Cody you may be able to help

[Boony]

Hi Cody,

Can you tell me why the EX II ignores the lump of Galena (Silver Lead) pictured below, it weighs 40 pound so it's not small.
I have a little bottle of gold that I panned some time ago (about half and ounce) the EX II ignores this also, I was told the the explorer tries to look at the individual grains of gold rather than the bulk, it was said also that the same thing applies to very fine gold chains.
However I'm still at a loss as to why the Galena won't show up on the detector.

All the best.....Boony

 

[Cody]

Detectors that ignore the soil as you know reject soil minerals. I think it is easiest to think of this simply as a discrimination circuit. Soil minerals are rejected based on pure ferrite plus some offset since there is no pure ferrite in the natural state. Galena is a mineral and the detector recognises it as such so rejects it.

This plus the rejection of some gold chain is why there are detectors that are specifically for detecting gold. This is why there are detector that are designed for gold detecting.

For a target to be accepted it must have a time constant that is "judged" to be in the accepted range. All targets have an associated long, medium, and short time constant. The microprocessor compares these and accepts or rejects a target based on the results. The minelab is going to reject any mineral and on the down side gold chain depending on size can look like minerals. Galena is very similar to "fools gold" pyrite which is a mineral and also rejected. If this did not happen we would be driven nuts from all the false signals from other soil minerals.

 

[Boony]

Hi Cody,

What you say makes sense, I can imagine the noise we would have to put up with if the EX II registered all minerals. I gather from what you say that if a gold nugget was large enough it would register on the Explorer, which is handy to know because come winter time I plan to go to the west coast here in Tassie and hopefully pick up a nugget or two, as it's summer time at the moment I keep out of the bush, I don't like snakes and while we only have three species here they all bite and are all poisonous.
Thanks for the info and the response.

Cheers....Boony

 

[HanoverHoleDigger]

while in manual hit in the upper right and sound awesome. IF you swith to auto sensitivy the machine elimnates the signal.