79 UIJRT | United International Journal for Research & Technology | Volume 02, Issue 12, 2021 | ISSN: 2582-6832 All rights are reserved by UIJRT.COM. Estimation of Volume of Sand Using Vertical Electrical Resistivity Imaging: A Case Study in Tombia, Yenagoa, Bayelsa State, Nigeria Eteh Desmond Rowland 1 , Francis Omonefe 2 , and Edeye Ejaita 3 1 Department of Geology, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria 2,3 Department of Physics, Niger Delta University, Wilberforce Island, Bayelsa State, Nigeria Email: 1 desmondeteh@gmail.com Abstract— The electrical resistivity survey using the Schlumberger electrode configuration was conducted in parts of the Yenagoa local government area, Bayelsa State, Nigeria. The survey was aimed at estimating the volume of sand in a piece of land measuring 60 m by 30 m known as the study area. Nine 1D Vertical Electrical Sounding Points were acquired in the study area. ABEM Terrameter SAS 1000 was the instrument used with IPI2win and ZONDIP software for processing. The result obtained reveals that the area contains three layers within the depth of investigation. Lateritic sand with resistivity ranging from 42 Ωm to 1029 Ωm and thickness varying from 1.3 m to 3.0 m made up the first layer. The second layer is sand with resistivity values ranging from 476 Ωm to 3089 Ωm with thickness varying from 10.8 m to 23.2 m. The third layer is sandy clay with resistivity values ranging from 24 to 1024 Ωm. The survey shows that a considerable quantity of sand can be dredged from the area. The estimated volume of sand within the area of study is estimated to be approximately 550,767.60 tonnes. The result shows that sand deposits can be mined economically for domestic and building purposes and are also suitable for other engineering and construction work due to their inherent water permeability and storage ability. Keywords— VES, 1D Resistivity, Volume of Sand, Tombia, Yenagoa. 1. INTRODUCTION Geo-electric methods are widely used in engineering research such as estimation of the volume of dredgeable sand, Hydrolysis, site investigation, etc. Sand is a substance that consists of very small grains of rock [9]. It occurs naturally as granular materials composed of finely divided rock and mineral particles. It is pertinent to note that sand deposits often serve as good groundwater and hydrocarbon reservoirs [10]. Sand is an important ingredient in the construction of major civil engineering works such as airports, bridges, roads, factories, etc. Therefore, the importance of sand cannot be overemphasized [11]. Sand mining is done to extract sand mainly from an open pit, beaches, inland dunes, and dredged from ocean beds and rivers beds [17]. This brings to bear the importance of sand exploration. The most common type of sand, found in non-tropical coast and continental areas in the silica which usually takes the form of quartz [8]. This type of sand is extremely resistant to weathering due to its chemical composition (SiO2), which makes the grain very hard [7]. It is used in manufacturing as an abrasive used to make concrete. Also, sand has industrial use as a raw material in glassmaking. Due to its increasing effective demands, sand is over-extracted at different depths varying from one to twenty meters, from different pits, streams, rivers, and basins [12]. As sand is extracted rapidly, groundwater evaporates fast, reducing groundwater recharge, increasing the failure of irrigation, wells, and the associated predicament in farming [18]. Sand mining is a direct cause of erosion which destroys farmland and local wildlife. Building sand is pit sand that can only be used for building or filling. It has no chemical associated with it. It can also be used as a filler for concrete [12]. The concept of electrical resistivity imaging techniques is arguably the most useful and successful techniques in hydrological, environmental investigation and the exploration of shallow alluvial aquifer all over the world [16]. This technique has a long history of success and to a large extent, dependable in the quest for subsurface investigation. Electrical methods of prospecting are more diversified compared to other known methods of exploration in geophysics [15]. Some of these electrical methods include Spontaneous (or Self) Potential, Electromagnetic Techniques, Telluric current and Magnetotelluric method, induced polarization method, and resistivity method [14]. As population increases in Bayelsa state, Niger Delta, the need to reclaim swampy areas for infrastructural development becomes necessary. The increasing demand for sand for domestic and industrial purposes makes in Niger Delta makes it necessary that detailed geological information of any site mapped for dredging should be carried out before dredging. This study is aimed at estimating the volume of sand in a borrow pit in Tombia, Yenagoa, Bayelsa State that can be used for filling and other engineering work. This study was carried out using the electrical resistivity method.