Searching inside a Mine with GPR or ???

[Gene-Yo]

Are there any usable techniques to search a hard rock gold mine with GPR or other equipment looking for large gold veins or nuggets the previous owners missed which are located within 1 to 5 feet of the currently dug walls / floors.

This is a hard rock mine with a large amount quartz and granite compositions and located in the Rocky Mountains.

Also, I heard that GPR would not work to find gold nuggets in highly mineralized soil or in hard materials like quartz. Is this correct or does anyone have any real proof one way or the other?

[ronjoly]

Are there any usable techniques to search a hard rock gold mine with GPR or other equipment looking for large gold veins or nuggets the previous owners missed which are located within 1 to 5 feet of the currently dug walls / floors.

This is a hard rock mine with a large amount quartz and granite compositions and located in the Rocky Mountains.

Also, I heard that GPR would not work to find gold nuggets in highly mineralized soil or in hard materials like quartz. Is this correct or does anyone have any real proof one way or the other?

i imagine this will be a long *** post and i'm probably typing this for nothing so i'll just throw out a bunch of ideas.

I AM NOT AN EXPERT so take what i say with a grain of salt

this is a tough question and nearly impossible to solve with geophysics tools.
nothing finds gold nuggets , if such a geophysics tool existed there would be a million gold mines.

to find gold you need to find the structure the gold exists in or metals associated with the gold or conductive rock anamolies that may be gold or associated metals .

if i was underground inside a mine looking for gold using geophysics tools
in granites i would try many different things.
first would be a spectrometer .. specifically potassium could give away where the quartz vein is versus the potassium quantities in the granite.

imagine the granite consists on average 5 percent potassium and 5 PPM Thorium and 4 PPM uranium and the quartz vein has 0 percent potassium , 1 ppm Thorium and 2 ppm uranium .. using the spectrometer you may have just found the quartz vein.
problem is spectrometers only sees at best a couple feet inside the rock.
another problem is mass effect , your surrounded above and below by gamma rays so you would need a small hand held spectrometer that is shielded on all sides but one.
a sheilded scintillometer may even work .. high counts could be granite .. low counts is the quartz

gpr is a really cool tool but may not be feasible
yes conductive soil and hard rock is tough on gpr but if the gpr travels along and sees poor reflectors then all of the sudden you have a strong deflection then it could be the quartz vein.
granite though is pretty damn hard but gpr may see the contrast between the granite and the crack the quartz filled.
i don't honestly think gpr will work but if you try make sure your station interval is insanely small. see if you can get access to 12.5 to 25 mhz gpr antennae .. these see the deepest

mag suscepability .. run the meter along the wall and see if the magnetic properties change once a quartz vein is encountered .. again you are dealing with mass effect inside a mine shaft and this tool may be useless.
if the quartz vein has a ton of pyrite associated with the gold then when a large drop in magnetic susceptability is encountered you may have found
the gold bearing quartz vein , vice versa with magnetic sulphides.

i think the best tool to use would be resistivity tools .. at it's most basic it would act as a volt meter measuring the resistance between 2 points.
this tool is normally used to map where faults or zones of weakness exist in the rock or to find conductive metal bodies.
the see deeper and map better you would use an array type tool .. i am not sure you can do IP dipole dipole underground .. check out Geonics Canada .. they have some good resistivity tools.

nothing beats dynamite or a drill rig though

lots of dumb ideas above but if i had the resources and unlimited money i would try some of the silly ideas.

luckily i get to use these tools, it's my job to do it or get it done by someone else