DOT investigating if Gypsum mine runs underneath I-90
SOUTH DAKOTA, — The State Transportation Department has decided to use what’s called “Electrical Resistivity”, to determine if the gypsum mine runs underneath Interstate-90.
DOT officials say they’re confident there’s nothing under the highway, but is investigating as a precaution. The department has no historical records of a mine in that location.
“We’re fairly confident that we’re okay, however fairly confident is not enough,” said Engineer Mike Carlson. “So we want to make that our interstate is safe, which we’re almost positive it is.”
DOT engineers in Rapid City are working with an expert from California on the investigation.