Cave explorers were surprised the first time they saw Black Hawk sinkholes, mine

Black Hawk sinkhole

BLACK HAWK, S.D. — A few local men had the rare opportunity to delve deep into the Black Hawk sinkholes, saying they had no idea what they would find.

 “My first thought was oh my gosh these poor people living on top of this mine,” David Springhetti, a spelunker, or cave explorer said. “Because it was immediately obvious this was a big mine.” [David has fifty years of experience exploring caves – spelunking.]

Three men who have been able to get into the gypsum mine in Black Hawk’s Hideaway Hills subdivision are certain that the mine extends further than the 12 homes that have been evacuated.

Chris Pelczarski, spelunker, said “One thing to note is that we were not able to map the entire mine because a lot of the mine has collapsed. Also, the passages are sumped, they go under water, so that’s preventing us from mapping so it’s really, at this point, using our technique it’s impossible to know how extensive the mine is, but we know there is more.”

But until an engineer is able to completely map out the mine. The men can only assume the direction the mine goes and for how long.

Nick Anderson, a geologist, explains gypsum is a soluble mineral used in dry wall. The mineral and how it reacts has proved to be a challenge to work with.

“When it gets wet it obviously disintegrates … The cave is sumped and the water is actually super saturated with gypsum right now and in the recent rain and hailstorm they had come in as freshwater goes down into the cave its actually interacting with super saturated water allowing more gypsum to dissolve into the water exacerbating the problem of the cave slowly eroding away.” said Anderson.

One local, who lived in the same area of Black Hawk in the early fifties, recalls the neighborhood children playing in the same mine. He says the mine stretched the entirety of East Daisy Street, where the sinkholes are.

 “It was just mines is all they were, just holes in the ground, and we were just young kids,” Dennis Namanny, former Black Hawk resident, said. “We were only seven or eight years old. We used to come over here and play Indians and cowboys in them.”

Paha Sapa Grotto cave exploring group is hosting an online presentation with an expert geologist, Thursday at 7 p.m., to discuss the sinkholes and the mine.

You can view Paha Sapa’s presentation HERE.

Categories: Local News, South Dakota News