GPZ 18" Coil Test Report

Hi all,

Back from my adventure. Despite of a few storms gave the new coil a very good running. The summary and the full daily diary (only if you're really bored) are down below:

Summary:
Overall I'm extremely impressed with the coil. As the saying goes "an ounce a day keeps the doctor away"... the doctor certainly kept away... and to average that from an area I already hit hard is downright amazing. So in plane language: got about 6oz for the 6 days I've been out. In saying that, most of the 124 bits that I found came from the "outskirts" of patches or areas where I've been thinking outside the square.
Ground coverage is a massive plus for this coil, while retaining the sensitivity to small pieces... it is the small ones that sometimes lead you to productive patches. A lot of the nuggets I picked up with the edge of the coil... have I been using the 14" instead of the 18" I would've easily gone past a fair few good targets. Not to mention that a missed target could be a missed patch, equalling to just one missed target but a few or a fair few. I like mathematics and the easiest way for me to explain it effectively is: (18-13.5)/13.5x100=33.33%... so that means you're covering 33.33% more ground with each sweep. The reason I used 13.5 is because the 14" ML coil is actually 13x14", which averages to 13.5". Anyway, 6x33.33%=2... meaning in 6 days prospecting I actually done 2 days worth of extra ground coverage as opposed to the standard coil... and that is without killing my arm, which brings me to the next point.
Another thing that amazed me is the light weight, it was less tiring to use it than the 14". Simply because it is lighter... need to weigh both to confirm but feels 100-200g lighter. The design is solid too... takes knocks on rocks in its stride. The skid plate is mounted exceptionally well: there is no dirt and small rocks getting in between the coil and the skid plate. The noise of coil dragging on the ground is pleasing, it sounds normal, no hollow hull sound so you're more brave dragging it over ground.
All those factors add up to less fatigue. Not to mention the boost to morale knowing that you're covering more ground without feeling the after-effects of the 19" anchor. The bigger coil definitely uplifted my spirits and made me go to areas I would normal avoid or breeze past, just the extra moral boost can make all the difference.
The coil was just as stable as the 14". Though when heavy storms moved in, and the ground got near-enough flooded, then I was having trouble with false signals. Not sure whether it was the wet ground, the area I was detecting or approaching thunderstorms... maybe a combination of all. It did annoy me for an hour or two but then went away.
As far as the depth is concerned. I did appear to get a bit more depth on a few targets. But it was hard to tell without side-by-side comparisons. Maybe there was nothing deeper or I haven't walked over it... I must admit I was mostly hammering "new" areas around my patches as I knew the 14" got most of it. I did find an old patch (not mine) with over 100 holes... deep ground. There were about two dozen fresh holes too... definitely not ground noise. I searched the area for an hour and got no reward... did they get it all or were they using something new? I wish I knew the answer as I was impressed by the depth of some of those holes.
A point of note: not sure if it is a coincidence but my average nugget size was impressively bigger. Usually I don't find many above 2g, but this trip found a fair few in 2-8.5g range. My last two trips were 372 nugs for 190g, 202 nugs for 122g and this trip was 124 nugs for 180-190g.
All in all this coil is permanently staying on my detector. I simply loved using it. Stayed tuned as the guys that developed the 18" coil got new tech coming out soon.

I made a fair few videos but need to get home before I can upload them. In the meantime here are a few
Cheers,

Stan O

Hi Stan
congrats, some nice gold there.
some of the patches im cleaning out are averaging as many as 80 to 100 bits to the ounce (very small bits)
is the larger coil still good on the .2s and .3s as well as the deeper stuff

regards
Mick

Awesome result Stan, that 18" after market coil on your GPZ7000 is dynamite, brilliant pictures and thanks for your report, I can't wait for your guys to get the new tech out, this is absolutely amazing stuff.

cheers dave

love it mate good work I will be intouch

Dave,
I was really enjoying using the 18" coil - you felt like some sort of boost. Glad you've seen it in action, otherwise I wouldn't be believing my own words.

Mick,
I would say it is just as sensitive as the 14" to small gold, at least up to 0.1g. I was picking up smaller bits but you do need to slow down, but anything above you pick up with ease at full flight. I put on a 14" ML coil on the new patch I found - had bits of 0.06 to 8.55g - two hours with it produced nothing else. By the end of the trip I got so used to the 18" coil that I cut the hole size down to less than half the coil width and was getting the target in 1st or 2nd scoop. Oh, there was another observation I made. Sometimes when you scoop up the nug and it's sitting on the top the 14" would not pick it up or be so faint that you'll end up throwing it back into the hole. With this new coil I found no such issue.

