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Old 08-15-2022, 10:36 AM
Jeff Kinzli Jeff Kinzli is offline
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Join Date: Apr 2018
Location: Dallas/Fort Worth, TX
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I'm not sure about the area, but what MAY be happening is that as you scrape away the surface dirt, you're scraping away a layer of either highly mineralized dirt, or dirt that has a bunch of decayed iron dust in it. That happens in old well-used sites, the rusting and decaying of iron all around deposits a layer of rust and decayed iron over the surface that is like a blanket. VLF detectors would have a horrible time with this and you'd likely get no depth in those spots. PIs would do a little better, and is sort of the environment that they were designed around (highly mineralized salt sand beaches). So you may have better luck with the PI there, especially if it has some way of rejecting iron. Sometimes this is done via pulse delay and other pulse timing tricks - it probably won't be a sure thing but hey, if it cuts down the iron by half you're doing great.

Good luck!
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