Petrophysical properties of rocks from the Bargilt iron ore deposit, Mongolia

Abstract. Iron ore deposits play a significant role in Mongolia’s mineral-based economy and require detailed geological and geophysical investigation for effective exploration and resource evaluation. This study focuses on the Bargilt iron ore deposit located in Khentii Province, Mongolia, within the MV-016657 license area operated by the state-owned enterprise Mongolrostsvetmet. The main objective of the study is to characterize the mineralogical composition, rock properties, and subsurface distribution of ore-bearing zones for better understanding of the deposit’s structure and potential. A combination of field geological mapping, petrographic analysis, and petrophysical interpretation was used to determine the mineral composition and textural relationships. Representative samples of ore-bearing (59 samples) and host rocks (440 samples) have been collected, measured and analyzed. Magnetite was identified as the dominant ore mineral accompanied by minor accessory minerals, while the host rocks are mainly composed of silicate gangue minerals. Petrophysical data were interpreted to identify subsurface anomalies associated with iron-enriched zones and to identify structural factors influencing mineralization. The study results indicate that the iron ore mineralization is structure-controlled and exhibits a variable spatial distribution influenced by lithological boundaries and fault systems. Integration of geological and petrophysical datasets provides a more reliable model of ore body geometry and its continuity. The study results demonstrate the effectiveness of combined methods for improving exploration accuracy and can serve as a basis for further detailed assessment of the Bargilt iron ore deposit for future development planning.

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