Joe,
Good luck with your trip tomorrow!! Really hope that you find much more than my little pocketful.


Cheers,

Stan

Hi all,

In case someone's real bored, here is the full diary of my trip:

Cheers,

Stan O


Initial test:
Caught up with forum members Dave and Veronica (davsgold) to test out the coil for the first time on Australian mineralized ground - I didn't have too many expectations. The spot I chose was an old known place and full of ironstone. I arrived first and by the time D&V arrived half an hour later I already had a first little bit: 0.12g. I think all were amazed at how well the coil was running - pining 5 more bits with ease, including a tiny 0.08g. In a weeks' time I'll be doing some proper prospecting at some proper variable ground.
6 bits: 1.6g

Day 0
Arrived on site at 1430, set up camp and out prospecting on Igor's Patch by 1540 (don't go rushing looking it up on the topo map... I named it after my grandpa). Not even 10 minutes into the hunt pick up a sweet sounding target, fairly loud. Ended up being a sunbaker specimen with about 0.5-1g in it. Another clear target nearby, this time a 1-1.5g speci at about 2-3". Next target was tricky (between 2 bigger rocks) and in an area I prospected well. Again a speci at about 3" with about 1.5g of the good stuff in it. Moved to the reef area, where I hammered every inch, an iffy signal but a target nonetheless. Removed a few bigger rocks - now a clear target. Dug it out from about 3" - longish 0.25g nug. While I was locating that longish nug I saw a rock with yellow on it, initially mistaking it for the target. The yellow on the rock did end up being the good stuff, but hardly sounded on the detector - very fine reefy gold. Next target was tricky as - had to go to Normal back to Difficult back to Normal and back to difficult to confirm it. Yes, ended up being a little 0.4g nuggy from about 4-4.5". Last for the day was a near surface speci with the tiniest amount of gold in it. This was from an area I covered with the 14" ML coil over and over again. The 18" so far seems to go well and very stable. No big or deep ones to compare to yet. Settings were Difficult, High Yield, Sensitivity 20, no Smoothing and there were thunderstorms around but the disruptions to the detector were minimal. Coil is very light and the arm didn't feel the 2 hours I've been out. Tomorrow is the first full day out of six. Excited!
7 bits: 4.5g

Day 1
The day started with great weather - warmish morning with a blue skies as far as eye can see. It ended with me writing this report inside the car instead of having a delicious dinner of a double steak with pasta. Oh, I got drenched and had a lighting strike crack not even 20m above my head - I just happened to be looking at the sky exactly where it cracked. Just goes to show... expect anything when out in the bush. Anyway, back to the start of the day. The first 4 hours of the day I spent looking at a new area I passed yesterday on the way to my patches. Aside from a curious dingo and a few annoyed camels, a roo or two hundred that spot didn't produce anything. Back to the original plan of hammering my hammered patches. Not even 15 minutes into the hunt I get a target that sounded exactly like a big bullet that slammed into the ground. Well, it sure had the shape but from a couple of inches pops a familiar (and welcome) colour - tipping the scales at 5.5g. This was an easy pickup for any detector with any coil. About 5 minutes later I get what I like hearing - a deep'un! It came in loud, broad and clear on the 18" coil. The 14" would've picked it up but I recon the 18" gave a much broader target area. Another point to note, I picked it up with the edge of the coil... have I had the 14", I'm not too sure I would've had a nice 55g speci (about 40g of gold in it) to keep me company tonight. It came from about 10", embedded in conglomerate type ground. For the rest of the day I picked up 7 more bits - including a 2.2g nug. A couple of small nuggets that I picked up came from a small area that I gridded. One was just 0.09g so it confirms that the coil retains it sensitivity - potentially punching deeper even on the smaller bits. All in all ended up with at least 45g for the first day. This is from a well hammered area and obviously Lady Luck plays a big role in your pickings for the day but I must say the coil impressed me so far. Even after nearly a full day swinging the 18" coil my arm feels normal, maybe even less fatigued than when using the standard 14" coil. Mental fatigue is way less too - which is important. I'm covering much more ground with each sweep and there is no hollow hull sound to listen to all day long. Engineering side of things seems to be 5-star - it is well build, balanced and can easily take accidental knocks on rocks. See what tomorrow brings - right now I'll be happy for the storm to clear so I can get more time on the ground with the beast. Ah, almost forgot... thunderstorms... as expected the coil picks them up too, just like the standard coil.
9 bits: 45-50g

