On Tuesday, October 12, 2021 at 8:11:28 AM UTC-4, Clive Arthur wrote:> On 12/10/2021 12:53, Don Y wrote: > > I caught the tail end (last 2-3 minutes) of a TV show which depicted > > a couple of guys hunting for gold deposits with the sorts of metal > > detectors you'd look for trinkets on a sandy beach. > > > > And, apparently, *finding* same! (gold just lying around in > > surface rock outcroppings? who'd guessed!) > > > > But, they each used detectors with small diameter (10"?) coils. > > > > Wouldn't a larger diameter give greater soil penetration? > > Are tehre other reasons why a small coil might be prefered > > (easier to carry?) > Idle speculation on my part, but I'd think that a larger coil would > encompass a larger search volume and would require a larger nugget to > give the same response as a smaller coil with a smaller nugget, > percentage wise. > > The detectorists probably know the likely size range of nuggets. Small > deep ones can't be detected, and large deep ones don't occur.Interesting that you use the correct term "detectorists". There was a rather good TV show by that name a few years back. I don't think they got continued funding and only produced two series. Too bad. I enjoyed it. Gold is not uncommonly found on the surface. The problem is quantity. Here in Virginia there are gold seams running through the state with various streams being panned for gold to this day. Here on Lake Anna, a tributary Contrary Creek is panned and even sluice machines used to extract gold from the stream bed (legal) and to extract gold from the surrounding banks (not legal because that land belongs to the owners). It is called Contrary Creek because the various mines from a previous century along the banks of the creek leach sulfur into the water making it uninhabitable for nearly all life. I see a few water bugs and a soft brown color deposited on the rocks which contrast nicely with the deep green of the pine groves along the shores. A very pretty spot. I don't think anyone has gotten rich panning gold in Virginia in some hundred years or two. -- Rick C. - Get 1,000 miles of free Supercharging - Tesla referral code - https://ts.la/richard11209
Metal detectors
Started by ●October 12, 2021
Reply by ●October 13, 20212021-10-13
Reply by ●October 13, 20212021-10-13
On 13/10/21 05:01, Don Y wrote:> On 10/12/2021 3:46 PM, Tom Gardner wrote: >> On 12/10/21 22:59, Don Y wrote: >>> On 10/12/2021 2:28 PM, Martin Brown wrote: >>>> On 12/10/2021 20:44, Don Y wrote: >>>>> On 10/12/2021 9:23 AM, Joe Gwinn wrote: >>>>>> On Tue, 12 Oct 2021 14:15:33 +0100, Martin Brown >>>>>> <'''newspam'''@nonad.co.uk> wrote: >>>>>> >>>>>>> On 12/10/2021 12:53, Don Y wrote: >>>>>>>> I caught the tail end (last 2-3 minutes) of a TV show which depicted >>>>>>>> a couple of guys hunting for gold deposits with the sorts of metal >>>>>>>> detectors you'd look for trinkets on a sandy beach. >>>>>>>> >>>>>>>> And, apparently, *finding* same! (gold just lying around in >>>>>>>> surface rock outcroppings? who'd guessed!) >>>> >>>> They must have known enough about the geology to be in about the right place >>>> then. >>> >>> No doubt! I was surprised that it would be that near the surface. >>> And, to wonder how they *knew* it would be there! >>> >>> (Did someone, someday, just happen to look down and say, "My! There's >>> a gold nugget by my left foot!" And, thereafter, the area known for >>> "gold just lying around"? If so, why is there *still* any left to >>> be found -- if it was common knowledge!) >> >> According to school geography lessons, the importance >> of Kiirunavaara was discovered when someone found his >> steel knife was attracted to the ground. >> >> I've never understood why gold (and similar) elements, >> which were produced in supernovae, aren't evenly >> distributed lone atoms. > > Why aren't celestial bodies perfectly round (oblate) orbs?They are good approximations.> Why Les Alpes and The Mariana Trench?Plate tectonics.
