Mineral resources vs Indicated CategorieMineral resources
A 'Mineral Resource' is a concentration or occurrence of material of intrinsic economic interest in or on the earth's crust in such form, quality and quantity that there are reasonable prospects for eventual economic extraction.Mineral Resources are further sub-divided, in order of increasing geological confidence, into inferred, .
Inferred Mineral Resource is that part of a mineral resource for which tonnage,grade and mineral content can be estimated with a low level of confidence. It is inferred from geological evidence and assumed but not verified geological/or grade continuity. It is based on information gathered through appropriate techniques from location such as outcrops, trenches,pits, workings and drill holes which may be of limited or uncertain quality and reliability.
Indicated resources are simply economic mineral occurrences that have been sampled (from locations such as outcrops, trenches, pits and drillholes) to a point where an estimate has been made, at a reasonable level of confidence, of their contained metal, grade, tonnage, shape, densities, physical characteristics.[2]
Measured resources are indicated resources that have undergone enough further sampling that a 'competent person' (defined by the norms of the relevant mining code; usually a geologist) has declared them to be an acceptable estimate, at a high degree of confidence, of the grade, tonnage, shape, densities, physical characteristics and mineral content of the mineral occurrence.
Resources may also make up portions of a mineral deposit classified as a mineral reserve, but:
- Have not been sufficiently drilled out to qualify for Reserve status; or
- Have yet to meet all criteria for Reserve status[2]
Mineral reserves/ Ore Reserves
Mineral reserves are resources known to be economically feasible for extraction. Reserves are either Probable Reserves or Proven Reserves.
A Probable Ore Reserve is the economically minerable part of Indicated, and in some circumstances,a Measured Mineral Resource. It includes diluting material and allowances for losses which may occur when the material is mined. A Probable Ore Reserve has a lower level of confidence than a Proved Ore Reserve but is of sufficient quality to serve as the basis for decision on the development of deposit.
A Proven Ore Reserve is economically minerable part of a Measured Mineral Resource. It includes diluting materials and allowances for losses which occur when the material is mined.
A Proven Ore Reserve represents the highest confidence category of reserve estimate. The style of mineralization or other factors could mean that proved Ore Reserves are not achievable in some deposits.
Generally the conversion of resources into reserves requires the application of various modifying factors, including:
- mining and geological factors, such as knowledge of the geology of the deposit sufficient that it is predictable and verifiable; extraction and mine plans based on ore models; quantification of geotechnical risk—basically, managing the geological faults, joints, and ground fractures so the mine does not collapse; and consideration of technical risk—essentially, statistical and variography to ensure the ore is sampled properly:
- metallurgical factors, including scrutiny of assay data to ensure accuracy of the information supplied by the laboratory—required because ore reserves are bankable. Essentially, once a deposit is elevated to reserve status, it is an economic entity and an asset upon which loans and equity can be drawn—generally to pay for its extraction at (hopefully) a profit;
- economic factors;
- environmental factors;
- marketing factors;
- legal factors;
- governmental factors;and
- social factors[2]
- political factors such as land ownership and laws in the country. e.g.in Zimbabwe the government gets 515[clarification needed] of the profit.