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Originally Posted by goldfinder
As usual your analysis is quite good JP.
The big problem w/ arcs and sparks is they don't necessarily have to go to metal - anything conductive would work like damp soil that has enough ionic activity to do some conduction.
One thing that may be fruitful is to have a high voltage probe like regular metal detectors use a coil. The voltage would not have to be high enough to do arcing. Then monitor the HV probe field for anomalies. Conductive metal in the ground would tend to distort the probe field. Might even be special distortions relative to different types of metal.
Goldfinder
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Hi goldfinder,
You are correct, the arc does not have to go to the metal. Looking at the state of advancement for LRLs today, I would think any detection at all is better than what we have come to expect. In the case of high voltage, we may get some false sparking that locates hot rocks, or mineralized areas. And we may get some sparks that locate metal and even gold. This might be a welcome amount of false signals as long as we got a hit or two on gold each day. Also, we might find there are better times to use this method of locating things, such as when it is not a rainy season, and the ground is relatively dry to raise its resistivity. When the ground is in this condition, we may find that ground which has metal buried in it has more conductive dirt above the buried metal due to corroded metal ions. If we find this ground has noticably different resistivity due to metalic ion activity, then maybe the sparks will favor discharging at this location, and mark out a place to dig, even though the sparks were not sparking onto buried metal. In an ideal ionic condition, we would welcome a cylinder of heavily ionized dirt which formed a conductive pipe directly down to the buried metal.
Others have done experiments in this area. A theory has been speculated that this is the principle that electrostatic detectors use to locate more conductive areas of ground which are expected to produce an area of less strongly charged air above the ground, which we would detect with the electric charge detector. If this is how they work, then they are not detecting gold, but anomalies in the air charge that could be related to a location of buried gold, or to something else, such as somebody dumped a bucket of water in the dirt an hour ago.
Someone once did some experiments along the lines we are talking, but not with high voltage.
It was more along the lines of frequency generators/MFD stuff.
It is interesting to read what he reported:
http://www.geotech1.com/forums/showthread.php?t=6663
"...You can take various loop antennas and sweep them in frequency and measure the power in the loop and watch it change linearly in the presence of various metals, but never showing a peak or dip at any specific frequency..."
That sounded interesting to me. While he disclaims MFD working in other parts of his post, he reported something that could maybe exploited in some way. It is interesting to note he pretty much gave up on MFD LRL detecting. But for a person who is a dowser, he shows some interesting experiments to look into. While he makes the point the ground absorbs power at low frequencies, I wonder what kind of signals you could get to work in the ground. After all, geologists put their probes in the ground to find buried metal or ores with induced polarization and resistivity studies. From what I recall, they have had success with spectral induced polarization, which may be approaching closer to what people are claiming works in MFD field trials.
In any case, I will believe MFD recoveries after I see them work reliably, not from reading stories.
Best wishes,
J_P