It can be found at Blackwater Mine, in a room near Freddie Lang at the back of the mine, next to a terminal and some lab equipment. It is in a small cave laboratory to the northwest after entering the main catwalk area.
Foreman Hibbs: Blackwater Mine has changed a lot over the years. Plenty of you already know what happens when a mine tunnel hits groundwater, so the pumps shouldn't be too surprising. But yeah, just to put any rumors to bed, we're also trying some new ways of getting at those precious rocks. And yes, it involves melting the Uranium while it's still underground and siphoning it up. Sure beats hauling it by hand, if it works. Now don't think that means any of you are getting extra time-off. Stop listening to this and get back to work.