3D high-precision tunnel gravity exploration theory and its application for concealed inclined high-density ore deposits

Based on the significant difference in density between ores and ore-hosting rocks and the large size of ore deposits, we have successfully developed a 3D high-precision tunnel gravity exploration method (TGEM) for detecting deeply buried high-density inclined orebodies in the full-space domain. Using four parameters, namely, the tunnel gravity anomaly and the tunnel gravity gradient anomaly in three directions (X, Y, Z), has allowed for overcoming the problem of multiple solutions when locating deeply buried orebodies. It also eliminates the effect of electromagnetic interference, which commonly affects other geophysical exploration methods, thus extending the application of the TGEM to the three-dimensional gravity gradient detection in large-scale tunnels at home and abroad. The TGEM has been applied effectively in the exploration of deeply buried Ge-Pb-Zn ore deposits of the Sichuan-Yunnan-Guizhou Triangle area. The accuracy of the TGEM for locating deeply buried high-density inclined ore deposits in the whole space domain has been verified through site exploration. Being highly accurate, unaffected by electromagnetic interference, and only minimally affected by topography, the TGEM shows great potential to be used for the exploration of similar deeply-buried ore deposits (bodies) around the world.