Vol. 20 No. 2 (2025): Buletin Sumber Daya Geologi

This bulletin contains five scientific papers discussing mineral and geothermal commodities, written by researchers from various institutions including the Center for Mineral, Coal, and Geothermal Resources, Universitas Padjadjaran, Bandung Institute of Technology, Universitas Tanjungpura, and PT Aneka Tambang Tbk.

The first article investigates the influence of geological structures on alteration and mineralization processes using geological mapping, petrographic analysis, and spectral data interpretation. The results indicate that alteration and mineralization are controlled by strike-slip faults trending northeast–southwest and northwest–southeast. The second article analyzes the characteristics of alteration and mineralization zones by integrating geological, geochemical, and geophysical data, identifying prospective subsurface zones of Zn-Pb-Ag and Au-Pb mineralization.

The third article develops a standardized framework for the classification and direct utilization of geothermal resources in Indonesia, based on two main criteria: fluid data quality and feasibility studies. This framework is expected to serve as a credible national reference for resource inventory, development planning, and investment promotion in direct-use geothermal projects.

The fourth article estimates bauxite resources using the ordinary kriging method from 47 test well samples, resulting in an estimated lateritic bauxite volume of 180,051 m³ and an overburden volume of 56,796 m³. The final article identifies the characterization, spatial distribution, and formation processes of acidic minerals in a geothermal field through modified volcanostratigraphic mapping and XRD analysis. The study identifies 12 volcanostratigraphic units—11 domes and 1 mound—with anhydrite and diaspore as the main acidic minerals.