How Do I Discriminate Junk From Gold With A Goldmaster 24k?

[Cascade Steven]

I am new to gold prospecting and nugget hunting and just recently purchased a new Goldmaster 24k.  To learn more about this endeavor I have been reading as much as possible on this and other forums.  I have read comments on this forum that one advantage of the VLF detector is its ability to discriminate between gold and junk in areas of past or historic mining activity.  And I have also read that the conductivity of gold will vary depending upon its purity.  At the risk of sounding dumb and having missed the obvious, my question is this:  How do I use the VLF to discriminate, find gold and avoid the trash in a trashy area that may have iron scrap, bird shot, empty 22 shell casings, aluminum foil and other modern and old trash?  Thank you to all of you in advance for your patience and help.

[Jim in Idaho]

For the most part, you can only discriminate ferrous from non-ferrous. You'll have to dig all the shell casings, and birdshot, and pulltabs if you want to find the nuggets. I usually dig everything when nugget hunting, as using discrimination will cost you some sensitivity. Each person has their own view on discrimination, however. Sometimes the site your detecting has so much iron junk, you simply have to use it.

Jim

[Cascade Steven]

Jim:  Thanks for your advice.  Much appreciated.

[Jeff McClendon]

The numbers displayed on the GM 24k when swinging over targets are probability estimates of ferrous or non ferrous targets. The lower numbers are usually iron or small non-ferrous targets (like small gold or aluminum/lead trash) that are having their conductive qualities shifted into the iron probability range due to mineralization or masking. Also, on any VLF detector rusting, cracked iron objects will be difficult to categorize so your detector will give ferrous and non-ferrous readings for things like rusty bent nails, barbed wire, you name it.

It is a really good idea to dig it all if possible, especially if there are shallower and larger ferrous or aluminum targets near the surface that could partially or totally mask smaller gold targets near them.

I agree with Jim and when I used my 24K I would discriminate in the iron range only if the ground noise/hot rocks were too much for the 24K's ground balance abilities.

[Cascade Steven]

Jeff:  Thanks for your help

[Steve Herschbach]

On 5/24/2021 at 3:52 AM, randyisscott said:

Hello, The GM24k is best suited to intermediates and experts. The upgraded features may cause a lot of confusion and difficulty for the beginner.

That need not be the case at all. The machine is very simple to operate (basic start guide below).

The issue at hand is nugget detecting. VLF discrimination in mineralized ground is unreliable at best. You should not use discrimination, but should be using all metal, digging all targets, and leaning hard on a magnet on a stick to separate ferrous from non-ferrous.

It is absolutely impossible to reliably separate gold nuggets from lead, aluminum, or any other non-ferrous items from other non-ferrous items, and at a minimum you must dig all non-ferrous items. Brass, copper, and silver do tend to deliver higher probability numbers, but so will large nuggets.

If you wish, I recommend using all metal, in conjunction with the meter reading, to make a dig or no-dig decision regarding ferrous. A ferrous object should bang repeatedly to far left, never bouncing above 40. You do ten sweeps, you get ten far left readings. If, on the other hand, you get one or more hits that bounce higher, especially if the bounce over 40, dig it. I've seen nuggets in bad ground read ferrous over and over, with only rare spikes to non-ferrous. But be aware that some ferrous also spiked high, and you will dig those. As you should, unless you like leaving nuggets in the ground. Look for reasons to dig, as opposed to reasons not to dig. You must dig targets, and lots of them, if you want gold.

By using all metal, and using the probability meter constantly, you will learn the odds via meter readings and repetition, and can shift the odds as you please by modifying the resulting dig/no-dig decisions. How that meter responds is key, and that varies with how fast you swing, and how the coil approaches the target. Bouncy numbers are common, and the weaker the target, the less you can believe what you are being told. In truly trashy areas I get more picky, in less trashy areas I get more aggressive.

The last method is go to the discriminate "beep mode" and use the actual tones and rejection settings, just like coin hunting. This makes dealing with the worst trash easier, but it also tends to miss more gold, so for me it is a last ditch approach for the trashiest locations. See my detailed review of the 24K for more on that.

Goldmaster 24K Quick Start

1. FACTORY RESET - Hold the Down button when turning on the detector. Press the Pinpoint button when “Fd” is on screen, to reset the machine to factory defaults. Just in case.
2. VOLUME - Set the volume to your preference (tap Speaker button, use Up and Down buttons).
3. THRESHOLD - Set the threshold to a faint hum (hold Speaker button, use Up and Down buttons). For silent search, turn the threshold down until it can’t be heard, but no farther.
4. SENSITIVITY - Set the sensitivity to a level that ensures smooth operation (Up and Down buttons). The 24K will generate a harsh overload sound if the coil is placed on ground too mineralized for the setting. If this occurs, reduce sensitivity until the overload tone does not occur.
5. GROUND BALANCE - The default mode is automatic XGB ground tracking. Simply raise and lower the coil over the ground a few inches, two or three times, and start detecting. Alternately, lock the ground tracking by tapping the Lock button (a Lock symbol appears on screen). While the tracking is locked, you can press the Cross Hair button to perform a Ground Grab. This updates the ground setting to what is currently under the coil. With a combination of Locked tracking and Ground Grab you can easily update the ground balance point as you swing.
6. DIG ALL TARGETS - With an emphasis on the faintest targets. A magnet on a pick or a wand can make quick work of excavated ferrous items, while recovering all non-ferrous targets. If an operator wishes to avoid digging ferrous items, employ the meter to ignore items that repeatedly, and reliably, produce far left meter indications. However, always remember that discrimination is unreliable on weak signals, and strive whenever possible to dig all targets while nugget detecting.
7. RETAINED SETTINGS - The Goldmaster 24K will retain your settings when powered off. Once you get the machine set for a particular area, it will be ready to go next time you power it up. When in doubt, repeat the steps above, starting fresh with a factory reset.

 

[DougB]

I bought my White's 24K from Jim McCulloch and even though ti have owned a several White's and Fishers over the years one of the best thing I did was get Jim's book : Advanced Nugget Shooting with the Goldmaster 24K "