So I've been out a couple times with the Fors (no luck so far) but my question is I keep getting some wacky pings in the high tones. Today I was out in a highly mineralized zone, lots of silver i think and lots of other metal that looked like silver but wasn't being picked up on the FORS. I ground balanced and I'd get tones and dig and find junk but other times I'd get like an 87 or 95 with one beep then go over it and get another..........I'd dig and come up with nothing, the signal just disappeared. Any ideas or help? I wouldn't mind a day trip with someone who could show me the ropes on proven ground, in southern Oregon.
Hi Oregonmp03… I think we all have experienced ghost signals on occasion while detecting. There are several possible solutions depending on circumstances. Below are some commonplace examples…
(a) sometimes a small target falls deeper into the hole such that it can no longer be detected. A few more scoops will sometimes bring up a target, but simply scan the hole with a pinpointer to be sure that is not the case.
(b) discriminated targets occasionally signal in the dirt, but many will not respond once the soil
has been disturbed or it has been removed from the hole. I don’t know if this type of scenario applies to your situation because I’m not familiar with that detector model…
(c) the most common scenario I’ve come across is disseminated / mineralized iron remaining from iron junk that has rusted away in the ground. Rust is a form of maghemite, a powerful magnetic susceptible iron oxide, and it will produce such signals. When you dig and disturb the rust deposit, it will not likely be able to respond any further with an audio signal… hence a ghost signal.
(d) we see similar results using PI units while prospecting silver up here on occasion. A perfectly good signal is dug and voila… no signal anywhere. Usually associated with sponge or disseminated or even with weak leaf silver, once out of the dirt it will simply not respond to the PI electromagnetic field. In all cases to date, a VLF motion all-metal mode has quickly located such targets in the dirt pile. Although this doesn't apply to your circumstances, you might as well know about it.
(e) we occasionally encounter signals generated by ground anomalies that differ both in type and strength of mineralizations from the general terrain. Examples include former campfire sites producing a positive hotrock effect even if actual rocks are not present, electrically conductive animal urination spots, or other relatively conductive spots usually related to the occurrence of various mineral salts. Sometimes an abrupt physical change to the soil type such as a small clay deposit with differing moisture, electrical and magnetic characteristics can produce a signal. But digging disrupts the electrical continuity or magnetic fraction such that it can no longer produce a signal, and it becomes apparent there is no metal target.
Jim.
