A 3D Geological Model of a Vein Deposit Built by Aggregating Morphological and Mineral Grade Data

André Sanches,Romeu Vieira,José Almeida,Paulo Sá Caetano

doi:10.3390/min7120234

André Sanches, Romeu Vieira + Show 2 more

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https://doi.org/10.3390/min7120234

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Abstract

The objective of this study was to establish a methodology for building a 3D geological model of a mineral vein deposit, encompassing morphology and wolframite content. The available data set includes stope data (vein thickness and wolframite quantity) and borehole data (vein thickness and wolframite modal classes). The data captured from boreholes and stopes differ in terms of their spatial distribution and clustering as well as the size and shape of each sample. Therefore, a specific methodology was designed to combine these two sources of information. The morphology model mapped vein thickness as a vein proportion variable, by applying a two-phase Direct Sequential Simulation (DSS) locally conditioned to borehole data. Regarding the evaluation of wolframite content, the variables are unable to be related directly to each other and are non-co-located. Therefore, a proximity study was made using DSS to build local conditional cumulative histograms (by borehole class and by mine level). The final model of wolframite quantity was generated using Probability Field Simulation. The proposed approach considers the initially identified problems, allowing the mineral potential of the deposit to be quantified by integrating the results of the two independent methodologies.

Highlights

The exploitation of mineral deposits in the European Union (EU) is essential to guarantee a sustainable supply of minerals in Europe
Figure 2. 3D view of boreholes and vertical section Px81 and horizontal section Pz75 used in the Figure 2. 3D view of boreholes and vertical section Px81 and horizontal section Pz75 used in the section section images for displaying results
The results show that: (i) The richest part of the modelled deposit corresponds to levels L1 and L2; (ii) the estimated mineral potential of the deposit is 618.47 tons, with the optimistic scenario being 769.73 tons and the pessimistic scenario being 537.19 tons; and (iii) the variation in wolframite quantity (WQ) by elevation indicates that the richest level is L2, supporting the interpretations of the wolframite content model

Summary

Introduction

The exploitation of mineral deposits in the European Union (EU) is essential to guarantee a sustainable supply of minerals in Europe. Ensuring that such deposits are properly explored, characterized, and exploited will reduce the dependence on minerals sourced from developing countries. One of the critical raw materials identified, is of interest because of its long history of mining in the central and northern areas of Portugal. The deposit has been exploited for several decades, making it a mining operation that contains an unparalleled record of information in Portugal with an extensive collection of sampling and geological data. It should be noted that there are few published studies that have applied geostatistical methodologies to this mineral deposit, mainly because of the difficulty of quantifying the variable spatial continuity of mineralization, deposit thickness, and wolframite content [2]

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