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Identifikasi Keterdapatan Mineral Radioaktif pada Urat-Urat Magnetit di Daerah Ella Ilir, Melawi, Kalimantan Barat Ngadenin; Indrastomo, Frederikus Dian; Widodo; Widana, Kurnia Setiawan
EKSPLORIUM Vol. 40 No. 1 (2019): MEI 2019
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2019.40.1.5350

Abstract

Ella Ilir administratively located in Melawi Regency, West Kalimantan. Regional geology of Ella Ilir area is composed of metamorphic rocks in Triassic–Carboniferous age which are intruded by Jurassic and Cretaceous granitic rocks. Radioactive minerals occurences in the area are indicated by magnetite veins radioactivities on Triassic to Carboniferous metamorphic rocks whose values range from 1,000 c/s to 15,000 c/s. Goal of the study is to determine the type of ore mineral deposits and to identify the presence of radioactive mineral in magnetite veins in Ella Ilir area. The methods used are geological mapping, radioactivity measurements, analysis on uranium grades, and mineragraphy analysis of severe magnetite veins samples. Lithologies of the study area are composed by biotite quartzite, metatuff, metasilt, metapellite, biotite granite, and ryolite. The east-west sinistral fault and the north-south dextral fault are the developed fault structures in this area. Mineral composition of magnetite veins are consists of iron ore, sulfide, and radioactive minerals. Iron ore mineral consists of magnetite, hematit, and goetite. Sulfide minerals consist of pyrite, pirhotite, and molybdenite, while radioactive minerals consist of uraninite and gummite. The occurences of magnetite veins are controlled by lithology and geological structures. The magnetite veins in metasilt are thick (1.5–5 m), filled the fractures in the fault zone. Meanwhile, the magnetite veins in metapellite are thinner (milimetric–centimetric), filled the fractures that are parallel to the schistocity. The ore deposits in the study area are iron ore deposits or magnetite ore deposits formed by magmatic hydrothermal processes.
Validitas dan Reliabilitas Data Estimasi Kadar Uranium Sektor Lembah Hitam, Kalan, Kalimantan Barat Muhammad, Adi Gunawan; Indrastomo, Frederikus Dian
EKSPLORIUM Vol. 40 No. 2 (2019): NOVEMBER 2019
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2019.40.2.5672

Abstract

Uranium (U) mineralisation in Lembah Hitam Sector in metasilt and schistossic metapellite rocks was assosiated with pyrite, pyrhotite, magnetite, molibdenite, tourmaline, and quartz minerals. The existence of U mineral was marked from its radiometric value reaching 15,000 c/s. The faster way to estimate U grade is using gamma-ray values calculation from gross-count gamma logging at borehole LH-01. The research is aimed to obtain the validity and reliablility of U grade estimating data. The logging estimation result then compared with geochemical analysis to obtain the correction factor (Fk). Geochemical analysis is using X-Ray Fluorescence (XRF) method on selected rock samples represent rock and mineralisastion depth interval inside the borehole. The result of uranium grade estimation using gross-count gamma ray calculation in depth 8.80–9.81 m is 456 eU while based on XRF analysis, the result is 177 ppm U. The correction factor (Fk), obtained from grade estimation at 8.80–9.81 m depth is 0.388. The value indicates that the validity and reliability estimation data is low. Ratio of U grade estimation depends on some factors, like gross-count gamma ray logging system; uranium disequilibrium, sampels size; and other radioactive elements. In order to increase the validity and reliability estimation data, XRF analysis samples should be added by considering the borhole diameter and depth interval.
Penentuan Daerah Prospek Logam Tanah Jarang di Pulau Singkep Ngadenin; Karunianto, Adhika Junara; Indrastomo, Frederikus Dian
EKSPLORIUM Vol. 41 No. 1 (2020): MEI 2020
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2020.41.1.5853

