Kalan is one of the focus areas for uranium exploration in West Borneo that conducted by BATAN. Situated in the central part of Kalan, previous works in Rabau Hulu Sector consisted of surface geology and radiometric anomaly mapping, trenching, drilling, logging, and conventional uranium resource estimation. Nevertheless, the complete resource estimation of the previous work was still using 2D modeling, and the latest one using 3D modeling is a method-application case study in one orebody. To increase the confidence level and completing the uranium resource estimation of all orebodies in this sector, a geostatistical estimation with 3D orebody modeling using SURPAC mine planning software was conducted in this paper. Gamma-ray log data from 32 drill holes were collected and then interpreted to obtain uranium grade-thickness data. Based on the correlation of grade-thickness data according to surface orebody orientation, the orebody 3D modeling was done. It resulted in 26 orebodies with one control system of lithology as the mineralization only taken place in the quartzite unit. This 3D model then used as a constraint for block model with 4x4x2 m block size and 0.25x0.25x0.125 m minimum block size. Block model calculation was performed using ordinary kriging which generated the kriging efficiency attribute for the determination of the resource category. Within 25 meters searching radius, the calculation resulted in 408, 480 tons of ore, while total uranium resource was 268 tons of uranium with 677 ppm average grade. There were 214 tons of uranium (79%) categorized as measured while the other 54 tons of uranium (21%) categorized as indicated.
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. ABSTRAK Pada estimasi sumber daya, metode geostatistik telah banyak digunakan dengan kelebihan adanya alat atribut tambahan untuk mengklasifikasikan kategori sumber daya. Namun demikian, pembobotan inverse distance (IDW) adalah satu-satunya metode yang sebelumnya digunakan untuk mengestimasi sumber daya uranium di Indonesia. Metode IDW tidak memberikan tambahan atribut yang dapat digunakan dalam mengklasifikasikan kategori sumber daya. Tujuan dari penelitian adalah mendapatkan praktek terbaik untuk aplikasi geostatistik pada estimasi sumber daya disesuaikan dengan informasi geologi dan penentuan atribut geostatistik yang dapat digunakan untuk kategorisasi sumber daya. Analisis geostatistik di Sektor Rabau Hulu diawali dengan korelasi tubuh bijih antara lubang bor. Tubuh-tubuh bijih di Sektor Rabau Hulu merupakan domain individual yang selanjutnya dipertimbangkan memiliki domain tegas. Tubuh bijih-15 dipilih untuk digunakan pada analisis geostatistik selanjutnya karena distribusinya yang luas dan paling banyak dipenetrasi bor. Tahapan dalam analisis geostatistik mencakup komposit downhole, analisis statistik dasar, determinasi outliers, analisis variogram, dan perhitungan ellipsoid anisotropi. Analisis geostatistik menghasilkan kemungkinan aplikasi dua atribut estimasi sumber daya, yaitu kriging efisiensi dan kriging varians. Berdasarkan penilaian teknis kemenerusan tubuh bijih terhadap intensitas lubang bor, kriging efisiensi dipertimbangkan sesuai dengan informasi geologi dan dapat digunakan sebagai parameter untuk penentuan kategori sumber daya.
This research aims to describe responds and cultural practice that happened in Mangkunagaran based on the repression of tourism world. This research is an analytical research based on ethnographic study. Triangulation data is collected from the interviewees together with the manuscript of dance performance and direct observation of Bedhaya Bedhah Madiun dance. Classification of tourism dance is responded by Puro Mangkunagaran as the objectification of Bedaya Bedhah Madiun as a free dance. The cultural response potentially alters the semiotic sign system associated with 'bedhaya' sign. This is a sign to Bedhaya to add the profanity of Bedaya as a tourist attraction. The objectivity of Bedhaya Bedhah Madiun by Puro Mangkunegara also has a potency to deconstruct the understanding of Bedhaya Bedhah Madiun as a tourist attraction, Bedhaya Bedhah Madiun is not an imitation from the origin and it is not full of variation. Cheap or expensive the dance is, becomes relative. Furthermore, secrecy does not exist in the stage reality, but moves to hyper reality (in the fantasy and nostalgia of the audience). Respond and cultural practice of indicated Puro Mangkunagaran as a cultural institution which is active in doing the production-reproduction of meaning and the tourism enhancement.
ABSTRAKDaerah Mamuju dan sekitarnya tersusun atas batuan gunung api dengan komposisi mineral mengandung unsur radioaktif seperti uranium (U) dan thorium (Th). Konsentrasi unsur radioaktif di daerah ini mencapai 1.529 ppm eU dan 817 ppm eTh. Mineral-mineral radioaktif yang teridentifikasi terdiri dari thorianite, davidite, gummite, dan autunite. Aktivitas tektonika kemunculan gunung api menyebabkan terbentuknya struktur-struktur geologi yang mengontrol pembentukan kompleks gunung api dan mineralisasi U-Th di daerah tersebut. Identifikasi struktur geologi regional dan rinci di lapangan sangat sulit dilakukan karena vegetasi yang lebat dan tingkat pelapukan yang tinggi. Kelurusan hasil interpretasi dari citra Landsat-8 merupakan manifestasi keberadaan struktur geologi yang mengontrol keberadaan U dan Th. Analisis kelurusan punggung bukit menggunakan formula Sastratenaya digunakan untuk mengetahui umur dan kronologi kelurusan yang terbentuk. Pengukuran laju dosis di daerah penelitian menunjukkan kecenderungan arah sebaran anomali radioaktivitas berarah tenggarabaratlaut. Hasil analisis menggunakan formula Sastratenaya menunjukkan bahwa struktur yang terbentuk adalah struktur berumur relatif tua dan memiliki arah dominan tenggara-baratlaut (N 140-150 o E). Berdasarkan interpretasi kelurusan, arah dominan memiliki kemiripan dengan arah sebaran gunung api dan sebaran radioaktivitas. Struktur yang mengontrol pembentukan gunung api dan terkait dengan mineralisasi U dan Th secara umum merupakan struktur berarah tenggara-baratlaut dan terbentuk bersamaan dengan proses mineralisasi U dan Th.Kata kunci: uranium, thorium, struktur geologi, kelurusan, formula Sastratenaya, landsat-8 ABSTRACT Mamuju area and its surrounding are composed of volcanic rock containing uranium (U) and thorium (Th) elements. Radioelements concentrations in the area
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