Sinkholes aren't anything new in the Black Hills
While they may not be common, sinkholes in the black hills aren't that unusual and Karl Emanuel has been studying them for years.
"2000 sinkholes just in Lawrence and Meade County," said Emanuel.
And that's mainly in undeveloped places.
"Whenever you get into a town they disappear and the reason they disappear is that they've been developed over the top of," said Emanuel. "So if an area is leveled for housing they push material into the holes, the holes disappear short term."
But Black Hawk is different.
"The ones that are in Black Hawk are a little more unusual because they are mine-related," said Emanuel.
The mine, running right under the interstate.
"Occasionally you can hear a truck going by on the freeway and you could feel it and that's scary," said Emanuel.
As cavers explored toward the east, they found themselves further underground.
"Which means it's just getting deeper and deeper as it goes off towards the freeway and the other side of the freeway, it's getting deeper and deeper and that's good thing from a stability standpoint," said Emanuel.
The Department of Transportation is still looking into the potential impact on the interstate.
Karl Emanuel will be hosting an online presentation with the Paha Sapa Grotto about the identification of sinkholes on Thursday, May 7th at 7 p.m. You can get to the website by clicking