Terms and Standards used for Mineral Deposits Classification


Terms and Standards used for Mineral Deposits Classification

The terms and standards used for the classifications of mineral deposits are described below.

Competence – It requires that the Public Report be based on work that is the responsibility of suitably qualified and experienced persons who are subject to an enforceable professional code of ethics (the Competent Person).

Competent Person – A Competent Person is a mineral industry professional, defined as a corporate member, registrant or licensee of a recognized professional body (including mutually recognized international professional organizations) with enforceable disciplinary processes including the powers to suspend or expel a member.

A competent person must have a minimum of five years relevant experience in the style of mineralization or type of deposit under consideration and in the activity which that person is undertaking.

Recognized Professional Organizations (RPO) and classes of membership under the standard, which meet these requirements, are listed in the standards or on their websites.

If the Competent Person is preparing documentation on Exploration Results, the relevant experience must be in exploration. If the Competent Person is estimating, or supervising the estimation of Mineral Resources, the relevant experience must be in estimation, assessment, and evaluation of Mineral Resources. If the Competent Person is estimating or supervising the estimation of Ore Reserves, the relevant experience must be in the estimation, assessment, evaluation and economic extraction of Ore Reserves.

CRIRSCO – CRIRSCO provides an international forum that enables countries to ensure consistency of their reporting standards.  It is an international advisory body without legal authority and relies on its constituent members to ensure regulatory and disciplinary actions at a National level. It was formed in 1994 under the auspices of the Council of Mining and Metallurgical Institutes (CMMI). It was established as grouping of representatives of organizations that are responsible for developing mineral reporting codes and guidelines in Australasia (JORC), Canada (CIM), Chile (National Committee, from 2004), Europe (PERC), Russia (NAEN/OERN, from 2011), South Africa (SAMREC), and the USA (SME).

In 2002 CMMI was disbanded. CRIRSCO is now a partner of, and partly funded by, ICMM, the International Council of Mining and Metals, which is a worldwide consortium of mineral companies and mining industry associations whose purpose is promoting high environmental and ethical standards in the industry.

Economic Demonstrated Resources – Economic Demonstrated Resources (EDR) are the resources judged to be economically extractable and for which the quantity and quality are computed partly from specific measurements, and partly from extrapolation for a reasonable distance on geological evidence. EDR provides longer perspectives of what is likely to be available for mining. This is a key national reporting category in which several categories of the standard are aggregated (Proved Reserves + Probable Reserves + Measured Resources + Indicated Resources). EDR provides a reasonable and objective indication of what is likely to be available for mining in the long term.

Exploration Results – Exploration Results include data and information generated by mineral exploration programmes that might be of use to investors but which do not form part of a declaration of Mineral Resources or Ore Reserves.

Exploration Target – An Exploration Target is a statement or estimate of the exploration potential of a mineral deposit in a defined geological setting where the statement or estimate, quoted as a range of tons and a range of grade (or quality), relates to mineralization for which there has been insufficient exploration to estimate a  Mineral Resource.

Feasibility Study – A Feasibility Study is a comprehensive technical and economic study of the selected development option for a mineral project that includes appropriately detailed assessment of applicable Modifying Factors together with any other relevant operational factors and detailed financial analysis that are necessary to demonstrate at the time of reporting that extraction is reasonably justified (economically mineable). The results of the study may reasonably serve as the basis for a final decision by a proponent or financial institution to proceed with, or finance, the development of the project. The confidence level of the study will be higher than that of a Pre-Feasibility Study.

Indicated Mineral Resource – An ‘Indicated Mineral Resource’ is that part of a Mineral Resource for which quantity, grade (or quality), densities, shape and physical characteristics are estimated with sufficient confidence to allow the application of Modifying Factors in sufficient detail to support mine planning and evaluation of the economic viability of the deposit.

Geological evidence is derived from adequately detailed and reliable exploration, sampling and testing gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes, and is sufficient to assume geological and grade (quality) continuity between points of observation where data and samples are gathered.

An Indicated Mineral Resource has a lower level of confidence than that applying to a Measured Mineral Resource and may only be converted to a Probable Ore Reserve.

Inferred Mineral resource – An ‘Inferred Mineral Resource’ is that part of a Mineral Resource for which quantity and grade (or quality) are estimated on the basis of limited geological evidence and sampling. Geological evidence is sufficient to imply but not verify geological and grade (or quality) continuity. It is based on exploration, sampling and testing information gathered through appropriate techniques from locations such as outcrops, trenches, pits, workings and drill holes.

An Inferred Mineral Resource has a lower level of confidence than that applying to an Indicated Mineral Resource and must not be converted to an Ore Reserve. It is reasonably expected that the majority of Inferred Mineral Resources could be upgraded to Indicated Mineral Resources with continued exploration.

Materiality – It requires that a Public Report contains all the relevant information that investors and their professional advisers would reasonably require, and reasonably expect to find in the report, for the purpose of making a reasoned and balanced judgement regarding the Exploration Results, Mineral Resources or Ore Reserves being reported. Where relevant information is not supplied an explanation must be provided to justify its exclusion. A general relationship between Exploration Results, Mineral Resources or Ore (Mineral) Reserves is shown in Fig 1.

