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INDONESIA
Eksplorium : Buletin Pusat Pengembangan Bahan Galian Nuklir
Published by Badan Riset dan Inovasi Nasional
ISSN : 08541418     EISSN : 2503426X     DOI : https://doi.org/10.55981/eksplorium
Core Subject : Science, Engineering,
Chemical Engineering, Chemistry & Bioengineering Earth & Planetary Sciences Energy Engineering Materials Science & Nanotechnology
EKSPLORIUM is published to deliver the results of studies, research and development in the field of nuclear geology. The manuscripts are the result of study, research and development of nuclear geology with scope: geology, exploration, mining, nuclear minerals processing, safety and environment, and development of nuclear technology for the welfare.
Arjuna Subject : Ilmu Bumi dan Planet (semua kategori) - Geologi
Articles 176 Documents
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Tectonic Structure of Northern Sumatra Region Based on Seismic Tomography of P and S Wave Velocity Silitonga, Beatrix Elisabet; Suardi, Imam; Firmansyah, Akmal; Hanif, Muhammad; Ramdhan, Mohamad; Sembiring, Andry Syaly
EKSPLORIUM Vol. 44 No. 1 (2023): MAY 2023
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6784

Abstract

The tectonic setting of Sumatra Island is strongly influenced by the oblique subduction of the Indo-Australian Plate, which subducts the Eurasian Plate at a speed of 52–60 mm/year. The movement of these plates resulted in the Northern Sumatra region having seismic sources from tectonic and volcanic activity. The data used in this study is in the form of seismic wave travel-time recorded by numerous seismic stations in the research area from January 2012 to December 2020. The data comes from 5,003 earthquakes recorded by the BMKG seismic network. The inversion is a simultaneous inversion between seismic velocity models (Vp and Vs) and hypocenter parameters by applying a double-difference seismic tomography algorithm. Tomogram results in parts of Aceh (Singkil and Subulussalam) and North Sumatra (Pakpak Bharat and Dairi) at a depth of 0 km show negative perturbations in Vp and Vs values and high Vp/Vs values. The anomaly is most likely related to cracks in fluid-saturated rocks. The tomograms in the south of Lake Toba at depths of 30 km and 40 km have high Vp and Vs perturbation values and low Vp/Vs values. This anomaly indicates a magma supply line that is no longer active or has cooled for a long time. Based on the seismic tomography modeling results, the subducted Indo-Australian Plate to the Eurasian Plate is visible in the study area.
Magmatic Evolution of Dago Volcano, West Java, Indonesia Adimedha, Tyto Baskara; Harijoko, Agung; Handini, Esti; Sukadana, I Gde; Syaeful, Heri; Ciputra, Roni Cahya; Rosianna, Ilsa; Indrastomo, Frederikus Dian; Pratiwi, Fadiah; Rachael, Yoshi
EKSPLORIUM Vol. 44 No. 1 (2023): MAY 2023
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6873

Abstract

Dago Volcano is a product of Miocene Sunda Arc volcanism located southeast of the capital city of Jakarta. The morphological change from flat lava flow to steeper lava morphology implies a process of magma evolution under Dago Volcano. This research provides an overview of the magma evolution that occurs on this volcano. The methods used include volcanostratigraphic analysis, petrographic analysis, mineral chemistry, and whole-rock geochemistry. The volcanostratigraphy of Dago Volcano is composed of two eruption centers and a flank eruption forming lava and cinder cones products. The mineralogical associations of Dago Volcano products include plagioclase, olivine, and clinopyroxene. The mineral textures of Dago edifices show zoning, sieve, and reaction rims textures. Geochemically, the Dago Volcano product has a magma affinity of med-K calc-alkaline with quite high levels of MgO, Ni, and Cr approaching the characteristics of primitive magma. The magma evolution process of Dago Volcano includes fractional crystallization and magma mixing which originates from the same magma source.
Characteristics of Nitrate Pollution in Shallow Groundwater on the South Slope of Mount Merapi, Yogyakarta, Indonesia Adi, Restu Dwi Cahyo; Wilopo, Wahyu; Setiawan, Hendy
EKSPLORIUM Vol. 44 No. 1 (2023): MAY 2023
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6876

