Bob - Steve tested some of the spongy gold we were getitng in Nevada and the pieces in the 2 pennyweight range on the TDI and they were invisible even when touching the coil. However they were invisible on the 5000 too. Plenty visible on the SDC and the new GPZ, and of course no problem on VLFs - just the VLFs dont get the depth of the PIs with their larger coils.
I think the new PI machines like the SDC see this stuff because they have very short delays or in the case of the GPZ nearly zero delay. They are gold nuggets / specimens with very short time constants, whose eddy currents decay very fast and are essentially gone during the delay cycle between transmit and receive on most PI machines. Mossy nuggets and some specimen gold in quartz falls into this category too.
Although I am not interested in selling, and I dont think Steve is either, but would be happy to meet up with you sometime and you could test some of these pieces to see how they perform.
Maybe sometime in the next month or so we could meet up with you and maybe Jim C. at La Porte or Sawtooth or ???
You have my email - send me an email if you want to chat about getting together, spongy gold detection or whatever. I also need to ask you if you ever got your extra copies of the ICMJ with the Butte nugget article.
