Detector screaming at pyritic vein material.

[goldshark]

I know the different tones for non ferrous, hot rocks, and ferrous metals. As stated earlier, the GB2 screams a Gold tone for the ore pieces. No nuggets present when crushed to -100 mesh, nothing left on screen or buck board. Fishaholic5 may have hit the nail on the head, when he said that a quantity of fine Au can trick the coil into detecting a nugget. I have found this on various ore piles, where the detector gives a Gold tone on some pieces, but not on other similar looking pieces. The pieces that give a tone definitely assay better then the ones that don't. I will assay some of the screamers next year when the snow melts, then give results here.

 

[jobinyt]

You answer your own question - the cons did not set of the detector - so the detectable material was likely elsewhere. I have found fine gold concentrations on bed rock with my detector but the signal is subtle - just background noise squelched out in most circumstances, and likely much richer than the concentration in your rock.

 

[goldshark]

Good point Jobinyt. I will do a little more testing to see if an excavator bucket left a rind of steel on the outside of the specimen. I have found many rocks that set off a good tone, which weren't mineralized at all. How ever, this specimen definitely gives the Au tone over an Iron tone, as well as some other pieces.Maybe I over looked something in my investigation. Will cut off another slice, and be more exacting in my process.

 

[goldshark]

You answer your own question - the cons did not set of the detector - so the detectable material was likely elsewhere. I have found fine gold concentrations on bed rock with my detector but the signal is subtle - just background noise squelched out in most circumstances, and likely much richer than the concentration in your rock.

What I actually meant to say was that the cons did not report any course Gold. I did not hit the cons with the metal detector, before roasting. I then roasted and panned the cons to see if it would expose the fine Gold. Much to my chagrin, I did not know to regrind after roasting, to further "open" the roasted sulfides. Even an old dog can learn a new trick. Lots of this ore around, so will have more to play with next year.

 

[Jah-nee]

Ultra small gold particles spread over a wide area set off the strong tone by fooling the detector into believing it's a larger nugget due to the area of return of signal to the coil.

Cheers Wal

Good point/knowledge... Jah-nee