The mining company that wants to extract a rare heat-resistant element from the ground under southeast Nebraska says a new report shows the deposit it plans to mine holds a significant amount of other rare elements. NioCorp Developments said Thursday that the latest analysis shows the amount of rare earth elements present where it plans to build the mine about 80 miles south of Omaha near the town of Elk Creek is the second-largest deposit in the United States. The Centennial, Colorado-based company estimates that there are 632.9 kilotons of rare earth elements there. Those elements are needed to make...