Day 2
Interesting day to say the least. I went to a reef I found - it's only about 2 meters square but produced a few specimens and jagged small nuggets of up to 0.5g. I hammered this little area but this 18" coil managed to sniff out a couple more targets. One was 0.3g reefy type gold piece - fair enough could've missed it. But picking up a speci with 1.5-2g in it from 6-7" deep proves it to me that this coil seems to be punching deeper. The rest of the day I spent in the flats (very vast area) that I largely avoided due to not finding anything. Not sure whether the extra ground coverage helped but found a very spread out patch. The best bits were 8.5g and 7.8g near round nuggies. A few more were over 2g. Ended the day with 25 nuggets and 1 speci for 40g of the good stuff. The coil was running smooth as silk and pinning those targets like a "Nugget Assassin". It was also a good day as the battery died just before sunset, unlike the day before where I lost an hour and a bit due to storms. I have a feeling that there might be more hiding in those flats - if any place can have an oz plus piece that'll be the spot. Tomorrow will tell.
26 bits: 40g

Day 3
Well, unfortunately nowhere near oz pieces, but today went good. I got a target(ish) kind of signal. It sounded exactly like ground noise except had some "whee" to it - enough to make you stop and scrape away rocks. After I dug down an inch or two the target started sounding like one. At about 10" out pops a 1.8g bit - I honestly don't think the 14" would've got it. Maybe at 8". Finished cleaning out the patch with the tally hitting 45 pieces of pure nuggie goodness (no specis) for a very surprising total of 51.3g. Best one was a 6.3g pieces right near the surface - no tricky target for any detector. So coil is performing exceptionally well over anything and everything I've thrown at it. The only noisy areas I've encountered are those with shallow layer of gravel over hard rock - the 14" never liked them either. Luckily those areas don't seem to carry much yellow, and if a target is encountered (like a shot pallet) it stands out well. The night sky is amazing today, so tomorrow will be a crispy morning. Big day tomorrow with lots and lots of walking... try and find a new patch but very little good looking ground left that I haven't covered. BTW 3 solid days of using the coil and my arm is not feeling it - the balance and weight is spot on - definitely lighter than the 14", I'll have to weight them when I get home.
45 bits: 51.3g

Day 4
Nothing of much note for today... covered lots and lots of ground - found 3 lonely floaters that haven't turned into anything. The other 10 were found around the patches, including an 8.1g chunky bit. Also found a sunbaking speci and a rock that's been rejected by someone as "hot rock" - it certainly looks the part. The signal boomed on my detector and I was not at all disappointed to see a hot-rock-looking piece - I knew the yellow will be there, and it was. Only a few specs are visible so must be more inside as it sounds like 1+ gram bit. Off to another area nearby tomorrow - I have a couple of patches over there and areas of deep stuff.
13 bits: 15.8g

Day 5
It's always dark when I get up - I try to make the most out of the day. This morning the moon was spectacular - or the effect of clouds on the moon shine - which formed a massive circle around the moon.
Curiosity had the better of me and on the way to my patch I turned off to virgin ground - after all I need something new for my next trip. After half-an-hour of bush-bashing I was on an area I liked the look of. The heart skips a beat when you get a target in those areas, unfortunately though all four targets ended up being old trash. On the way back to the car I detoured via a known area... came across someone's old patch. Ground was gravel type and very deep, if old un-filled holes were anything to go by. There were easy over 100 old holes, some shallow pushings and what struck me most - about two dozen fresh(ish)-looking holes. A few were extremely deep and not in the pushed area. That was the ideal place to test out the new coil. After nearly an hour of walking up and down, cris-crossing the whole area (50x50m), trying different settings, I gave up as I couldn't get a slightest beep out of the machine. How did that someone get so many targets and with what? I couldn't even get a spec. I went back to my patch (one I was initially going to check out earlier in the day). There I couldn't produce a target either - I wasn't very focused though - still frustrated that I couldn't pick up a target at that other spot. Eventually I got 3 little random ones. To put any doubt behind me I went back to the new patch I found this trip on Day 2 - where I got several in the 2-8.5g range and a few dozen going down to well below 0.1g. I whacked the 14" ML coil and searched the patch for over 2 hours without finding anything. I guess it proved to me that the new 18" is just as sensitive and goes as deep. Why didn't the new coil pick up targets at deeper areas - maybe it doesn't go deeper, maybe I didn't walk over itvor maybe there was nothing else at that fine line of "deeper than previous ones but not by much". Bear in mind I only spent 3-4 hours in those deeper areas, just didn't have the patience. However, those fresh holes do baffle me, new tech being tested? Minelab releasing something this year, or???
3 bits: 1.2g

