Fig.1 Geological sketch map of Main section and East section in Bayan Obo ore deposit (adapted from references[23-24])

Fig.2 Magnetite specimens and microscopic characteristics of Bayan Obo deposit

Fig.3 Tectonic of the Luzong basin(a) and regional geological map of Huangtun copper-gold deposit(b)(cited from reference [33])

Fig.4 Pyrite specimen and micrograph in breccia tube of Huangtun copper-gold deposit

Fig.5 Schematic diagram of sampling position for thermal resistance test of magnetite in Bayan Obo main mine area

Fig.6 Logarithmic distribution of magnetite resistivity in Bayan Obo iron mining area

Fig.7 Logarithmic vertical projection of magnetite resistivity in Bayan Obo iron mining area

Fig.8 Photos of magnetite samples under a reflector

Fig.9 Comparison of resistivity of magnetite samples from Bayan Obo iron mining area with pure magnetite samples and oxidized magnetite samples

Fig.10 3D distribution of resistivity isosurface of magnetite in Bayan Obo iron mining area

Fig.11 Sampling position diagram of thermal resistance test sample in Huangtun copper-gold mining area

Fig.12 Scatterplots of pyrite resistivity of borehole in the breccia pipe in Huangtun copper-gold mining area

Fig.13 Scatterplots of pyrite resistivity of borehole outside the breccia pipe in Huangtun copper-gold mining area

Fig.14 Logarithmic statistical diagram of pyrite resistivity in Huangtun copper-gold mining area

Fig.15 Schematic diagram of the resistivity profile of pyrite in the 18th exploration line of Huangtun copper-gold mining area

Fig.16 Comparison of the resistivity variation of pyrite with breccia pipe and mineralization distribution in the 18th exploration line of Huangtun copper and gold mining area (base map based on reference [34])

Fig.17 3D distribution of average resistivity of pyrite in Huangtun copper and gold mining area