Classification
The Organisation for Economic Co-operation and Development / Nuclear Energy Agency (“OECD/NEA”) and the International Atomic Energy Agency (“IAEA”) prepare periodical updates (usually every two years) of world uranium ‘resources’. These updates are published in Uranium Resources, Production and Demand, commonly known as the ‘Red Book’. The latest edition (OECD/NEA & IAEA, 2008) gives data as at 1 January 2007. It should be noted that the OECD/NEA ‘resources’ are not necessarily consistent with and should not be confused with Mineral Resources as defined by JORC (2004). The OECD/NEA primarily reports ‘Identified Resources’ which consist of ‘Reasonably Assured Resources’ (“RAR”) and ‘Inferred Resources’, recoverable at a cost of less than US$130/kgU.
National agencies from some 40 countries provide estimates of uranium ‘resources’ and other data in response to questionnaires distributed by the NEA/IAEA. For the NEA/IAEA classification scheme, ‘resource estimates’ are divided into the following categories that reflect the level of confidence in the quantities reported. The ‘resources’ are further separated into categories based on the cost of production. All ‘resource’ estimates are expressed in terms of metric tonnes of recoverable uranium (U) rather than uranium oxide (U3O8). Estimates refer to quantities of uranium recoverable from mineable material, unless otherwise noted. ‘Resources’ are divided, according to different confidence levels of occurrence, into the four categories discussed below.
- Reasonably Assured Resources (“RAR”) refers to uranium that occurs in known mineral deposits of delineated size, grade and configuration such that the quantities which could be recovered within the given production cost ranges with currently proven mining and processing technology, can be specified. Estimates of tonnage and grade are based on specific sample data and measurements of the deposits and on knowledge of deposit characteristics. RAR have a high assurance of existence. Unless otherwise noted, RAR are expressed in terms of quantities of uranium recoverable from mineable ore. RAR are approximately comparable to Measured and Indicated Resources under the JORC Code.
- Inferred Resources (“IR”) refer to uranium, in addition to RAR, that is inferred to occur based on direct geological evidence, in extensions of well-explored deposits, or in deposits in which geological continuity has been established but where specific data, including measurements of the deposits, and knowledge of the deposit’s characteristics, are considered to be inadequate to classify the resource as RAR. Estimates of tonnage, grade and cost of further delineation and recovery are based on such sampling as is available and on knowledge of the deposit characteristics as determined in the best known parts of the deposit or in similar deposits. Less reliance can be placed on the estimates in this category than on those for RAR. Unless otherwise noted, IR are expressed in terms of quantities of uranium recoverable from mineable ore. IR are approximately comparable to Inferred Resources under the JORC Code.
The resources are further separated into categories based on the cost of production:
- less than US$40/kg U;
- less than US$80/kg U; and
- less than US$130/kg U.
This classification is used for national and international resource estimates. The JORC code applies to reporting individual deposits by mining companies.