting and resting my feet in the large hole I had to dig to retrieve it. The close-up pic shows the nugget still encased in the clod of clay that came from the bottom of the large hole.

(http://members.optusnet.com.au/~quarman1/9.5 gram Nugget Hole.jpg)

(http://members.optusnet.com.au/~quarman1/Closeup of 9.5 Nugget still encased in clay.jpg)


The pic below is our combined nugget haul again over a 10 day period spent detecting for our 2nd trip.

(http://members.optusnet.com.au/~quarman1/Nugget Haul from 2nd Trip.jpg)




The final two pis below are at a monument to a large nugget found by a detector which for those of you who live in the Golden Triangle would be aware of, as well those who live near too or have travelled to the triangle.

If I had lifted something of that size out of a hole I would most likely Kark over in shock.

(http://members.optusnet.com.au/~quarman1/Large Nugget Monument.jpg)

(http://members.optusnet.com.au/~quarman1/Closeup of Large nugget Monument.jpg)


After each trip we shared both of our total haul equally between us by weight with my friend to keep his largest 14g piece and for me my 9.5g piece.

At least our nugget haul from both trips helped towards our fuel and accommodation costs.


Unfortunately the Nugget Sizes in the photos do not do justice to the heading of this thread "Detecting Larger Nuggets"

Edited by Gary to add the final sentance
 


Title: Re: Detecting Larger Nuggets
Post by: Doug on Wednesday January 21 2015 12:16:40 AEDT PM
  
I thought I would add some colour to this thread with some pics in regards to my 2 trips to Wedderburn.

The first two below were taken when my friend snagged this 14 gram piece with his 11” mono during our 1st trip and him standing in its hole. This piece ended up being the largest found.

(http://members.optusnet.com.au/~quarman1/14 gram Nugget.jpg)

(http://members.optusnet.com.au/~quarman1/14 gram nugget hole.jpg)


The pic below is our combined nugget haul over the 10 days we spent detecting for the 1st trip.

(http://members.optusnet.com.au/~quarman1/Nugget haul from 1st trip.jpg)




The next two pics below is the 9.5 gram piece I found with the 25” mono on our 2nd trip with me sitting and resting my feet in the large hole I had to dig to retrieve it. The close-up pic shows the nugget still encased in the clod of clay that came from the bottom of the large hole.

(http://members.optusnet.com.au/~quarman1/9.5 gram Nugget Hole.jpg)

(http://members.optusnet.com.au/~quarman1/Closeup of 9.5 Nugget still encased in clay.jpg)


The pic below is our combined nugget haul again over a 10 day period spent detecting for our 2nd trip.

(http://members.optusnet.com.au/~quarman1/Nugget Haul from 2nd Trip.jpg)




The final two pis below are at a monument to a large nugget found by a detector which for those of you who live in the Golden Triangle would be aware of, as well those who live near too or have travelled to the triangle.

If I had lifted something of that size out of a hole I would most likely Kark over in shock.

(http://members.optusnet.com.au/~quarman1/Large Nugget Monument.jpg)

(http://members.optusnet.com.au/~quarman1/Closeup of Large nugget Monument.jpg)


After each trip we shared both of our total haul equally between us by weight with my friend to keep his largest 14g piece and for me my 9.5g piece.

At least our nugget haul from both trips helped towards our fuel and accommodation costs.


Unfortunately the Nugget Sizes in the photos do not do justice to the heading of this thread "Detecting Larger Nuggets"

Edited by Gary to add the final sentance
 


Some nice nuggets! well done! ::62::
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Alluvium on Wednesday January 21 2015 16:36:02 AEDT PM
Hello Ron & Gary.

Ron this bloke you know of, that's using a 16”in coil to find big gold should persist with swinging his 18”inch mono. There would a number of deeper bigger nuggets missed with his 16”in mono.
The field flux of each coil are different, he may think he is seeing all gold at depth, but I assure you he is not, even by using the double sweep method as you say,

Totally agree on knowing your equipment backwards, and about the many variables of nugget response characteristics.
Would there be any chance this chap detects mainly in WA? If he does, I can then understand why he sticks by using his 16”in, mono.
=============================================================
Gary thanks for those great photos of your Wedderburn adventures, you fellows done quite well there. You certainly would have paid you way each trip.
 
On noticing the depth of the hole dug by your friend for his nice piece, it looks about approx 1’ft in depth, this is why he could get gold responses in that depth ground when using his 11”inch mono with its more concentrated field.

Where it shows you standing in that hole up to near your knees in depth, I would say at about the 2’ft mark, knowing you are a tall bloke with long legs, these are 18”inch coil depths, where I would say it was the minimum size coil to utilize especially in that hot ground up there.

A little trick you could try next time, is to skid an 18”inch DD coil on the ground, while using it in Normal timing, place your 5000 in cancel mode, and then crank up your gain and stabilizer a bit, if it is getting a little noisy, put the Audio in Quiet mode.

What happens is it handles that hot ground  and EMI up there a lot better, and also has an advantage because it transmits on the TX winding as in a DD coil, but it receives any signals on both of the windings.

There is quite an advantage doing this, and the bigger the DD coil the better it works. Using Cancel this way still gets the depths required.

Good luck and Cheers.  Alluvium.





Title: Re: Detecting Larger Nuggets
Post by: GARY on Thursday January 22 2015 11:04:10 AEDT AM
Crikey Doug my photos are large enough as is and you reproducing them in your reply makes them overpowering.

Yes Alluvium, having now done a review of the video taken of the 14 gram dig, my friend measured it at 11.5” Also a review of the video on the 9.5 gram,  I see I forgot to measure, maybe due to expecting a larger piece after such a dig. I would say somewhere between 18” and 24” in depth. The first response I got at ground level with the 25” coil on this nugget was a very broad one, very much like a hot ground response. I decided to have a scratch so removed a few inches of clay and the signal started to sound more promising. I reckon an 18” coil would have given a clearer response at the surface than the 25” coil.

The other two nuggets shown beside the 9.5 gram piece on the top row in the photo of our total nugget haul for that 2nd trip, were found with my NF18” mono. They were both deep also for their size. The rest of the nuggets in both of the nugget haul photos were found with the Commander 11” mono and a NF12” mono.

Thanks for the little trick with a DD coil however I only have a 16 inch XP DD coil (reverse phase wound) which inverts the signal response to a Hi/Lo on larger gold. Of course with the GPX series you can now invert the response using the detector. Anyway what happens with this type of XP DD coil for it to cancel EMI you then have to switch into Mono mode. Therefore not sure if it still then works the same as a normal DD coil in Cancel mode and receive through both windings?

On a final note, which I had forgotten about from my video clips taken during the 2nd Trip, we met a local fella out on the goldfield who showed us a 48 gram piece he had detected at 18” with his 4000. However the biggest surprise was when he said he had to dig down 7 feet for a 106 gram piece. I questioned him with what detector and what size coil. He said the 4000 and a 42” x 26” coil which he pointed to in the back of his 4WD.

Gary

Edited by Gary to fix an error in what I said.


Title: Re: Detecting Larger Nuggets
Post by: WM6 on Thursday January 22 2015 11:14:55 AEDT AM
  

 with his 4000. However the biggest surprise was when he said he had to dig down 7 feet (2.13m) for a 106 gram piece. I questioned him with what detector and what size coil. He said the 4000 and a 42” x 26” coil which he pointed to in the back of his 4WD.


Guy is fisherman obviously.


Title: Re: Detecting Larger Nuggets
Post by: GARY on Thursday January 22 2015 11:53:16 AEDT AM
Yes WM6 I was going to also write "I will let you all make up your own mind on that one."

The only true indication of a nugget's depth is to be very careful when digging and see it still resting in situ either in the side or bottom of the hole. Doing a measurement after the nugget is out in the ground taken from the hole is only an estimate of its exact depth.

I have only once taken enough time to dig and find a nugget still in situ, which is the one I have had a bail / bale (spelt two ways) attached to hang around my neck.

Edited by Gary for spelling


Title: Re: Detecting Larger Nuggets
Post by: Alluvium on Thursday January 22 2015 14:31:30 AEDT PM
Hello Gary.

Thank you for the details about your digs, it all fits in regards to the depths, coil size, etc. If an operator has a fair idea on the grounds depth that he is detecting in, it should be then detected accordingly, with the right sized coil.

It’s no good using a really large coil if you are only on 1’Ft or (300mm) deep soils. The exception is they can still be utilized on the shallower ground, if you want to cover a lot more area when out prospecting.

Your comment about that chap you met at Wedderburn who found a nugget at 7’ft deep, Mate he would have had to have a 10’ft ground loop, to even get a sniff on it.
He was either having a lend of himself, or thought he was putting it over you blokes. The coil he said he used, are a Mono loop.

Talking of fair dinkum nugget depths and coil sizes, a good friend’s Wife found a 120 oz nugget in hot ground at a genuine 1metre deep, it was below the upper soils and  through a washed gravel layer, sitting in clay on the bottom and had never been disturbed.

The amazing thing about this was she was using a SD 2200 and cop this, it was found with a small elliptical 12’in x 7”in NF mono coil, it was a very iffy signal to start with but she has good hearing, (Don’t they all).

Her husband could hear it much better with his GP 3000 using an 18” round NF mono coil, but then again, she had scraped a couple of inches off the top before he had walked over.

