two groups headlined “resources”and “reserves”. Descriptive adjectives give three classes of resource(inferred, indicated and measured)and two classes of reserve (probable and proved).
Which term should be used in a particular case hinges on the quantity, quality and scope of available information. When the information is mainly geological, materials that offer a reasonable chance of being worked at a profit can be called “mineral resources” and put into one of the three sub categories. Resources in the lowest sub category (“inferred”) are real enough but, perhaps because of geological uncertainties or gaps in the sampling, do not command a high level of confidence where tonnage, grade and other important parameters are concerned. With measured resources, they do.
Mineral Resources are sub-divided, in order of increasing geological confidence, into Inferred, Indicated and Measured categories. An Inferred Mineral Resource has a lower level of confidence than that applied to an Indicated Mineral Resource. An Indicated Mineral Resource has a higher level of confidence than an Inferred Mineral Resource but has a lower level of confidence than a Measured Mineral Resource