Black Hawk Sinkhole And Abandoned Mine No Threat To I-90

RAPID CITY, S.D. (AP) – The South Dakota Dept of Transportation says a sinkhole in the Black Hills community of Black Hawk, west of Rapid City, that forced the abandonment of a dozen homes this spring does not pose a danger to nearby Interstate 90.

       The department hired Rapid City-based FMG Engineering to look for underground abnormalities after the sinkhole exposed the fact that part of the Hideaway Hills development was built over an abandoned gypsum mine.

       FMG reported it didn’t find any voids under the freeway with borings revealing that none of the areas of abnormalities identified in initial investigations were voids or anything else that causes concern for the integrity of the interstate.

      Both the South Dakota Dept of Transportation and its federal counterpart “are confident there is no threat to I-90 because of the mine discovery.”