I have recently been shown a submerged mine in a lake and have conducted some exploratory dives. The site has been kept somewhat secret in that a handful of divers have seen the opening to the mine but as far as locals know, no one has ever explored the mine. There is a restriction very early on in the mine that requires a sidemount configuration, and from what I have been told no one has ever even attempted to explore the mine nor dives sidemount.

I have completed exploration on one side of the mine (there is a couple forks) and am hoping to finish exploration on the other half in the near future.

The mine begins with a vertical shaft then at the bottom of the shaft the mine goes horizontal and maintains a constant depth (so far). At the bottom of the mine in the horizontal shaft there is a weird layer of "fog" of particulate in the water that is about 4-5 feet in height in the passage, above this "fog" the water is again clear. The mine use to be either a gold or silver mine from the late 1800s to early 1900s.

Does anyone have any idea what this "fog" could be or what causes it? I apologize in advance about being vague, but I want to keep the location under wraps cause I am guest to the location.