Day 6
What a way to wake up - like an astronaut - levitating in mid air. No, not a dream - just a mini tornado hitting my camp. Lucky I was in a canvas tent, so it stayed put... outside I could hear the camp getting a trashing - things flying about. Even the heavy duty two-burner stove got flown a meter or two. Lovely, torrential downpour started a few minutes later. As it was the day I was leaving later in the afternoon I went for a scoot-around to check out the condition of the only way in/out. Well, needless to say that when a track goes through a flood plain, a fair bit of rain turns it into just that. I was confined to the area I was camped at, which ended up being not such a bad thing. After calling work saying I might be a day or two late coming back, and the wife telling her what's happening (big mistake - nearly had the SES sent my way) I got back to business. Just out of the tent a strong signal - on the surface too... surely not, ah it is - rainbaking speci with up to 2g in it. Nothing else came out of the camp area so I moved to the area where I started on Day 1. While getting absolutely drenched with rain I started doing the tricky spots... it paid off with 19 bits, including a 6.5g nuggie. The annoying thing was some sort of electrical interference while the ground was drenched - maybe it was just that spot. Every few seconds up to a few minutes I'll get a signal on the left-to-right swing. Once the wind dried up the ground that weird phenomena was gone... bedrock was very close to the surface too. Interestingly, on the way back to camp I was walking fairly fast (it was getting dark quick) while keeping the coil close to the ground. Not swinging it, just down and in front. A little change in tone stopped me at an area I hammered this trip and last. I waved the coil - like something's there but not sure... moved the rocks... still not sure. Removed an inch and now I had a target to work with... from 4-5" out came a 0.4g nugget... how in the world did the coil pick it up!? It stopped raining about 1600 so if it doesn't rain until midnight I'll be packing up and going. After 6 solid days with a big coil, covering well over 100km my arm is not feeling it at all.
21 bits: 18.5g

A very detailed report Stan, thanks, and once again thanks for allowing myself and Veronica to be with you on the very first time the coil was used in Australia, it is very impressive, and will be keen to see what your guys come up with next.

cheers dave

hey mate slow day yesterday with only 1 nuggy, no where near your tidy haul

Hey Joe,

At least you found some colour mate... better than coming home with empty pockets! How big was the bit you found?

Thank you Stan, for the excellent report and Dave for the videos.

It looks promising......and very interesting if there was new tech out and about.
I believe some good finds are not being posted so it could be correct.
It has to happen sometime since Minelab said there was great latitude for ZVT to be improved upon.

Cheers
Kev.

Hey Kev, thanks mate. It's very interesting testing out something new, especially being the only one in Australia. In a couple of days I'll take it for another spin on different ground.


Cheers,

Stan O

hey stan all ended up with 36gm in species off a new little patch near one of our bigger ones, just when you think shes gone happy days

New to the 7000 and have a larger coil as well. Just wondering if you could share your settings. Cheers
PS fantastic finds for six days

goldfinder wrote:New to the 7000 and have a larger coil as well. Just wondering if you could share your settings. Cheers
PS fantastic finds for six days

G'day goldfinder

Do you mean the GPZ 19" Minelab coil, or the standard GPZ 14" Minelab coil, also what settings are you using so a base idea can be made about if there are better settings that you could use.

cheers dave

Thanks for the reply Dave. I just realised that the topic refers to a new aftermarket coil for the GPZ7000. I was referring to the standard 19'' coil. I have had the GPZ7000 for almost a year but due to work commitments that arose after the purchase I haven't as yet used it. Planning on changing that in a few weeks.


Cheers Steve

More coils being tested this week