Reply by ●October 13, 20212021-10-13
On 12/10/2021 20:41, Don Y wrote:> On 10/12/2021 6:15 AM, Martin Brown wrote: >> On 12/10/2021 12:53, Don Y wrote: >>> I caught the tail end (last 2-3 minutes) of a TV show which depicted >>> a couple of guys hunting for gold deposits with the sorts of metal >>> detectors you'd look for trinkets on a sandy beach. >>> >>> And, apparently, *finding* same! (gold just lying around in >>> surface rock outcroppings? who'd guessed!) >>> >>> But, they each used detectors with small diameter (10"?) coils. >> >> 8-10" is about the sweet spot for a coil that is easy to work with and >> sensitive enough. Modern metal detectors can distinguish ferrous from >> non-ferrous metals which is a big help finding precious metals. >> >> I have yet to see one that can recognise and ignore coke can ring pulls. > > What originally caught my attention (I had just turned on the TV > in order to watch a movie/DVD and hadn't yet switched the video source) > was that they were out in the wilderness -- grass, trees, shrubs, > etc. I am used to seeing folks combing beaches for lost wedding rings, > etc. > > "What the hell are they looking for out there??"Meteorites are the other high value metallic surface objects that can be found in the desert with a metal detector if you know where to look. Larger chunks of nickel iron ones command a high price. You can get micrometeorite dust from the black gunge that collects into your rainwater gutters by sweeping it with a Nd magnet. Interesting thing for a school project with a microscope to look at them. eg. https://www.iflscience.com/space/how-hunt-micrometeorites/> I would imagine they got fewer false positives simply because > it didn't appear that there was any sign of "civilization", nearby. > > [But, I only saw the last 2-3 minutes when they found a nugget and > congratulated themselves] > >>> Wouldn't a larger diameter give greater soil penetration? >>> Are tehre other reasons why a small coil might be prefered >>> (easier to carry?) >> >> That and being able to get a better fix on the target. The sensitivity >> to objects in the ground extends a couple of coil diameters outwards >> in all directions. How deep in depends also on how wet the soil is. > > Surely, one could carry a smaller, "wand" style detector for that sort of > effort.One of my neighbours is a skilled metal detectorist and has several interesting finds to his name. A few early medieval silver and gold coins but mostly civil war buckles & shot and the odd Roman artefact as well. He belongs to a local group that go out almost every weekend. -- Regards, Martin Brown
Reply by ●October 13, 20212021-10-13
On 2021-10-13 00:46, Tom Gardner wrote:> On 12/10/21 22:59, Don Y wrote: >> On 10/12/2021 2:28 PM, Martin Brown wrote: >>> On 12/10/2021 20:44, Don Y wrote: >>>> On 10/12/2021 9:23 AM, Joe Gwinn wrote: >>>>> On Tue, 12 Oct 2021 14:15:33 +0100, Martin Brown >>>>> <'''newspam'''@nonad.co.uk> wrote: >>>>> >>>>>> On 12/10/2021 12:53, Don Y wrote: >>>>>>> I caught the tail end (last 2-3 minutes) of a TV show which depicted >>>>>>> a couple of guys hunting for gold deposits with the sorts of metal >>>>>>> detectors you'd look for trinkets on a sandy beach. >>>>>>> >>>>>>> And, apparently, *finding* same! (gold just lying around in >>>>>>> surface rock outcroppings? who'd guessed!) >>> >>> They must have known enough about the geology to be in about the right place then. >> >> No doubt! I was surprised that it would be that near the surface. >> And, to wonder how they *knew* it would be there! >> >> (Did someone, someday, just happen to look down and say, "My! There's >> a gold nugget by my left foot!" And, thereafter, the area known for >> "gold just lying around"? If so, why is there *still* any left to >> be found -- if it was common knowledge!) > > According to school geography lessons, the importance > of Kiirunavaara was discovered when someone found his > steel knife was attracted to the ground. > > I've never understood why gold (and similar) elements, > which were produced in supernovae, aren't evenly > distributed lone atoms. > >Water has a way of sorting stuff by weight, size and chemical affinity. Jeroen Belleman
Reply by ●October 13, 20212021-10-13
