Deep in a former iron mine in what is now a Minnesota state park, scientists and government officials today (July 20) wielded pickaxes to chip away, at least symbolically, at the mysteries surrounding the subatomic particles known as neutrinos.

On Tuesday, July 20, 1999, scientists and officials of the U.S. Department of Energy, the State of Minnesota, DOE’s Fermi National Accelerator Laboratory and the University of Minnesota will break ground in a former iron mine, now a Minnesota state park.