What wavelength can penetrate soil to 15 feet?

[Gold Dredger]

Any idea what concentration you need to be profitable? Or what concentration PI loops can detect?

Also, a bit of googling shows a bunch of PI detectors of various types are already available on the market. Are these not sufficient for you? Or are you looking at scaling up your operation?

Most PI detectors have a depth of less than 30 inches. I am wanting a larger 5-15 feet depth capability. Current detectors are good at finding surface pay streaks of modern flood gold. The deposits I am after are the ancient deposits which will be larger pieces and much more concentrated. Try to imagine the epic floods that resulted as the glaciers retreated and you will understand why. My overhead is minimal as I only run a 5 inch dredge (10hp) motor and a BobCat. I am already profitable.

 

[Drakkith]

@Gold Dredger Well, you seem to be more knowledgeable than most who come here asking for help. Since I know virtually nothing about detectors of this type or of gold mining in general I think I'll bow out of this thread. Best of luck to you.