On 2021-10-13 06:05, Don Y wrote:> On 10/12/2021 3:05 PM, Clive Arthur wrote: >> On 12/10/2021 17:28, Don Y wrote: >>> On 10/12/2021 5:11 AM, Clive Arthur wrote: >>>> On 12/10/2021 12:53, Don Y wrote: >>>>> I caught the tail end (last 2-3 minutes) of a TV show which depicted >>>>> a couple of guys hunting for gold deposits with the sorts of metal >>>>> detectors you'd look for trinkets on a sandy beach. >>>>> >>>>> And, apparently, *finding* same! (gold just lying around in >>>>> surface rock outcroppings? who'd guessed!) >>>>> >>>>> But, they each used detectors with small diameter (10"?) coils. >>>>> >>>>> Wouldn't a larger diameter give greater soil penetration? >>>>> Are tehre other reasons why a small coil might be prefered >>>>> (easier to carry?) >>>> >>>> Idle speculation on my part, but I'd think that a larger coil would encompass a larger search volume and would require a larger nugget to give the same response as a smaller coil with a smaller nugget, percentage wise. >>> >>> Yes, but you could tweek the rest of the electronics, accordingly, >>> to improve the sensitivity (?) >>> >>>> The detectorists probably know the likely size range of nuggets. Small deep ones can't be detected, and large deep ones don't occur. >>> >>> I'm not sure small deep ones *cant* be detected. That's the point. >>> >>> OTOH, your point wrt the hunters knowing the likely sizes of >>> stuff they will find is probably true -- for their locale. >>> >>> (the whole idea of gold being accessible so close to the >>> surface was interesting... what other ores can be similarly >>> located?) >> >> A former colleague and his friend (from the UK) went gold prospecting in Australia a couple of years ago for a couple of months. They did it for fun, a holiday, but also with a sense of well, you never know... > > IIRC, the folks on this show had aussie accents (but I'm not an expert on > accents -- other than my own) > >> As it happens, they found about enough gold to buy food and beer. Their trip was arranged through an agency. I do wonder if said agency distributes gold throughout their prospecting area. >> >> Maybe it's all just an easter egg hunt. > > Too funny! But, stranger things have been known to happen! > > I recall a show where a guy sat in a field of clover and periodically pulled > up a four-leaf-clover -- disproving the myth of their scarcity. Maybe it's > just a matter of BELIEVING that you will find something...?My wife has this uncanny ability of finding four-leaved clovers everywhere. She can just casually glance down on a random patch and pick a handful. Myself, I just don't spot them. I suppose she must see them in a different colour or something... Jeroen Belleman
Reply by ●October 13, 20212021-10-13
On 13/10/2021 08:12, Rick C wrote:> On Tuesday, October 12, 2021 at 8:11:28 AM UTC-4, Clive Arthur wrote:<snipped>>> The detectorists probably know the likely size range of nuggets. Small >> deep ones can't be detected, and large deep ones don't occur. > > Interesting that you use the correct term "detectorists". There was a rather good TV show by that name a few years back. I don't think they got continued funding and only produced two series. Too bad. I enjoyed it.There were three series, and they're how I know the correct term. I didn't see the TV shows when broadcast, but we watched them all last year as they were available on the BBC web site. Very well made and very enjoyable. The third series reached a natural conclusion and was the right time to stop, like eating a good meal. -- Cheers Clive
Reply by ●October 13, 20212021-10-13
On 10/13/2021 1:19 AM, Jeroen Belleman wrote:>> I recall a show where a guy sat in a field of clover and periodically pulled >> up a four-leaf-clover -- disproving the myth of their scarcity. Maybe it's >> just a matter of BELIEVING that you will find something...? > > My wife has this uncanny ability of finding four-leaved clovers > everywhere. She can just casually glance down on a random patch > and pick a handful. Myself, I just don't spot them. I suppose she > must see them in a different colour or something...The guy in the show I referenced made the point that most folks don't EXPECT to find them and, don't disappoint themselves! He, OTOH, *expects* to find them so just keeps looking until he finds them. <shrug> Makes some sort of sense. Personally, *I've* never found one! (but, I don't sit in fields of clover TRYING TO!)