Abstract

Groundwater is the primary clean water source for most Indonesian society. The increasing use of groundwater is inevitable due to the rapid development in Indonesia, particularly in Yogyakarta. Shallow aquifers are vulnerable to contamination due to anthropogenic influences. Therefore, this research aims to determine shallow groundwater's physicochemical and chemical characteristics on the southern slope of Mount Merapi, specifically focusing on nitrate and chloride concentrations in groundwater. This research collected monthly data from eighteen dug wells or springs and rainfall data in the study area during the rainy and dry seasons from August 2022 to January 2023. The analyzing sample used argentometry to determine chloride concentration and ultraviolet spectrophotometric to determine nitrate concentration in Yogyakarta Environmental Health and Disease Control Technical Center (BBTKLPP) laboratory. The physicochemical parameters were tested directly in the field using Hanna instruments. The results indicate that a significant portion of shallow groundwater has high nitrate concentrations, corresponding to the growing settlements in the research area. Furthermore, according to the comparison graph between nitrate and chloride, the nitrate source was indicated as anthropogenic. Fecal matter from sanitation practices using septic tanks will likely influence the nitrate increase.
Prediction of Potential Acid Mine Drainage Formation in High Sulfidation Epithermal Deposit using Geochemical and Mineralogy Approaches Syaputra, Rizky; Kusuma, Ginting Jalu; Badhurahman, Abie
EKSPLORIUM Vol. 44 No. 1 (2023): MAY 2023
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6652

Abstract

Identification of acid mine drainage (AMD) can be predicted using a geochemical and mineralogy characterization approach to identify rocks forming and neutralizing acids. Geochemical characterization using static and kinetic tests. The static test is the first step to determining the potential for acid formation in rocks by comparing the potential for forming and neutralizing acids, which are characterized by uncertain behavior that causes predictions to be inaccurate. Kinetic tests were carried out to predict the long-term acid-producing potential better. Furthermore, mineralogical characterization is needed to assess the importance of sample mineral content in predicting AMD. Tests were conducted on rock samples from high sulfidation epithermal (HSE) deposits in North Sulawesi, Indonesia. The samples represent the different geological domain conditions found in HSE deposits. The main acid-producing components are pyrite and secondary minerals (alunite) capable of buffering acidity. The results showed a lower change in leachate pH (from day 30 to 180) and were accompanied by the release of species (high dissolved metals).
The Effect of Fly Ash Ratio Addition as Layering Material Using Free Draining Column Leach Test Method on Laboratory Scale Hernanda, Suriandi; Kusuma, Ginting Jalu; Badhurahman, Abie; Syaputra, Rizky
EKSPLORIUM Vol. 44 No. 1 (2023): MAY 2023
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6707

Abstract

Acid mine drainage (AMD) is formed due to the oxidation of sulfide minerals in the presence of water and air. AMD already entering the environment can damage the aquatic ecosystem due to low pH and high dissolved metal concentrations. Efforts to prevent the formation of AMD are by regulating the stockpiling of materials containing sulfide or potential acid forming (PAF) with non-acid forming (NAF) to avoid oxidation reactions of sulfide minerals. The purpose of this study was to simulate the effect of adding fly ash ratio as a PAF rock coating material to the quality characteristics of leachate using the laboratory-scale free draining column leach test (FDCLT) method. Adding fly ash ratio as a layering material significantly affects the quality of the resulting leachate. This is due to the physical condition of the fly ash material, which cannot prevent the meeting of AMD-forming components.
Radioactive Mineral Distribution on Tin Placer Deposits of Southeast Asia Tin Belt Granite in Bangka Island Ngadenin, Ngadenin; Sukadana, I Gde; Muhammad, Adi Gunawan; Indrastomo, Frederikus Dian; Rosianna, Ilsa; Ciputra, Roni Cahya; Adimedha, Tyto Baskara; Pratiwi, Fadiah; Rachael, Yoshi
EKSPLORIUM Vol. 44 No. 2 (2023): NOVEMBER 2023
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6969

