ECONOMIC EVALUATION OF IRON FORMATION USING DUAL AND MULTI ENERGY XRT AND CT ANALYSES

International audience ron-ore industries need to optimize exploration, mining and processing in order to be competitive on the market. Rapid and in-field evaluation of the iron content, its matrix minerals (quartz/ carbonates) and associated heavy metals (e.g. REE phosphates, sulfides, zircon, native gold) which may be extracted as byproducts during beneficiation or metallurgical processing, allows to increase resource efficiency in a holistic approach. Dual and multi energy X-ray transmission imaging (DE-/ME-XRT) was used on different iron oxide ore types: banded and nodular magnetite-hematite-quartz ore from northern Iran, and jaspilite ore from banded iron formation in South Africa.XRT allowed to quantify the areal density and mass fraction of iron and the quartz matrix, and thus to distinguish waste from valuables. CT allowed to quantify size, distribution and orientation of internal structures, such as banding, folding and fractures and the mineral groups hosted in fractures. Comparison of the XRT and CT data with laboratory chemical and mineralogical data shows that the data provided by both methods are reliable. Data processing, such as blob analysis, can be successfully applied for distinguishing iron oxide rich parts from waste. Heavy minerals such as baryte, uraninite, galena and monazite can be detected and quantified.XRT can be used as a real-time inline process for continuous monitoring. CT data recording and reconstruction depends strongly on the acquisition parameters and is typically in the range of hours per meter. Therefore, CT should be performed on selected samples in a workshop at mine site or laboratory. Machine and measurement protocols, X-ray parameters and resolution can be customized in collaboration with the mining geologist and processing engineers.