Benkala porphyry Cu-Mo deposit, Kazakhstan
Multimethod exploration at Benkala deposit has been carried out by Nord-West Ltd. in 2013. Again, at the first stage the zones associated with sulfide mineralization were outlined using magnetic, resistivity & IP profiling. Then 2D resistivity tomography (ERT) and AMT data were collected and inverted both separately and jointly using Zond software
to image deep structure of ore bodies. The ERT data inversion (a) covers only uppermost 400 m, which corresponds to secondary mineralization zone in weathered layer. The AMT data inversion (b) resolves structures up to 800-1000 m depth, but is less detailed.
The most efficient approach is the joint inversion of ERT and AMT data, which combines high spatial resolution of the ERT data and large investigation depth of the AMT data. Joint inversion (c) makes it possible to image accurately both resistive zones H1 and H2 and conductive zone L. Deep part of the central conductive zone L was interpreted as the primary vein-disseminated sulfide mineralization, while zone H1 corresponds to the granite-diorite intrusion and zone H2 corresponds to quartz-diorite dyke complex.