Trend surface modelling of Karlapat bauxite deposit, Eastern Ghat Group, Orissa, India

Abstract

The Karlapat bauxite deposit occurs in the Eastern Ghat Group of rocks in Orissa and has developed in the khondalites. Mineralogical and physical observations on bore hole samples reflect the presence of a maximum of six weathered zones from top to bottom. These zones are termed as topsoil, siliceous laterite, ferruginous laterite, bauxite, lithomarge and altered khondalite. Four-dimensional trend surface models are developed for the data of 45 and 36 bore holes from north and south blocks, respectively, on Al2O3 and SiO2 to delineate the zones of metallurgical grade bauxite (SiO2<5% and Al2O3>40%). The results indicate about 15 m thickness of bauxite in the north block while it could be up to 20 m thick in the south block, leaving about 10 m of laterites at the top of each block. High grade bauxite (>47% Al2O3) is also encountered at specific locations.