Advice On Some Machines For *wicked*black Sand Coast In 2024

[Steve Herschbach]

ATX or for the worst of the worst, Infinium. VLF is no good in that stuff. A high power PI will blow back on you. The key is having both ground balance and a pulse delay. The ATX and Infinium both have a pulse delay control although Garrett marks it as a discrimination control. I picked up a used Infinium last year because I can get it to work on almost pure magnetite running a 10x14 mono coil, a feat most other PI detectors like my Axiom fail at. The secret ironically is the Infinium is not overpowered, and simply advancing the pulse delay until it is stable is the main tuning method. A DD may be needed. You will of course not hit small gold items and depth will be somewhat limited, but you will be able to detect. I get ring and coin type targets exceeding 12". If not, then the ground is simply undetectable, and yes, there is such a thing. If magnetite content is high enough it is like trying to detect through an iron plate.

Where I’m detecting. This is not black colored sand but magnetite, same stuff you are dealing with. I've seen people confuse black colored material derived from slates, shales, or other dark materials with true magnetic black sands but they are not the same thing. Pure magnetite often has a gun metal blue sort of look to it. The easiest way for the uninitiated to know is simply drop a magnet in the stuff.

Non-ground balancing machines like the Sea Hunter or Impulse AQ can also be made to work if you advance the pulse delay far enough. TDI is a good possibility.

My Infinium chestmount with 10x14 mono. I really, really like that coil, a real gem. The advanced pulse delay eliminates thin foils. Small surface targets like hair pins read on both edges of the coil, a double blip response, and I generally ignore surface stuff unless larger. Larger targets will read in the center of the coil where small targets only hit on the edges. I mainly look for mellow centered high tones. As a ground balancing PI the Infinium breaks targets into two classes, high tone and low tone. Low tones are generally high conductors like pennies, dimes, quarters. I normally skip those in favor of high tone low conductors - rings and nickels. The tones work to full depth. Long story short with tones and a good coil as close to discriminating PI as you can get.

[skywatcher]

10 hours ago, EL NINO77 said:

If I were you, I would try a PI detector with ground balance, which has a timing setting... for example Garrett ATX,

good day

 

Yes that is my thought also but i have never owned a nice pi detector i have been lazy hitting all the easy beaches and now i have to get new gear to be able to detect this black magnetic sand. ATX, or fisher aq are the 2 that i see the best feedback from.

[skywatcher]

2 hours ago, Steve Herschbach said:

I picked up a used Infinium last year because I can get it to work on almost pure magnetite running a 10x14 mono coil, a feat most other PI detectors like my Axiom fail at.

Good day

 

Thats a 20+year machine i know does not make a difference if it works right. So can u get replacement parts from garret for it and how expensive are repairs and its durability. ATX seems heavy but looks like it will do the job,  I use the hip mount while land detecting on the excal and have had 2 already and cables always have some issues the cable placement and thickness on the fisher i dont like very much.

Rons detectors said the gpx 5000 works but i know a jungle, creek gold prospector that sometimes tries it out at these beaches and performance is ok on certain areas but not in the black wicked patches.

Im waiting for minelab to make a new beach machine but it prob wont be a pulse.

I will search for a tdi or infinium and if that fails will try the atx thats best plan i can come up with thanks.

 

 

 

 

[Steve Herschbach]

28 minutes ago, skywatcher said:

Thats a 20+year machine i know does not make a difference if it works right. So can u get replacement parts from garret for it and how expensive are repairs and its durability.

The ATX new with warranty does have advantages, but I like the light weight of the hip mounted Infinium.... and that coil! Garrett still services the Infinium which is good as I don't know that they are a particularly reliable detector. I owned quite a few and most seemed to develop one problem or another. This one was serviced a couple years ago, costs are reasonable but in your case the shipping might be more a worry.

I have considered getting another new ATX but I keep hoping Fisher or Nokta or anybody will come out with a newer lighter waterproof model. The options new with warranty for waterproof ground balancing PI detectors is remarkably limited at this time. ATX is pretty much it.

[Erik Oostra]

Even white sand can be black sand.. This is on Magnetic Island.. The island was formed 275 million years ago when molten granite pushed through the Earth's crust to form a dome shaped blob.. This blob has been eroded into the steep hilly island it is today.. There's huge granite boulders everywhere.. The island has 8 gold mines up in the hills.. Some bays have deep layers of black sand covered by white coral sand.. In those bays I've been using my Equinoxes with large coils, but my black sand is no where near as bad as yours.. In really bad patches (for me) the GPX5000 also worked well.. 