Abstract

Rare earth elements (REE) are strategic material used in high-tech and clean energy devices. In Indonesia, REE contained in monazite, zircon, and xenotime minerals as accessories minerals in tin mining located in the granite tin belt of Riau Islands to Bangka Belitung. Singkep is one of the potential areas of REE because its location is in the granite tin belt. The goal of the study is to determine the REE prospects in Singkep Island. The method used by taking 25 pan concentrated samples on some tailing ex tin mining on the Singkep island. These samples were taken from each rock formation on Singkep Island in sequence from older to younger rocks formation, respectively. They are Permian Carboniferous of Bukit Duabelas quartzites, Permian Carboniferous of Persing Metamorphic Rocks, Triassic Muncung granite, Jurassic Tanjungbuku granite, Holocene swamps deposits and alluvium. Each sample of pan concentrated is divided into two parts for REE content and grain mineral analysis. All 25 samples were analyzed for REE content, while only 14 samples for the grain mineral. The results of REE content and grain mineral analysis indicate that the REE prospect area located in the tailings ex tin mining in the rock formation of the Muncung granite area. The highest concentration of lanthanum reached 20100 ppm, cerium 37100 ppm, yttrium 9872 ppm, and neodymium 2840 ppm in monazite, zircon, and allanite.
Karakterisasi Geoteknik Fondasi Kandidat Tapak PLTN dengan Metode Seismik Refraksi Haryanto, Dwi; Rachael, Yoshi; Kamajati, Dhatu; Prasetyo, Gagah Hari; Syaeful, Heri; Indrastomo, Frederikus Dian
EKSPLORIUM Vol. 42 No. 2 (2021): NOVEMBER 2021
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2021.42.2.6538

Abstract

Presidential Regulation (Perpres) number 38 of 2018 concerning the National Research Master Plan for 2017–2045, the Government of Indonesia establishes several main areas that will become national research priorities, one of which is the energy sector. In the research theme of electricity technology based on new and renewable low/zero carbon energy, there is the topic of research on commercial-scale Nuclear Power Plant (NPP) technology. On the research topic, it was determined that within the research period of 2020–2024, a prototype nuclear power plant would be produced. Research related to the geotechnical characterization of the nuclear power plant site using the seismic refraction method was carried out to complement the previous research data. The purpose of this study was to determine the subsurface rock layer profile for estimation of work related to nuclear power plant foundations. Geological mapping and geophysical data acquisition, processing, as well as soil/rock interpretation based on the compression wave velocity (Vp) parameter are carried out to achieve this goal. The results of geological mapping show that there are 2 igneous rock units, namely quartz diorite and andesite. The results of processing and interpreting seismic refraction data produced a cross-sectional model of Vp in the subsurface rock layers. There are 3 rock layers in the research location, namely soil layer (Vp = 361–715 m/s), weathered igneous rock layer (Vp = 1.386–2,396 m/s), and fresh igneous layer (Vp = 3.789–6.133 m/s). The estimated density of fresh igneous rock based on calculations is 2.43–2.74 g/cm3. The modeling results can show the depth and structure of the subsurface layer of fresh igneous rock that can be the foundation of nuclear power plants.
Interpretasi Vulkanostratigrafi Daerah Mamuju Berdasarkan Analisis Citra Landsat-8 Indrastomo, Frederikus Dian; Sukadana, I Gde; Saepuloh, Asep; Harsolumakso, Agus Handoyo; Kamajati, Dhatu
EKSPLORIUM Vol. 36 No. 2 (2015): NOVEMBER 2015
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2015.36.2.2772

