Recently, in Indonesia gold exploration activities are not only focused along volcanic-magmatic belts, but also starting to shift along metamorphic and sedimentary terrains. The study area is located in Rumbia mountains, Bombana Regency, Southeast Sulawesi Province. This paper is aimed to describe characteristics of alteration and ore mineralization associated with metamorphic rock-related gold deposits. The study area is found the placer and primary gold hosted by metamorphic rocks. The gold is evidently derived from gold-bearing quartz veins hosted by Pompangeo Metamorphic Complex (PMC). These quartz veins are currently recognized in metamorphic rocks at Rumbia Mountains. The quartz veins are mostly sheared/deformed, brecciated, irregular vein, segmented and relatively massive and crystalline texture with thickness from 1 cm to 15.7 cm. The wallrock are generally weakly altered. Hydrothermal alteration types include sericitization, argillic, inner propylitic, propylitic, carbonization and carbonatization. There some precious metal identified consist of native gold and ore mineralization including pyrite (FeS2), chalcopyrite (CuFeS2), hematite (Fe2O3), cinnabar (HgS), stibnite (Sb2S3) and goethite (FeHO2). The veins contain erratic gold in various grades from below detection limit <0.0002 ppm to 18.4 ppm. Based on those characteristics, it obviously indicates that the primary gold deposit present in the study area is of orogenic gold deposit type. The orogenic gold deposit is one of the new targets for exploration in Indonesia.

In Indonesia, gold is commonly mined from porphyry, epithermal and skarn type deposits that are commonly found in volcanic/magmatic belts. However, were recently numerous gold prospects discovered in association with metamorphic rocks. This paper is intended to describe an alteration and ore mineralogy hosted by metamorphic  rocks at Rumbia mountains, Bombana regency, Southeast Sulawesi province, Indonesia. The study area is found the placer and primary gold hosted by metamorphic rocks. The placer gold is evidently derived from gold-bearing quartz veins hosted by Pompangeo Metamorphic Complex (PMC). This study is conducted in three stages, three stages including desk study, field work and laboratory analysis. Desk study mainly covers literature reviews. Field work includes mapping of surface geology, alteration and ore mineralization as well as sampling of representative rocks types, altered rocks and gold-bearing veins. Laboratory analysis includes the petrologic observation of handspecimen samples, petrographic analysis of the thin section and ore microscopy for polished section, XRD (X-ray diffraction), ICP-AES (Inductively Coupled Plasma Atomic Emission Spectroscopy), ICP-MS (Inductively Coupled Plasma Emission Mass Spectrometry and FA/AAS (Fire Assay/Atomic Absorbtion Spectophotometry) analysis. The results shows that the alteration characteristics of hydrothermal gold deposits in Mendoke and Rumbia mountain consist of 3 (three) alterations namely sericitic, argillic dan propylitic. Characteristics of mineralization hydrothermal gold deposits in the research area are generally p related to gold-bearing quartz veins/veinlets consist of chalcopyrite, pyrite, chrysocolla, covellite, cinnabar, magnetite, hematite and goetite in rocks categorized into greenschist facies. There are three generations of veins identified including the first is parallel to the foliations, the second crosscut the first generation of veins/foliations, and the third is of laminated deformed quartz+calcite veins at the late stage. The  quartz veins commonly deformed, segmented, massive, laminated,   irregular, brecciated, and occasionally sigmoidal. The veins contain erratic gold in various grades from below detection limit <0.0002 ppm to 18,4000 at found in third generation veins which are laminated quartz±calcite in argillic alteration. ppm. The protoliths of metamorphic rocks in Rumbia Mountain, which comes from sedimentary rocks, spesifically pelitic rocks and graywacke. Based on those characteristics, it obviously indicates that the primary gold deposit present in the study area is of orogenic gold deposits type. The orogenic gold deposit is one of the new targets for exploration in Indonesia.

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Air tanah atau air sumur merupakan sumber air bersih terbesar yang digunakan. Kendala yang paling sering ditemui dalam menggunakan air tanah adalah masalah kandungan zat besi (Fe) dan zat Kapur (CaCO3) yang terdapat dalam air baku. Air yang tercemar logam Fe dan zat kapur yang tinggi, bila akan dikonsumsi maka perlu dilakukan pengolahan terlebih dahulu. Pengolahan air untuk menurunkan kadar Fe dan zat kapur dalam air dapat dilakukan secara kimia dan fisika. Proses adsorpsi zat besi (Fe) dan zat kapur (CaCO3) dalam air secara alami dapat dilakukan menggunakan tempurung kelapa, arang sekam padi, biji kelor, maupun kulit pisang. Oleh karena itu, penelitian ini bertujuan untuk mengetahui apakah limbah kulit pisang Kepok (Musa acuminate) dapat digunakan sebagai biofilter zat besi dan zat kapur pada air. Penelitian ini menggunakan metode eksperimen yang akan melihat efektifitas perlakuan limbah kulit pisang kepok sebagai biofilter zat besi dan zat kapur pada air bersih. Penelitian ini akan dilakukan di Laboratorium Kesehatan Daerah Provinsi Sulawesi Tengah mulai dari bulan Januari sampai Juli tahun 2018. Hasil penelitian menunjukkan bahwa Limbah kulit pisang Kepok (Musa acuminate) efek-tif sebagai biofilter zat besi (Fe) dan tidak efektif sebagai biofilter zat kapur (CaCO3).

Penelitian ini dilakukan di Pegunungan Mendoke pada Lengan Tenggara Pulau Sulawesi Indonesia. Tujuan penelitian adalah untuk mengetahui geomorfologi, stratigrafi dan struktur geologi di Pegunungan Mendoke. Metode penelitian yang digunakan adalah studi pustaka, pekerjaan lapangan, analisis laboratorium berupa analisis petrografi, serta interpretasi data labororium dan  hasil pengamatan lapangan. Hasil penelitian menunjukkan bahwa geomorfologi di daerah penelitian terdiri atas 3 (tiga) satuan, yaitu satuan dataran rendah, satuan perbukitan rendah berlereng sangat landai hingga agak curam dan  satuan pegunungan berlereng agak curam hingga sangat curam. Adapun stratigrafi daerah penelitian dibagi menjadi 7 (tujuh) satuan, yaitu Satuan Sekis Mengkoka, Satuan Sekis Pompangeo, Satuan Intrusi Diorit, Satuan Serpentinit Harzburgit Ultramafik, Satuan Batupasir Konglomerat Langkowala, Satuan Batupasir Boepinang dan Satuan Endapan Aluvial. Daerah penelitian dikontrol oleh struktur geologi berarah tenggara-baratlaut dan  timur-barat. Katakunci: Pegunungan Mendoke, geomorfologi, stratigrafi, struktur geologi.