EL
Υπόγεια εκμετάλλευση σκληρό ροκ εξόρυξη τρύπα δόξα υπόγεια εξόρυξη
EN
Underground hard-rock mining refers to various underground mining techniques used to excavate "hard" minerals, usually those containing metals, such as ore containing gold, silver, iron, copper, zinc, nickel, tin, and lead.
Wikipedia
