Determination of Reserve Estimate of Quartzite Deposit using Geoelectric Sounding and Laboratory Measurement - A Case Study of Ipinsa area, near Akure, Southwestern Nigeria

Abstract

A total of 36 Vertical Electrical Sounding data and laboratory analysis was carried out at southern part of Ipinsa, near Akure, Southwestern Nigeria with the aim of determining the reserve estimate of a portion of the quartzite deposit in the area. The Vertical Electrical Sounding (VES) method adopted Schlumberger configuration with half current electrode spacing varying from minimum of 1 to maximum of 40 to 150 m. The VES results delineated three to six geoelectric layers which correspond to the top soil, weathered layer, weathered basement, fractured basement and the presumed fresh basement. At the top soil, the resistivity varies from 38 to 878 ohm-m, while the thickness value ranges from 0.1 to 6.8 m. At the weathered layer, resistivity varies from 17 to 9749 ohm-m, while the thickness value ranges from 0.1 m to infinity. The weathered basement resistivity ranges from 24 to 18088 ohm-m, while the thickness values range from 0.6 m to infinity. The partially fractured basement resistivity varies from 62 to 1331ohm-m and its thickness range from 4.0 to 5.1 m. The quartzite layer resistivity value in the study area is generally greater than 150 ohm-m, with average thickness of 8.86 m. From the 14 quartzite samples collected across the study area, the average density value was determined to be 2.51 g/cm³ (2510 kg/m²). The area extent of the quartzite deposit was calculated to be 1,024,729 m², while the volume of the quartzite deposit is 9,079,098 m³. The mass of the quartzite deposit was estimated to be 22,788,538 tonnes.

Keywords: Vertical electrical sounding, laboratory measurement, density, thickness, area, volume and tonnage.