Abstract

Bangka Island is an area rich in primary and secondary tin deposits. Tin deposits are formed around the contact between granite and older rocks, while secondary tin deposits are formed in the modern channels and paleochannels. Many previous researchers have researched radioactive minerals in primary tin deposits and modern channel deposits, but research on radioactive minerals in paleo channel deposits has never been carried out. The characterization of radioactive minerals in paleo channel deposits was done in this study to determine the potency of radioactive minerals in secondary tin deposits by comparing the content of radioactive minerals in paleochannels with modern channels and tin mine tailing deposits. The data used were mineralogical data and radioactivity data, along with the uranium and thorium content of the rocks from several previous studies. Data showed significant mineral content differences in paleo channel, modern channel, and tin mine tailings deposits. Mineral (monazite and zircon) content in tin mine tailing deposits was the highest. Source rocks for the radioactive minerals monazite and zircon are predicted to be the granitic rocks or tourmaline quartz veins of primary tin deposits. The radioactivity value of rocks in the paleo channel is relatively the same as the modern channel, ranging from 20 to 150 c/s. Uranium content in paleo channel is the same as modern channel deposits, ranging from 10 to 15 ppm eU. The thorium content of the rocks in the paleo channel ranges from 1 to 60 ppm eTh, while in the modern channel, it ranges from 1 to 45 ppm eTh. The radioactivity value and uranium content of the rocks are less effective for determining potential areas of radioactive minerals in placer tin deposits. In contrast, data on thorium content are quite effective for determining potential areas of radioactive minerals in placer tin deposits.
Validation of The Gravimetry Method for Determining Rare Earth Elements Oxides Pratama, Afiq Azfar; Hidayat, Amalia Ekaputri; Rommy; Indryati, Suci; Laksmana, Roza Indra; Trinopiawan, Kurnia; Purwanti, Tri; Widana, Kurnia Setiawan; Putra, Aditya Widian; Anggraini, Mutia; Nasrullah, Dzaki Hasan
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.2024.6972

Abstract

The demand for minerals to meet technological developments is increasing, including minerals that contain rare earth elements (REE). The levels of REE in solids can be determined using conventional analysis methods (gravimetry) and instruments. Even though the instrument method provides more accurate results with a small amount of analyte, the cost is higher compared to the gravimetric method, which requires more analyte and provides good results. Therefore, the gravimetric method is a solution for areas with limited instruments and budgets. The study aims to validate the gravimetric method for determining REE oxides levels, evaluate its precision and accuracy, and assess its feasibility of use. In this study, two methods were used for REE analysis: the ASTM E2941-14 method with sample weight modification and the addition of acid to increase REE oxides recovery and a precipitation method using oxalic acid. The validation stages include sample dissolution, precipitation, filtration, and ash-making. The research results show that the RSD value is 0.3154, which is smaller than 2/3 of Horwitz's CV, namely 4.1727, which means it meets the precision acceptance requirements of ISO/IEC 17025:2017. The REE oxides recovery value, which indicates accuracy, also increased to 97.74%. Therefore, the gravimetric method can be used as an alternative for determining REE oxides levels.
Empirical Equation between Predominant Frequency and Sediment Thickness in Plampang, West Nusa Tenggara Iswanto, Eko Rudi; Riyanto, Theo Alvin; Suntoko, Hadi
EKSPLORIUM Vol. 44 No. 2 (2023): NOVEMBER 2023
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6918