I think that this was an exception rather than the rule, as anyone that is really seriously looking for big deep gold, shouldn’t be using a small coil for a start, and especially an elliptical one.

Regards.  Alluvium.

Edit for correction, sorry.   Alluvium.


Title: Re: Detecting Larger Nuggets
Post by: Alluvium on Sunday January 25 2015 13:35:12 AEDT PM
  

There is a general perception that larger nuggets are (or should be) more easily detected (ie detected deeper).  
That is, the bigger the target, the easier it is, or should be, to detect at depth.

     - What factors, that we can control as prospectors, maximise detection depth?
     - Can it be explained in largely not technical terms to readers?
     - Are any new detectors (even prototypes) showing promise in achieving greater detection depths?

Allan says larger nuggets “have LONG TIME CONSTANTS” … OK, but what does that mean to a detectorist in selecting tools (eg detectors, coils), optimising settings or selecting ideal conditions for searching for them? …. from a prospectors, not designers, point of view.  

How can one maximise the detection or detection depth for large nuggets (1 oz + say)?  
Does one seek or avoid certain geology shallow or deep ground or soil type, always use largest coil, which detector settings? Generalities, not detail.

Perhaps Alluvium can do this from a successful (big nugget finder’s) point of view? If he were looking for a big nuggets (1+ oz) what tools would he want need to find them at depths over 30 cm?  

Huego  ::62::

==============================================================================

Hi  Huego.

I had better start sometime, so I will put a few details together to try to help any new comers with what I have found out over the years in detecting for these larger nuggets.
Your quote:     - What factors, that we can control as prospectors, maximise detection depth?
                          - Can it be explained in largely not technical terms to readers?

There are a few basic factors when it comes to looking for big nuggets at depth, firstly an operator should use the best detector that you are able to afford, then assuming you know how to use it well, fit a large coil, with this meaning nothing under 18”inches across, and make that a round coil too.

What I use 98% of the time is a GPX 4500 detector with a Nugget Finder 18”in round mono coil.

There are a few hints I can give you on this and these are: - No matter what anyone tells you, the Normal Timing is the deepest penetrating one of them all, and has been throughout all the PI models.
Another Fact is, the larger the coil the bigger the field fluxes size, meaning that its field output goes deeper into the ground and over a wider area.

When talking on Coil Shape, a Round coil puts out to a large extent, a clearly better shaped field, and is much more superior to that of an Elliptical one.
An Elliptical Coil’s size is roughly judged by its width, rather than its length, therefore when searching for large deep gold a round coil is best for that task.

With Timings, the ones to use are dictated by the ground conditions that you encounter out in the field where you are detecting. This choice can only be made through the experience gained out there over a long period of learning.

But I will try to make it easier for say a newbie; in a lot of areas you cannot use Normal timing because of the high mineralization in the ground, so my next best choice to use, would be the Enhance Timing.
These 2 Timings on a 4500 or 5000 are your best chance of finding the deep gold; there are numerous other settings within these detectors that I will go into depth at another time.

Quote:    - Are any new detectors (even prototypes) showing promise in achieving greater detection depths?

Yes there are many new detectors that I have heard of, most know now or have heard of the new M/Lab detectors that are not far off.

This GPZ 7000 looks like Phil Beck has re-designed a 5000 board to fit in a 30/30 case, it’s very heavy and supposed to be simpler to use, but that is debatable. It does have a new chipped 14”in coil with its lead up the inside of the stem, but uses a different plug, also a pack of re-chargeable batteries on board, a sender unit for cordless H/phones and a GPS.    (Kitchen Sink an option).

This coil is a new style DD and is quite thick and heavy; they have tried to knock some weight off it in a remake, but didn’t cut the weight by much at all. It is not to replace the GPX 5000 and is in the mid range we have heard, although the proposed price does not reflect that. And all just in time for Easter this year.

Next we have the “Supergold” as one guy has called it, (Could it Be?) and is set for release mid-year.   -- - - - - - - - - It's (“The Deep detector”) You will need to sell lots of your gold to buy it, and a back hoe too.

Then there is First Texas (Fisher-Technetiks etc.) in the USA making up a new PI, we have heard it is a joint effort by Carl Moreland and David Johnson, so it should have what it takes, let’s hope it does anyway.

Whites where are you??

Alan Westerson in the United States should not be far away now with his PI, although there could be a twist of a possible Turkish delight to this somewhere??

There have been whispers about a better Garret PI, but that’s died down presently.

So now we have a look at a few from private techs in OZ.

There is the QED from bugwhiskers, then Moodz special PI hybrid, and now a bloke on the free forum posting some details, and a photo of his advanced PI circuit board,  he is named Pixulator.

I have been out with bugwhiskers and Moodz and can tell you they are not vapor detectors; we have been testing proto-types over the last 8 years and have seen remarkable ideas and top results.

Coil development is also ongoing, and there is surprising results here, that we have seen for ourselves when using them out in the field, and all on the detectors we are using today. - - - - - - - - - - - - - - - - - - - - - - - - - - -  - - - - - - -

This has a very big future and things should be moving along very soon.

Cheers for now Alluvium.





Title: Re: Detecting Larger Nuggets
Post by: geof_junk on Sunday January 25 2015 21:46:17 AEDT PM
Good post Alluvium Lets hope that I have a wide choice for a replacement for my aging ML3000 the current choice is no good, and I want it for my next trip to WA. fingers crossed.


Title: Re: Detecting Larger Nuggets
Post by: GARY on Monday January 26 2015 16:04:37 AEDT PM
Alluvium again has raised some more interesting points towards the problems that can increase or restrict the extra depth we desire.

If the Normal timing was able to handle mineralisation with a mono coil then less of the deeper gold would still be in the ground.  While at Wedderburn I had an opportunity to view a QED operating with both a 10” and 18” mono over the very mineralised ground at Beggary Hill. My GPX5000 in Normal with my 18” mono was incapable of doing the same until I switched into either of the other three timings designed especially for this type of ground. Apparently the QED only uses a single timing and from tests I have viewed on YouTube that single timing is capable of matching the depth in the ground of a GPX’s Normal timing.

I found this of interest also which I read on another forum that mono coils larger than 25” in diameter are of little use on any Minelab detector due to the pulse not being strong enough to generate the proper magnetic field. Therefore the detector will not operate correctly and why trusted coil manufacturers do not go any larger.




Btw Happy Australia Day today too us Aussies.

Gary



Edited by Gary to add extra wording





Title: Re: Detecting Larger Nuggets
Post by: Huego on Tuesday January 27 2015 09:15:32 AEDT AM
Hi Alluvium, Gary and others

Alluvium, thanks for sharing your experiences and wisdom with me and others, over the recent years. I really do appreciate that as I’m sure many others do. Many don’t appreciate just how much MD history you have experienced and seen first-hand with the big name companies and their ‘tricks’ in the goldfields. (The biggest nugget I have found is still the one I purchased from you some years ago.)

The “best detector” is somewhat elusive as I know there are better than the 5000, even from personal experience …. and for the big ones my old 2200 is probably a pretty good machine. I tested and saw tested the early QED and know how light, quiet and good it is even on noisy ground and handling EMI too. As for what I can afford, well that depends on what is available to me … and I am disregarding any that the main manufacturers are offering, for now anyway.

I would need to upgrade my coil to one or two over 18” for the current detector.  Maybe a Nugget Finder 18” round mono coil would be too noisy with my 2200, so i will wait until a superior machine maybe a QED 2, is available to me. I think I have a large (heavy garbage-looking lid) coil maybe a DD that came with the 2200. I have never used it.  That a round coil is “superior to … an Elliptical one” is something I needed to hear.

A GPZ 7000 is certainly NOT on my list of dream machines, an any price, for Easter this year or any other time. Good luck  to Whites and Alan Westerson’s MDs …. and I still have an occasional  penchant for some Turkish delight.

As I keep in touch with Bugs occasionally, I will continue to look forward to seeing his latest upgrades to the QED- 2 and in action. But I know little of what Moodz has made but remain optimistic with that too.  I think there is a patent matter in progress which will show the true metal of justice vs bullying which may determine and open up the future of MD, and perhaps the goldfields, again.

I will speak to you later of coil developments and which you recommend. I enjoyed some long chats with Jim S before his passing about some ideas he was doodling with. He was a gem of guy too. I would be great to catch up with you again Alluvium as we have a lot we can discuss. Its been too long.


Best regards,

Huego  ::62::

PS: always editing to correct spelling errors or improve clarity of expression or ideas. NO apolgies for that.


Title: Re: Detecting Larger Nuggets
Post by: Aziz on Wednesday January 28 2015 22:07:19 AEDT PM
Hi all,

no need for new coil & detector technologies.
There is no gold in the ground anymore!
see here: http://golddetecting.4umer.net/t20496p30-gpz7000-release-delayed
*LOL*

One thing is for sure:
The ultimate thermo-nuclear melt-down to your wallet is coming...
With the new GPZ-7000!
(A drip-feed tech release of course. We will see at least three upcoming models with this technology in the future. Every model will be a drip-feed model. No interchanging & 3rd party coils. A hard wired coil will be there.)
*LOL*

If you guys keep follow your vested interests instead of working & sharing together for the same goal (developing a desired top technology detector to meet the thread title), you will blatantly fail. If you don't kill your evil greed, you will blatantly fail too.
I'm sick of this game. Either you work & share together or I'll initiate the ultimate end game..
Period.
^sif


Title: Re: Detecting Larger Nuggets
Post by: Huego on Wednesday January 28 2015 23:25:33 AEDT PM
  
Hi all,

....... The ultimate thermo-nuclear melt-down to your wallet is coming... With the new GPZ-7000!
(A drip-feed tech release of course. We will see at least three upcoming models with this technology in the future. Every model will be a drip-feed model. No interchanging & 3rd party coils. A hard wired coil will be there.)


