Anglo American Annual Report 2012

ORE RESERVES AND MINERAL RESOURCESDEFINITIONSORE RESERVESAn ‘Ore Reserve’ is the economically mineable part of a Measured and/orIndicated Mineral Resource. It includes diluting materials and allowancesfor losses, which may occur when the material is mined. Appropriateassessments and studies have been carried out, and include considerationof and modification by realistically assumed mining, metallurgical, economic,marketing, legal, environmental, social and governmental factors. Theseassessments demonstrate at the time of reporting that extraction couldreasonably be justified. Ore Reserves are sub-divided in order of increasingconfidence into Probable Ore Reserves and Proved Ore Reserves.A ‘Proved Ore Reserve’ is the economically mineable part of a MeasuredMineral Resource. It includes diluting materials and allowances for losseswhich may occur when the material is mined. Appropriate assessments andstudies have been carried out, and include consideration of and modificationby realistically assumed mining, metallurgical, economic, marketing, legal,environmental, social and governmental factors. These assessmentsdemonstrate at the time of reporting that extraction could reasonablybe justified.A ‘Probable Ore Reserve’ is the economically mineable part of an Indicated,and in some circumstances, a Measured Mineral Resource. It includes dilutingmaterials and allowances for losses which may occur when the material ismined. Appropriate assessments and studies have been carried out, andinclude consideration of and modification by realistically assumed mining,metallurgical, economic, marketing, legal, environmental, social andgovernmental factors. These assessments demonstrate at the time ofreporting that extraction could reasonably be justified.MINERAL RESOURCESA ‘Mineral Resource’ is a concentration or occurrence of material of intrinsiceconomic interest in or on the Earth’s crust in such form, quality and quantitythat there are reasonable prospects for eventual economic extraction. Thelocation, quantity, grade, geological characteristics and continuity of a MineralResource are known, estimated or interpreted from specific geological evidenceand knowledge. Mineral Resources are sub-divided, in order of increasinggeological confidence, into Inferred, Indicated and Measured categories.A ‘Measured Mineral Resource’ is that part of a Mineral Resource for whichtonnage, densities, shape, physical characteristics, grade and mineral contentcan be estimated with a high level of confidence. It is based on detailed andreliable exploration, sampling and testing information gathered throughappropriate techniques from locations such as outcrops, trenches, pits,workings and drill holes. The locations are spaced closely enough to confirmgeological and grade continuity.An ‘Indicated Mineral Resource’ is that part of a Mineral Resource for whichtonnage, densities, shape, physical characteristics, grade and mineral contentcan be estimated with a reasonable level of confidence. It is based onexploration, sampling and testing information gathered through appropriatetechniques from locations such as outcrops, trenches, pits, workings and drillholes. The locations are too widely or inappropriately spaced to confirmgeological and/or grade continuity but are spaced closely enough forcontinuity to be assumed.An ‘Inferred Mineral Resource’ is that part of a Mineral Resource for whichtonnage, grade and mineral content can be estimated with a low level ofconfidence. It is inferred from geological evidence and assumed but notverified geological and/or grade continuity. It is based on informationgathered through appropriate techniques from locations such as outcrops,trenches, pits, workings and drill holes which may be limited or of uncertainquality and reliability.COMMON TERMINOLOGYDepositA deposit is a concentration (or occurrence) of material of possible economic interest, in or on the earth’s crust, that may include mineralized material thatcannot be estimated with sufficient confidence to be classified in the Inferred category. Portions of a deposit that do not have reasonable and realisticprospects for eventual economic extraction are not included in a Mineral Resource.GradeThe relative quantity, percentage or quality, of a metal or mineral/diamond content estimated to be contained within a deposit.Cut-off (grade)A grade (see grade units) above which the Mineral Resource or Ore Reserve is reported as being potentially economic.Run of Mine (ROM)The mined material delivered from the mine to the processing plant is called run-of-mine, or ROM. This is the raw unprocessed mineralised material andincludes mineralised rock and varying amounts of internal and external contamination (either unmineralised rock or mineralised material below the cut-offgrade). Contamination is usually introduced by the mining process to ensure all the mineralised material is mined or to provide a minimum mining height. ROMmaterial can have highly variable moisture content and maximum particle size.Inferred (in LOM Plan)/Inferred (ex. LOM Plan)Inferred (in LOM Plan): Inferred Resources within the scheduled Life of Mine Plan (LOM Plan).Inferred (ex. LOM Plan): The portion of Inferred Resources with reasonable prospects for eventual economic extraction not considered in the Life of Mine Plan(LOM Plan).Mine LifeThe extraction period in years for scheduled Ore Reserves comprising Proved and Probable Reserves only.This is the current view of the period of production based on current Ore Reserve tonnes and average annual planned production rate.Life of Mine PlanA design and costing study of an existing operation in which appropriate assessments have been made of realistically assumed geological, mining,metallurgical, economic, marketing, legal, environmental, social, governmental, engineering, operational and all other modifying factors, which are consideredin sufficient detail to demonstrate at the time of reporting that extraction is reasonably justified.228 Anglo American plc Annual Report 2012