GEOMETALLURGICAL STUDY OF COPPER AND GOLD DOMAIN, BATU HIJAU PORPHYRY DEPOSIT, SUMBAWA REGENCY, WEST NUSA TENGGARA

• Main Author: Azhari, Bintang
• Format: Final Project
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/46544
• Institution: Institut Teknologi Bandung

Batu Hijau Open Pit is the second-largest porphyry Cu - Au deposit in Indonesia with 2,6 Blbs Cu and 2,7 Moz Au proven reserved. By 2017, PT. AMNT had started phase-7 of pit development by uncovering, enlarging the pit, and planning the extraction strategy. This research is aimed to help extraction planning by collaborating geological aspects with metallurgical performances of the ore to maximize the profit of this phase. Core logging, petrographical & mineragraphical analyses, and XRD was carried out to obtain geological characteristic including lithological distribution, alteration, and mineralization zone. Secondary data from PT. AMNT are included in form of geological map and section reference, borehole collar, structural geology & lithology, Cu & Au grade, and Cu & Au flotation recovery to obtain better geological condition and to correlate geological and metallurgical aspects. A series of Middle Miocene – Pliocene intrusions has been identified and consists of (older-younger) Andesite, Quartz Diorite, Intermediate Tonalite, and Young Tonalite. The alteration shows the existence of enclosed Biotite - Magnetite – Quartz ± Actinolite zone by Chlorite - Sericite - Quartz ± Calcite ± Epidote zone and Kaolinite - Quartz on the top of paleosurface. Oxidation zone exists as a cap of others mineralization while pyrite dominant zone encloses chalcopyrite and bornite dominant zone. Higher copper and gold grade tend to exist near the Intermediate Tonalite intrusion, while the youngest intrusion (Young Tonalite) shows lower grade than others. Lower Cu and Au recovery identified on top of the research area shows good correlation with the number of identified oxide minerals. Lower Au grade also shows a good correlation with lower Au recovery. Based on those analyses, ten and nine Cu and Au geometallurgical domains are constructed that reflects geological aspects with metallurgical performance. Recommendation for each zone processing is also suggested to optimize the generated output.