If you guys keep follow your vested interests instead of working & sharing together for the same goal (developing a desired top technology detector to meet the thread title), you will blatantly fail. If you don't kill your evil greed, you will blatantly fail too.  I'm sick of this game. Either you work & share together or I'll initiate the ultimate end game..
Period.

^sif

Aziz,

I follow you BUT you must be referring to a small handful of designers here who do the theoretical and practical side of MD development. (I am NOT one of those, my "skills", for what they are worth, lie elsewhere.)  Thats just a fact. So who are you imploring to?

Seems to me you can't get get others with ideas to always reveal (publicly) what it is you wish to hear, or want to know, that can allow for the collaboration you seek. Some may have invested or have made plans which they can't or won't change at this stage. Maybe there are risks they dont wish to take. Its the way of world.. everyone is an individual who DO things, SAY things, REVEAL things in their own way, and their own time. It can NOT be pushed. You have been generous with your time, ideas, simulations and knowledge but perhaps others are not feeling as enthused to share as you do.  ::402::

Huego  ::62::


Title: Re: Detecting Larger Nuggets
Post by: Larry on Wednesday January 28 2015 23:40:52 AEDT PM
  
  
Hi all,

....... The ultimate thermo-nuclear melt-down to your wallet is coming... With the new GPZ-7000!
(A drip-feed tech release of course. We will see at least three upcoming models with this technology in the future. Every model will be a drip-feed model. No interchanging & 3rd party coils. A hard wired coil will be there.)


If you guys keep follow your vested interests instead of working & sharing together for the same goal (developing a desired top technology detector to meet the thread title), you will blatantly fail. If you don't kill your evil greed, you will blatantly fail too.  I'm sick of this game. Either you work & share together or I'll initiate the ultimate end game..
Period.

^sif

Aziz,

I follow you BUT you must be referring to a small handful of designers here who do the theoretical and practical side of MD development. (I am NOT one of those, my "skills", for what they are worth, lie elsewhere.)  Thats just a fact. So who are you imploring to?

Seems to me you can't get get others with ideas to always reveal (publicly) what it is you wish to hear, or want to know, that can allow for the collaboration you seek. Some may have invested or have made plans which they can't or won't change at this stage. Maybe there are risks they dont wish to take. Its the way of world.. everyone is an individual who DO things, SAY things, REVEAL things in their own way, and their own time. It can NOT be pushed. You have been generous with your time, ideas, simulations and knowledge but perhaps others are not feeling as enthused to share as you do.  ::402::

Huego  ::62::

Perhaps others don't have any new ideas to present. That is what I see.

I have been a lurker for a while, and I have to say, Aziz is just about the only member of this forum who is continually doing development work and presenting it to all members. Aziz seems to me to be struggling financially to purchase parts to do his development, and I think he is deserving of support to carry on his work, but no one seems to be willing to offer to help him out. How about 10 members donate $10 to Aziz to help him out to buy the parts he needs for his work?


Title: Re: Detecting Larger Nuggets
Post by: Huego on Thursday January 29 2015 00:06:47 AEDT AM
  

Perhaps others don't have any new ideas to present. That is what I see.

I have been a lurker for a while, and I have to say, Aziz is just about the only member of this forum who is continually doing development work and presenting it to all members. Aziz seems to me to be struggling financially to purchase parts to do his development, and I think he is deserving of support to carry on his work, but no one seems to be willing to offer to help him out. How about 10 members donate $10 to Aziz to help him out to buy the parts he needs for his work?



Oh I believe there are lotsa ideas out there. But they are under wraps and Aziz knows or senses that and it frustrates him as he is so willing to show his skills and ideas.

From what I read it seems Aziz may well be short of funds but prefers to progress at his pace, one he can afford. He does not like to feel owing to others either. He also like to show how much can be achieved with so little capital. He has been offered help and finances before and rejected it. I don’t believe he wants or needs money, he wants to work together with others here. Tell me if I'm wrong Aziz.

 ::419::


Title: Re: Detecting Larger Nuggets
Post by: Alluvium on Saturday January 31 2015 12:23:47 AEDT PM
               Minelab Detector Depths.       The Hype, the Promises.     Are you a believer??

==============================================================
                                                  
                                                               Detector Models.      

In discussing M/Lab detectors, and the extra depth promoted at each new models release. With this meaning, (that their latest detector will find gold nuggets at greater depths more-so than your last unit could). The question I put forward is, does it?

To answer the above, it basically comes down to always using your own judgment, not from listening to other people’s opinions. So when you obtain and test one, you can personally see if this new detector does actually have an advantage in depth over your previous model, as has been stated in the advertising.                                                                    

You will only gain accurate knowledge from your own findings and experiences, and that is achieved from being out there detecting yourself, and by using each new model extensively over a fair while, before passing any judgment about it.

But for a person to just go and blindly accept the spin and rumour used at every new models launch, and especially of being coaxed into believing that the manufactures predicted gain in depth percentage figures are gospel. This to me does bring some concern.                                                                                                                                          

We have all seen these (ongoing improvements) printed boldly in the glossy advertising brochures and magazines, well to look on these as a fact, would be unwise and totally wrong.                              

See my thoughts below on “depth gains” when using (Minelab’s own facts and figures), as stated in bold print from those many hand out brochures etc, at each new model’s release.

Side Note:   I have kept these brochures etc in my possession, ever since the company’s formation in 1985 and I will quote their actual figures in the text as written below.

============================================================================
 
To firstly obtain a depth reference, I will use a reasonable measure of 300 mm, =  (12”inches depth) . (This is an educated guess), and put forward just to get a starting point.  So therefore we can now propose the best depth obtained with a late model VLF detector.
 
With it also as having a reasonably clear audible response, when being swept over a (naturally buried in situ, 1oz + gold nugget) located 300mm down, in fairly mineralised ground.
 
This meaning that the 300mm is the Maximum target depth attainable on this VLF detector, under these above circumstances.
====================================================================
                                                                                                                                                        
                                                        The VLF Detector:                                                              
                                                                                                                                                                            
 
In mid 1993 at that particular time, the top of the range VLF model (before the PI machines), was the M/Lab, XT17000 VLF (blue box) detector, it was supplied with an 8”inch DD coil.

A very good detector in its day, and I had much success with one in Vic and WA.
It was sometime later stated in another brochure, that if the (newly developed) M/Lab 11”inch coil, was used instead of the supplied 8”in, this would increase a 17000’s depth capability by 20%.                                                                                

This would therefore add another 60mm depth to the 300mm. But for this exercise we will be fair, and go with the original 8”inch supplied coil and the 300mm depth.                                                                          

=========================================================================                                                                                                                                              
                           The Depth Facts:                          The SD Range of Pulse Induction detectors.

When the SD 2000 Pulse Induction detectors were released in April 1995, it was stated by M/Lab that a SD2000 was 3 times better in depth than the XT17000 in mineralised soils.

Using this statement above, we will add this to the original 300mm depth of the VLF machine.

So therefore, 300mm x 3 = 900mm. or (nearly 3’ft deep).

===========================================================================

In June 1996 the new SD 2100 arrived, it was promoted as up to 30% better in depth over the SD2000 on nuggets that were less than 5gms in weight, and 15% better depth on gold over 5 grams and up.                          

This extra depth over the SD 2000’s would mean this, 30% = 270mm + 900mm = 1170mm, depth.                          

Or if we only use the 15% = 135mm + 900 = 1035mm, or 3ft.4 ¾”ins, depth on the better size gold.
==========================================================================                                                              
A new SD 2200 D model in June 1998 is quoted in the M/Lab brochures as 4 times better in depth than a conventional VLF detector.                                                                                                                                            

So now if we go back to the start using the 300mm x 4  = 1200mm, or  3’ft 11 ¼”ins, depth attainable using a SD 2200D                                                                                                                                      

We would have to be talking at those depths, on finding a 30 to 50 oz fairly flat nugget sitting face upwards
towards the coil, to even have a chance to achieve this, especially if buried in mineralised ground.

Plus you would have to be swinging at least an 18”inch coil or bigger).                                                                            

But I can tell you, the above scenario is  highly unlikely to happen!

=========================================================================
                                                              
                                                           The GP Detectors.

The GP Extreme PI came out with much fanfare in November 2000, and M/Lab sent a letter out to all previous customers on its release, openly boasting of it having an increase in depth averaging 25% to 30% more than any, other detector.

