After 7 years of prospecting, I finally bought my first detector and went to a well known dealer. After a lot of research, I had the search down to the Goldbug 2, or GMT. After talking to the dealer in person, I left with the Minelab GM 1000
. The ease of use was appealing and he was leaning that way FOR me, which made me more comfortable (Not to mention the reputation for quality gold machines they produce).
I couldn't get any leads from him on WHERE I could try it out for some success, so I went to a "pay to play" claim in Tuolumne County. On factory quick start, I couldn't take two steps without a target-
most targets would scream and bounce between full non-ferrous, then back to ferrous... Once in a while I would see the machine was picking up full ferrous and not make a peep. I began digging all of the targets that seemed schizophrenic in the readings and recovered a ton of nails, tiny foil bits, a very old spike and bottle caps.
I know this is the norm for most "gold" detectors, and you should dig every target to be sure, however, this machine from everything I have read and watched should be able to discriminate, even in high trash, or highly mineralized ground?
Anyone else having these issues with the readings? It didn't matter which coil I used (I tried both for about 4 hours each).
Any help is appreciated!
Hi NorCal7… there is a lot of frustration and discouragement expressed on this thread. I will suggest a few measures that you can employ to help you get back on to the right path.
Join a local club with claims in the area. Let others know that you are new to the hobby and ask if you can tag along to see how they do things in the field. This approach will significantly shorten your learning curve, so don’t underestimate its value. Do this, and meanwhile practice with your detector whenever convenient, your backyard is a good place to start.
A newcomer searching with a high frequency detector in excessively trashy areas is akin to plunging into deep water before you have learned to swim. Initially at least, put yourself on ground that is reasonably free of trash. It will reduce the frustration, and help you to concentrate on evaluating each target signal that you do come across. Keep in mind that before you can put any trust in visual target ID or discrimination, you must acquire a reasonably strong signal. That normally means removing some surface material to get the coil closer to the target. Make a guess as to whether you think it is ferrous trash or something non-ferrous, then dig it to find out.
On tiny targets, including gold, don’t put any trust in either target ID or discrimination regardless of the signal strength. Unless such a target produces an obvious negative hotrock signal… a “boing” signal typically produced by magnetite-bearing mafic hotrocks as you sweep back and forth across it… all such small targets must be dug.
Discrimination should never be used as a primary search mode unless you are searching an excessively trashy area or an area inundated with hotrock signals, and have good reason to believe there is gold present in sufficient size and at a detectable depth to warrant doing so. Using discrimination costs you too much depth and sensitivity, and especially so as the soils magnetic susceptible iron mineralization increases. That said, you can certainly use it as you wish to spot-check signals found while searching in the motion all-metal mode.
Otherwise, in all other field conditions, use the true motion all-metal mode and make use of your visual ID meter to help with target ID on decently strong signals. Pay strict attention to the audio, learn to distinguish positive signals from negative hotrock “boing” signals, and wide blaring rusty iron signals from the more discrete non-ferrous signals. If in any doubt at all, dig the target… especially as you’re initially learning about your detector responses to different types of targets.
Keep the sensitivity adjusted properly to the ground mineral conditions for stable performance. Initially keep it adjusted such that normal sweeping in target free areas does not produce excessive ground signals to the point where you can’t hear a small target signal at depth because you can’t distinguish it from the ground noise. As 63bkpkr noted, practice with a suitable size nugget made of lead or part of a nickel attached to a poker chip or something that you can’t easily lose. It is not quite the same thing as detecting undisturbed targets in the field, but it will still help you with adjusting the detector’s sensitivity feature.
“most targets would scream and bounce between full non-ferrous, then back to ferrous... Once in a while I would see the machine was picking up full ferrous and not make a peep.”
The targets that “wrap around” are larger ferrous items. Due to a combination of their inductance, conductivity and magnetic characteristics larger iron targets usually will oscillate between full non-ferrous and variable ferrous readouts, That is your visual tip-off but also do listen to the wider blaring audio and become acquainted with the signals produced by such iron.
Iron discrimination will normally handle most small nails, and other non-descript small iron targets. These may very well generate a full ferrous readout and as you observed, they will “not make a peep” because such targets have been effectively filtered from producing an audio signal. Just remember that as the dirt’s iron mineral magnetic susceptibility increases, and as the target’s depth increases, the reliability of discrimination and target ID substantively decrease.
To search high trash areas, adjust your ground balance by pumping the coil over clean ground that is free of target signals, and then set it to the “fixed” position so that it is no longer in autotracking mode. Frequently check your ground balance by pumping the coil over clean ground and adjust it as needed. Then turn it back off. This prevents the detector from repeatedly autotracking into subsurface rusty or disseminated iron and ensures you remain reasonably well ground-balanced to the dirt. This factor alone probably contributes a good many of the false signals that you guys are experiencing when hunting trashy areas.
In high trash areas use a smaller coil to help with target separation and target ID, and as mentioned earlier here, don’t forget to make good use of your pick magnet when digging targets. The pick magnet is your most reliable discriminator.
When searching highly magnetic susceptible iron mineralized dirt, keep in mind that small coils see less dirt and therefore less magnetic susceptible iron mineralization, thus permitting you to use significantly higher sensitivity levels. In any event, small coils are more sensitive to small gold under any conditions.
I hope these ideas will help you. Learning high frequency VLF units and nugget hunting can be frustrating at times for the newcomer, but stay the course, be patient and enjoy the great outdoors. With experience everything will eventually fall into line and make perfect sense.
Jim.
