Same Drillholes. Same Deposit. Different Reserve. Can two geologists use the same drillhole data and arrive at different iron ore reserves? YES..and that's why You Guys must read it Clear The difference does not necessarily come from the data itself, but from the geological and modelling decisions applied to that data. Several choices can influence the final outcome: 1. Geological Domaining Different interpretations of lithology, mineralization continuity, weathering, and geological boundaries can produce different estimation domains. 2. Variogram & Spatial Continuity Variogram parameters determine how sample information is interpreted spatially. Range, nugget, sill, anisotropy, and direction can significantly influence block estimates. 3. Search Strategy Search ellipse orientation, search radius, minimum samples, maximum samples, and sectoring determine which samples contribute to each block. 4. Estimation Method IDW, Ordinary Kriging, or other estimators can produce different grade distributions, even when using the same database. 5. Block Size & Density Block dimensions influence selectivity and grade smoothing, while density directly affects tonnage. 6. Modifying Factors The resource model is only the starting point. Pit design, slope constraints, cut-off grade, dilution, ore loss, mining recovery, processing recovery, costs, and market assumptions ultimately influence the conversion from resource to reserve. Therefore: > Same data ≠ Same interpretation > Same interpretation ≠ Same model > Same model ≠ Same reserve This is why resource and reserve estimation is not simply an exercise in applying an estimation algorithm. It requires geological understanding, statistical discipline, modelling judgment, and realistic mineability assumptions. The objective is not to produce the largest number. The objective is to produce a reserve that is defensible, realistic, economically viable, and mineable. Better Geology → Better Model → Better Reserve → Better Mine. #IronOre #MineralReserve #ResourceEstimation #GeologicalModelling #Geostatistics #BlockModel #ReserveCalculation #Mining #MinePlanning #Geology #IronOreMining #Reconciliation