 

 

 

[skywatcher]

2 hours ago, Erik Oostra said:

The island was formed 275 million years ago when molten granite pushed through the Earth's crust to form on dome shaped blob.. This blob has been eroded into the steep hilly island it is today.. There's huge granite boulders everywhere.. The island has 8 gold mines up in the hills..

Interesting !

I always believed minelab would be the first to solve the black sand issue since they say all their research team is in australia and there are lots of harsh mineralized areas and islands near for them to test.

Many things we dont understand About earth as a detectorist we study history and topography but now that you mention forming of the earth and its crust ect nerd talk my mind clicked.

Here we have many plates pushing rubbing thats how the strip conected north and south not a geologist but im sure that has something to do with the pacific beaches that sit within the nazca plate and carribean plate being undetectable on pacific side.

I thank all the wonderfull people here for the great insight and experience. Maybe a machine will work or not i will give the garret atx or infinium a try. One detector that rules all is what we want will we ever get it. Thanks gents!!

[kac]

Garrett Seahunter MK2 handles black sand well. We have similar conditions along with hot rocks in the Rockport and Gloucester beaches.

Machine is heavy so any extensive beach combing I'd recommend the hip mount that is included. Stock coil isn't super deep but will do much better than a vlf with similar coil size. I usually use the 10x14 for that.

Downside is you can get a little falsing on swing with the hip mount.

Can be emi sensitive. I can hear chatter when people put their wifi alarms on even a few hundred feet away from the houses.

Larger coil seems a little floaty in the surf

Larger coil not that sensitive to small jewelry

Can't discriminate out iron but bottle caps and pieces of lobster traps sound awesome!

[RONS DETECTORS MINELAB]

On 5/8/2024 at 10:26 AM, skywatcher said:

Rons detectors said the gpx 5000 works but i know a jungle, creek gold prospector that sometimes tries it out at these beaches and performance is ok on certain areas but not in the black wicked patches.

I’ve heard in non-variable ground of highly concentrated iron that the GPX-5000 specific ground balance has a slower tracking speed and will help get a better ground balance, but I will have to try this out when I get back to Gold Beach and see if it handles the iron any better especially with a DD coil.

Anyone tried using specific in these iron enriched environments with any success on the 5000?

 

[skywatcher]

On 5/9/2024 at 8:06 AM, kac said:

 

Machine is heavy so any extensive beach combing I'd recommend the hip mount that is included. Stock coil isn't super deep but will do much better than a vlf with similar coil size. I usually use the 10x14 for that.

Downside is you can get a little falsing on swing 

 

Good day

 

Yes lots of falsing with the seahunter here in the concentrated volcanic patches.  Just got around to reading about the new nokta pulse machine thats coming out on the forum sounds interesting. Pretty much gave up on a beach huntertdi since there will be nobody to call when its damaged. The detector Mr steve recommended the infinium so far has grabbed my imagination these older machines do work better at the beaches here and also im still able to change coils quick and send it off to repair. One thing i have noticed for beach machines coils is that in like 2 -3 years the heat salt water i dont excatly know but they loose depth.

So im searching for a infinium found a few that look ok and negotiating but its always models that are in bad shape that still have stock coil at high prices. will the ground tracking  do the trick who knows! might be good idea to ask forum if anybody wants to sell theirs.

[EL NINO77]

Since I have free time on Sunday, I decided to do a test of the Garrett ATX PI detector on a 25 kg bag of 97% magnetite...on a nickel coin. /1zloty PL/., how to check again... which ATX setting will work best on such an extremely high - perhaps the highest mineralization... that we can encounter..
After a short trial of various settings for the ATX, it turned out to be optimal to set the discrimination / timing / at least to the value 5, which turned out to be stable even on such mineralized material if the magnetite is 97%.. sensitivity to 8, threshold to 11, and volume on the 13th
 
With such a setting, the ATX can detect a nickel coin through a 10 cm thick layer of 97% magnetite, plus it gives a good signal at a height of up to 15 cm above the bag of magnetite...

I think it's a really good result...

To compare the strength of the mineralization, he took the Minelab Equinox 800... set in the Beach Program at sensitivity 15... where it can be seen that the Equinox 800 is already at the height of the coil 20 cm above the bag with 97% magnetite... it switches to the reduced TX mode...
But even in such a case, you cannot work stably above such a concentration of magnetite.. if you would like to sweep with a coil  above magnetite....