MINELAB....the 4500 & 5000 do WHAT!!!

[dwt]

Check it out people, the April edition of Gold Gem & Treasure mag, page 14 under heading " The Garrett ATX Hits the Ground Running".
firstly let me say i loove my 5k a new found joy of the machine since i started picking up some gold, but i have to say i am very SHATTERD by the response of MINELAB in one of their comments to the author of the above topic in the GG&T mag, for those who dont or wont get a copy it basicly states that, MINELAB agreed that there is a "hole" in the GPX theory, it has to do with the induction of electrical eddy currents and the decay rate of those eddy currents.
Are you left a little bit....."WTF" as i was...what in the bloody hell is an eddy current.....for anyone like myself who is left a little bewilderd the short end is they are admitting that these detectors can over look gold................ 8.(
I do not know the ins and outs of the settings used on the 4500 & 5000 but from the authors description the users of the machines are highly experienced.
The author does go onto explain he is not affiliated with any metal detector company or detector shop and has 30 years of experience using metal detectors in the search of gold..... draw your own conclusions, but i will be having more of a play with my 5000 settings the next time im out.......And if i get my hands on "Eddy Current"...... its gunna get messy

 

[Ben78]

I haven't got mine yet to read in full but I don't understand what you are trying to say??

 

[dwt]

I haven't got mine yet to read in full but I don't understand what you are trying to say??

cool Ben78,............"and the owner of the Prospectors Patch, Jamie, were stunned when the 5000 missed seven out of the eight targets with not even a murmur"
the above is strait out of the GG&T mag the author who wrote the piece is explaining that in a test done on some speci's the 4500 & 5000 were not even picking up on the gold, and that this is caused by the "eddy currents".

QUOTE from GG&T..... "I (the author) phoned minelab in Adelaide and explained what we'd heard and observed with these specimens and i told them we reckond there was a hole in the GPX theroy. Now cop this! They agreed! Strait up Minelab said i was spot on with the reasons i put forward on why this happens. It was all to do with the induction of electrical eddy currents and the decay rate of those eddy currents" end quote

 

[Diggerdude]

This 'hole' in the 5000 timings is quite well known, but is no reason to be concerned. The pieces they were testing were specimens , very finely deceminated gold in quartz/greenstone matrix. Most of this gold was initially found with a whites GMT a $700 vlf! Over 50oz were found most of which made no signal on the 5k, I tested them on mine too.
It is great to know the atx can find those specimens, but so can most $500 VLF's, as all of this gold was found within 100mm of the surface.
The 5k is still king of hill on nuggets and blows the atx away on big deep stuff.

DD

 

[dwt]

This 'hole' in the 5000 timings is quite well known, but is no reason to be concerned. The pieces they were testing were specimens , very finely deceminated gold in quartz/greenstone matrix. Most of this gold was initially found with a whites GMT a $700 vlf! Over 50oz were found most of which made no signal on the 5k, I tested them on mine too.
It is great to know the atx can find those specimens, but so can most $500 VLF's, as all of this gold was found within 100mm of the surface.
The 5k is still king of hill on nuggets and blows the atx away on big deep stuff.

DD

so what do you do for the fine stuff mate...

 

[Ben78]

so what do you do for the fine stuff mate...

Use a $500 VLF...

So did the ATX pick up these specimens? Seeing as they work on the same principle of eddy currents and decay periods?

 

[Redfin]

I recall reading that report on the Finders Forums by the author 'Bilbo".
He has done well to get it into print.

 

[Tassie Daz]

I believe that the ATX did pick up those species, if I remember the contents of the article. (I read that article some time ago. I get my GG&t very early)

 

[gcause]

Had the same reaction when I read that article dwt. Congrats to Bilbo it is a great article.
Glad I have options with the detectors I invested in 5000, SD2200 and Garrett VLF. I wouldn't want to miss out on a potential 50 ounces like that.

 

[dwt]

so what do you do for the fine stuff mate...

Use a $500 VLF...

So did the ATX pick up these specimens? Seeing as they work on the same principle of eddy currents and decay periods?

yes and no, the atx missed some as well, they ended up using a Whites GMT, personally i'd have a crack with a sadie and some fine tuning first......hate to think that $6500 plus for a detector and coils was going to need a $500 back up unit.. :|

 

[Diggerdude]

Yes apparently the ATX can detect these species, which was very surprising for a PI. My choice would still be the GMT it's a hell of a lot cheaper and detected them easy.
We tested a piece from the same patch a bit bigger than a golf ball, it had about 1.5oz of finely disseminated gold in it. The gold was easily visible but was lots of tiny specks all through it and no chunks. I could not get my gpx to make a noise no matter what settings I used, even rubbing it on the coil. Yet it screamed at the GMT.
I don't see the point paying $4000 just to find species as many cheap VLFs already do this well.
The article is correct though, the gpx is not perfect and is best accompanied with a VLF to cover all bases.

DD

 

[Teemore]

So who's Bilbo?????
Why does he have to hide his identity???
Does anyone that writes for that magazine have a real name???
Can understand not wanting to give away their personal glory hole which they don't do anyway so why not a real name?
Cheers Tom

 

[Reeks]

Can any tech wizards explain why a 5000 will struggle with these certain speci's?
My sd2200 gets a strong signal on lead through solid rock 6inches thick.

Interesting topic.

 

[Goldpick]

I think the issue is that the rocks with disseminated or very fine gold, are simply not conductive enough for the coil to receive a return signal. The coil sends out magnetic pulses which in turn create eddy currents in metal objects, which in turn are received by the coil again, but in this case, the eddy currents created by the detector simply disperse due to such low conductivity, or something like that. It's not really a failing of the detector, more of an issue of having the wrong tool for the wrong job, hence why a high frequency vlf detector will nearly always be preferable for fine gold specimens, and ore sampling. Besides, if you were to be able to pick up disseminated gold in rocks, you may just read it as as highly mineralised ground vs a single detectable object.

Just because you pay over $6000 for a detector, it does not guarantee that it will find gold in every single form, but what they do excel at is achieving excellent depth in highly mineralised ground, something that is hard to achieve with a VLF detector. The fact that the gpx5000 can pick up sub gram gold is an achievement in itself with the expanded range of soil timings, hence part of the reason why it can command a higher pricing than the previous models and other brands, whilst still retaining good depth on med-large gold. The 5000 comes close to a do-it-all gold detector, but not quite, besides, I'd imagine most owners would be searching for larger gold than specimen sized stuff anyway.

As for the ATX vs 5000 arguement, they both have their pros and cons regarding size of gold detected, design, features, detection depth and ability in highly mineralised ground, all without being a clear winner as a go to machine for every single circumstance. I don't think the ATX was ever intended to compete with the 5000 anyway, hence its price point and limited detection depth compared to the 5000 on certain sized gold.

I'd be looking at the SDC2300 to hopefully fill that void, and be on par with the ATX on the smaller gold. But at the expense of depth due to no real coil options, otherwise you will be eating into the 5000's market share. Just my view on things.

 

[Guest]

That GGT article, while headlined for the ATX, was more of a great plug for Whites GMT not the ATX. The GMT found all those speccis in situ whilst the ATX only picked them up in "tests". As DD said the GMT would be much better value for money if you're looking for finely disseminated gold speccis.