Characterization of Sub Surface Laterite Ore Using Aerial Photogrammetry and Geophysics

Abstract

The uncertainties associated with mapping iron ore bodies are minimized through the application of integrated techniques. Laterite deposits, which are rich in iron and other valuable minerals, present significant economic potential as one of the ingredients for cement raw mix. The predicted expansion of cement industry in Pakistan necessities the exploration of new laterite deposit. Nevertheless, traditional exploration techniques such as core drilling and trenching provide univocal subsurface information but are costly, time-consuming, and often inefficient. This study integrates various techniques, such as Aerial Photogrammetry, Magnetic and 2D Electrical Resistivity Tomography (2D ERT) surveys, to delineate subsurface laterite ore mineralization zones with reduced exploration cost. The Aerial Photogrammetry survey provides the Topographic map, while the magnetic surveys identify magnetic anomalies with strengths ranging from 50360 nT to 50780 nT. The depth of these identified magnetic anomalies was estimated using forward modeling. Based on forward modeling the laterite ore lies at approximately five meters depth. Additionally, the findings from the 2D ERT survey elaborate on the subsurface lithology, distinguishing layers such as topsoil, shale, and laterite. The ERT survey reveals the thickness of topsoil was three meters and have resistivity range from 10 to 50 Ω.m. The resistivity of shale varies between 50 and 150 Ω.m, with a thickness of two meters. While the laterite ore was identified with the resistivity values between 150 to 1200 Ω.m at five meters depth. The cost associated with core drilling was 5,40,000 Rs and the Magnetic and ERT survey cost was 2,92,000 Pakistani Rupees (PKR). This study Thus reveals that the integration of Aerial Photogrammetry, magnetic surveys, and 2D ERT is an efficient, cost-effective, and expeditious approach for exploring laterite ore mineralization zones