The Colorado company working to build a mine in southeast Nebraska to extract a rare heat-resistant element says it has purchased a key piece of land the mine would be built on. NioCorp Developments said Monday that it had purchased the land near Elk Creek where the proposed niobium mine would be built. The company didn’t release the price of the land, but the purchase came a week after NioCorp secured $10 million in funding from an investment fund. The proposed mine is expected to create over 400 jobs and require more than $1 billion in construction costs. NioCorp is working to raise enough money to build the mine.