UAV-based aeromagnetic survey in prospecting prediction of gold deposits

The article discusses aeromagnetic survey in prospecting a gold-bearing skarn deposit as a case-study of the Choya ore field. Such gold-bearing deposits feature weak-contrast magnetic properties, no sharp outlines and low-contrast magnetic fields. For this reason, interpretation of aeromagnetic survey results uses special analytical and modeling methods. The aeromagnetic surveys were aimed to identify and trace magnetically contrast skarn zones which may have ore control. The aeromagnetic surveys used unmanned aerial vehicles (UAVs). The magnetic field has a weakly differentiated structure, which may be due to the dominance of the regional magnetism over the local. For this reason, the key transforms of the field were calculated. The transforms reveal some features of the magnetic field as follows: the vertical derivative of the anomalous magnetic field makes it possible to eliminate the regional component conditioned by large deep-seated objects; the full horizontal gradient of the anomalous magnetic field accentuates the zones of the highest changes in the field, which imply the vertical boundaries existing in the section. The high-quality interpretation used the lineament analysis and identified the linear features of the field. In the 3D model interpretation, the most informative 3D inversion result is the section of the magnetic susceptibility for the depth of 65 m. The section contains characteristics of two types: axes of structures having the negative magnetic susceptibility and the interfaces of blocks having different magnetic susceptibilities. The joint interpretation of the available geological data and the magnetic survey results improves reliability of prospecting mineral-promising areas.

Grib N. N., Ermolin E. Yu., Melnikov A. E., Grib G. V., Kachaev A. V. UAV-based aeromagnetic survey in prospecting prediction of gold deposits. MIAB. Mining Inf. Anal. Bull. 2022;(1):115-130. [In Russ]. DOI: 10.25018/0236_1493_2022_1_0_115.

N.N. Grib¹, Dr. Sci. (Eng.), Professor, Deputy Director for Research, e-mail: grib-n-n@yandex.ru,
E.Yu. Ermolin, Cand. Sci. (Geol. Mineral.), General Director, Service Geophysical Company JM Service LLC, 195274, Saint-Petersburg, Russia, e-mail: ermolin_stud@list.ru,
A.E. Melnikov, Cand. Sci. (Geol. Mineral.), Leading Researcher, Melnikov Permafrost Institute, Siberian Branch of Russian Academy of Sciences, 677010, Yakutsk, Russia,
G.V. Grib¹, Cand. Sci. (Geol. Mineral.), Head of Laboratory,
A.V. Kachaev¹, Head of Laboratory,
¹ Technical Institute (branch) of M.K. Ammosov North-Eastern Federal University, 678960, Neryungri, Russia.

N.N. Grib, e-mail: grib-n-n@yandex.ru.

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