NEW MEXICO GEOLOGIC REPOSITORY HELPS SOLVE COSMIC RIDDLES

For almost 30 years, salt deposits have hosted repositories for ecotoxic wastes. The most recent entry is the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico. The WIPP isolates wastes, mostly containing long-lived alpha-emitting radionuclides and chemically hazardous constituents from nuclear weapons research and production, in thick bedded salt 655m below the southeastern New Mexico desert. Underground mines have hosted astrophysical observatories since the 1960s. Examples are the Homestake gold mine in South Dakota, the Soudan iron ore mine in Minnesota, and the Creighton nickel mine in Ontario. A deep geologic repository, whether functioning as an afterthought to mineral extraction, or being excavated and operated just for waste disposal, can offer essentially the same infrastructure support as a single-purpose mine. To make even better use of the WIPP, without compromising its primary mission, the U.S. Department of Energy (DOE) has encouraged proposals to search for weakly interacting massive particles (WIMPS), to discriminate among neutrino flavors, and to study other hot topics in particle astrophysics and cosmology. The WIPP underground environment is eminently suited for such work. 655m of overburden shields against almost all cosmic radiation, and the salt host rock contributes less natural background radiation than virtually any other geologic medium.