(Quoting that on some nuggets found while testing were recorded at up to 55% deeper in depth, than on the SD2200 D).                                                                                                                                                          
A latter brochure toned that down a bit to 55% deeper on smaller nuggets, then saying it has gains of up to 18% more depth on larger gold nuggets.                                                                                                                            

Now if we only use their 18% figure here, added to the unlikely 1200mm depth quoted on the 2200D.
So 18% of 1200mm =  216mm  added to the 1200mm  = 1416mm, or  (4’ft 7”+ins).  
Being the quoted Depth obtainable on a GP Extreme on larger gold?

Really this is getting bloody ridiculous; we would now (possibly) be starting to look for an incredibly limited number, of very rare monster gold nuggets, with an extra large surface area and having an immense mass.                        

This nugget would theoretically have to be in the region of maybe 300 to 500 ozs weight, or more than likely, well upwards of that.     Then of the operator (fantasizing) or being very hopeful, that you could find one of these monsters, at that fanciful and improbable depth.                                                                                                                                                                                                                                                                                                                  
Sure you may get a signal on a big ferrous target down there, but it’s likely to be a buried, Car Door.

==========================================================================

The next detector was the GP3000, released in July 2003 the brochure quoted an improvement in having, “An Enhanced stable Ground Balance and Clearer Target Signal, to Maximise detection depth”.                                                                                                              

This it did, but not at these previous depths quoted above for the GP Extreme.                                                                

Minelab must have woken up that their endlessly increasing percentage depths quoted about their detectors depth ability, and was now a little on the nose.

==========================================================================                                                    
In 2005 the GP3500 appeared with the usual promise of (More Depth, Sensitivity and Accuracy).                            

Quote:  ”As you can detect in Fixed mode more easily, this is giving greater depth”. This point is true but just to a very small advantage. Yet once again this detector only had very minor increments of depth gain (and only on certain targets).  

With no actual depth percentages quoted by m/lab again?

=========================================================================
                                                        
                                                              The GPX Range.

The GPX 4000’s released in late 2006 were promoted as a new revelation to gold finding, and to a fair extent they were.
With only mild suggestions stated about depth gains in their promotion of these.

=========================================================================

M/Lab’s next model in April 2008 was the GPX 4500; this was the 4000 souped up substantially, much more than the previous 4000, and they also promised some extra depth.                                                                            

Like the Extreme,  having this Quote: The GPX Depth Advantage allows you to find gold much deeper than ANY other detector.

But this was without any percentages stated, and not pushed or flogged to any extent.

=========================================================================

With the last detector released in late August 2010 being the GPX 5000, the Brochures quoted this machine as such, with all of these new features, combined with the established GPX ability to see through ground mineralisation, , that this results in you gaining the GPX Depth Advantage                                                                        

Will it ever end???

Unlike the 4500 it was very smooth running and has a silky threshold, the G/Balance was better and settled quicker, it also had a new timing added being the Fine Gold timing.

The new timing works at its best when hunting-out the many tiny sub-gram specks of gold, which are still out there in quite reasonable quantities, and the 5000 was also finding them at very good depths for their size, this was happening because most operators were using little mono-loop coils, 8”inch etc.

Fine Gold timing has been pushed and promoted continuously, and that is, it will find large gold at depth too, and  just as well as it finds the small gold.  

How can that be, when all our testing showed this not to be the Case There have been very few large deep nuggets found with the GPX5000 detectors over the last 4 years, and that’s mainly because 95% of operators are running it in the Fine Gold timing with tiny mono coils.                                                                                                                                  

It’s just not going to happen.
                                                                                                                                     

If you want to find big deep gold, the 5000 has to be used in Normal Timing with a large coil, and most likely, it would be best using a DD coil.                                                                                                                                                      
Note:  Even though the 5000 is quoted to better handle the atmospherics, it is still upset badly by EMI and  other similar interference sources, moreover just as much so as the previous GPX4500 model.

Re: What is the difference between a 4500 and 5000 Price??                                                                                                                                                                                  

Here is the story. The 5000 is near the exact same board as the 4500, basically the only difference is the two gain set resistors on the AD797 preamps, from 470 ohms (that was common on all models) but the 5000 has the resistors dropped down to 330 ohms.  

Apart from the switch layout and a few lines of code there is nothing different.
Everyone says it is much quieter, obviously correct, as it has not got the all important front end gain.

If the detector had one more gain stage to make up the difference, they could have retained the depth of the 4500 and still had the first stage head room that they are trying to achieve.

=================================================================

Who is game to believe this latest advertising brochure???

Cheers from Alluvium.

Edited for the grammar. Alluvium
Doug it still will not come up with a preview so I can edit it there???







Title: Re: Detecting Larger Nuggets
Post by: Doug on Saturday January 31 2015 12:38:36 AEDT PM
Alluvium.
Bilbo on finders  i think agrees with your sentiments. and is certainly skeptical of ML depth claims.
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Doug on Saturday January 31 2015 13:07:25 AEDT PM
  
              Minelab Detector Depths.       The Hype, the Promises.     Are you a believer??

==============================================================
                                                  
                                                               Detector Models.      

In discussing M/Lab detectors, and the extra depth promoted at each new models release. With this meaning, (that their latest detector will find gold nuggets at greater depths more-so than your last unit could). The question I put forward is, does it?

To answer the above, it basically comes down to always using your own judgment, not from listening to other people’s opinions. So when you obtain and test one, you can personally see if this new detector does actually have an advantage in depth over your previous model, as has been stated in the advertising.                                                                    

You will only gain accurate knowledge from your own findings and experiences, and that is achieved from being out there detecting yourself, and by using each new model extensively over a fair while, before passing any judgment about it.

But for a person to just go and blindly accept the spin and rumour used at every new models launch, and especially of being coaxed into believing that the manufactures predicted gain in depth percentage figures are gospel. This to me does bring some concern.                                                                                                                                          

We have all seen these (ongoing improvements) printed boldly in the glossy advertising brochures and magazines, well to look on these as a fact, would be unwise and totally wrong.                              

See my thoughts below on “depth gains” when using (Minelab’s own facts and figures), as stated in bold print from those many hand out brochures etc, at each new model’s release.

Side Note:   I have kept these brochures etc in my possession, ever since the company’s formation in 1985 and I will quote their actual figures in the text as written below.

============================================================================
 
To firstly obtain a depth reference, I will use a reasonable measure of 300 mm, =  (12”inches depth) . (This is an educated guess), and put forward just to get a starting point.  So therefore we can now propose the best depth obtained with a late model VLF detector.
 
With it also as having a reasonably clear audible response, when being swept over a (naturally buried in situ, 1oz + gold nugget) located 300mm down, in fairly mineralised ground.
 
This meaning that the 300mm is the Maximum target depth attainable on this VLF detector, under these above circumstances.
====================================================================
                                                                                                                                                        
                                                        The VLF Detector:                                                              
                                                                                                                                                                            
 
In mid 1993 at that particular time, the top of the range VLF model (before the PI machines), was the M/Lab, XT17000 VLF (blue box) detector, it was supplied with an 8”inch DD coil.

A very good detector in its day, and I had much success with one in Vic and WA.
It was sometime later stated in another brochure, that if the (newly developed) M/Lab 11”inch coil, was used instead of the supplied 8”in, this would increase a 17000’s depth capability by 20%.                                                                                

This would therefore add another 60mm depth to the 300mm. But for this exercise we will be fair, and go with the original 8”inch supplied coil and the 300mm depth.                                                                          

=========================================================================                                                                                                                                              
                           The Depth Facts:                          The SD Range of Pulse Induction detectors.

When the SD 2000 Pulse Induction detectors were released in April 1995, it was stated by M/Lab that a SD2000 was 3 times better in depth than the XT17000 in mineralised soils.

Using this statement above, we will add this to the original 300mm depth of the VLF machine.

So therefore, 300mm x 3 = 900mm. or (nearly 3’ft deep).

===========================================================================

In June 1996 the new SD 2100 arrived, it was promoted as up to 30% better in depth over the SD2000 on nuggets that were less than 5gms in weight, and 15% better depth on gold over 5 grams and up.                          

This extra depth over the SD 2000’s would mean this, 30% = 270mm + 900mm = 1170mm, depth.                          

Or if we only use the 15% = 135mm + 900 = 1035mm, or 3ft.4 ¾”ins, depth on the better size gold.
==========================================================================                                                              
A new SD 2200 D model in June 1998 is quoted in the M/Lab brochures as 4 times better in depth than a conventional VLF detector.                                                                                                                                            

So now if we go back to the start using the 300mm x 4  = 1200mm, or  3’ft 11 ¼”ins, depth attainable using a SD 2200D                                                                                                                                      

We would have to be talking at those depths, on finding a 30 to 50 oz fairly flat nugget sitting face upwards
towards the coil, to even have a chance to achieve this, especially if buried in mineralised ground.

Plus you would have to be swinging at least an 18”inch coil or bigger).                                                                            

But I can tell you, the above scenario is  highly unlikely to happen!

=========================================================================
                                                              
                                                           The GP Detectors.

The GP Extreme PI came out with much fanfare in November 2000, and M/Lab sent a letter out to all previous customers on its release, openly boasting of it having an increase in depth averaging 25% to 30% more than any, other detector.

