Mineralogy and Geochemistry of Gold Ore Low Sulfidation -Epithermal at Lamuntet, Brang Rea, West Sumbawa District, West Nusa Tenggara Province
There are two Artisanal Small scale Gold Mining (ASGM) location in Lamuntet, Brang Rea Subdistrict, West Nusa Tenggara Regency, namely Nglampar and Song location. Nglampar and Song location are included in the low sulfidation epithermal gold deposit system. The research purposes to analyze mineralogy and geochemistry of gold vein deposits and determine system of low sulfidation gold ore in Nglampar, Lamuntet Village. The methods used to determine the mineralogy of gold vein deposits are petrography, mineragraphy and X-ray diffractometer (XRD) analysis, while geochemical analysis using Scanning Electron Microscope (SEM) with Energy Dispersive X-Ray Spectroscopy (EDS), Fire Assay (FA) and Atomic Absorption Spectrophotometry (AAS). The results showed that the minerals contained were quartz (Qz), sericite (Ser), Chalcedon (Chc), chlorite (Chl), pyrite (Py), sphalerite (Sph), galena (Gn) , gold (Au), chalcopyrite (Cp), argentite (Ag), arsenopyrite (Apy), Azurit (Az), Malakit (Mal) and bornite (Bn). Abundant mineral availability such as sphalerite, galena, chalcopyrite and arsenopyrite are characterized by high levels of Zn, Pb, Cu and As the metal in vein deposits. This can be seen on the chemical content of ore in gold vein deposits ie Au 0.1 ppm -27.8 ppm, Ag 3 ppm-185 ppm, Pb 101 ppm - 35,800 ppm, Zn 73 ppm-60,200 ppm, Cu 26 ppm - 1,740 ppm, and As 150 ppm - 6,530 ppm. Based on the results of SEM-EDS analysis shows that the type of gold mineral is the electrum because of the content of Ag> 20%. Based on those characteristics of the mineralogy and geochemistry in this study showed that low sulfidation gold ore in this area is categorized as polymetallic gold-silver system.
Barnes, H.L., 1979, Geochemistry of Hydrothermal Ore Deposits, second edition, John Wiley & Sons Inc, Canada.
Boyle, R.W., 1965, Geology, Geochemistry and Origin of the lead-zinc-silver deposits of The Keno Hill-Galena Hill area, Yukon Territory, Geology Survey Canada Bull, 111.
Cooke, D.R., and Simmons, S.F., 2000, Characteristics and Genesis of Epitermal Gold Deposits, Society of Economic Geologists Review, vol.13, p.221-244.
Corbett, G.J., 2002, “Epitermal Gold For Explorations”, Australian Institute Of Geoscientists Presidents lectute : AIG News No.67, p. 8.
Corbett, G.J. and Leach, T.M., 1998, Southwest Pacific-Rim Gold-Copper Systems : Structure, Alteration, and Mineralization, Society of Economic Geologists Special Publication number 6, p. 69-94 and 137-200.
Chryssoulis, S.L. and Cabri, L.J., 1990, The Significance of Gold Mineralogical Balances in Mineral Processing, Transaction Institution of Mining and Metallurgy (Sect. C : Mineral Process Extraction Metallurgy), 99.
Grayson.R.F., 2007, Fine Gold Recovery-Alternatives to Mercury and Cyanide, World Placer Journal, vol.7, p.66-161.
Hamilton, W.B., 1979, Tectonics of the Indonesian region, United States Agency for International Development, United States Government Printing Office, Washington
Harris, D.C., 1990, The Mineralogy of Gold and its Relevance to Gold Recoveries, Mineral Deposita 25 (Suppl) S3 – S7.
Herman D.Z., 2007, Kajian Potensi Tambang Dalam pada Kawasan Hutan Lindung Daerah Taliwang, KAbupaten Sumbawa Barat, Nusa Tenggara Barat, Proceeding Pemaparan Hasil Kegiatan Lapangan dan Non Lapangan Tahun 2007 Pusat Sumber Daya Geologi.
n.d., 2015, Laporan Kajian Wilayah Pertambangan Rakyat Kabupaten Sumbawa Barat, Energi dan Sumberdaya Mineral Sumbawa Barat.
Van Bemmelen, R.W., 1949, The Geology of Indonesia, Vol. IA. General Geology, The Hague, Martinus Nijhoff.
Webb, J.S., 1958, Observations on Geochemical Exploration in tropical Terrain, International Geology Congress 20th, (Mexico 1956), Symposium Explorations Geoquim. 1, 143-173.
White, N.C., and Hedenquist, J.W., 1995, Epitermal Gold Deposits: Styles, Characteristics and Exploration, Published in SEG Newsletters, 1995, No.23, p. 1, 9-13.
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