If you are wondering why this is the 2nd most popular coil we carry, after reading these field tests you’ll know why!
A Field Report of The GP Extreme
Using the Coiltek Manufacturing 5 X 10 JOEY COIL
by Wayne Loewen
To all concerned:
I have had some interesting experiences field testing the sd2200d and the GP Extreme in Atlin BC for the 3rd year in a row. After the astounding results of the 2200 testing the past two years i never thought it would be eclipsed by another detector. It is unfortunate that i never had a chance to be part of minelabs early testing program for the extreme last year however its better late than never. The reason i chose atlin for the third year in the row is because it has a variety of the most hostile mineralization found anywhere and the area is noted for nuggets not dust. Fortunately i have a friend-customer who gave me access to the leases where i did my tests. This customer presently owns a 2200 which provides a majority of his income-he related to me that he had paid for it twice over in the first month of ownership. I will relate the very interesting results of my tests as accurately as i can and you can draw your own conclusions. First most of the lease has exposed or very shallow bedrock which was extensively hand mined in the 1800’s as old tailings abound. As well it has again been extensively remined by modern heavy equipment. I had detected this area in the past two years with minimal results-11 nice nuggets in 2 afternoons in 1999 including a 1 ouncer(my first find) and 10 nuggets in 2000 in 3 afternoons.
The area that i detected this year i had gone over in 2000 with the find of only one 8 gram nugget. A new patch had been opened to bedrock just a short way up a tributary to the main creek. It had been scanned thoroughly with the 2200 with the minelab 11 inch widescan with some nice nuggets being found by the chap who lives in atlin. I put a Coiltek Manufacturing 5×10 eliptical coil on my gp extreme and redid the patch resulting in 25 flagged targets. I put the same Coiltek Manufacturing 5×10 eliptical coil on the 2200 and the signal strengths were identical. This patch was quite heavily iron mineralized(basalt) however we did uncover a few more nuggets one 4 grammer at 15 inches and quite a few targets turned out to be iron shards from the cat tracks and hoe bucket. Most of these nuggets had never been moved perhaps for millions of years and this was an excellent opportunity to try and determine if halo effect leaching made a difference in detection depth versus an air test. The ph of the soil in varying regions could make a difference from spot to spot. We determined in some cases the detection of an unmoved buried nugget could be detected at almost twice the distance of an air test after digging it up. In a desert area with near neutral ph i’m sure this effect would be less.
Off the main creek the same area that I had thoroughly detected previously with the 2200 and had only found one 8 gram nugget my son Scott & myself reworked with the 2200 and a gp extreme. Initially my son used the 5×10 eliptical Coiltek Manufacturing coil and i used the Coiltek Manufacturing 24 inch eliptical coil. The ground was hot hot hot-in one nugget patch i only flagged one target which turned out to be a half ouncer. We then changed coils and my son used the minelab 11 inch double d because of the extreme mineral. I put the Coiltek Manufacturing 5×10 eliptical on the gp extreme and went over the same patch i had covered with the 24 inch eliptical which on a test was able to pick up my .4 Gm test nugget at 6 inches. What a surprise-i took out 18 more nuggets out of the same patch including the biggest one at over 2 ft. Most of the nuggets were no more than 2 to 8 inches in the bedrock cavities. The 2200 was stone dead in this area no matter what coil was used. Heres the clincher-we all know about iron mineralized hot rocks-both machines handled the basalt on this area well.
I took samples of the schist type bedrock home and i found myself another type of hotrock of which this area is loaded with- graphite. Everyone knows graphite conducts electricity. With the large coil on the gp extreme the extreme circuitry could not handle the large amount of graphite below the larger coil and it blanked out all those nuggets. When i put the Coiltek Manufacturing 5x 10 eliptical on the circuitry was able to handle the smaller area of mineralization beneath the coil and all those nuggets showed up loud & clear.
I had every minelab coil available and 4 Coiltek Manufacturing coils for testing. The 5×10 Coiltek Manufacturing on the gp extreme found every one of those 37 nuggets. We did not score one nugget in that area with the 2200. In all the areas throughout bc ,schist or various stages of its matamorphosis contains graphite in most of them because its a very common mineral in most of our gold recovery areas. Right now i personally know of three other areas where the bedrock is hot hot with graphite. When using the gp with the small eliptical coil i had to really slow the sweep speed down to a crawl in places to allow the circuitry time to adjust to the changes but it sure worked like a hot damn. I’m sure this technology could be improved. What astounds me is i have never heard or seen any writings in regard to graphite being a problem. All i’ve ever heard talk about is iron mineralized hot rocks as being a problem and if this is all one had to contend with here the 2200 would be sufficient. So far the most extreme performance i’ve witnessed is what i’ve just described as well as an earlier test where i picked up a buried 4 inch gasline at a good eight feet with the extreme and a Coiltek Manufacturing 24 inch double d coil. The 18 inch minelab coil only hit 4 ft. I’m looking for performance and if i have to get it from varied sources so be it but how many people are like me that have the resources and even the interest to do these field tests. Attached is a pic of my finds and a pic of the terrain we detected with a pic of the 18 nugget patch. I wrote this article solely with the intent that this hopefully filters down to the tech people in the chance more improvements may be forthcoming and for others who have had the same experience and never identified the problem. Hopefully this will be a benefit to someone-by the way i can back up everything i say as these sites are still available and i have witnesses to all i’ve seen & done. I’ve been at the gold recovery game for over 42 years and have used gold detectors for the past 20 years however results were poor until i got my first 2200. I would appreciate any comments or feedback on what i have related.