(Quoting that on some nuggets found while testing were recorded at up to 55% deeper in depth, than on the SD2200 D).                                                                                                                                                          
A latter brochure toned that down a bit to 55% deeper on smaller nuggets, then saying it has gains of up to 18% more depth on larger gold nuggets.                                                                                                                            

Now if we only use their 18% figure here, added to the unlikely 1200mm depth quoted on the 2200D.
So 18% of 1200mm =  216mm  added to the 1200mm  = 1416mm, or  (4’ft 7”+ins).  
Being the quoted Depth obtainable on a GP Extreme on larger gold?

Really this is getting bloody ridiculous; we would now (possibly) be starting to look for an incredibly limited number, of very rare monster gold nuggets, with an extra large surface area and having an immense mass.                        

This nugget would theoretically have to be in the region of maybe 300 to 500 ozs weight, or more than likely, well upwards of that.     Then of the operator (fantasizing) or being very hopeful, that you could find one of these monsters, at that fanciful and improbable depth.                                                                                                                                                                                                                                                                                                                  
Sure you may get a signal on a big ferrous target down there, but it’s likely to be a buried, Car Door.

==========================================================================

The next detector was the GP3000, released in July 2003 the brochure quoted an improvement in having, “An Enhanced stable Ground Balance and Clearer Target Signal, to Maximise detection depth”.                                                                                                              

This it did, but not at these previous depths quoted above for the GP Extreme.                                                                

Minelab must have woken up that their endlessly increasing percentage depths quoted about their detectors depth ability, and was now a little on the nose.

==========================================================================                                                    
In 2005 the GP3500 appeared with the usual promise of (More Depth, Sensitivity and Accuracy).                            

Quote:  ”As you can detect in Fixed mode more easily, this is giving greater depth”. This point is true but just to a very small advantage. Yet once again this detector only had very minor increments of depth gain (and only on certain targets).  

With no actual depth percentages quoted by m/lab again?

=========================================================================
                                                        
                                                              The GPX Range.

The GPX 4000’s released in late 2006 were promoted as a new revelation to gold finding, and to a fair extent they were.
With only mild suggestions stated about depth gains in their promotion of these.

=========================================================================

M/Lab’s next model in April 2008 was the GPX 4500; this was the 4000 souped up substantially, much more than the previous 4000, and they also promised some extra depth.                                                                            

Like the Extreme,  having this Quote: The GPX Depth Advantage allows you to find gold much deeper than ANY other detector.

But this was without any percentages stated, and not pushed or flogged to any extent.

=========================================================================

With the last detector released in late August 2010 being the GPX 5000, the Brochures quoted this machine as such, with all of these new features, combined with the established GPX ability to see through ground mineralisation, , that this results in you gaining the GPX Depth Advantage                                                                        

Will it ever end???

Unlike the 4500 it was very smooth running and has a silky threshold, the G/Balance was better and settled quicker, it also had a new timing added being the Fine Gold timing.

The new timing works at its best when hunting-out the many tiny sub-gram specks of gold, which are still out there in quite reasonable quantities, and the 5000 was also finding them at very good depths for their size, this was happening because most operators were using little mono-loop coils, 8”inch etc.

Fine Gold timing has been pushed and promoted continuously, and that is, it will find large gold at depth too, and  just as well as it finds the small gold.  

How can that be, when all our testing showed this not to be the Case There have been very few large deep nuggets found with the GPX5000 detectors over the last 4 years, and that’s mainly because 95% of operators are running it in the Fine Gold timing with tiny mono coils.                                                                                                                                  

It’s just not going to happen.
                                                                                                                                     

If you want to find big deep gold, the 5000 has to be used in Normal Timing with a large coil, and most likely, it would be best using a DD coil.                                                                                                                                                      
Note:  Even though the 5000 is quoted to better handle the atmospherics, it is still upset badly by EMI and  other similar interference sources, moreover just as much so as the previous GPX4500 model.

Re: What is the difference between a 4500 and 5000 Price??                                                                                                                                                                                  

Here is the story. The 5000 is near the exact same board as the 4500, basically the only difference is the two gain set resistors on the AD797 preamps, from 470 ohms (that was common on all models) but the 5000 has the resistors dropped down to 330 ohms.  

Apart from the switch layout and a few lines of code there is nothing different.
Everyone says it is much quieter, obviously correct, as it has not got the all important front end gain.

If the detector had one more gain stage to make up the difference, they could have retained the depth of the 4500 and still had the first stage head room that they are trying to achieve.

=================================================================

Who is game to believe this latest advertising brochure???

Cheers from Alluvium.

Edited for the grammar. Alluvium
Doug it still will not come up with a preview so I can edit it there???







So the main reason the gpx5000 runs more smoothly and is quieter is that the coil preamp gain has been substantially  reduced?
This could  result in  potentially less depth on some nuggets compared to the 4500?
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Doug on Saturday January 31 2015 13:21:59 AEDT PM
 Maybe the 40% depth claim is only getting back the huge depth loss that occurs with some nuggets when one uses any of the smooth timings in the gpx!!!!
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Alluvium on Saturday January 31 2015 13:26:39 AEDT PM
  
Maybe the 40% depth claim is only getting back the huge depth loss that occurs with some nuggets when one uses any of the smooth timings in the gpx!!!!
doug ::419::

Hello Doug and members.

I think the fine print on that brochure tells it all.

My thoughts about the new GPZ 7000 are, if they promote it as the one expected, the so called deep seeking model detector we all heard was coming, I’m afraid there are going to be many disappointed people out there, including myself.

How can you say this one (details released yesterday) has all new technology, when it is still a PI machine? It may have a chipped coil attached, but surely this fact alone cannot be what this all new tech is?

The only thing I can come up with, is the thought that they put out 2 lots of test machines, for the major group of testers, they were given one version, but then had another small group out there testing a detector with different software for deep gold..

Now could it be that when they had the results from both parties, they have now combined these into the one machine? I hope I am right, as the version I know of, ain’t no world beater.

Nah --- I am not that lucky.

Just my thoughts Boys.  Alluvium.


Title: Re: Detecting Larger Nuggets
Post by: Doug on Saturday January 31 2015 13:38:40 AEDT PM
  
  
Maybe the 40% depth claim is only getting back the huge depth loss that occurs with some nuggets when one uses any of the smooth timings in the gpx!!!!
doug ::419::

Hello Doug and members.

I think the fine print on that brochure tells it all.

My thoughts about the new GPZ 7000 are, if they promote it as the one expected, the so called deep seeking model detector we all heard was coming, I’m afraid there are going to be many disappointed people out there, including myself.

How can you say this one (details released yesterday) has all new technology, when it is still a PI machine? It may have a chipped coil attached, but surely this fact alone cannot be what this all new tech is?

The only thing I can come up with, is the thought that they put out 2 lots of test machines, for the major group of testers, they were given one version, but then had another small group out there testing a detector with different software for deep gold..

Now could it be that when they had the results from both parties, they have now combined these into the one machine? I hope I am right, as the version I know of, ain’t no world beater.

Nah --- I am not that lucky.

Just my thoughts Boys.  Alluvium.


The new technology they claim can only be what they have recently patented which is constant current sampling and another patented method to reduce EMI.
The funny part is that if the detector uses CC technology as was pointed out here by another poster ML "forgot" to cite an early patent  that mentions using CC their  patent! Whites also have CC patent and may come out with a new detector although they could have a big fight with ML with their patent! We shall see!
doug ::419::
 


Title: Re: Detecting Larger Nuggets
Post by: bearslayer on Sunday February 1 2015 08:43:31 AEDT AM
Having said all that, when is the QED or Moodz' world beater or any other detector being touted on this forum ever going to be seen by the ordinary detector operator?
You all deride Minelab equipment constantly but you forget one thing.

No detector in history has cleaned up the goldfields better than all the Minelab models.


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday February 1 2015 09:25:12 AEDT AM
  
Having said all that, when is the QED or Moodz' world beater or any other detector being touted on this forum ever going to be seen by the ordinary detector operator?
You all deride Minelab equipment constantly but you forget one thing.

No detector in history has cleaned up the goldfields better than all the Minelab models.

pre sd2000 days it was not ML detectors that were cleaning up the goldfields!
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: bugwhiskers on Sunday February 1 2015 09:28:02 AEDT AM
  
Having said all that, when is the QED or Moodz' world beater or any other detector being touted on this forum ever going to be seen by the ordinary detector operator?
You all deride Minelab equipment constantly but you forget one thing.

No detector in history has cleaned up the goldfields better than all the Minelab models.

You are forgetting that the biggest nugget found in OZ was found many years ago with a Garrett detector.
Thank you for admitting that the goldfields have been "cleaned up". The latest models have just picked up the stragglers.
The days of people with an SD2000 finding enough gold in the first week to buy a house are long, long gone.
The "gold detector" marketing spin and propaganda is falling on ever defeaning ears.
I hear the new model is named Jupiter. We can only hope it doesn't end up just being "Gas Giant" like it's namesake.
If it does, the comment of the day is, shove it up Uranus !


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday February 1 2015 09:51:43 AEDT AM
  
No detector in history has cleaned up the goldfields better than all the Minelab models.

And for this ML have Eric Foster  and some of the other early pioneers to thank in my opinion! Eric foster had a Gb'ing  Pi detector that could be used in the goldfields 11 years before the SD2000 came onto the market!!! Eric's pi  detector the goldscan 4 could be purchased from Finders in  Dunolly  Vic!
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: greylourie on Sunday February 1 2015 10:08:45 AEDT AM
  

A little trick you could try next time, is to skid an 18”inch DD coil on the ground, while using it in Normal timing, place your 5000 in cancel mode, and then crank up your gain and stabilizer a bit, if it is getting a little noisy, put the Audio in Quiet mode.

