[Rockhounds] Giant Sinkhole Opens Up In South Dakota and Exposes Abandoned Mine

[Murowchick, James]

I taught Geology Field Camp for many years in the Black Hills, staying in Rapid City, so I'm quite familiar with the local geology.  If you look at the area (Black Hawk is a few miles NNW of Rapid City along I-90) in Google Earth, you can see the large gypsum mine to the south of Black Hawk that is currently operating, mining in the Gypsum Spring Formation, and maybe some in the Spearfish formation. Why anyone would think there's no gypsum under Black Hawk that could dissolve and produce a sinkhole is beyond me.  Sounds like some lawsuits will be coming.
Jim
James B Murowchick, Ph.D.
Professor Emeritus
Geochemistry & Mineralogy
UMKC Department of Earth & Environmental Sciences
420 Flarsheim Hall
5110 Rockhill Road
Kansas City, MO 64110
murowchickj at umkc.edu
816 235-2979



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Subject: [Rockhounds] Giant Sinkhole Opens Up In South Dakota and Exposes Abandoned Mine

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About a dozen houses in Black Hawk, South Dakota, were evacuated after a sinkhole opened under the Hideaway Hills development. The ground started to give way on the 27th of April and while it has left a lot of uncertainty for the locals, the situation has led to a unique discovery. The residential homes were built over an abandoned gypsum mine.

The authorities are already trying to figure out how this could’ve happened but in the meantime, explorers of a local caving group called *Paha Sapa
Grotto* decided to take a look inside.

The *Paha Sapa Grotto* is a subchapter of the National Speleological Society and is a world leader in caving science, exploration, and conservation. “When we heard about the sinkhole, we knew it was on a geological unit that could potentially have caves in it,” Nick Anderson, a member of Paha Sapa Grotto, told *Bored Panda*. “We also knew that county emergency management wouldn’t have much experience in this area so we offered to help to determine the scope of the problem.”

https://www.boredpanda.com/sinkhole-south-dakota-black-hawk-old-gypsum-mine/
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