GOLDFINDER EXPLORATIONS (Gold Detectors)
Authorized Coiltek Manufacturing dealer for Canada
11 Belmont Dr. St.
Alberta Alta. T8N0C3
Bus: 780 459 3700
Bus Fax: 780 460 4388
GP Settings Used
Wayne was kind enough to give an explanation of the settings he used on the GP as well as the unique way in which he got the optimum settings on the GP to handle the mineralization. What’s that old saying? “Neccessity is the mother of inventiion?” Here’s what Wayne reported, once again, thanks Wayne for sharing this valuable information.
I picked a spot where the graphite mineralization was most severe. I took out my .4 gram nugget that I always carry in my wallet encased in clear packing tape. I set the nugget on the graphite loaded schist bedrock and played with the gp settings until I could clearly diferentiate the nugget signal from the mineral signal.
I never use discrimination as I found out in past tests that I could blank out a large nugget as well as iron so I play safe. I found the best setting was balance on tracking-rx on normal-soil on sensitive-Disc-all metals-boost to deep-signal to full-tone to full-volume to full and threshold to a comfortable level so I could hear the signal going both positive or negative.
I slowed my sweep speed down to a critical point where I was still moving the coil fast enough to pick up the .4 gm nugget somewhere between 4& 6 inches above it and at the same time it allowed the circuitry time to adjust so the mineral drone died out and did not blank out the nugget. When I increased my sweep speed too much I could not pick up the nugget. My speed of sweep corresponded with the mineral response. When the mineral got less I could sweep faster. The sweep speed was determined entirely by the mineral severity. Once you learn the difference between the mineral sound and a metal sound its easy.
All the nuggets that I found gave very clear positive signals. The big one was just over two feet down and it gave me such a loud signal I almost didn’t dig it because I thought it was a large hunk of iron from some past operation. The big one just looked like a muddy fist size rock until I picked it up.Thats when I got my adrenalin rush, realizing I was holding was the biggest hunk of gold I had ever found.
Here’s what professional gold prospector Steve Charley, from Australia has to say about the Coiltek Manufacturing JOEY
Coiltek Manufacturing 10 X 5″ field test results… Posted by Steve in KB June 25, 1999 at 05:35:23
Just bought the 10 X 5″ elliptical and took it out to a hammered patch where I found quite a few small nuggets earlier this year. When I first worked the patch I gridded it with the Minelab 11″ DD. Returned soon afterwards and cross-gridded it with the 8″ mono. Shortly after that I went back out there with a set of Timberwolf headphones and a Koss EQ/30 equalizer and wandered through the patch, again using the Minelab 8″ mono. The point of that trip was to see whether re-gridding it with the headphones and equalizer would be justified. Well, I only found 3 pieces totalling just over a gram in 3 hours wandering, so decided it wasn’t worth re-gridding.
So today I went out there again with the 10 X 5″ elliptical. Since working the spot a few months ago we’ve had a lot of rain, and being very clayey soil, I figured it was a variable which might have an influence on the signals. To ensure that this varaible was controlled, I wandered though the patch for 4 hours marking each signal with a cross. Then I put on the 11″ DD and checked each signal – nothing. Did the same with the 8″ mono. All but two of the signals couldn’t be picked up by the 8″ mono. Those two were very dubious – going dead slow from one direction I thought maybe I could hear them, but it wouldn’t have been enough to stop me even at that pace.
Digging up all the marked signals, I ended up with 18 nuggets totalling 13.2 grams (ie 203.7 grains). Individual weights of the nuggets are as follows (in grams) : 0.2, 0.3, 0.3, 0.3, 0.5, 0.5, 0.5, 0.6, 0.6, 0.7, 0.7, 0.8, 0.9, 1.1, 1.2, 1.2, 1.3, 1.5.
Nuggets were detected at depths of 0.5 cm from the surface down to 15 cm depth. Most nuggets were either on top of the bedrock or down a few centimetres into it where it was decomposed. Ground was highly mineralised and shallow, with the bedrock (mostly decomposed), starting at a depth of 12 cm from the surface under a clay layer.
A Minelab SD2200D was used in the test, set on shallow boost, Tracking, All Metal mode and with Level Adjust knob set halfway. Tone was set at the highest possible setting. Threshold set at about 11 o’clock. Koss EQ/30 was set on full volume with treble and mid on full and bass turned off. Volume of Grey Ghost headphones was adjusted as required to suit the ground noise.
I also tried deep boost and no boost but the signals were much easier to distinguish against the ground noise with the detector set in shallow boost.
CONCLUSION: I’m going to go back and grid the area now with this dynamite little coil, so draw your own conclusions.
Priority mail service means you will be swinging this coil in 2 to 3 days.
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