Organizations responsible for developing mineral reporting codes and guidelines:
- Australia: JORC
- Chile: National Committee
- Canada: CIM
- South Africa: SAMREC
- USA: SME
- United Kingdom: National Committee
- Western Europe: IGI and EFG
The former Soviet system for classification of reserves and resources, developed in 1960 and revised in 1981, is still used today in Russia and other CIS republics. Essentially, it divides mineral concentrations into seven categories, in three major groups, based on the level of exploration performed: fully explored reserves or resources (A, B, C1), evaluated reserves or resources (C2) and prognostic resources (P1, P2, P3).
Reserves and resources that can be matched to the usual international categories are classified into five main classes designated by the symbols
Capital letters are used to designate ores that are economic. Sometimes, the same group of letters are written in lower case when the mineralization is considered subeconomic. A simple classification into classified (A,B,C1,C2) “balansovye” (balance) = commercially exploitable reserves and unclassified “zabalansovye” (out-of-balance) = uneconomic resources is used. Synonyms of “balansovye” and “zabalansovye” which are often met, and used descriptively, are “konditsionniye” (conditioned) and “nekonditsionniye” (unconditioned).
Category A The reserves in place are known in detail. The boundaries of the deposit have been outlined by trenching, drilling, or underground workings. The quality and properties of the ore are known in sufficient detail to ensure the reliability of the projected exploitation.
Category B The reserves in place have been explored but are only known in fair detail. The boundaries of the deposit have been outlined by trenching, drilling, or underground workings. The quality and properties of the ore are known in sufficient detail to ensure the basic reliability of the projected exploitation.
Category C1 The reserves in place have been estimated by a sparse grid of trenches, drill holes or underground workings. This category also includes reserves adjoining the boundaries of A and B reserves as well as reserves of very complex deposits in which the distribution cannot be determined even by a very dense grid. The quality and properties of the deposit are known tentatively by analyses and by analogy with known deposits of the same type. The general conditions for exploitation are known. The ore tonnage is derived from estimates of strike length, dip length and average thickness of the ore body. Allowance for barren blocks may be made statistically.
Category C2 These reserves are based on an extremely loose exploration grid, with little data. The limits of the orebody are defined mainly by extrapolation within known geological structures, and from comparison with other similar deposits in the vicinity. The grade and mineral properties of the orebody are determined from core samples and comparison with similar mineral deposits in the area. The reserves have been extrapolated from limited data, sometimes only a single hole. This category includes reserves that are adjoining A, B, and C1 reserves in the same deposit.
Category P1 Resources in the P1 category may extend outside the actual limits of the ore reserves defined in the C2 category. The outer limits of P1-type resources are determined indirectly by extrapolating from similar known mineral deposits in the area. P1 is the main source from which C2 reserves can be increased.
Category P2 These resources represent possible mineral structures in known mineral deposits or ore-bearing regions. They are estimated based on geophysical and geochemical data. Morphology, mineral composition and size of the orebody are estimated by analogy with similar mineralized geologic structures in the area.
Category P3 Any potential ore-bearing deposits are classified as resources in the P3 category. The presence of these resources relies on the theoretical definition of a “favourable geological environment”. Resource figures are derived from figures of similar deposits in the region.
Estimates of Prognostic Resources (P1, P2, and P3) routinely depend on assumptions and projections regarding the probable dimensions (length, width and depth) and grade of the deposit that are subject to confirmation by more detailed investigations.
Reconciliation of Russian and International Reporting Systems A broad equivalence between the classifications may be presented as:- Russian International reporting Code, JORC, etc
A,B Proved Reserve / Measured Resource
C1 Proved or Probable Reserve / Indicated Resource
C2 Probable reserve / Indicated Resource / Inferred Resource
P1 Inferred Resource
P2 Reconnaissance Mineral Resource (or UNFC code 334)
P3 no equivalent