ABSTRACT: The meaning and definition of terms like resource,, reserve, mine rai, ore etc. Used in earth sciences differfrom engineer to academician and even politician.. This difference results In some sort of confusion andmisunderstanding. In this paper, the definition criteria of some terms like raw material, natural resource, mineral resource, mineral reserve,, mineable reserve and saleable reserve have been defined with examples..The last part of the paper includes Hasançelebi iron ore deposit as a case study