Abstract

Mamuju and its surrounding area are constructed mainly by volcanic rocks. Volcanoclastic sedimentary rocks and limestones are laid above the volcanic rocks. Volcanic activities create some unique morphologies such as craters, lava domes, and pyroclastic flow paths as their volcanic products. These products are identified from their circular features characters on Landsat-8 imagery. After geometric and atmospheric corrections had been done, a visual interpretation on Landsat-8 imagery was conducted to identify structure, geomorphology, and geological condition of the area. Regional geological structures show trend to southeast – northwest direction which is affects the formation of Adang volcano. Geomorphology of the area are classified into 16 geomorphology units based on their genetic aspects, i.e Sumare fault block ridge, Mamuju cuesta ridge, Adang eruption crater, Labuhan Ranau eruption crater, Sumare eruption crater, Ampalas volcanic cone, Adang lava dome, Labuhan Ranau intrusion hill, Adang pyroclastic flow ridge, Sumare pyroclastic flow ridge, Adang volcanic remnant hills, Malunda volcanic remnant hills, Talaya volcanic remnant hills, Tapalang karst hills, Mamuju alluvium plains, and Karampuang reef terrace plains. Based on the Landsat-8 imagery interpretation result and field confirmation, the geology of Mamuju area is divided into volcanic rocks and sedimentary rocks. There are two groups of volcanic rocks; Talaya complex and Mamuju complex. The Talaya complex consists of Mambi, Malunda, and Kalukku volcanic rocks with andesitic composition, while Mamuju complex consist of Botteng, Ahu, Tapalang, Adang, Ampalas, Sumare, danLabuhanRanau volcanic rocks with andesite to leucitic basalt composition. The volcanostratigraphy of Mamuju area was constructed based on its structure, geomorphology and lithology distribution analysis. Volcanostratigraphy of Mamuju area is classified into Khuluk Talaya and Khuluk Mamuju. The Khuluk Talaya consists of Gumuk Mambi, Gumuk Malunda, and Gumuk Kalukku, while Khuluk Mamuju consists of Gumuk Botteng, Gumuk Ahu, Gumuk Tapalang, Gumuk Adang, Gumuk Ampalas, Gumuk Sumare, and Gumuk Labuhan Ranau.
Geologi dan Identifikasi Cebakan Bijih di Daerah Batubesi, Belitung Timur Ngadenin, Ngadenin; Indrastomo, Frederikus Dian; Karunianto, Adhika Junara; Rakhma, Ersina
EKSPLORIUM Vol. 38 No. 1 (2017): MEI 2017
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2017.38.1.3376

Abstract

The Batubesi area in Belitung Timur is located in the eastern part of the Southeast Asian granites tin belt zone, so that it expected as a potential area for the occurence of ore deposit such as iron and cassiterite associate with monazite and other accessories minerals. The study aimed to understand the geological setting and to determine the occurrence of primary ore deposit and its radioactive accessories minerals. The methodologies in this research are geological mapping, uranium and thorium grade measurement, petrography, mineragraphy and grain counting analysis. The area composed by granite and metasandstone units. Types of granites are biotite and hornblende granites. The geological structures founded in this area are SW-NE sinistral and NW-SE dextral faults. Ore deposit in the area is primary iron ore deposits of skarn iron tin polymetallic type where magnetite is the main mineral while monazite and zircon are radioactive accessories minerals. The other accessories minerals are hematite, ilmenite, cassiterite, and rutile.
Pola Tahanan Jenis dan Konduktivitas Batuan Mengandung Mineral Radioaktif di Botteng dan Takandeang, Mamuju, Sulawesi Barat Muhammad, Adi Gunawan; Indrastomo, Frederikus Dian; Sukadana, I Gde
EKSPLORIUM Vol. 38 No. 1 (2017): MEI 2017
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2017.38.1.3540

Abstract

The general investigation activities of radioactive minerals in Mamuju Area, West Sulawesi is a respon of the environmental radioactivity measurement result, which shows the existence of high radioactivity value. High radioactive mineral content found in Botteng and Takandeang Villages. From the outcrops, they composed of leucite-basalt rocks; meanwhile the subsurface characteristics of this area are unknown. To characterize the subsurface geology, related to uranium and thorium mineralization in Botteng and Takandeang area, geophysical measurement conducted using resistivity and Induced Polarization (IP) methods. The measurements carried out using Wenner and dipole-dipole configurations. The measurements started with the creation of six measurement paths where three lines: GF/BTGY-01, GF/BTGK-02, and GF/BTGK-04 are in Botteng and three other lines: GF/TKDK-01, GF/TKDK-07 and, GF/TKDY-06 are in Takandeang. Measurements conducted by crossing the surface radiometric anomaly distribution. The result showed anomaly occurences on autobreccia distribution in GF/TKDY-6, GF/TKDK-07, and GF/BTGK-04 locations. Several mineralization indication on surface identified in GF/BTGK-0, and GF/TKDK-01 sections, charaterized by chargeability anomalies more than 25.14 ms and 81.4 ms respectively. All significant anomalies are recomended as drilling location.
Geological Structure Control on the Formation of Metal Mineralization at Quartz Veins in Jendi Village, Wonogiri Regency, Central Java Widagdo, Asmoro; Sukadana, I Gde; Indrastomo, Frederikus Dian
EKSPLORIUM Vol. 43 No. 2 (2022): NOVEMBER 2022
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2022.43.2.6623

