One group of cavers was uncertain to explore the forgotten tunnels underneath Black Hawk

Experienced cavers Adam Weaver, Nick Anderson, and David Springhetti. Taking the leap into the sinkhole, uncertain, not knowing what they'll find.

"We did not know what to expect," said Anderson.

"We didn't know what was down there," said Weaver.

What they got was a long-forgotten gypsum mine shaft.

"To find that in a residential neighborhood in a sinkhole was completely unexpected," said Anderson.

Filled with old mining equipment, two cars, and a skeleton.

"We noticed that there were a number of bones, a small pile of bones, at the bottom there and the mammoth site personnel have identified that as an infant cow," said Springhetti.

But their job wasn't to sightsee, it was to map out the mineshaft.

"It goes about five hundred feet in one direction and about one hundred and fifty feet in the other direction," said Weaver.

Both sides ending in a collapse, making it unsafe to go further. As if being in the mines wasn't already unsafe.

"Not touching the ceiling, not touching the walls, looking around constantly to make sure that where we were walking wasn't going to be somewhere where the ceilings already cracking and there is a number of places in that mine where the ceiling has fractures. It's uncertain of how stable they are," said Weaver.

And on the surface, it might not be safe either.

Meade County is investigating reports of cracks in homes and more holes and depressions in neighborhood yards.

Thursday, May 7th, Paha Sapa Grotto will be hosting an online presentation about the identification of sinkholes and you can find the link

.