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Validitas dan Reliabilitas Data Estimasi Kadar Uranium Sektor Lembah Hitam, Kalan, Kalimantan Barat
DOI: http://dx.doi.org/10.55981/eksplorium.2019.5672
Abstract
ABSTRAK
Mineralisasi uranium (U) di Sektor Lembah Hitam pada batuan metalanau dan metapelit sekistosan berasosiasi dengan mineral pirit, pirhotit, magnetit, molibdenit, turmalin, dan kuarsa. Kehadiran mineral U ditandai dengan nilai radiometri batuan yang mencapai 15.000 c/s. Estimasi cepat kadar U adalah menggunakan perhitungan gamma ray hasil logging gross-count gamma lubang bor LH-01. Penelitian ini bertujuan untuk mendapatkan validitas dan reliabilitas data estimasi kadar U. Hasil estimasi kadar U logging disebandingkan dengan analisis geokimia untuk mendapatkan faktor koreksi (Fk). Analisis geokimia menggunakan metode X-Ray Fluorescence (XRF) pada sampel batuan terpilih di interval kedalaman yang mewakili batuan dan mineralisasi di lubang tersebut. Estimasi kadar U di kedalaman 8,80–9,81 m berdasarkan gross-count gamma ray menunjukkan nilai kadar 456 ppm eU, sementara analisis XRF menunjukkan rerata kadar 177 ppm U. Nilai faktor koreksi (Fk) yang didapatkan dari estimasi kadar di kedalaman 8,80–9,81 m adalah 0,388. Nilai tersebut menunjukkan validitas dan reliabilitas data estimasi yang digunakan rendah. Kesebandingan estimasi kadar U dipengaruhi oleh beberapa faktor, antara lain: sistem logging gross-count gamma ray, ketidaksetimbangan uranium, ukuran sampel, dan unsur radioaktif lainnya. Untuk meningkatkan validitas dan reliabilitas data estimasi, maka diperlukan penambahan sampel analisis XRF dengan mempertimbangkan lingkar dan interval kedalaman lubang bor.
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.
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[1] S. Tjokrokardono, D. Soetarno, M. S. Sapardi, L. Subiantoro, and R. Witjahyati, “Studi Geologi Regional dan Mineralisasi Uranium di Pegunungan Schwanner Kalimantan Barat dan Tengah,” in Prosiding Seminar Geologi Nuklir dan Sumberdaya Tambang, 2004, pp. 64–84.
[2] IAEA, Technical Reports Series No.212: Borehole Logging for Uranium Exploration, A Manual. Vienna: International Atomic Energy Agency, 1982.
[3] P. R. Williams, C. R. Johnston, R. A. Almond, and W. H. Simamora, “Late Cretaceous to Early Tertiary Structural Elements of West Kalimantan,” Tectonophysics, vol. 148, no. 3–4, pp. 279–297, 1988.
[4] G. A. F. Molengraaff, Borneo-expedition. Geological Explorations in Central Borneo (1893-94) by Dr GAF Molengraaff, Enf Rev Ed. 1902.
[5] Amiruddin and D. S. Trail, “Peta Geologi Lembar Nanga Pinoh Kalimantan Skala 1 : 250.000,” Bandung, 1993.
[6] S. Papeschi, G. Musumeci, and F. Mazzarini, “Heterogeneous Brittle-Ductile Deformation at Shallow Ccrustal Levels Under High Thermal Conditions: The Case of a Synkinematic Contact Aureole in Theinner Northern Apennines, Southeastern Elba Island, Italy,” Tectonophysics, vol. 717, pp. 547–567, 2017.
[7] Ngadenin, F. D. Indrastomo, K. S. Widana, and Widodo, “Identifikasi Keterdapatan Mineral Radioaktif pada Urat-Urat Magnetit di Daerah Ella Ilir , Melawi , Kalimantan Barat,” Eksplorium, vol. 40, no. 1, pp. 33–42, 2019.