Reply by ●October 13, 20212021-10-13
On 10/13/2021 12:52 AM, Tom Gardner wrote:> On 13/10/21 05:01, Don Y wrote: >> On 10/12/2021 3:46 PM, Tom Gardner wrote: >>> On 12/10/21 22:59, Don Y wrote: >>>> On 10/12/2021 2:28 PM, Martin Brown wrote: >>>>> On 12/10/2021 20:44, Don Y wrote: >>>>>> On 10/12/2021 9:23 AM, Joe Gwinn wrote: >>>>>>> On Tue, 12 Oct 2021 14:15:33 +0100, Martin Brown >>>>>>> <'''newspam'''@nonad.co.uk> wrote: >>>>>>> >>>>>>>> On 12/10/2021 12:53, Don Y wrote: >>>>>>>>> I caught the tail end (last 2-3 minutes) of a TV show which depicted >>>>>>>>> a couple of guys hunting for gold deposits with the sorts of metal >>>>>>>>> detectors you'd look for trinkets on a sandy beach. >>>>>>>>> >>>>>>>>> And, apparently, *finding* same! (gold just lying around in >>>>>>>>> surface rock outcroppings? who'd guessed!) >>>>> >>>>> They must have known enough about the geology to be in about the right >>>>> place then. >>>> >>>> No doubt! I was surprised that it would be that near the surface. >>>> And, to wonder how they *knew* it would be there! >>>> >>>> (Did someone, someday, just happen to look down and say, "My! There's >>>> a gold nugget by my left foot!" And, thereafter, the area known for >>>> "gold just lying around"? If so, why is there *still* any left to >>>> be found -- if it was common knowledge!) >>> >>> According to school geography lessons, the importance >>> of Kiirunavaara was discovered when someone found his >>> steel knife was attracted to the ground. >>> >>> I've never understood why gold (and similar) elements, >>> which were produced in supernovae, aren't evenly >>> distributed lone atoms. >> >> Why aren't celestial bodies perfectly round (oblate) orbs? > > They are good approximations. > >> Why Les Alpes and The Mariana Trench? > > Plate tectonics.Why are there plates? That suggests some nonuniformity in composition.
Reply by ●October 13, 20212021-10-13
On 10/13/2021 12:56 AM, Martin Brown wrote:> One of my neighbours is a skilled metal detectorist and has several interesting > finds to his name. A few early medieval silver and gold coins but mostly civil > war buckles & shot and the odd Roman artefact as well. He belongs to a local > group that go out almost every weekend.I've found $20 bills, many times, just lying on the ground, floor, etc. But, I don't go out *looking* for them! It seems a collosal time sink to *hope* you might stumble on something...
Reply by ●October 13, 20212021-10-13
On 2021-10-13 10:34, Don Y wrote:> On 10/13/2021 1:19 AM, Jeroen Belleman wrote: >>> I recall a show where a guy sat in a field of clover and periodically pulled >>> up a four-leaf-clover -- disproving the myth of their scarcity. Maybe it's >>> just a matter of BELIEVING that you will find something...? >> >> My wife has this uncanny ability of finding four-leaved clovers >> everywhere. She can just casually glance down on a random patch >> and pick a handful. Myself, I just don't spot them. I suppose she >> must see them in a different colour or something... > > The guy in the show I referenced made the point that most folks > don't EXPECT to find them and, don't disappoint themselves! > > He, OTOH, *expects* to find them so just keeps looking until he > finds them. > > <shrug> Makes some sort of sense. Personally, *I've* never found one! > (but, I don't sit in fields of clover TRYING TO!)When my wife tells me she sees some, I fully expect to find them, but I still don't. Not that I'm short of four-leaved clovers, thanks to my spouse. People must think I'm superstitious sometimes, with all these funny clovers. I'm not. I just love my wife. Jeroen Belleman
