Stuart and Tonya Junker loved their quiet neighborhood near South Dakota’s Black Hills — until the earth began collapsing around them, leaving them wondering if their home could tumble into a gaping hole. They blame the state for selling land that became the Hideaway Hills subdivision despite knowing it was perched above an old mine. Since the sinkholes began opening up, they and about 150 of their neighbors sued the state for $45 million to cover the value of their homes and legal costs. “Let’s just say it’s really changed our lives a lot,” Tonya Junker said. “The worry, the not sleeping, the ‘what if’ something happens. It’s all of it, all of the above.” Sinkholes are fairly common, due to collapsed caves, old mines or dissolving material, but the circumstances in South Dakota stand out, said Paul Santi, a professor of geological engineering at the Colorado School of Mines. The combination of such large sinkholes endangering so many homes makes the Hideaway Hills situation one to remember. “I can say just from having taught classes about case histories with geologic problems that this would be a case that will end up in textbooks,” Santi said. Crews built Hideaway Hills, located a few miles northwest of Rapid City, from 2002 to 2004 in an area previously owned by the state where the mineral gypsum was mined for use at a nearby state-owned cement plant. Attorney Kathy Barrow, who represents residents who live in 94 subdivision homes, said the state sold the surface but held on to the subsurface, and it did not disclose it had removed the soil’s natural ability to hold up the surface. Some of the land slightly sunk over time after the subdivision was built, and a hole opened up beneath a back porch, but the situation escalated after a large sinkhole opened up in 2020 near where a man was mowing his lawn. That prompted residents to connect with Barrow and testing revealed a large, improperly sealed mine beneath the northeastern part of the subdivision, and a 40-foot-deep (12-meter-deep) pit mine in another corner of the neighborhood, Barrow said. Since that first giant collapse, more holes and sinkings have appeared and there are now “too many to count,” Barrow said. The unstable ground has affected 158 homes plus destabilized roads and utilities. In one spot, an old truck can be seen in a hole beneath a house porch, still resting where a landowner pushed it into a mine cavern in the 1940s, Barrow said. The area near the 2020 collapse has been vacated and gated off, but people still live in many of the other homes, usually because they can’t afford to leave. Residents are panicked but stuck, Barrow said. “They’re worried about school buses falling into a hole. They worry about their houses collapsing on their children in their beds at night,” Barrow said. “I mean, you spend your whole life putting money and building equity in your home. It’s your most prized asset, and these people’s asset had become not only worthless but almost a negative because they’re dangerous to live in.” An attorney for the state declined to comment, but the state has asked a judge to dismiss the case. In court documents, the state entities being sued said they “would like to […]