GEOLOGIC WASTE ISOLATION – THE HARDLY KNOWN PRACTICAL SUCCESS STORY

Governments have isolated potentially and actually dangerous materials in geologic traps since at least 1959, and private companies since at least 1972. Categories of permanently disposed waste include radioactive and “non-radioactive” liquids and solids. A current U.S. example is the Waste Isolation Pilot Plant (WIPP) in Permian salt beds of the Delaware Basin near Carlsbad, NM, that has since 1999 disposed of -655m beneath the surface- some radioactive waste generated by our country’s nuclear weapons program. While salt is a favorite host rock for German and U.S. repositories, other countries have used and intend to use different disposal media such as igneous and metamorphic rocks, claystone, limestone, and confined aquifers.

Applied to waste disposal, mining geology reverses its “normal” perspective: from extracting valuable materials out of traps to inserting waste into traps. Since suitable geologic traps have confined highly flammable and toxic fluids for tens to hundreds of millions of years in the past, a similar (for fluids) or even better (for solids) performance can be reasonably expected for the future. Thus the “problem” of geologic isolation of dangerous materials was long ago solved by nature for natural materials and has again been solved by scientists and engineers for man-made materials by the application of geologic knowledge and mining experience.