Important Terms Mineral : A naturally occurring substance that has a definite chemical composition is a mineral. Rock : A rock is an aggregate of one or more minerals but without definite composition of a constituent of mineral. Ores : Rocks from which minerals are mined are known as ores. Although more than 2,800 types of minerals have been identified, only about 100 are considered ore minerals. Mining : Mining is the extraction of valuable minerals or other geological materials from the earth, usually from an orebody, lode, vein, seam, reef or placer deposit. Open Cast Mining : Open-pit, open-cast or open cut mining is a surface mining technique of extracting rock or minerals from the earth by their removal from an open pit or borrow. Shaft mining : Shaft mining is a form of underground mining using shafts driven vertically from the top down into the earth to access ore or minerals. Drilling : Drilling is a cutting process that uses a drill bit to cut a hole of circula...