"Sniffing" Out Junk Metal to Get the Gold

 (Fisher's Gold Bug Pro.)

Until just recently, I haven't had occasion to use my Fisher Gold Bug Pro much, although I have bench tested it and took it for a spin in the field on one occasion a couple of years back. However, over the past two months I've been swinging this great little detector at a placer site in Northern New Mexico...no, not for nuggets since this location contains only very small gold for the most part. What I'm learning is that the Gold Bug Pro is very good at "sniffing" out potential placer gold pockets and in this post I'll explain the details.

A Multi-Faceted Gold Detector

First off, the Fisher series of Gold Bug metal detectors (Gold Bug 2, Gold Bug Pro) has proven to be extremely effective at finding nuggets and very small pieces of gold in numerous gold-bearing locations both here in the United States and elsewhere in the world (Australia comes to mind first in this regard). Of the two machines, the Gold Bug 2 has been around for a while now and is undoubtedly better known, as well as having proven itself as an efficient gold getter. In fact, nugget hunters in Alaska have used the Gold Bug 2 to recover numerous nuggets, large and small, at both pay-as-you-go sites and on their claims or in open areas. Ditto for selected locations in Arizona, California, Nevada, and the Aussie Outback. The Gold Bug Pro was designed as an advanced, multi-faceted version of the Gold Bug 2, with its primary function as a gold detector like its well-known predecessor. However, the Gold Bug Pro was designed to operate as a relic and coin detector in addition to its gold detecting capabilities. I'm not here to speak on the Gold Bug Pro's abilities in these latter two regards, but on its usefulness in small-scale placer sampling and mining.

I've used my Gold Bug Pro five separate times now at a wet placer location in Northern New Mexico's highly mineralized Tusas Region. Those of you familiar with this neck of the woods (like my friend "Rattlesnake" Jim) are probably thinking I'm hitting the Placer Creek area in or near Hopewell Lake State Recreation Area. Well, you're somewhat close but no cigar! No, I'm not at Hopewell nor would I ever attempt to work any area where you're required to get a U.S. Forest Service permit to wield a lowly gold pan, which is exactly the case at the State Recreation Area these days. I am dead set against that sort of nonsensical, bureaucratic bullshit any time, anywhere and I get pretty damn angry just thinking about those sorts of idiotic rules when it comes to small-scale gold mining and prospecting. You Feds and New Mexico state bureaucrats and politicians screwed up royally with that Hopewell Lake deal and as far as I'm concerned you can take your panning and sluicing restrictions (and permits) and shove them as far up your rear ends as they can possibly go. How's that for feedback, you ass clowns?

 (Northern New Mexico is a land of great beauty, not to mention the presence of placer gold in selected locations.)

Anyhoo, now that I've gotten that out of my miner's system, allow me to move on with my discussion concerning the Gold Bug Pro. What do I like about this machine? How about its light weight, control setting simplicity, easy ground balancing, and the fact it is highly sensitive to extremely small pieces of gold when used with its 4.7-inch, circular "nugget" search coil? Pretty good for starters, don't ya think? There are other pluses as well, but I'll let sleeping dogs lie in this regard because this isn't a detector review per se. Since the area I've been prospecting is not noted for lots of gold, let alone nuggets or large or coarse pieces, the role I've committed my Gold Bug Pro to at this site is as a "sniffer" for metals associated with placer gold deposition, or alternately...concentrations of heavy black sands that may contain gold. Most of the gold myself (and my pard Ernie Martinez) have recovered at this site is in the micron or flour gold range interspersed with occasional larger pieces such as small and medium flakes. The largest piece of gold we've pulled out of this spot would have qualified as a small nugget had it contained more volume and been less flat. So that's what we're dealing with, gold-wise. That, and lots of exposed or very shallow bedrock. Most importantly, the bedrock is, for the most part, angular and very fractured making it ideal for capturing even the smallest pieces of gold. Therein lies the usefulness of my Gold Bug Pro.

