Application of wide-field electromagnetic method in deep mineral exploration of Tongling:A case study of the Dongguashan copper mine
The Dongguashan copper mine in Tongling City is currently the largest modern underground open-pit copper mine in China.The shallow mineral resources in the area have been developed to maturity,with ore bod-ies buried at depths ranging from-690 m to-1007 m,and the mining history has exceeded 50 years.To search for a secondary mineralization space in the Dongguashan copper mine area,to clarify the distribution of strata,structures,and magmatic rocks at depths between-1 km and-3 km,and to reveal the spatial distribution of the Ordovician-Silurian interface closely related to mineralization,a three-dimensional wide-field electromagnetic exploration was carried out in the Dongguashan mining area.In this paper,for the strong electromagnetic interfer-ence exploration environment of the Dongguashan copper mine,reasonable wide-field electromagnetic data acquisi-tion parameters were designed through on-site interference investigation and data collection experiments,obtaining high-quality wide-field electromagnetic data.After fine denoising of the noisy data in the strong interference area,a pseudo-two-dimensional inversion was carried out.Then,based on the geological information,combining regional physical property data,inversion results,drilling data,and the spatial distribution of strata,rock bodies,and ore bodies exposed by tunnels within 1000 m,the three-dimensional inversion of WFEM data guided by geological structures and rock physical properties was carried out.This validated the fine electrical structure of the survey area within 1000 m and,following the interpretation principle of"from known to unknown,from shallow to deep",inferred the spatial distribution of deep rock bodies and the Ordovician-Silurian interface within the range of 1-3 km.It provides geophysics basis for the exploration of deep and marginal ores of the Dongguashan ore body,prediction of mineralization target areas,and site selection for drilling.
wide-field electromagnetic methoddeep mineral explorationfine denoising3D inversion
NETL
NSTL
万方数据
