THE EFFECT OF GOLD CHARACTERISTICS ON GOLD RECOVERY VALUE IN TUMPANGPITU GOLD MINING, BANYUWANGI, EAST JAVA, INDONESIA

• Main Author: Laudza Putra, Khafarel
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/79763
• Institution: Institut Teknologi Bandung

Gold is a valuable element that has a long history as currency and jewelry and has many important uses in modern industry. Indonesia is one of the countries that has gold-producing mines. These mines are spread across various regions of Indonesia and have an important role in the Indonesian economy. One of the areas in Indonesia where gold mining is located is the Tumpangpitu area, which is located in Banyuwangi Regency, East Java Province. Based on data from the Joint Ore Reserves Committee (JORC), the Tumpangpitu area has gold mineral reserves of 794 million grams in porphyry deposits and 70 million grams in epithermal deposits. The research location is in the Pit A area, on the PT Bumi Suksesindo Mining Business License (IUP) with coordinates X:173500-174550 and Y: 9045700-9046900, administratively located in the Tumpangpitu area, Pancer Village, Pesanggaran District, Banyuwangi Regency, East Java Province, Indonesia. This research discusses the characteristics of gold in oxide, transition and sulfide samples which have an influence on the process of extracting gold from the ore body, while the aim of this thesis research is to obtain a comparison of the characteristics of gold in sulfide, transition, and oxide samples and to obtain a relationship between the characteristics of gold on the effectiveness of gold recovery values in sulfide, transition and oxide samples. The samples used in this research were differentiated based on the level of rock oxidation found in the research area. The oxidation levels in these rocks are divided into three based on the percentage of sulfide minerals present in the rock. Oxide rocks are rocks with a complete oxide mineral composition (all sulfide minerals in the rock have been change into oxide minerals), transitional rocks are rocks with a mineral composition that still shows the presence of sulfide and oxide minerals, while sulfide rocks are rocks with the presence of sulfide minerals without the presence of minerals oxide. Rock sampling was carried out on wallrock and drillcore samples which were differentiated based on the level of oxidation (sulfide, transition, and oxide) and Au content in the rock. The analysis carried out in this research was the Analytical Spectral Device (ASD) and Assay carried out at PT Bumi Suksesindo, while the identification of gold characteristics was carried out using petrographic analysis and Scanning Electron Microscopy Energy Dispersive X-Ray Spectroscopy (SEM-EDS) carried out at the Balai Besar Pengujian Minyak "Lemigas" Jakarta. The lithology in the study area consists of dacite and breccia lithology with matrix supported and has undergone strong alteration characterized by the presence of altered mineral groups of silica + alunite ± dickit, silica + kaolinite ± dickit and kaolinite + dickit ± silica. The results of identifying the characteristics of gold contained in oxide samples are adsorbed gold (surface-bound gold), while gold in transition and sulfide rocks is invisible gold or submicroscopic gold as solid solution gold. The gold recovery value obtained by the bottle roll test was 80%, while the recovery value obtained by comparing the Au/CN value to Au/FA was relatively high, namely more than 80% dominant, with an average recovery value of 78%. In transition rocks, the gold recovery value obtained based on the bottle roll test is 62%, while the recovery value obtained by comparing Au/CN and Au/FA values is relatively moderate, with an average recovery value of 60%. In sulfide rocks, the gold recovery value obtained by comparing the Au/CN value to the Au/FA value obtained is relatively low, with an average recovery value of 26%. The difference in gold recovery values for each sample shows that the characteristics of gold in oxide, transition and sulfide rock samples influence the gold extraction process from the ore body using the heap leach method. The use of cyanide in gold processing on transition and sulfide samples has not been able to produce optimal gold recovery values.