Taking the Guesswork Out

To take the guesswork out of things at this spot I first fire up my Gold Bug Pro in the all-metal mode, turn the gain up to the 50-75 range, and advance the threshold to just this side of barely audible. I then ground balance the machine to the ground I choose to scan (usually crevices packed tightly with dirt and gravel) and begin scanning the nugget coil slowly over those areas. In most instances I'll soon get a target display signal in the 40 or less range (ferrous metals) or alternately, in the above 40 range (lead, gold, or aluminum at times). In other instances, I'll get indications that don't sound like ferrous metal pieces (rusty nails, bits of oxidized metal) but that read high on the machine display's iron oxide scale. This tells me I'm dealing with a pocket (or lots) of black sands. Whatever the case, when I receive any of these signals it's time to dig and see what's hidden in that particular crevice or narrow trench (much of the bedrock is traversed with pockets and crevices as well as narrow, "V"-shaped trenches). Test pans taken from signal-indicated pockets usually contain rusty iron (nails, wire [or in one case part of an old horseshoe!], lead fishing "split-shot" weights, and the like). Oh, did I mention gold too?! The best test pan we've gotten thus far came from a solitary four-inch section of "V" shaped bedrock trench packed with dried clay at the bottom that contained 10 separate pieces of gold, including a very large flake, about five or six smaller flakes, and some unusually heavy pieces of flood or flour gold. No, we're not going to strike it rich at this spot but we're getting some very beautiful gold out of it just the same. And my Gold Bug Pro has proven itself to be an extremely useful tool for sniffing the gold out and enabling us to recover it from its hiding places on bedrock. One thing to remember here is something I've said over and over again in Bedrock Dreams, always be aware of the relationship to placer gold of visual (or auditory) clues like rusty metal and lead.

 (Any crevice containing oxidized iron scraps or lead objects may also contain placer gold.)

In a future post I'll throw in some photos I took of this site and its bedrock.

Now for you full-on detector geeks out there, here are a few Gold Bug Pro specifications and personal comments:

Mechanical: S-rod with electronics housing on rod; three-piece breakdown construction; non-metallic telescoping rod; adjustable position arm rest (having an arm rest is a big plus, by the way).

Weight: two pounds, eight ounces with battery installed (this light weight makes the Gold Bug Pro a dream to swing around and causes little to no arm fatigue).

Standard Search Coil: waterproof 4.7 inch closed-frame biaxial (I also have the larger 11-inch DD elliptical search coil but have not used it as yet).

Batteries: The Gold Bug Pro uses a single, 9-volt rectangular alkaline battery (lasts about 16 hours).

 (Only a single 9V alkaline battery is needed to power the Gold Bug Pro.)

Operating Principle: Very low frequency (VLF) induction balance (induction balancing is what makes the Gold Bug Pro so easy to ground balance and block out unwanted signals like "hot" rocks).

Operating Frequency: 19 kilo-hertz (kHz), crystal-controlled (this type of VLF frequency allows for good ground balancing in conjunction with target discrimination.)

Ground Balance Range: From ferrite to salt water, inclusive (ferrite is essentially black sands and iron oxide).

Temperature Operating Range: 14 degrees Fahrenheit (F) on up to 122 F (I doubt you'll be digging anything up at 14 degrees with things frozen solid!).

So there you have it.

Hit me up on e-mail if you have questions about the Gold Bug Pro or my particular use of it lately. Best to one and all...

(c) Jim Rocha (J.R.) 2015

Questions? E-mail me at jr872vt90@yahoo.com


  1. 1.5
    I guess here in Aus., the gold bug for many years "filled in a gap" or short fall of all the minelab P.I's (a topic/post comes to mind about how a speci with visible gold, the owner of the speci would buy anyone a beer if they could get their ML to sound off on it, no-one could and when they finally gave up, they would have to shout him as such) So it's somewhat common knowledge how the P.I's inability to "sound off" on many a speci gold has now been addressed with the SDC 2300 and the GPZ 7000, that gap between PI and VLF has now been closed.
    That's the thing with gold prospecting, what was good at the time, (years ago) may still work, but people/prospectors also need to always keep up to date with new tech to maximise effectiveness.
    Also I've found the best material out of crevices is hard packed, meaning the material hasn't been touched out of that hole for a very long time or ever. To often I've seen what should be "better" crevices that "would off" concentrated the gold more, but have been got at by other's a few years back, sure there might be flood gold or they didn't clean it out prob. but from my experiences it is always better going for the hard pack/untouched, A post I found some time back....
    So I guess these two posts below are what these detectors are best at....
    The GB2, like the GMT, excels at finding small gold in:
    Trashy areas
    Very mild to moderate ground
    Shallow ground
    Mullock heaps
    And more so In combinations of some or all of the above.

