#TITLE_ALTERNATIVE#

• Main Author: HERMALA YUNIAJI (NIM 12007064), RR
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/13809
• Institution: Institut Teknologi Bandung

The research area is located in Batu Hijau mine area within the contract of work PT. Newmont Nusa Tenggara and located in Sumbawa Subdistrict, West Nusa Tenggara with coordinate 08o 57’55” East Longitude and 116o52’21” North Latitude. Batu hijau is a significant copper-gold porphyry deposit in Indonesia. In porphyry deposits, the process of economic ore mineralisation is controled by lithology, alteration process, and vein distribution in research area. Examination of eleven well in section 050 shows that lithology in research area from old to young are Andesitic Tuff Unit, Diorite Unit, Tonalite Unit (Strong Altered Tonalit and Weak Altered Tonalite). From macroscopic and microscopic analysis, there are four alteration zone in research area, (1) Biotite-Chlorite-Quarzt Zone (T 300-320°C, pH 6-7), Chlorite-Sericite-Calcite-Quartz Zone (T 280-320°C, pH 5-6), Chlorite-Epidote-Calcite-Quartz Zone (T 240-320°C, pH 6-7), Kaolinite- Illite Zone (T 200-220°C, pH 4-5). Mineralisation zones in research area are bornite dominant zone (Bn > Cp, Py), Calcopyrite (Cp > Bn, Py), and Pyrite (Py > Cp, Bn). There are six types of veins, from old to young. They are Mt Vein, A vein, AB vein, B vein, C vein, and D vein. Quartz vein density zones in research area are abudant quartz vein density zone (10–50%), moderate quartz vein density zone (5–10%), rare quartz vein density zone (1–5%), and very rare quartz vein density zone (0–1%). There is a positive relationship between quartz vein density distribution and Au- Cu assay content. The higher quartz vein density in Section 050, the higher Au-Cu assay content, and vice versa.