Mineral resource classification is used to organize information about ores and other mineral deposits of economic value.


Deposits are classified based on the level of geological knowledge and economic feasibility, and is used as a guide for industrial planning and financing. Mineral deposits can be classified into three main groups:   

  • Mineral prospects
    A mineral prospect has the least level of confidence and refers to a deposit of geological interest that may not be of economic value.
  • Mineral resources
    A mineral resource is a mineral concentration which is known, estimated and interpreted from specific geological evidence and knowledge and with reasonable prospects for economic extraction.
  • Ore reserves
    An ore reserve is an economical minable part of a mineral resource where appropriate assessments and studies have been carried out to show that the deposit can be mined at a profit after consideration of all factors impacting a mining operation.

There are several classification systems worldwide, however the Canadian CIM classification (see NI 43-101) and the Australasian Joint Ore Reserves Committee Code (JORC Code) are defined as standards. The JORC-code classifies resources and reserves in more detailed sub-groups:   

  • An inferred mineral resource is a deposit which has been sampled (usually by drilling) to a point at which an estimate of its grade and tonnage is made at low confidence. Generally this is very approximate and subject to uncertainties.
  • An indicated mineral resource is a deposit in which tonnage, density; shape, physical characteristics, grade and mineral content can be estimated with a reasonable level of confidence. However, the continuity of the deposit is not verified.
  • A measured mineral resource is an economic deposit with a high level of geological confidence and confirmed geological continuity. The deposit has undergone enough sampling that a 'competent person' (which is defined by the JORC-code) has declared it to be an acceptable documented resource estimate.
  • A probable ore reserve is the economically minable part of an indicated, and in some circumstances, a measured mineral resource.  The level of confidence is sufficient as a basis for decision on developing a deposit.
  • A proven ore reserve is an economically minable part of a measured mineral resource and therefore holds the highest level of geological confidence. The deposit is also proved minable in terms of economic, mining, metallurgic, marketing, legal, social and governmental factors.

    Introduction Minerals

    Mineral resources

    Mineral prospecting and exploration  

    Mineral extraction