3D inversion modelling of gravity data to identify gold mineralization zones in region “X”, Pongkor

Abstract

Gold originates from hydrothermal liquids and is deposited in the form of epithermal deposits. Structures such as faults play an important role in the process of gold deposition because they form hydrothermal flow paths to the surface. One method that can be used for gold exploration is the gravity method. This method can identify gold mineralization zones in the faults of a research area. Three-dimensional (3D) inversion modeling can be used to obtain further information on a target. Such modeling allows the process to be more realistic because the geometry model can be fitted to the actual conditions in the field, which allows the measurements to be more accurate. The gravity data acquisition for this study was performed by PT. Antam Tbk gold mining company in Pongkor. The hydrothermal deposit area is categorized as containing low sulfidation epithermal deposits. Analysis and interpretation of the gravity data were performed using derivative analyses, a spectrum analysis, and 3D gravity inversion modeling. The results show gold mineralization zones in the middle of the study area that have high gravity anomalies at the faults. There are eight faults detected in the potential gold mineralization zone. From the inversion result, the density of the rocks in the gold mineralization zone was determined to be in the range of 2.80–3.34 g/cm3.