CPC Subgroup
E21F 17/16 Modification of mine passages or chambers for storage purposes, especially for liquids or gases (storing fluids in natural or artificial cavities or chambers in the earth B65G5/00)
Full Title
Methods or devices for use in mines or tunnels, not covered elsewhere (mine lighting F21, H05B) > Modification of mine passages or chambers for storage purposes, especially for liquids or gases (storing fluids in natural or artificial cavities or chambers in the earth B65G5/00)