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Locating only large nuggets...

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Locating only large nuggets... Empty Locating only large nuggets...

Post  Mountain Prospector Tue Feb 26, 2013 4:11 am

Hello, Newbie to Australian gold detecting and if this idea is just wrong, please let me know.

The basic concept revolves around finding only large nuggets of multiple ounces that lie below the range of the large 18-21 inch (there about), coil setups that get down on large objects I think about 2 - 3 feet?

I was thinking of using what some companies are making now of a deep seeking PI with a large coil of four or five foot square to locate deep signals. Then going over the same target with a magnetometer to see it is is ferrous or not.

This isn't a new method, but does anyone have experience of doing this in Australia or heard of it being done for large nugget hunting? Any opinions on the viability of doing this? My thinking is even if it isn't gold, non-ferrous metals are worth quite a bit at the moment.

Any stories or thoughts on this method would be very much appreciated.

Cheers

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Post  Digginerup Tue Feb 26, 2013 10:04 am

Hi MP, I have no info to help you but it sure sounds interesting, keep us informed of your progress if you get on the ground somewhere.

Wayne. cheers


Last edited by Digginerup on Fri Mar 01, 2013 9:51 am; edited 1 time in total
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Locating only large nuggets... Empty Hi Wayne

Post  Mountain Prospector Tue Feb 26, 2013 9:29 pm

Digginerup wrote:Hi MP, I have no info to help you but it sure sounds interesting, keep us informed of your progress if you get on the ground somewhere.

Wayne. cheers

Hi Wayne, thanks for the comment. It seems by the lack of many responses this isn't an activity that many people do. I have already sourced the equipment over here in Europe that I think would do the job well, but will do some tests before buying them.

The main reason I am asking for info is traveling all the way to Aus is a big adventure with a lot of thinking of where to live, transportation. legalities etc.. So it would be good to get it as close to right the first time as possible.

Cheers
MP

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Post  kon61 Tue Feb 26, 2013 9:54 pm


G'day Mountain Prospector.Welcome to the forum.

Discrimination only for large nuggets at depth? Impossible.I won't say the best of them,but more the most expensive of gold detecting equipment today will indicate maybe non ferrous at depth but not separate all alloys and leave just the gold behind. I know of a couple of guys who imported a couple of high end price detectors from overseas,coming into the 10s of $thousands of dollars,only to find out that they could not handle our high iron rich,magnetic soils.This though I say for our soils in Australia.It could be a whole different ball game coming from Scotland though.I personally will not stick my neck out telling you what to invest in when I haven't used them personally,but I will say this,if the ground you intend detecting over,is low in iron content(mineralization),you should have no problems reaching depths (2 to 3 feet) on say half a kilo size slug+ of gold with a GPX 5000 coupled to say a 20 inch mono coil and above.Now if your talking depths well above the meter plus,look into some of the gold bullion/cache detecting gear,offered by Nokta,OKM,or Lorenz.

Cheers kon61.
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Post  Digginerup Tue Feb 26, 2013 9:55 pm

Hi MP, I could not say if or how many people do this sort of thing here in Australia, who makes these "deep seeking PI"
that you refer to?, some information on your proposed setup might wake the sleeping forum and get you some response, have you had any personal experience with this detecting method, your dead right when you say travelling to Australia is a big adventure, the legalities of prospecting vary across the country almost as much as the ground does, some of our gold country can be very inhospitable to the inexperienced, or even the experienced for that matter, then again some of it has pub and a fish n chip shop on every corner, is there any gold in Scotland, some pics of any gold related activity in your area would be nice if you have any.

Wayne. cheers
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Post  Guest Tue Feb 26, 2013 10:13 pm

g'day mt prospector
a few blokes got together here in the triangle (vic) and made huge coils (from memory i reckon they were 4ft plus)hooked up to minelabs, they gave up..
these blokes have been in the game since the start of detectors and know the aussie ground like the back of there hand and they had no luck.
so i'd look into it heaps before you fork out too much doe on equipment...(espeically if said equipment was designed overseas as it may not work in our goldfields)
i have a 40 inch coil and it is not easy to find suitable ground in vic to use it due to bushes,trees etc
so if you do go ahead with this idea, i'd suggest the open areas of western australia would be more suitable for giant coils.
cheers

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Locating only large nuggets... Empty Good info and some answers to the replies...

