Claim Missing Document
Check
Articles

Found 2 Documents
Search

Identifikasi Pola Struktur Geologi Sebagai Pengontrol Sebaran Mineral Radioaktif Berdasarkan Kelurusan Pada Citra Landsat-8 di Mamuju, Sulawesi Barat Indrastomo, Frederikus Dian; Sukadana, I Gde; Suharji
EKSPLORIUM Vol. 38 No. 2 (2017): NOVEMBER 2017
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2017.38.2.3874

Abstract

Mamuju area and its surrounding are composed of volcanic rock containing uranium (U) and thorium (Th) elements. Radioelements concentrations in the area reach 1,529 ppm eU and 817 ppm eTh. Radioactive minerals identified in the area are thorianite, davidite, gummite, and autunite. The geological structures were formed by tectonic activities which controlled the creation of volcanic complex and U-Th mineralization in the complex. Identification of geological structure in the field is very difficult due to densely vegetation and higly degree of weathering. The interpreted lineaments from Landsat-8 imagery are the manifestation of geological structures which have controlled the existence of U and Th. Lineaments analysis using Sastratenaya formula is used to obtain the relative age and chronologies of the lineaments. Dose rate measurements in the area show the trend of radioactivitiy anomalies are trending northwest–southeast. The Sastratenaya formula results the formed structures are relatively older and dominantly directing northwest–southeast (N 140o–150o E). Based on the linement interpretation, the dominant direction has similliarity with volcanic and radioactivity distribution. Structures which controlling the volcanic formation and related to U and Th mineralization generally are the northwest–southeast trending structures, which were created along with U and Th mineralization.
Geostatistics Application On Uranium Resources Classification: Case Study of Rabau Hulu Sector, Kalan, West Kalimantan Syaeful, Heri; Suharji
EKSPLORIUM Vol. 39 No. 2 (2018): NOVEMBER 2018
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17146/eksplorium.2018.39.2.4960

Abstract

In resources estimation, geostatistics methods have been widely used with the benefit of additional attribute tools to classify resources category. However, inverse distance weighting (IDW) is the only method used previously for estimating the uranium resources in Indonesia. The IDW method provides no additional attribute that could be used to classify the resources category. The objective of research is to find the best practice on geostatistics application in uranium resource estimation adjusted with geological information and determination of acceptable geostatistics estimation attribute for resources categorization. Geostatistics analysis in Rabau Hulu Sector was started with correlation of the orebody between boreholes. The orebodies in Rabau Hulu Sectors are separated individual domain which further considered has the hard domain. The orebody-15 was selected for further geostatistics analysis due to its wide distribution and penetrated most by borehole. Stages in geostatistics analysis cover downhole composites, basic statistics analysis, outliers determination, variogram analysis, and calculation on the anisotropy ellipsoid. Geostatistics analysis shows the availability of the application for two resources estimation attributes, which are kriging efficiency and kriging variance. Based on technical judgment of the orebody continuity versus the borehole intensity, the kriging efficiency is considered compatible with geological information and could be used as parameter for determination of the resources category.