Abstract

Quartz veins in the Jendi area and its surroundings are formed by geological structures with distributions and patterns that need to be known. This study uses data on striation, quartz vein orientation, and metal content in quartz veins. The use of this data aims to determine the relationship between the vein direction pattern and its metal mineral content with the main structure that forms it. The results of this study can be useful in determining the structural model and distribution of veins in the study area. The research method was carried out through a series of field and laboratory work. Fieldwork includes measuring striation data, measuring the orientation of quartz veins, and taking quartz vein samples. Studio work includes stereographic analysis of striation data, rosette diagram analysis of vein measurement data, and analysis of metallic element content of quartz veins. The quartz vein mineralization zone in the study area is controlled by a right slip fault with a northwest-southeast trend that forms a transtension zone with a north-south trend. The north-south trending veins are generally thick, long/continuous, and have a high metal content.
Distribution and Characteristics of Rare Earth Elements in Uranium-Ore Deposits from Rirang Area, West Kalimantan Province, Indonesia Adimedha, Tyto Baskara; Farenzo, Rayhan Aldizan; Sukadana, I Gde; Nugraheni, Rosmalia Dita; Pratiwi, Fadiah; Ciputra, Roni Cahya; Indrastomo, Frederikus Dian; Syaeful, Heri; Rachael, Yoshi
EKSPLORIUM Vol. 45 No. 1 (2024): MAY 2024
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2024.7058

Abstract

Uranium and rare earth elements (REE) are essential elements for the development of green environmentally friendly, and sustainable energy. To meet the increasing demand for these raw materials, Indonesia has taken steps to explore and map potential deposits, including the Rirang Sector in Melawi Regency, West Kalimantan. However, the available information on the mineralization of these elements in the area is limited. Therefore, this study aimed to provide a detailed characterization on the petrology and geochemical characteristics of uranium ore and to synthesize the mineral genesis of uranium and REE-bearing ore in the Rirang Sector. The analytical methods used included petrography, micro-XRF, and geochemical analysis. The results showed that uranium mineralization was present in brannerites, uranophane, and swamboite associated with tourmaline and monazite ore. Similarly, REE concentrations were hosted by REE-bearing minerals, such as monazite, xenotime, and loparite. Geochemically, the uranium concentration in the monazite ore ranged from 1,110 – 28,440 ppm, while the total REE (TREE) concentration varied between 85,320 to 138,488 ppm. The formation of uranium and REE mineralization were due to the metasomatism process and its association with the Na-rich fluid of felsic intrusion. Notably, the weathering process did not enrich uranium and REE content in the soil but rather decreased it due to the leaching process and the absence of clay minerals capable of absorbing the REE cations on the surface of clay crystal structures.
Characterization of Radioactive and Rare Earth Elements in Heavy Minerals from River Sediments in Marau Region, Ketapang, West Kalimantan Pratiwi, Fadiah; Rachael, Yoshi; Widodo; Fauzi, Rachman; Madyaningarum, Nunik; Adimedha, Tyto Baskara; Indrastomo, Frederikus Dian; Sukadana, I Gde
EKSPLORIUM Vol. 45 No. 1 (2024): MAY 2024
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2024.6971

Abstract

Alluvium deposits from the Kendawangan River located in Marau, Ketapang, West Kalimantan have been known for their radioactive and rare earth mineral potential. In this paper, heavy minerals taken from alluvium deposits will be characterized to determine the elemental distribution of uranium, thorium, and rare earth elements in each mineral and their mineralogical composition. The samples are taken by panning and prepared using the flotation method to obtain heavy mineral concentrates. Geochemical analysis was carried out using a Bruker M4 Tornado plus Micro-XRF and continued with mineralogical analysis using AMICS (Advanced Mineral Identification and Characterization System) software. It was found that the distribution of heavy minerals from the sand samples was dominated by manganoan ilmenite, ilmenite, rutile, zircon, magnetite, and monazite, as well as thorite, cassiterite, xenotime, allanite, and other minerals in small quantities. Uranium, thorium, and rare earth elements are found in monazite, thorite, xenotime, zircon, and allanite.