Integration of geology and geophysics in mineral exploration in the Benue Trough, Nigeria: the Onuahia lead-zinc deposit - a case study.

Author(s):  
L I MAMAH ◽  
M C EZEPUE ◽  
H I EZEIGBO
Author(s):  
O. J. Airen ◽  
D. A. Babaiwa

2D Electrical Resistivity (ER) and Instantaneous Potential (IP) geophysical techniques were used at Eziama village in Abia state of Nigeria to investigate possible Pb-Zn mineralization. The dipole-dipole electrode configuration was employed for data acquisition and Earth Imager software was used for inversion of the acquired data. The analysis of the result of the study showed the presence of the Pb-Zn ore along traverses 1, 2 and 3 while traverses 4 and 5 appear barren. Along traverse 1, the mineralized zone falls within the fractured basement and is characterized by low resistivity (about 316 – 5623 ohm-m) and high chargeability (33.2 – 128 ns) at lateral distance of 73 – 103 m. On traverse two, the ore body was identified at lateral distance of about -18 to 53 m as delineated on the IP structure with resistivity and chargeability of the anomalous zone ranging from 4.6 – 677 ohm-m and 41.8 – 142 ns respectively at depth of about 21.4 m while on traverse three, two ore bodies labeled a, a’ and b, b’ on the ER and IP cross-sections were delineated at lateral distance of about -130 to -93 m and 78 to 98 m respectively with depth to the top of the suspected ore bodies ranging from about 7.1 m for body ‘a’ and about 14.3 m for ‘a’. Traverses four and five however showed no prospect for Pb-Zn mineralization. The result of this investigation has once again demonstrated the usefulness of combined electrical resistivity and induced polarization techniques in solid mineral exploration.


Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 726 ◽  
Author(s):  
Zhenwei Guo ◽  
Longyun Hu ◽  
Chunming Liu ◽  
Chuanghua Cao ◽  
Jianxin Liu ◽  
...  

The electromagnetic (EM) method is commonly used in mineral exploration due to the method’s sensitivity to conductive targets. Controlled source audio-frequency magnetotellurics (CSAMT) is developed from magnetotelluric (MT) method with an artificial EM source to improve the signal amplitude. It has been used for mineral exploration for many years. In this study, we performed a case study of the CSAMT application for the Eagles-Nest lead–zinc (Pb–Zn) ore deposits in Jianshui, China. The Eagles-Nest deposit is located in southwest in China in forest-covered complex terrain, making it difficult to acquire the geophysical data. Based on the previous dual-frequency induced polarization (IP) results, we designed four profiles for the CSAMT data acquisition. After data processing and inversion, we mapped the subsurface resistivity distribution. From the CSAMT results, we inferred the location of the ore body, which was verified by the drilling wells. The Pb–Zn ore body was found at a depth between 373.70 m to 407.35 m in the well.


Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1247
Author(s):  
Eko Gerald Ejiga ◽  
Noer El Hidayah Ismail ◽  
Ismail Yusoff

Digital edge detector operations using magnetic derivatives in conjunction with spectra depth analysis were performed on high-resolution aeromagnetic signals to enhance the delineation and interpretation of depth, structural, and intrasedimentary features within the Middle Benue Trough (MBT) of North Central Nigeria, which could serve as a guide for mineral exploration. The derivatives revealed high-amplitude and short-wavelength anomalies over areas underlain by crystalline basement complexes, major volcanic zones, and aggregates of intrasedimentary volcanic and plutonic rocks. Geologic lineaments trending predominantly NE–SW and NW–SE, as well as minor trends of E–W and N–S, suggest that the area has undergone differential stress regimes across geologic time. The spectral depth analysis indicates a two-source depth model. The deep depth ranges from 1.9 to 6.1 km with an average of 3.9 km, whereas the shallow depth ranges between 0.3 and 1.9 km with an average of 0.8 km and is found to emanate from magnetic signals of post-Cretaceous near-surface igneous intrusions as well as other magnetized bodies embedded within the sediments. The spatial distribution of various hydrothermal minerals such as lead–zinc–barite deposits, as well as salt mineralization, is associated with the widespread Tertiary–recent magmatism and governed by pre-existing tectonic structures in the region.


2018 ◽  
Author(s):  
Nnaemeka Chidubem Onyeagba ◽  
◽  
Thomas Seifert
Keyword(s):  

2022 ◽  
Vol 41 (1) ◽  
pp. 54-61
Author(s):  
Moyagabo K. Rapetsoa ◽  
Musa S. D. Manzi ◽  
Mpofana Sihoyiya ◽  
Michael Westgate ◽  
Phumlani Kubeka ◽  
...  

We demonstrate the application of seismic methods using in-mine infrastructure such as exploration tunnels to image platinum deposits and geologic structures using different acquisition configurations. In 2020, seismic experiments were conducted underground at the Maseve platinum mine in the Bushveld Complex of South Africa. These seismic experiments were part of the Advanced Orebody Knowledge project titled “Developing technologies that will be used to obtain information ahead of the mine face.” In these experiments, we recorded active and passive seismic data using surface nodal arrays and an in-mine seismic land streamer. We focus on analyzing only the in-mine active seismic portion of the survey. The tunnel seismic survey consisted of seven 2D profiles in exploration tunnels, located approximately 550 m below ground surface and a few meters above known platinum deposits. A careful data-processing approach was adopted to enhance high-quality reflections and suppress infrastructure-generated noise. Despite challenges presented by the in-mine noisy environment, we successfully imaged the platinum deposits with the aid of borehole data and geologic models. The results open opportunities to adapt surface-based geophysical instruments to address challenging in-mine environments for mineral exploration.


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