Underground Mining of Near-Surface Regolith on the Moon and Mars

Lunar and Martian regolith contain volatile elements within, and on the surfaces of, individual regolith particles. This appears to create potential resources for the manufacture of fuels for spacecraft, including satellites and vehicles on an orbit, transiting between orbits, or even transiting between planetary bodies. However, one of the problems with mining regolith for its volatiles content is that disturbance of the regolith, unavoidable during excavation and handling, may break some of the volatiles free, losing them and thereby reducing the recovered fraction of ore. Grade reduction by gaseous dissipation is seldom a problem on Earth, but could be a serious operational constraint on the Moon or Mars. The method described in this paper, Surface Caving, combines aspects of terrestrial caving techniques and trenchless pipelaying to create an innovative new mining method to minimize loss of volatiles ore during its acquisition.