X-Terra 705 and soil mineralization -- Longhair? :D

Dirt.Hound

Jr. Member
Mar 5, 2013
71
29
Detector(s) used
Minelab X-Terra 705
Primary Interest:
Metal Detecting
Hey... I have another question regarding my 705, in regards to soil mineralization. I've always been under the impression that we have fairly mild soil conditions here... but something I just read on another forum has me second guessing myself.

Another use posted that a GB value or 28 or less = hot, or highly mineralized soild, while 30 or more = mild. Is this true? If (big IF) memory serves, I usually GB in somewhere between 11 and 17 with my 705... does this mean the soil I'm hunting is hot? If so, this will definitely have an effect on the coil I wish to purchase... Guess I'll have to take note of my GB values from now on... pretty sure my Tek Gamma GB's around high 40s to high 50s around here... different scale than the 705 though...

I was convinced that the 9" LF CC was the coil for me... but perhaps this new information means it may not be my best option... thoughts?
 

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Longhair

Hero Member
May 26, 2012
781
418
Backside Of Nowhere In Mid-Michigan
Detector(s) used
Fisher F2,
Fisher 1280X,
MineLab Xterra 705,
MineLab Explorer SE
Primary Interest:
All Treasure Hunting
There is a little known feature on the 705 that allows you to "more" scientificly measure both magnetic and conductive mineral levels.

First, you need to hook up your stock 9" MF CC. The machine's response to everything starts with the frequency used, and mineralization is no different. Coil configuration is also important due to the difference of soil volume within the detection field at the time of sampling.

Procedure in Normal GB mode with GB Tracking "OFF" and Sens=20:
A. Auto-noise cancel in the area you will hunting with the coil held 3 feet above the ground and parallel to it.
B. Locate a target free area of soil.
C. Engage Normal GB & remain in the GB screen.
D. Place coil on the soil. Do not press the coil against the ground! This will distort the coil shape and give an inaccurate result. Simply allow the weight of the machine to lightly keep it against the ground.
E. Press the Auto GB button and raise coil about two feet above the ground before Auto GB has completed. If by the time you reach the apex of pulling the coil up to two feet it doesn't complete, then pump up and down from just above the ground to two feet high as accurately as possible. Recall that Auto GB signals with a tone when completed.
F. While still in GB mode press and hold Patterns button to get the numbers. The numbers are six digits in length but read out in three groups of two that will repeat if the Patterns button is held down. Therefore 99 99 99(almost a million) is the largest number possible and 0(00 00 00) is the smallest. Forty-six thousand would appear as the following sequence, 04--60--00. Make a note of the numbers which we will call the "IRON NUMBER"(Magnetite...Black-Sand).
G. As a reference, numbers in the thousands are mild ground, medium grounds tens of thousands , and hot hundreds of thousands. For clarity:
1. 0(zero) >> 10K mild ground.
2. 10K >> 100K medium ground.
3. 100K >> 1M hot to scorching.

Procedure in Beach GB mode with GB Tracking "OFF":
Toggle by Holding GB button down for 3sec:
The same as above in normal GB except that your are measuring conductivity. Great for Ocean beaches, salt flats, & dried up lake beds etc. I would also take three samples in the exact same spot and average them to get an average number, using either of the above procedures.
 

OP
OP
D

Dirt.Hound

Jr. Member
Mar 5, 2013
71
29
Detector(s) used
Minelab X-Terra 705
Primary Interest:
Metal Detecting
Wow... thanks! I'm gonna print that off and do it next time I am out (Saturday! ... only 4 more eternit... err days away). Thanks so much for this info... I would never have known this otherwise haha. Do you mind if I PM you the results when I get them to discuss it further?
 

atomicscott

Bronze Member
Aug 18, 2011
1,564
1,055
Riverside CA
Detector(s) used
Current: Nokta Makro Simplex+, Teknetics Patriot, Fisher Gold Bug (original), GP Pinpointer (Garrett Clone) Lesche. Owned: Omega 8000, Minelab X-Terra 505, Fisher F2, Tesoro Vaquero, & Compadre, Whit
Primary Interest:
All Treasure Hunting
Awesome info again, Longhair! 15 or 17 ground phase number is much less than the 30% (+2) of ground balance that Digger suggests will be an advantage to use the DD coil. If you use that formula, it seems that you would definitely benefit from a DD coil. I have a 6" 18.75 DD on the way, although they are different frequencies, it will be interesting to see how it compares to the 6" 7.5khz coil I've been using lately in the trashy areas. My average GB numbers here rarely go over 15, usually closer to 12 or 13. DD coils also cover more ground per swing due to the larger detecting pattern at max depth.
 

Bart@Big Boys Hobbies

Supporting Vendor
Supporting Vendor
Jul 24, 2005
4,591
1,217
Moore Oklahoma
Detector(s) used
Call for your Treasurenet special discount! Be sure to mention Tnet when you call!
Primary Interest:
Metal Detecting
Thanks Long Hair! GREAT post!
 

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