Subsurface Investigation for Tantalite Mineralization using Magnetics and Electrical Resistivity Methods, in Sepeteri, Oyo State, Nigeria


The study aims to map the depth of the tantalite mineralization as well as its location around the Olorunda mining site using integrated geophysical methods. Eight (8) profiles were conducted for the magnetic survey using G-856AX proton magnetometer in E-W direction with a total of 158 data points, profile length of 190 m, 10 m station spacing, and 20 m profile spacing. Six (6) vertical electrical soundings (VES) data points were measured on the points that have high magnetic susceptibility using the Schlumberger array configuration of the electrical resistivity techniques with a spread of 100 m. The anomaly map has a range of 19nT to 78nT for the magnetic intensity which depicts the area of magnetic susceptibilities. The Reduced to equator anomaly map has a range from 16.6nT to 77.4nT for the magnetic intensity which depicts the area of magnetic susceptibility directly above the sources. The first vertical derivative (FVD) map has a range from -1.69nT to 1.89nT. The source parameter imaging depth (SPI) map has a range from 4.3 m to 20.9 m. The total gradient map has a range of from 0.31nT/m to 3.30nT/m. The elevation map has a range from 349 m to 372 m. The high magnetic areas are in the southwestern, west, central, and eastern parts of the Olorunda mining site. The resistivity values of the study area range from 121 Ώm to 2500 Ώm. The low resistivity values reveal high conductivity areas of the study area, as a result of the pegmatite rocks around the mining site. The VES reveals the depth of tantalite mineralization at 35.8m, 44.3 m, 55.1 m, 42 m, 46.5 m, and 4.18 m.



Tantalite; first vertical derivative; source parameter imaging; vertical electrical-sounding.