Old photos show South Dakota mine that caused sinkhole wasn’t so hidden

Sinkhole connected to an old mine forced families to evacuate in 2020.(Screenshot from KELOLAND News |YouTube.)

Historic photographs from the 1960s show the US state of South Dakota operated a second gypsum mine beneath portions of the Black Hawk area that began to collapse in April 2020, forcing residents to evacuate their homes.

The photos, taken by the US Department of Agriculture and other agencies, contradict state claims it conducted surface mining only, according to Fox Rothschild LLP, who is seeking class action status in a lawsuit on behalf of 300 homeowners against the state.

The images also demonstrate that the whole neighbourhood may be in danger of collapse, not just the portion of Hideaway Hill that has done so already, the law firm noted.

“We have been digging to find these pictures, and what they show is the state was doing plenty of digging too – underground, in the northwest part of the subdivision” says Kathleen Barrow of Fox Rothschild.

“This is further proof that the state of South Dakota is responsible for the danger my clients are facing and the damage to their homes and neighbourhood.”

The photos show a mine entrance in the side of a cliff, not far from where the state was also conducting surface mining.

Hideaway Hill residents are suing the state, real estate agents, county officials and developers after public records revealed the Meade County Planning Board knew about the mine when it approved the Black Hawk housing development.

Old photos show South Dakota mine that caused sinkhole wasn't so hidden
GIS analysts say the sinkholes are developing because ground and surface water has been eating away at the gypsum, which is highly soluble in water. (Image courtesy of Fox Rothschild LLP.)

Meade County is investigating how the Meade County Planning Board approved the subdivision in 2002.

Most of the world’s gypsum, used in fertilizer, filler in paper and textiles and retarder in cement, is produced by surface mines.

In the US, gypsum is mined in about 19 states, including Oklahoma, Iowa, Nevada, Texas and California. Together, these five states account for about two-thirds of the country’s annual production of gypsum.