The Miamisburg Environment Management Project (MEMP)

Mound was established as the first permanent Atomic Energy Commission facility in support of atomic weapons research when the site was first occupied in May 1948. The Dayton area had supported secret operations for the War Department during World War II. Known only as the Dayton Project, extensive chemical and metallurgical research had been done in the support of the Manhattan Engineering District. At the end of the war, that work was moved from facilities in Dayton to permanent facilities in Miamisburg.

http://www.globalsecurity.org/wmd/facility/mound.htm