Somehow I can’t see a rare earth mine in Nebraska. Rare Earth Elememts seem to always be in arid or desert locations.
Coal was commercially mined in Missouri. Can’t think of any mines in Nebraska...just corn.
Coal was commercially mined by black workers brought in for that purpose in Southern Iowa. Opera star Simon Estes is descended from them.
https://mrdata.usgs.gov/mineral-resources/ree.html
More:
http://netnebraska.org/article/news/971924/elk-creek-niobium-mine-could-be-operational-late-2016
You will be vindicated to know that the mine is on a farm, and there is corn (or at least was when this test hole was being drilled!
It is, there are rare earth elements in NE.
This is either 1) a rare earth “pipe” caused by an asteroid strike, and the rare earths are from the asteroid. Or 2) possibly an extrusion on the southwest edge of the mid continent rift. (Which we do not see because it is buried by 600 feet or so of soil. (This is probably known by geologists, which I am not, so I mention both as possibilities. )
https://crustal.usgs.gov/projects/AGREED/Elk-Creek.html
and
https://crustal.usgs.gov/projects/AGREED/index.html
and
https://www.mindat.org/loc-219396.html
https://en.wikipedia.org/wiki/Midcontinent_Rift_System
“the rift’s eastern arm trends south to central lower Michigan. The western arm runs from Lake Superior southwest through portions of Wisconsin, Minnesota, Iowa, and Nebraska to northeastern Kansas.[1]”
The iron and copper deposits in Michigan and Minnesota are associated with the Mid continent rift.