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Spatial Modelling of Central Block Using Geostatistics, Pottangi Bauxite Deposit, Koraput, Odisha
  • DEBASTUTI GHOSH
DEBASTUTI GHOSH
Former Petrophysicist, Schlumberger

Corresponding Author:[email protected]

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Abstract

The Koraput district is one of the most important centres for bauxite mining in Odisha. Bauxite deposits of Pottangi are located In Navdapur taluka going northwards towards Pottangi village which is a part of Koraput district,Odisha,situated on ‘Sirimanda Parbat’. The mines at Pottangi are under the charge of National Aluminium Company Limited (NALCO). The present study deals with the geostatistical modelling of the Central Block of the Pottangi bauxite deposit, Koraput district, Odisha while taking into account the various lithological structural and textural characteristics of the area. Exercises on population modelling showed that Al2O3, SiO2 and TiO2 exhibited skewed distributions while Fe2O3 displayed a symmetric distribution. Log-transformations were then performed on geo-variables displaying skewed distributions. The interrelationships and the degree of association among the variables have been established through bivariate analysis.3-D omni-directional experimental semi-variograms of Al2O3, SiO2, Fe2O3 and TiO2 were constructed at 50m lag interval. For these experimental semi-variograms spherical models were fitted through Point Kriging Cross-validation techniques using GEXSYS software. The entire deposit was divided into a number of blocks with optimum Selective Mining Unit. The result of block kriging was used to compute an ore inventory and to establish grade tonnage relationships estimating the quantity of bauxite ore and waste material, average grade of the ore and waste to ore ratio following a step-wise integration of the block grade frequency distribution of a range of grades. The following work done represents advanced geostatistical techniques for improved modelling of the Central Block of Pottangi Bauxite deposit, Koraput, Odisha. The geostatistical techniques used helps in a better evaluation of reserve estimates.