What happens is it handles that hot ground  and EMI up there a lot better, and also has an advantage because it transmits on the TX winding as in a DD coil, but it receives any signals on both of the windings.

There is quite an advantage doing this, and the bigger the DD coil the better it works. Using Cancel this way still gets the depths required.

Good luck and Cheers.  Alluvium.





Hello Alluvium.
I enjoy reading your posts. You offer a lot of useful information and guides. Sadly not many are willing to provide the kind of info and detail you give out so freely. Or if they have, its buried deep in posts long forgotten.

Thanks for posting about using Cancel with DD coils. I have heard it mentioned briefly in passing, I think on this forum. But never really understood what was happening.
The fact that both coils are used as receive coils is very interesting.
So that must mean that these devices have two preamps. ( I am always late to the party.)

_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------------
 
With the new machine, I wonder how the Super D 14" coil will factor into the equation.  I wonder if it will be relying heavily on the use of a type of Cancel mode.

Is there some kind of trend, with each successive model mopping up certain bands of targets missed with the previous release ? Improved sensibility to smaller stuff, with smoother and better audio ? I mean that is what new models are brought out for, isn't it ? To find what was missed....

I guess we will find out soon enough.


Title: Re: Detecting Larger Nuggets
Post by: bugwhiskers on Sunday February 1 2015 10:24:50 AEDT AM
greylourie,

The post below should answer your 2nd last paragraph.


http://australianelectronicgoldprospectingforum.com/general-chat-and-discussion-forum/drip-feed/msg32742/?topicseen#msg32742


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday February 1 2015 10:31:00 AEDT AM
  
  

A little trick you could try next time, is to skid an 18”inch DD coil on the ground, while using it in Normal timing, place your 5000 in cancel mode, and then crank up your gain and stabilizer a bit, if it is getting a little noisy, put the Audio in Quiet mode.

What happens is it handles that hot ground  and EMI up there a lot better, and also has an advantage because it transmits on the TX winding as in a DD coil, but it receives any signals on both of the windings.

There is quite an advantage doing this, and the bigger the DD coil the better it works. Using Cancel this way still gets the depths required.

Good luck and Cheers.  Alluvium.





Hello Alluvium.
I enjoy reading your posts. You offer a lot of useful information and guides. Sadly not many are willing to provide the kind of info and detail you give out so freely. Or if they have, its buried deep in posts long forgotten.

Thanks for posting about using Cancel with DD coils. I have heard it mentioned briefly in passing, I think on this forum. But never really understood what was happening.
The fact that both coils are used as receive coils is very interesting.
So that must mean that these devices have two preamps. ( I am always late to the party.)

_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------------
 
With the new machine, I wonder how the Super D 14" coil will factor into the equation.  I wonder if it will be relying heavily on the use of a type of Cancel mode.

Is there some kind of trend, with each successive model mopping up certain bands of targets missed with the previous release ? Improved sensibility to smaller stuff, with smoother and better audio ? I mean that is what new models are brought out for, isn't it ? To find what was missed....

I guess we will find out soon enough.


For  oldies like me what is needed i think is a lightweight, simple to use turn on and go  Pi detector. Spend our time detecting not tweaking and  fiddling or having to spend  12 months or more trying to understand or master a plethora of different variables!!!!
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: greylourie on Sunday February 1 2015 10:39:23 AEDT AM
  

And for this ML have Eric Foster  and some of the other early pioneers to thank in my opinion! Eric foster had a Gb'ing  Pi detector that could be used in the goldfields 11 years before the SD2000 came onto the market!!! Eric's pi  detector the goldscan 4 could be purchased from Finders in  Dunolly  Vic!
doug ::419::

And that model was later refined and modernised into the TDI range. I have seen recently some interesting comments and one or two videos by Australian users of the Whites P.I's.  I think the micro is only used to supply TX timing and integrator gating previously done by 555's and 4538's.
For a detector that does not ( I think ? ) send the signal into the digital realm, just goes to show what a guru Eric Foster is.
Quite respectable for a machine that only has a single preamp, target channel, and a channel for ground.

Imagine if Whites decided to add extra Target channels, and massage the signal through a micro..........


Title: Re: Detecting Larger Nuggets
Post by: greylourie on Sunday February 1 2015 10:41:02 AEDT AM
  
greylourie,

The post below should answer your 2nd last paragraph.


http://australianelectronicgoldprospectingforum.com/general-chat-and-discussion-forum/drip-feed/msg32742/?topicseen#msg32742

I think you hit the nail on the head.

Sadly, they are quite deluded if they are trying to patent and hold exclusive right of any and all forms of timing/ground balancing. I've seen the posts mentioning Colani, Fosters and others.

That horse bolted out the proverbial stable door decades ago. Sorry, but they "missed"  it there.

The Goldscan has a two integrators. One for ground, and one for target.
A certain company came along and plugged in an extra target channel. And all of a sudden there is this God complex.

I can appreciate people adding snubbing/clamping for the TX. Sending the signal into the digital realm for massaging. This is all good. Improvement.

But to just plug on an extra target channel every 2 years, or whatever.... And then declare that all Gb'ing methods are yours is bullcrap.

Quite clearly the first commercially produced GB'ing detector was produced as the Goldscan. Anything after that is just a tweak.

I can appreciate a company trying to protect and maintain market dominance.

Are they going to declare all othe GB'ing P.I manufacturers are in breach of their all-encompasing GB'ing patents.
They going to take them all on ?         

Pfffff..... God complex ..


Title: Re: Detecting Larger Nuggets
Post by: greylourie on Sunday February 1 2015 10:56:32 AEDT AM
  
  
  

A little trick you could try next time, is to skid an 18”inch DD coil on the ground, while using it in Normal timing, place your 5000 in cancel mode, and then crank up your gain and stabilizer a bit, if it is getting a little noisy, put the Audio in Quiet mode.

What happens is it handles that hot ground  and EMI up there a lot better, and also has an advantage because it transmits on the TX winding as in a DD coil, but it receives any signals on both of the windings.

There is quite an advantage doing this, and the bigger the DD coil the better it works. Using Cancel this way still gets the depths required.

Good luck and Cheers.  Alluvium.





Hello Alluvium.
I enjoy reading your posts. You offer a lot of useful information and guides. Sadly not many are willing to provide the kind of info and detail you give out so freely. Or if they have, its buried deep in posts long forgotten.

Thanks for posting about using Cancel with DD coils. I have heard it mentioned briefly in passing, I think on this forum. But never really understood what was happening.
The fact that both coils are used as receive coils is very interesting.
So that must mean that these devices have two preamps. ( I am always late to the party.)

_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------------
 
With the new machine, I wonder how the Super D 14" coil will factor into the equation.  I wonder if it will be relying heavily on the use of a type of Cancel mode.

Is there some kind of trend, with each successive model mopping up certain bands of targets missed with the previous release ? Improved sensibility to smaller stuff, with smoother and better audio ? I mean that is what new models are brought out for, isn't it ? To find what was missed....

I guess we will find out soon enough.


For  oldies like me what is needed i think is a lightweight, simple to use turn on and go  Pi detector. Spend our time detecting not tweaking and  fiddling or having to spend  12 months or more trying to understand or master a plethora of different variables!!!!
doug ::419::

Sadly Doug,

The best we can hope for from a commercial manufacturer might be a something like a TDI SL weight-wise.
Maybe Whites will come out with a TDI that uses a micro to optimise and simplify use. And improve performance/detection. They could automate the frequency scan, and make a few other tweaks..

By all accounts the Garrett is a heavy beast. So that rules it out for potential users with your requirements.But has a nice interface.

All the input I have read from users of the TDI SL, make positive comments about its weight.



Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday February 1 2015 11:07:35 AEDT AM
  
  
  
  

A little trick you could try next time, is to skid an 18”inch DD coil on the ground, while using it in Normal timing, place your 5000 in cancel mode, and then crank up your gain and stabilizer a bit, if it is getting a little noisy, put the Audio in Quiet mode.

What happens is it handles that hot ground  and EMI up there a lot better, and also has an advantage because it transmits on the TX winding as in a DD coil, but it receives any signals on both of the windings.

There is quite an advantage doing this, and the bigger the DD coil the better it works. Using Cancel this way still gets the depths required.

Good luck and Cheers.  Alluvium.





Hello Alluvium.
I enjoy reading your posts. You offer a lot of useful information and guides. Sadly not many are willing to provide the kind of info and detail you give out so freely. Or if they have, its buried deep in posts long forgotten.

Thanks for posting about using Cancel with DD coils. I have heard it mentioned briefly in passing, I think on this forum. But never really understood what was happening.
The fact that both coils are used as receive coils is very interesting.
So that must mean that these devices have two preamps. ( I am always late to the party.)

_______________________________________________________________________________
------------------------------------------------------------------------------------------------------------------------------
 
With the new machine, I wonder how the Super D 14" coil will factor into the equation.  I wonder if it will be relying heavily on the use of a type of Cancel mode.

