CPC Subgroup
E21C 41/22 for ores, e.g. mining placers
Full Title
Methods of underground or surface mining (E21C45/00 takes precedence); Layouts therefor (for peat E21C49/00) > Methods of underground mining (winning machines therefor E21C25/00 - E21C39/00); Layouts therefor > for ores, e.g. mining placers