Abstract

Soil characteristics mapping is one of the essential aspects in the development of a region. Soil characteristics such as the predominant frequency and thickness of the sediment layer are needed to ensure the capacity of soil against the load of an infrastructure construction. The existence of tectonic activity causes West Nusa Tenggara Province to be an area with high seismic activity. Along with the plan to accelerate the development of the Samota Area, seismic studies are one of the aspects that determine project feasibility. The predominant frequency value from the results of microtremor measurements is used in the development of an empirical formula to predict soil thickness in the Plampang area. The empirical formula from previous research is used as a conformity test of the empirical formula obtained. Empirical equations are then used to map variations in sediment thickness in the Plampang area, which are justified based on geological data. The results of the sediment thickness map based on the empirical formula for the Plampang area showed a good correlation with the predominant frequency and also showed a good correlation with the results of the formula that has been carried out by previous studies
Separation of Thorium (Th) from Monazite Sand of Bangka Island using Primene JMT Solvent Extraction Method Claudia, Dita; Fabiani, Verry Andre; Nurhadini, Nurhadini; Prassanti, Riesna
EKSPLORIUM Vol. 44 No. 2 (2023): NOVEMBER 2023
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6480

Abstract

Thorium is an essential element as an alternative nuclear fuel to replace uranium. Thorium is found in the mineral monazite, which is a by-product of the alluvial tin mining process. Many methods have been used to extract and separate thorium from uranium and REEs from monazite, one of which is the organic solvent extraction method. In this research, the primene JMT, which is an extractant of primary amine compounds, was used in the method. The studied parameters are feed pH, JMT primene concentration, and stirring speed. The results show that the optimum conditions for Th extraction in monazite using solvent extraction method primene JMT were obtained at pH 0.5, extractant concentration of 2%, and stirring speed of 300 rpm with Th recovery of 94.05% while U and REE were not extracted.
Analytical Method Validation of Thorium in Ore Sample Using UV-Vis Spectrophotometer Indryati, Suci; Hidayat, Amalia Ekaputri; Pratama, Afiq Azfar; Laksamana, Roza Indra; Widana, Kurnia Setiawan; Ramlan, Muhammad Alif; Purwanti, Tri; Prassanti, Riesna; Anggraini, Mutia; Rommy, Rommy
EKSPLORIUM Vol. 44 No. 2 (2023): NOVEMBER 2023
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/eksplorium.2023.6965

Abstract

Monazite contains several rare earth elements (REE) along with radioactive elements, i.e., thorium (Th) and uranium (U). Thorium content in monazite is several times higher than uranium. Monazite contains around 12% thorium oxide, but the thorium content in this mineral varies depending on location. To determine the thorium content in monazite, an appropriate and validated analytical method is needed so that the reliability of the test results can be trusted. Apart from that, method validation is one of the clauses in SNI ISO/IEC 17025:2017 that must be fulfilled by the laboratory to be certified and produce reliable data. This research aims to validate analytical methods for non-standard and modified methods that are likely to be used outside the scope. In this research, the method used to digest and analyze thorium in mineral samples refers to the ASTM E2941-14 method with several modifications. Therefore, the analysis method needs to be validated. Validation of the analytical method is carried out by testing several parameters such as linearity and working range tests, accuracy, precision (repeatability), Limit of Detection (LOD), and Limit of Quantitation (LOQ). The results of linearity, accuracy, and repeatability tests that meet the acceptance requirements can be used as a method of validation evaluation. The results of the method validation parameter test met the acceptance requirements, with the linearity test showing a coefficient of determination (R2) of 0.997, the accuracy test showing % a recovery value of 106.22%, and the precision (repeatability) test showing %RSD of 3.76% with LOD value is 0.650 mg/L, and LOQ is 0.724 mg/L. Based on the results of these parameter tests, the method for analyzing thorium in mineral samples was validated.

Page 16 of 18 | Total Record : 176

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