We don't have a database of abandoned uranium mines, unfortunately, although we do have items on specific abandoned mine sites.
If you use the keywords "uranium mines [your state]" and "uranium directory [your state]" in our catalog, the older items you see as a result may be useful. Being older, they may provide locations, etc. for mines that are now no longer in operation. Not as functional as a database, but the older directories and maps in particular can provide details not found elsewhere. For example: Location of uranium mines in the Powder River Basin, 1930-1979, Map Room Book Collection (Floor 1) G4262.P62H2 195- .L6.
Certainly the EPA has a lot of information out there, especially on uranium mines in Arizona; the DOE is another resource. For the mines themselves, it may be useful to focus on publications from the USGS and the state geological surveys/abandoned mine agencies. A basic Google search using "uranium mines" and [your state] should bring up the relevant state agency. The following may be helpful examples:
Uranium resources and environmental investigations, USGS; includes a few data sets.
Wyoming Dept. of Environmental Quality is responsible for Abandoned Mine Lands--I didn't find much on their website but they would be worth contacting. Same for the Wyoming Geological Survey.
Thanks, Lisa D