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The study of a large amount of factual material about the formation conditions of gibbsite or boehmite and their mutual transformations in lateritic bauxites allowed us to solve the problem of boehmite formation and its spatial and genetic relationship to gibbsite. The boehmite formation occurred only during the formation of sedimentary-lateritic bauxites from alluvial and lacustrine sediments that underwent bleaching and resilification at the stage of sediment flooding, as well as on bleached bedrock under sedimentary-lateritic bauxites. The most intense boehmite formation occurred at a depth of 20–30 m from the surface and was accompanied by an alumina input, which was realized here in the form of boehmite along with the gibbsite formation due to the hydrolytic decomposition of kaolinite and partially due to the input alumina. In the upper profiles, the recrystallization of bauxites occurs with the replacement of dissolving boehmite with gibbsite, with a decrease in the total Al2O3 content and an increase in the amount of crystallization water. In classic lateritic bauxites, the boehmite content is highly insignificant; that is, its formation in them practically does not occur or is very much inhibited.

The procedures used for bauxite resource estimation are summarised using examples from Australia, Africa, South America and Asia. In the all studied cases the bauxite resources were estimated by drilling and sampling drill holes at 0.25–0.5 m intervals. Short sampling intervals are necessary for accurate estimation of the mineralisation contacts. Samples of the non-consolidated bauxites usually beneficiated by sieving and removing the barren fine grained material prior to chemical assays. Consolidated bauxites are not beneficiated and processed in a conventional manner. Bauxites density is preferably measured using the sand replacement method which is a formally certified technique for measuring bauxite density at the Australian deposits. Bauxites grade is estimated using conventional geostatistical techniques, which are commonly applied after geometry of the bauxite seam is flattened using ‘equal thickness unfolding’ method, or, in some cases, using ‘top flattening’ approach. Conversion resources to the ore reserves requires the following mining and processing conditions to be taken into considerations:Haulage distance;A vertical mining selectivity of 0.25–0.5 m;Pre-production infill drilling is usually used for grade control purposes;Grindability of the bauxites and quantification of the Bond Work Index;Optimal mesh size for bauxite beneficiation;Detailed chemical and mineralogical characterisation of the crude bauxite, including deleterious components, in particular iron and silica;Characterisation of the pre-desilication behaviour of the bauxite;Characterisation of the alumina extraction;The refinery parameters, including recovered alumina, refinery caustic consumption and red mud loading; Presence of the organic carbon, oxalate formation rate and carbonate formation rate;The mud settling rate, mud compaction and overflow clarity.