Is there some kind of trend, with each successive model mopping up certain bands of targets missed with the previous release ? Improved sensibility to smaller stuff, with smoother and better audio ? I mean that is what new models are brought out for, isn't it ? To find what was missed....

I guess we will find out soon enough.


For  oldies like me what is needed i think is a lightweight, simple to use turn on and go  Pi detector. Spend our time detecting not tweaking and  fiddling or having to spend  12 months or more trying to understand or master a plethora of different variables!!!!
doug ::419::

Sadly Doug,

The best we can hope for from a commercial manufacturer might be a something like a TDI SL weight-wise.
Maybe Whites will come out with a TDI that uses a micro to optimise and simplify use. And improve performance/detection. They could automate the frequency scan, and make a few other tweaks..

By all accounts the Garrett is a heavy beast. So that rules it out for potential users with your requirements.But has a nice interface.

All the input I have read from users of the TDI SL, make positive comments about its weight.



Unfortunately I believe the biggest problem with the TDI is the Gb method.The method used i believe was posted on Geotech and from memory takes some  late samples which will tend to  significantly reduce the signal particularly on longer TC targets.  If you turn off the Gb as you do on the gs5 and do air tests you will find that the gs5 can match any ML for detection range! Other factors that may impact on detection depth on the TDI maybe are much less gain and Eric  flat tops the pulse and uses the old methods of a resistor for coil damping? Still taking everything into account the TDI costs a fraction of the overpriced 5000 and in my opinion offers very good value for money. In my opinion the TDI with a range of coils would have detected the majority of the gold  found by "Bloodgold2"and his crew in the N Queensland!
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday February 1 2015 11:15:39 AEDT AM
 What is interesting is that the deepest nuggets ever detected by a Pi  was by a detector used in the early 1980's in WA-Corbyn's  wheeled detector! Pictures of it  and the depths of some of nuggets he found with it can be seen in Mike Wattones book :Quest for gold.NO Pi detector today could match the depths Corby got on at least one nugget! (4cm nugget at over 36" in mineralized ground)
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: greylourie on Sunday February 1 2015 11:43:03 AEDT AM
  


Unfortunately I believe the biggest problem with the TDI is the Gb method.The method used i believe was posted on Geotech and from memory takes some  late samples which will tend to  significantly reduce the signal particularly on longer TC targets.  If your turn off the Gb as you do on the gs5 and do air tests you will find that the gs5 can match any ML for detection range! Other factors that may impact on detection depth on the TDI maybe are much less gain and Eric  flat tops the pulse and uses the old methods of a resistor for coil damping? Still taking everything into account the TDI costs a fraction of the overpriced 5000 and in my opinion offers very good value for money.
doug ::419::


I wonder what a TDI would be like with active flyback clamping. Would there be any improvement ? Maybe something could be added and/or changed
From what I have read, the SL is slightly hotter on Low conductors because of a small tweak in that models sample timing.


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday February 1 2015 11:49:22 AEDT AM
  
  


Unfortunately I believe the biggest problem with the TDI is the Gb method.The method used i believe was posted on Geotech and from memory takes some  late samples which will tend to  significantly reduce the signal particularly on longer TC targets.  If your turn off the Gb as you do on the gs5 and do air tests you will find that the gs5 can match any ML for detection range! Other factors that may impact on detection depth on the TDI maybe are much less gain and Eric  flat tops the pulse and uses the old methods of a resistor for coil damping? Still taking everything into account the TDI costs a fraction of the overpriced 5000 and in my opinion offers very good value for money.
doug ::419::


I wonder what a TDI would be like with active flyback clamping. Would there be any improvement ? Maybe something could be added and/or changed

Not easy on a SM board! On a gs5 maybe?
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: bugwhiskers on Sunday February 1 2015 12:44:40 AEDT PM
All PI detectors (old and new) would benefit from the new front end recently patented by Dave Emery.
How he will market this I don't know..... maybe a retrofit potted module.


Title: Re: Detecting Larger Nuggets
Post by: greylourie on Sunday February 1 2015 12:48:51 AEDT PM
I have seen a lot of posts elsewhere from Reg. He has gone to a lot of effort to make the TDI's hotter. It seems this has  worked well for small targets.

But this thread is about detecting larger nuggets.  If we bang more energy out, hot ground sends back angry waves which swamp out signals.

Then I read Alluviums interesting post about Cancel mode.... obviously for a different detector.

But hang-on,..... I have also seen posts from Reg where he urges TDI users battling ground issues to try DD's on their machines. Seems like DD's help offset things in very extreme conditions.

But I have not seen  posts on using any model of TDI with large coils for deep nugget search. I wonder what their depth is like, with GB On, using larger coils ? Hmmm.
Mind you, I don't know if the TDI TX period  has the oomph to tickle really deep big ones. There might be a compromise there.

And then like is mentioned, the moment that GB is switched on, depth is lost.  Subtractive GB. But don't other detectors use subtractive GB, in multiple channels ? How is depth retained there...... ahhh.

Unless you use something  2010101019. Or follow up on Deemon and Aziz's various efforts.


Title: Re: Detecting Larger Nuggets
Post by: greylourie on Sunday February 1 2015 12:50:08 AEDT PM
  
All PI detectors (old and new) would benefit from the new front end recently patented by Dave Emery.
How he will market this I don't know..... maybe a retrofit potted module.

Are there any links to details ?


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday February 1 2015 13:14:20 AEDT PM
  
  
All PI detectors (old and new) would benefit from the new front end recently patented by Dave Emery.
How he will market this I don't know..... maybe a retrofit potted module.

Are there any links to details ?

The patent application may not yet have been published?
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Aziz on Sunday February 1 2015 20:43:59 AEDT PM
Hi all.

If ML won´t be able to offer/achieve the 40% detection depth increase, I will be doing it with ease.
But you guys aren´t really interested in team-working or sharing. Why should I share my knowledge with you now?

You have disappointed me. Very.
^


Title: Re: Detecting Larger Nuggets
Post by: WM6 on Sunday February 1 2015 23:20:15 AEDT PM
  

No detector in history has cleaned up the goldfields better than all the Minelab models.

I read somewhere that most gold has been found using old fashion BFO and TR machines and not with modern TI devices.


Title: Re: Detecting Larger Nuggets
Post by: Davor on Monday February 2 2015 08:24:33 AEDT AM
Aziz, I'm not that much into seeking gold but you know that I'll help as much as I can.


Title: Re: Detecting Larger Nuggets
Post by: BILLY on Monday February 2 2015 10:19:44 AEDT AM
  
Hi all.

If ML won´t be able to offer/achieve the 40% detection depth increase, I will be doing it with ease.
But you guys aren´t really interested in team-working or sharing. Why should I share my knowledge with you now?

You have disappointed me. Very.
^


  Come on now Aziz.  Just about everyone here has offered help, its just you have ideas that only you understand.  I am no electronics expert, but I could probably get just about anything you want in electronics.  Just let me know what you need.


Title: Re: Detecting Larger Nuggets
Post by: 6666 on Thursday November 30 2017 09:02:26 AEDT AM
Any word on that Dave Emery patent being published or granted ?


Title: Re: Detecting Larger Nuggets
Post by: Dontbstme on Sunday January 20 2019 01:38:40 AEDT AM
Ok guys. This topic is ancient now, but it requires some clarity.

Why PI does not detect the really huge gold nuggets at the dreamed super depths?
Because it can not - this is the simple answer. Someone have mentioned the "long time constants" issue from the beginning of the tread and this is the very reason why the limits of PI have been reached long time ago. Not conspiracy or greed. Even much bigger coils would change this reality very little, not enough to justify the enormous difficulties to utilise them.

On the other hand VLF can do better with the "long time constants", much better, BUT not on every terrain and certainly not on the  heavy magnetic soil. There is a level of magnetic interference that VLF can handle with huge coils better than PI, but beyond that it becomes useless.
However not all ground in Australia is highly magnetic and definitely not every large gold nugget was found in the worse highly mineralised soil.



Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday January 20 2019 10:14:54 AEDT AM
  
Any word on that Dave Emery patent being published or granted ?

I have been informed that its about to be granted.
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday January 20 2019 10:27:20 AEDT AM
  
Even much bigger coils would change this reality very little, not enough to justify the enormous difficulties to utilise them.
I don't fully agree with this. Ground loops will  potentially detect large objects much deeper than any hand held coils. The reason is that with coils the Rx signal falls  as 1/r^6 for objects beyond the diameter of the coil.eg for an 18"mono  the Rx signal at 36" is 1/64th that of the object at 18"For a  large ground loop  the Rx signal falls off as 1/R^2  ie only by factor of 4. This is why Eric Foster and the late Jimmy Stewart were working on  ground loops.
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday January 20 2019 11:05:01 AEDT AM
  
  
Even much bigger coils would change this reality very little, not enough to justify the enormous difficulties to utilise them.
I don't fully agree with this. Ground loops will  potentially detect large objects much deeper than any hand held coils. The reason is that with coils the Rx signal falls  as 1/r^6 for objects beyond the diameter of the coil.eg for an 18"mono  the Rx signal at 36" is 1/64th that of the object at 18"For a  large ground loop  the Rx signal falls off as 1/R^2  ie only by factor of 4. This is why Eric Foster and the late Jimmy Stewart were working on  ground loops.
doug ::419::

Here is a ground loop system (Ultratem deep mode) used for detecting large bombs to depths of 3.5 M. This  system would i am sure detect large  nuggets far deeper than anything currently available.
http://www.gapgeo.com/media/18165/eod-ultratem_v2.pdf
http://www.gapgeo.com/media/12445/geopak_mltx_200.pdf
The transmitter can generate up to 200 amps into a 100x100m loop and in the TD switch off in 50 usecs! For nugget hunting a much smaller Tx loop would be used.
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday January 20 2019 11:18:39 AEDT AM
  
On the other hand VLF can do better with the "long time constants", much better, BUT not on every terrain and certainly not on the  heavy magnetic soil. There is a level of magnetic interference that VLF can handle with huge coils better than PI, but beyond that it becomes useless.
However not all ground in Australia is highly magnetic and definitely not every large gold nugget was found in the worse highly mineralised soil.

