But why would it be subject to eminent domain? The land still belongs to the federal government. I don't think you can seize a lease just because the government doesn't think you're making optimal use of it.
"The case arose in the context of condemnation by the city of New London, Connecticut, of privately owned real property, so that it could be used as part of a "comprehensive redevelopment plan." However, the private developer was unable to obtain financing and abandoned the redevelopment project, leaving the land as an _undeveloped empty lot._"