[8] H. S. Karyono and M. Ruhland, “Use of Multiscalar Processing of Remotely Sensed Data in Kalan Fracturation Networks West Kalimantan, Indonesie for Future Mineralization Research,” ISPRS J. Photogrametry Remote Sens., vol. 45, pp. 428–441, 1990.
[9] A. S. Sastratenaya, “Deformation et Mobilite Megaprisme Tectonique De Pinoh-Sayan, Kalimantan, Indonesie,” These Docteur, L’Universite Louis Pasteur De Strassbourg, France, 1991.
[10] S. Tjokrokardono, L. Subiantoro, and M. Widodo, “Sintesis Geologi dan Mineralisasi Uranium Kalan dan Sekitarnya, Kalimantan Barat,” 2006.
[11] S. Tjokrokardono, “Prospek Pengembangan Cebakan Uranium di Kalan, Kalimantan,” J. Nukl. Indones., vol. 1, pp. 1–12, 1998.
[12] BATAN-CEA, Prospect to Develop Uranium Deposits in Kalimantan Volume I and II, Introduction General Reconnaissance. 1977.
[13] R. B. Tate, “Cross-border Correlation of Geological Formations in Sarawak and Kalimantan,” Bull. Geol. Soc. Malaysia, vol. 28, pp. 63–96, 1991.
[14] P. E. Pieters and Sanyoto, “Peta Geologi Lembar Pontianak/Nangataman, Kalimantan Skala 1:250.000,” Bandung, 1993.
[15] L. B. Davies, R. Hall, and R. Amstrong, “Cretaceous Crust in SW Borneo: Petrological, Geochemical and Geochronological Constraints from the Schwaner Mountains,” in Proceedings Indonesian Petroleum Association, 38th Annual Convention and Exhibition, 2014, p. IPA14-G-025.
[16] L. B. Davies, SW Borneo Basement: Age, origin and character of igneous and metamorphic rocks from the Schwaner Mountains. London: Royal Holloway University of London, 2013.
[17] N. I. Setiawan, Y. Osanai, N. Nakano, T. Adachi, K. Yonemura, A. Yoshimoto, J. Wahyudiono, and K. Mamma, “An Overview of Metamorphic Geology from Central Indonesia: Importance of South Sulawesi, Central Java and South–West Kalimantan Metamorphic Terranes,” Bull. Grad. Sch. Soc. Cult. Stud. Kyushu Univ., vol. 19, pp. 39–55, 2013.
[18] N. I. Setiawan, Y. Osanai, N. Nakano, T. Adachi, L. D. Setiadji, and J. Wahyudiono, “Late Triassic Metatonalite from the Schwaner Mountains in West Kalimantan and its contribution to Sedimentary Provenance in the Sundaland,” Ber. Sedimentol., vol. 12, no. 28, pp. 4–12, 2013.
[19] H. T. Breitfeld, R. Hall, T. Galin, M. A. Forster, and M. K. BouDagher-Fadel, “A Triassic to Cretaceous Sundaland-Pacific Subduction Margin in West Sarawak, Borneo,” Tectonophysics, vol. 694, pp. 35–56, 2017.
[20] S. Tjokrokardono and A. S. Sastratenaya, “Rich Mineralized Boulders of the Rirang River, West Kalimantan.,” in Proceeding of Technical Committe Meeting on Uranium Deposits in Asia and the Pacific: Geology and Exploration, 1988.
[21] J. Pablo, R. Lozano, and J. P. Bernal, “Characterization of A New Set of Eight Geochemical Reference Materials for XRF Major and Trace Element Analysis,” Rev. Mex. Ciencias Geológicas, vol. 22, no. 3, pp. 329–344, 2005.
[22] D. C. George, B. E. Heistand, and J. E. Krabacher, “Grade Assignments for Models Used for Calibration of Gross-Count Gamma-Ray Logging Systems.” U.S. Dept. of Energy Asistant Secretary for Nuclear Energy, Colorado, p. 62, 1983.
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