Modelagem geológica e de blocos de um depósito de fosfato

Abstract

The block modeling is a fundamental step for the development of a mining project, being the basis for most pit projects, allowing a qualitative and quantitative analysis of the ore to be mined profitably. For this reason, the development of a model representative of the lithology, structural, geometric, mineralogical, chemical and physical becomes imperative in the mine planning stages. The evolution of mining software and the computer itself, with increased processing capacity, allowed a breakthrough in the development of these models in 3-D environment. In this context, the first part of this work showed in a didactic way the fundamentals of block modeling, classification of resources and reserves and evaluation methods for deposits. Like the classical methods of estimation and geostatistics. The second part applies the 3-D modeling of a phosphate deposit known in the brazilian literature, using the method of the inverse square of the distance (IQD) to estimate the block's grade. This case study was conducted by 3-D array of blocks, with the purpose to develop the Geological and Mineral Resources model, with parameterization of measured and indicated resources. The results demonstrate the feasibility of using the technique of modeling and estimation applied to the validation of the resource model showing good results in the global statistics analysis with differences between composites and estimated blocks less than 10%. The visual validation showed good results between the contacts of the blocks and drill holes and good reproduction of the local mean values between the composite samples and estimated blocks. The measured and indicated mineral resources were totaled a deposit with 106 Mt with a mean grade of 8.1% P2O5, consistent with the literature.