The effect of accumulation in 2D estimates in phosphatic ore

Abstract

The geological modeling of stratiform deposits can become very complex, often making use of geological envelopes of small thickness and requiring the use of subblocks (based on Cartesian coordinates) to produce a coherent block model. However, geological events after the formation of the deposit (folds, faults, etc.) can change the direction of spatial continuity of certain attributes, with the mixing of samples belonging to different formation eras (in the case of stratiform deposits) in the same elevation. This study presents a solution for deposits with stratigraphic grades combined with samples of different origins. The solution is a two-dimensional estimate obtained by accumulating the thicknesses of P 2 O 5 in a phosphate deposit (as compared to traditional statistical analysis in three dimensions).Keywords: accumulation, ordinary kriging, phosphate. (dobras, falhas, etc.) Resumo A modelagem geológica de depósitos estratiformes pode-se tornar muito complexa, muitas vezes fazendo uso de envelopes geológicos de pequena espessura e exigindo o uso de sub-blocos (com base em coordenadas cartesianas) para produzir um modelo de blocos coerente. No entanto, eventos geológicos após a formação do depósito

How the use of stratigraphic coordinates improves grade estimation

“…At the end of the estimation process, the accumulation is divided by the mass fraction at each block to return unbiased grade estimates (Marques et al, 2014). Furthermore, the jackknife cross validation was performed.…”

Grade estimation with samples of different length

“…Each sample length corresponds to the seam thickness. In this case, practitioners usually work with the variables accumulation (product of grade and thickness) and thickness (Krige 1978; Bertoli et al 2003; Marques, Hundelshaussen and Costa 2014). The grade estimates are obtained by dividing the accumulation estimates by the thickness estimates.…”