 Yes you have highlighted  some the limitations of VLF technology  for nugget hunting ie  the high and variable X  signal over heavy magnetic ground and particularly VRM ground.Most of  our goldfields in Australia tend to be quite mineralized and some are just horrific So any VLF technology will be some what restricted as to where it can be used.
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: bugwhiskers on Sunday January 20 2019 11:20:25 AEDT AM
  
Any word on that Dave Emery patent being published or granted ?
[/quote
  
Any word on that Dave Emery patent being published or granted ?

Dave phoned this morning. It has been granted and he has the certificate. The web crawlers haven't picked it up yet. I will post the link when available.

Search on US 10181720


Title: Re: Detecting Larger Nuggets
Post by: Dontbstme on Sunday January 20 2019 18:45:36 AEDT PM
  
  
On the other hand VLF can do better with the "long time constants", much better, BUT not on every terrain and certainly not on the  heavy magnetic soil. There is a level of magnetic interference that VLF can handle with huge coils better than PI, but beyond that it becomes useless.
However not all ground in Australia is highly magnetic and definitely not every large gold nugget was found in the worse highly mineralised soil.

 Yes you have highlighted  some the limitations of VLF technology  for nugget hunting ie  the high and variable X  signal over heavy magnetic ground and particularly VRM ground.Most of  our goldfields in Australia tend to be quite mineralized and some are just horrific So any VLF technology will be some what restricted as to where it can be used.
doug ::419::

I have done some tests on a "horrific" mineralised soil comparing GPX5000 with 10" mono to a very capable VLF with 10"DD, not on gold but on small ancient copper coins. If the two detectors were set to equally silent to the ground interference they both had the coin at 8" with this difference that the VLF also added very reliable direct discrimination, both visual and audio.
I know what the general perception regarding VLF is, but it is based only on what the big companies have to offer and they do offer much to put it mildly.

A question.
How would you describe a "horrific" ground in comparison to Iron ore? What percentage of Iron (or other metals) in ore would you say corresponds to the horrific definition?
I am asking so I can use some comparative method of testing.

I have also got as far as working VLF on pure black magnetite with limited results compared to PI, but working never the less. Considering no other VLF including the mighty CTX3030 would get to work there at all it's a step forward I would say.
I also managed to penetrate 92% Iron ore and get a tiny hammered gold coin across with VLF and with stable signal.
That tiny gold coin for some reason is undetectable by PI detectors.


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday January 20 2019 19:00:09 AEDT PM
  
  
  
On the other hand VLF can do better with the "long time constants", much better, BUT not on every terrain and certainly not on the  heavy magnetic soil. There is a level of magnetic interference that VLF can handle with huge coils better than PI, but beyond that it becomes useless.
However not all ground in Australia is highly magnetic and definitely not every large gold nugget was found in the worse highly mineralised soil.

 Yes you have highlighted  some the limitations of VLF technology  for nugget hunting ie  the high and variable X  signal over heavy magnetic ground and particularly VRM ground.Most of  our goldfields in Australia tend to be quite mineralized and some are just horrific So any VLF technology will be some what restricted as to where it can be used.
doug ::419::

I have done some tests on a "horrific" mineralised soil comparing GPX5000 with 10" mono to a very capable VLF with 10"DD, not on gold but on small ancient copper coins. If the two detectors were set to equally silent to the ground interference they both had the coin at 8" with this difference that the VLF also added very reliable direct discrimination, both visual and audio.
I know what the general perception regarding VLF is, but it is based only on what the big companies have to offer and they do offer much to put it mildly.

A question.
How would you describe a "horrific" ground in comparison to Iron ore? What percentage of Iron (or other metals) in ore would you say corresponds to the horrific definition?
I am asking so I can use some comparative method of testing.

I have also got as far as working VLF on pure black magnetite with limited results compared to PI, but working never the less. Considering no other VLF including the mighty CTX3030 would get to work there at all it's a step forward I would say.
I also managed to penetrate 92% Iron ore and get a tiny hammered gold coin across with VLF and with stable signal.
That tiny gold coin for some reason is undetectable by PI detectors.

Horrific ground is that ground containing VRM maghemite. Frequency dependent magnetic susceptibility  soils are a huge problem for metal detectors.
The tiny gold coin i suspect has a very small Tc.
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday January 20 2019 19:23:08 AEDT PM
  
  
  
  
On the other hand VLF can do better with the "long time constants", much better, BUT not on every terrain and certainly not on the  heavy magnetic soil. There is a level of magnetic interference that VLF can handle with huge coils better than PI, but beyond that it becomes useless.
However not all ground in Australia is highly magnetic and definitely not every large gold nugget was found in the worse highly mineralised soil.

 Yes you have highlighted  some the limitations of VLF technology  for nugget hunting ie  the high and variable X  signal over heavy magnetic ground and particularly VRM ground.Most of  our goldfields in Australia tend to be quite mineralized and some are just horrific So any VLF technology will be some what restricted as to where it can be used.
doug ::419::



I have done some tests on a "horrific" mineralised soil comparing GPX5000 with 10" mono to a very capable VLF with 10"DD, not on gold but on small ancient copper coins. If the two detectors were set to equally silent to the ground interference they both had the coin at 8" with this difference that the VLF also added very reliable direct discrimination, both visual and audio.
I know what the general perception regarding VLF is, but it is based only on what the big companies have to offer and they do offer much to put it mildly.

A question.
How would you describe a "horrific" ground in comparison to Iron ore? What percentage of Iron (or other metals) in ore would you say corresponds to the horrific definition?
I am asking so I can use some comparative method of testing.

I have also got as far as working VLF on pure black magnetite with limited results compared to PI, but working never the less. Considering no other VLF including the mighty CTX3030 would get to work there at all it's a step forward I would say.
I also managed to penetrate 92% Iron ore and get a tiny hammered gold coin across with VLF and with stable signal.
That tiny gold coin for some reason is undetectable by PI detectors.

Horrific ground is that ground containing VRM maghemite. Frequency dependent magnetic susceptibility  soils are a huge problem for metal detectors.
The tiny gold coin i suspect has a very small Tc.
doug ::419::

Here are some good papers on the  on magnetic soils and Frequency dependent magnetic susceptibility.
Workshop on Soil Magnetism:Multidisciplinary Perspectives,Emerging Applications and New Frontiers Report
https://www.gichd.org/fileadmin/pdf/LIMA/SoilMagn_Proceedings2008.pdf
Another  with very heavy maths!!
https://www.gichd.org/fileadmin/GICHD-resources/rec-documents/DRDCsoil2009-Terrascan.pdf
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Doug on Sunday January 20 2019 19:56:26 AEDT PM
Some more "light reading on VRM and magnetic soils.
Transient VRM Response From a Large Circular Loop Over a Conductive and Magnetically Viscous Half-Spac
e
very very heavy maths!!!
https://gif.eos.ubc.ca/sites/default/files/sdevriese/files/tgrs-cowan-2675406-x.pdf
Another
http://www.ipgg.sbras.ru/ru/science/publications/publ-magnetic-relaxation-of-a-horizontal-layer-effect-on-047274
The magnetic relaxation effect on TEM responses of a uniform earth
N.O. Kozhevnikov *, E.Yu. Antonov
http://emf.ru/sotr/publ/rgg-2008.pdf
Viscous magnetization of 0.04—100 jum magnetites
http://rmag.soil.msu.ru/articles/73.pdf
Soil Electromagnetic Properties and Metal Detector Performance Theory and Measurement
G. Cross, Terrascan Geophysics
http://cradpdf.drdc-rddc.gc.ca/PDFS/unc103/p531943_A1b.pdf
 Technical Note TN-36
THE MAGNETIC SUSCEPTIBILITY OF SOILS IS DEFINITELY COMPLEX
J. Duncan McNeill
April, 2013
https://www.geomatrix.co.uk/cms/resources/downloads/tn-36-mag-sus-of-soils-is-complex.pdf
doug ::419::


Title: Re: Detecting Larger Nuggets
Post by: Dontbstme on Sunday January 20 2019 20:55:32 AEDT PM
There got to be a way to simplify your answer Doug.
I need an example of rock or ore that can be used for a comparative measurements. It does not have to describe the universe or the deepest mathematical formulae.

I am in a possession of stones that exhibit variable conductivity and magnetic properties measured in different directions on the same samples and they have proven to be real crap, but still not an impossible barrier.

May be you can trow a few rock samples over the post for me. I'll pay the shipping cost what ever it will be.