First Off - You want to learn everything there is to know about the code? Get out of the house and go to the mountains
I will not give you the answer to the question until you research it and out of the house and in the mountains.
You say your a know it all when it comes to prospecting?!
Ok know it all, go to the mountains and get me some pictures of rock faces and bare ground where mineral deposits are, and get some ore samples about the size of your fist.
Take a lot of photos of rock outcroppings, small buttes, look for caves.
You want to learn code? Outline everything you see in that photo, even if you have to enlarge it.
It is there, force yourself to do it and don't argue every little point... because people get tired of hearing rants.
If you refuse help or want to argue about it... you will meet my ignore button.
This is your last chance, if you hassle me one more time... I'm finished with you and could care less what you say after that, because you surely don't want to try and want the answer right this instant.
USGS files; how the heck do you think they got that info? They went out and explored.