Exploration  results of minerals

Fig 1 General relationship between Exploration Results, Mineral Resources or Ore Reserves

Measured Mineral Resource – A ‘Measured Mineral Resource’ is that part of a Mineral Resource for which quantity, grade (or quality), densities, shape, and physical characteristics are estimated with confidence sufficient to allow the application of Modifying Factors to support detailed mining planning and final evaluation of the economic viability of the deposit.

Geological evidence is derived from detailed and reliable exploration, sampling and testing gathered through appropriate techniques from locations  such as outcrops, trenches, pits, workings and drill holes, and is sufficient to confirm geological and grade (or quality) continuity between points of observation where data and samples are gathered.

A Measured Mineral Resource has a higher level of confidence than that applying to either an Indicated Mineral Resource or an Inferred Mineral Resource. It may be converted to a Proved Ore Reserve or under certain circumstances to a Probable Ore Reserve.

Mineral Resource – A ‘Mineral Resource’ is a concentration or occurrence of solid material of economic interest in or on the Earth’s crust in such form, grade (or quality) that there are reasonable prospects for eventual economic extraction. The location, quantity, grade (or quality), continuity and other geological characteristics of a Mineral Resource are known, estimated or interpreted from specific geological evidence and knowledge, including sampling. Mineral Resources are sub divided, in order of increasing geological confidence, into Inferred, Indicated and Measured categories.

Modifying Factors – These are considerations used to convert Mineral Resources to Ore Reserves. These include, but are not restricted to, mining, processing, metallurgical, infrastructure, economic, marketing, legal, environmental, social and governmental factors.

National Reporting Organizations – National Reporting Organizations (NRO) are bodies which develop and are responsible for mineral reporting codes, standards, and guidelines for a country or a group of countries.

Ore Reserve – An ‘Ore Reserve’ is the economically mineable part of a Measured and/or Indicated Mineral Resource. It includes diluting materials and allowances for losses, which may occur when the material is mined or extracted and is defined by studies at Pre- Feasibility or Feasibility level as appropriate that include application of the Modifying Factors. Such studies demonstrate that, at the time of reporting, extraction could reasonably be justified.

The reference point at which Reserves are defined, usually the point where the ore is delivered to the processing plant, must be stated. It is important that, in all situations where the reference point is different, such as for a saleable product, a clarifying statement is included to ensure that the reader is fully informed as to what is being reported.

Preliminary Feasibility Study – A Preliminary Feasibility Study (Pre-Feasibility Study) is a comprehensive study of a range of options for the technical and economic viability of a mineral project that has advanced to a stage where a preferred mining method, in the case of underground mining, or the pit configuration, in the case of an open pit, is established and an effective method of mineral processing is determined. It includes a financial analysis based on reasonable assumptions on the Modifying Factors and the evaluation of any other relevant factors which are sufficient for a Competent Person, acting reasonably, to determine if all or part of the Mineral Resources may be converted to an Ore Reserve at the time of reporting. A Pre- Feasibility Study is at a lower confidence level than a Feasibility Study.

Probable Ore Reserve – A ‘Probable Ore Reserve’ is the economically mineable part of an Indicated, and in some circumstances, a Measured Mineral Resource. The confidence in the Modifying Factors applying to a Probable Ore Reserve is lower than that applying to a Proved Ore Reserve.

Proved Ore Reserve – A ‘Proved Ore Reserve’ is the economically mineable part of a Measured Mineral Resource. A Proved Ore Reserve implies a high degree of confidence in the Modifying Factors.

Public Reports – These are reports prepared for the purpose of informing investors or potential investors and their advisers on Exploration Results, Mineral Resources or Ore Reserves. They include, but are not limited to, annual and quarterly company reports, press releases, information memoranda, technical papers, website postings and public presentations.

Scoping Study – A Scoping Study is an order of magnitude technical and economic study of the potential viability of Mineral Resources. It includes appropriate assessments of realistically assumed Modifying Factors together with any other relevant operational factors that are necessary to demonstrate at the time of reporting that progress to a Pre Feasibility Study can be reasonably justified.

Subeconomic Demonstrated Resources – Subeconomic Demonstrated Resources are similar to Economic Demonstrated Resources in terms of certainty of occurrence and, although considered to be potentially economic in the foreseeable future, these resources are judged to be Subeconomic at present. These resources are also at a proved and probable level of certainty.

Transparency – It requires that the reader of a Public Report is provided with sufficient information, the presentation of which is clear and unambiguous, to understand the report and not be misled by this information or by omission on material information that is known to the Competent Person.

United Nations Framework Classification – The principal objective of the United Nations Framework Classification (UNFC) is to provide a method of standardization for regulatory and statistical purposes, both governmental and intergovernmental. Its development was begun in the 1990s by UNECE and proceeds under a global mandate from the UN Economic and Social Council. UNFC classification is more complex and more extensive than CRIRSCO’s. It covers oil and gas resources as well as solid minerals. UNFC has a very different purpose from the codes and standards which are aligned with CRIRSCO. Key definitions and terminology used for reporting solid mineral reserves and resources (and exploration results) within these two classification systems have been aligned through extensive co-operative efforts between CRIRSCO and UNECE since 1999.

UNFC is a generic classification framework for solid minerals and oil and gas. It is an important tool for global and governmental communication. It is not a public reporting standard. There are no underlying principles as there are in a reporting standard. It has no recognition by market regulators. It is a classification and carries no concept of any certification of competency. It does not define a Competent Person who takes personal responsibility.