What area is this with the tours.In College I majored for several years in Geology. This was in the early 1970's in an active mining district.
Fellow students and I did explore a 1860 hard rock basalt mine shaft in the copper country.
Very interesting. Veins of Pure copper and crystals were still embedded in the mine walls.
The old leather harnesses and the narrow gauge track they uses on the mules were there too.
Probably the biggest danger was falling down a vertical air shaft and they had wooden fences to mark them off.
There was a bit of craftsmanship on the part of the old timers in how they used wood and stone to build walls.
The main entrance shaft was on a 30 degree incline and you could go down until you hit the ground water level.
Eventually all these old mine entrances were filled and sealed.
Some mines shafts were first stuffed with old 1950 auto wrecks to plug the opening then filled with dirt.
About 10 years ago I guess the autos rusted away enough and a shaft opened up and had to be fenced off and then resealed. This was in the city limits.
Back in the 1970's when some of the mines were still active you were waken in the middle of the night by dynamite blasting that shook the whole house.
In the summer there are 3 or four electrically lit mines open to tourism in that area if one is interested.
One mine actually supervises and allows repelling down the air shafts to the lower levels for exploration. in the dark.
Rappelling would be fun.