The race to the bottom has been narrowed to the Henderson molybdenum mine in Empire, Colorado, and the Homestake gold mine near Lead, South Dakota. On 21 July NSF announced awards of $500 000 apiece to the two finalist teams—culled from a field of eight—to produce conceptual designs for the Deep Underground Science and Engineering Laboratory (DUSEL).
Physicists want a deep underground lab to block out cosmic rays for studies of neutrinos, dark matter, nucleosynthesis, and proton decay. Scientists in other disciplines would use the multipurpose lab to study rock deformation and fluid flow, technologies for digging tunnels, and organisms that thrive at high temperature and pressure.
As mines, both sites offer preexisting excavation, infrastructure, and local know-how. Henderson, a relative newcomer to the site competition, is a modern, active mine that would need further excavation to provide sufficient overburden to shield physics experiments. The now-defunct Homestake is deeper, but...