Post  Mountain Prospector Wed Feb 27, 2013 7:00 am

Thanks guys, good info. I will reply to the some of the individual comment as follows...

kon61: Cheers for the answer. I think my wording was wrong now reading it again. I didn't mean to only discriminate gold sort of thing, I meant to say I wanted to only look for large nuggets as opposed to small nuggets as a large PI coil won't generally locate small nuggets. It is possible to detect only gold, but the neutron generator and gamma spectrometer is a bit pricey at the moment. You are right that the manufacturers would be something like from the companies you list. There are some Bulgarian and Polish companies that are making or can make a deep seeking, large coil PI. There is no discrimination on these PI's at all and is what the magnetometer would be for. My main question would be will the PI with a 1.5sq meter coil detect that half kilo slug you mention at greater depths? I have seen them detect non ferrous pieces of metal, cake tin sort of size, down a couple of meters. How it would do on gold and in highly mineralized ground, I don't know yet.



fencejumper: Very Interesting info, thanks. I wonder why those guys gave up. It could have been because digging very deep holes only to find an old tin can might have been driving them mad, I know it would me, lol. Even here in Europe, I hate digging iron as there is so much of it. The bit about finding suitable ground though, that is exactly the type of info that helps in a big way. I was sort of hoping to detect in the Victoria area as me and the desert heat don't seem to get along. Even Victoria would be ok for me in only your winter time. I will have to look more into this now if places in Victoria will not be good for a large coil. I really suffer in high heat areas.

Digginerup: Cheers for the reply. I have put the general setup in the other replies, but basically it is to use a PI with a 1.5 meter coil and a proton magnetometer to check for ferrous or non ferrous material. Yes, there is gold here, and even a gold mine is opening up 5 miles down the road from me. But, it is usually small gold and no big nuggets, yet. I will get a link for a video I have on YouTube which shows me sniping for gold a while back. I got about 3 or 4 grams in a day, which for me was amazing, so you can see there isn't a lot.


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Locating only large nuggets... Empty Hi again fencejumper ciould I ask more please

Post  Mountain Prospector Wed Feb 27, 2013 7:18 am

fencejumper wrote:g'day mt prospector
a few blokes got together here in the triangle (vic) and made huge coils (from memory i reckon they were 4ft plus)hooked up to minelabs, they gave up..
these blokes have been in the game since the start of detectors and know the aussie ground like the back of there hand and they had no luck.
so i'd look into it heaps before you fork out too much doe on equipment...(espeically if said equipment was designed overseas as it may not work in our goldfields)
i have a 40 inch coil and it is not easy to find suitable ground in vic to use it due to bushes,trees etc
so if you do go ahead with this idea, i'd suggest the open areas of western australia would be more suitable for giant coils.
cheers


Hi, I was wondering if you could tell me more about your 40 inch coil, like how far down are you getting signals in that mineralized ground? And at what sizes? I taking it that the coil is hooked up to a PI machine like a Minelab? The coil I want to use is a bit bigger, but yours would give me some good understanding of what to expect from the Aus soil.

Regards, MT

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Post  Guest Wed Feb 27, 2013 9:21 am

the 40" detects will detect a bit of steel the size of a smoke packet easily at a metre deep, but you must remember that you can detect steel deeper than gold with a p.i in hot ground and steel will give a better signal than the same size/shape nuggy at the same depth..
sorry i can't help with depth on a half kilo nuggy...yet Razz
cheers

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Locating only large nuggets... Empty That's perfect

Post  Mountain Prospector Wed Feb 27, 2013 10:00 am

fencejumper wrote:the 40" detects will detect a bit of steel the size of a smoke packet easily at a metre deep, but you must remember that you can detect steel deeper than gold with a p.i in hot ground and steel will give a better signal than the same size/shape nuggy at the same depth..
sorry i can't help with depth on a half kilo nuggy...yet Razz
cheers

Thanks a lot mate, that's good info. I'm aware that gold has some sort of quick loss to it's signal and therefore harder to detect with a PI, so all we need to do is get you a half kilo chunk and run some tests Smile

Maybe until the big one is available for in ground testing, I'll find out if lead or some other metal also has similar electrical properties with a PI and try that.

Since you said that a large coil is a problem in Victoria due to terrain, I have been watching a few videos and can see you are right that W Aus would be much easier, but I think Victoria is still do-able with an over the shoulder, harness arrangement. It would be a lot slower than dragging the coil behind a quad like I have seen a guy doing on YouTube, but still might be worth it.

Anyway, thanks again, this has given me lots to think about.

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Post  Guest Wed Feb 27, 2013 3:54 pm

Hi
A minelab sd2200d coupled with an 18" DD will easily pickup a 32 ouncer at 28 inches.The problem is with looking for big is that they are rare.A good way to explain it is look at the night sky in ratio,the planets are the Big Nuggets and the stars make up the rest
Cheers Dig

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Locating only large nuggets... Empty Thanks Dig and the rest that have replied :)

Post  Mountain Prospector Thu Feb 28, 2013 6:34 am

Thanks Dig, you got it spot on and have put this topic into perspective that the rarity factor is the real issue. This idea might be more a case of whether or not I wish to try my luck, than whether the equipment can do the job. It's my dream, but one must be realistic also. The equipment will most likely work well, but finding a big lump might be a major lottery as far as the odds go.

