Experimental Geophysical Characterization Targeting High-Grade Limestone Deposits in South Korea

High-grade limestone (HL) is a crucial resource in a wide range of industries. Geophysical surveys are effective for targeting HL deposits because of their distinct chemical and physical characteristics compared to surrounding rock. However, existing studies estimating limestone grades have primarily focused on case studies and literature reviews, often overlooking the insights available from geophysical survey data. In this study, a geophysical survey strategy was optimized by characterizing the geophysical properties of an HL mine in South Korea where contact metamorphism had altered the rock. Rock samples included HL and surrounding lithologies affected by igneous intrusion, comprising dolomite marble, skarn, altered igneous rock, and unaltered igneous rock. Laboratory analyses were conducted to determine the geophysical properties of the rock samples, including the density, porosity, magnetic susceptibility, resistivity, and induced polarization. Optical microscopy, X-ray diffraction, and X-ray fluorescence helped identify the rock lithology. HL exhibited low magnetic susceptibility, chargeability, and percent frequency effect compared to other lithologies. Consequently, magnetic and induced polarization surveys were proposed as effective geophysical techniques for detecting this type of limestone deposit. The proposed optimized geophysical survey approach enables more efficient identification and delineation of HL deposits, improving resource exploration accuracy and reducing time and costs in locating valuable deposits.