QUALITATIVE CHARACTERISTICS OF BAUXITE „OŠTRELJ“ NEAR BOSANSKA KRUPA

Abstract

SUMMARY
Qualitative characteristics of bauxite deposit „Oštrelj“ are defined through extensive laboratory testing
of chemical and mineralogical-petrographic composition, and geomechanical characteristics. Chemical
composition has shown that it is a relative poor bauxite with low Al/Si module (2,28). Low values of
Al/Si module are result of lower Al2O3 concentration (48 %), and higher SiO2 concentration (21 %),
what these bauxites define as high silicic or »acidic«. Identified are increased concentrations of larger
number of analyzed trace elements (B, Co, Cr, Li, Mn, Ni, Sn, V, Zn) comparing to the medium content
in the Earth's crust. Mineralogical composition, structure and texture are uniform.
Holders of Al mineralization are bemite and diaspor (to a lesser extent) as crypto-crystalline phases of
rock matrix. Lower Cretaceous age (K1) of roof layers over bauxite deposit is paleontologicaly
documented, while in the bauxite any fossils are not registrated. Values of geomechanical paramers of
layers under and over bauxite is uniform. In bauxite value of compressive strength is increased, which
is equivalent to chemical and mineralogical composition, and structural and textural characteristics of
tested bauxite samples.