Having this large coil PI/Mag set up is something I have wanted to do for a few years now to search for deep objects here in Europe, so I will most likely buy the equipment anyway. Due to my back not being what it was, the digging can be done with a mini excavator, something that is difficult to get permission for with gold prospecting, so I hear.

Basically I can understand now that a trip to Australia must be well funded with the view of having the great adventure of meeting it's people/way of life, and if I find some gold then great also.

Well, our summer is coming up and I will soon be getting out my drysuit and the 4" gravity dredge ready to try my luck over here. Depending on the results, maybe that will finance a nice holiday to Aus to do some detecting next year.






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Post  Nebuchadnezzar Thu Feb 28, 2013 2:14 pm

Interesting idea Mountain Prospector, and in my humble opinion quite doable using a modern detector with the right coils fitted and some sound prospecting knowledge.

It would be a great advantage if you had an understanding of how gold travels and where the biggies are likely to end up, so that you can concentrate only on these areas, otherwise you might just end up wasting endless hours, days, months looking in the wrong places. For example, you are not going to find big nuggets in shallow ground, all the easy gold has long gone, so you will need to know how to recognise deeper ground where the nuggets might be hiding, such as along creek banks and where there are subtle changes in the slope of the gradient. This knowledge usually comes with experience but their are a few key rules that can help here, the No.1 being stick to localities known for producing big gold, and then try to figure out the main path the gold travelled along, which might or might not be along the main bulldozed ground.

Another thing is the ground where big nuggets are found is usually old ground that has been worked hard over the years and probably seen hundreds if not thousands of detectors. Being good with your detector is not much chop here: you need to be great - better than all those before you, or more thorough. You can be thorough by checking places where others hadn't bothered to search, such as under big logs or around tree roots etc. Sometimes luck can play a part and you find a big one that has miraculously been missed for one reason or another.

Older Minelab PI detectors are probably better at finding deeper gold, however, I feel the 4500 would be the go. Larger coils work exceptionally well with them, I have picked up 1 gram nuggets at over one and a half feet down. I feel the latest 5000 does not handle third party coils (which you will need) as good as the 4500. Saying this would probably cause a forum uproar but that's just too bad.

Coils come in different sizes and types which you should become familiar with. Coils you may want to think about are a 22-25" round mono for deep penetration (bigger coils usually come at a trade-off), a 24x12 elliptical mono (or similar) for use in scrubbier ground, and maybe some big DDs where a discriminator might be useful or excessive mineralisation is a problem. The discriminator isn't all that good on a Minelab PI but probably better than nothing. DDs are also good on the salt lakes where many big nuggets have been found. You will need a strong back and super strong arms to swing these coils around all day long, but there are third-party accessories available that can help.

Hope this helps.
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Post  Tributer Thu Feb 28, 2013 11:44 pm

Coils about a metre in diameter give or take have their place when you have a spot that has produced big nuggets at depth in recent times. Some experienced prospectors have a good network and if they know of a spot where something good was found or there is deep ground below a patch they find thats when the big coils are dusted off..........on the odd occassion. Using a huge coil on a regular basis would be a huge challenge and you would have to have heaps of specific spots picked out that would suit the coil (many spots would suit a smaller 18-24 inch coil better).

In my opinion you have far better odds of finding big nuggets swinging a 18 or 20 round mono in sens extra if it can handle it. It will moan and groan but a 15 ounce piece will still sound out among the broader groundnoise groaning. You will cover alot of ground, and can still use them in and around obstacles and grass. When you find a good nugget or two with an 18 or 24 inch coil......then wheel out the monster coil.

Having said that i was impressed seeing the 5 metre coil carried on a conduit frame mounted to the shoulders (operator in centre of coil) that was used to find the Muonionalusta meteorites in Switzerland that were 10 kg in size and over a metre down under glacial sediments.
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Locating only large nuggets... Empty Size of coil may vary and prototype sluice tested today

Post  Mountain Prospector Mon Mar 04, 2013 3:02 pm

Hi, some more good ideas I see. Well, it's true, the size of the coil may vary but one thing is for sure, I won't be carrying it. It will be on a cart of some sort and either pulled by a quad or by hand.

Now I'm working on designing the housing for the fluxgate gradiometer, so that should be interesting when it's ready and working.


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