    Whites GMT for Sluicing:
    "The whites GMT, supposedly able to track the pay streak, black sand deposits,"

    1. I think the main point Jim's making is the heavies, nails lead etc! Most newly formed placers will always contain these heavies! Really if your sluice shows no lead shot/rusty nails, then your digging in the wrong spot unless your working high bench's!
      As for the black sands, most of our Aussie heavy sands are non magnetic, so the detector won't pick them up..

  2. Jim,
    Thank you for bringing to attention one of the Gold Bug Pros most valuable assets. Its ability to visually detect black sand deposits with it Ferris meter. In my option David Johnson the chef engineer who designed the GBP is a genius. I must be honest I am a Fisher dealer, but I have a Minelab SDC 2300 and my digging partners have Minelab 4500 and the 7000. All three of us have GBP and GB2.
    How we take full advantage of the GBP is to plot the ground that gets high Ferris readings. We will then use Lowe’s sprinkler flags to plot the area. Some use spray paint but we don’t like to upset the environmental Nazis to much. Next we will fan sample per Frerris numbers. Then Drywash or detect with the GB2 or PI’s. Sorry PI’s don’t identify black sand pockets.
    Remember use equipment for its intended use. Detectors are just like golf clubs, each one has a purpose. Any one who says this is the only one that will work or the best technology is probably the same person telling you he “got ALL the gold” and we know how true that is.
    I think EVERY prospector/treasure hunter should have a GBP. May not use it all the time, but you will use it if your good. I always recommend it as a FIRST detector. Fast recovery swing time. 5” coil for gold. 10 & 11”open coil for treasure. EASY to ground balance. Easy to learn . I have a client that has a GBP with a 11”& 5” coil. Has paid for it with rings and treasure on the beach 50X over. NO JOKE. Went on a club outing found 2- ½ gram nuggets on Saturday with a 5” coil, came home went to the beach Sunday night after Holiday found a grip of coins& jewelry….and yes lot of trash. Also to be used in DRY sand only. Yep you need a PI for wet sand.

  3. This may help some from my mentor Jim Straight.
    ("following the streak")
    Using a metal detector to seek concentrated pockets of magnetic black sand to nugget shoot for associated placer gold.
    Early day "electronic prospectors" working placer gold fields soon learned to offset the ground balance of a VLF/TR-type detector and listen for the ground -noise of concentrations of magnetic black sand. While concentrations of black sand readings do not promise gold, gold is often associated with heavy concentrations of magnetic black sand. Although this trick was crude, a handful of persistent detectorists did "pretty well" using this method to find "bread and butter" nuggets while tracing black sand concentrations that carried placer gold.
    Later VLF-type detectors had some sort of a "black sand" control, such as the Tesoro Diablo MicroMAX . More recent VLF's, such as the White's GMT, the Minelab X-Tetrn 70, the Teknetics T2. and the f isher Goldbug Pro, incorporate some sort of a Fe304 reading designed to display the amount of magnetic susceptibility of the soil.

  4. The readings are most sensitive to motion and most accurate in the "All Metal" mode. The trick is to vigorously pump the search coil up and down as if ground balancing. The objective is to walk around over different ground while pumping the coil, seeking the highest concentrations of black sand expressed in numerated micro-cgs units, which measure the amount of magnetic susceptibility in the ground regardless of the type of soil.
    Thus, as an example, some nugget hunters use Bar graph readings to find an Eolian-type placer deposit where strong winds blow away the "fines" leaving a concentration of heavier minerals such as placer gold.
    However, gold may not always be associated with black sand. A lot depends upon the metallogenet ic processes in the particular gold field. Notice on pg. xi that both the Columbia and Colorado Plateaus are capped with non-metalliferous basaltic flows, so any accumulation of black sands from the weathering of the basalt capping would not carry gold.
    One last thing if you want to find black sand as some of my friend who mine professionally do. Look into the Fisher Gemini 3. That’s a whole new story, one for a another time.
    Thanks Jim, for always being honest and generous with your knowledge. Weren’t for You, Jim Straight and a few others I would be frustrated still.


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