We visited Missouri Mines State Historic Site on May 20, 2016, and it is located at 0492, 4000 MO-32, Park Hills, St. Francois County, Missouri. We have visited here prior to 2016, but these are the digital photos I found. I believe some of my ancestors may have mined here and so I enjoy visiting for historic purposes.
These are a few of the same photos as seen in the above slideshow video.
After an area is mined, what is left is chert, or rock, and I think my time outside looking at the mounds of rock left behind from many years was more powerful than the rest of the place. There is much thought to be done about the change mining makes on an environment. We brought a few pieces of rock home and put them in the garden.