Eksplorium: Buletin Pusat Pengembangan Bahan Galian Nuklir (Nov 2019)

Validitas dan Reliabilitas Data Estimasi Kadar Uranium Sektor Lembah Hitam, Kalan, Kalimantan Barat

  • Adi Gunawan Muhammad,
  • Frederikus Dian Indrastomo

DOI
https://doi.org/10.17146/eksplorium.2019.40.2.5672
Journal volume & issue
Vol. 40, no. 2
pp. 75 – 88

Abstract

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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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