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All Journal Jurnal Geocelebes Jurnal Ilmiah Ilmu Terapan Universitas Jambi JURNAL TEKNOLOGI MINERAL FT UNMUL
Indrajati, Rahmat
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Control & Systems Engineering Earth & Planetary Sciences Education Energy Engineering Industrial & Manufacturing Engineering Mechanical Engineering

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Estimasi Sumber Daya Batubara Menggunakan Metode Poligon Pada PT. Jhonlin Baratama Kecamatan Sebamban, Kabupaten Tanah Bumbu, Provinsi Kalimantan Selatan Dzulfikar, Trio; Nahumury, Bevie; Indrajati, Rahmat; Tandy, Lia Medy
JURNAL TEKNOLOGI MINERAL FT UNMUL Vol 12, No 1 (2024): Jurnal Teknologi Mineral FT UNMUL Juni 2024
Publisher : Universitas Mulawarman

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30872/jtm.v12i1.10255

Abstract

Perhitungan sumber daya batubara merupakan hal dasar yang harus dilakukan dalam setiap kegiatan tambang, hal tersebut merupakan langkah awal yang nantinya akan digunakan sebagai kajian dalam tahapan selanjutnya (eksploitasi). Perhitungan sumber daya batubara yang akurat membantu para perancang tambang untuk membuat rencana penambangan yang optimal, baik dari segi produksi, segi waktu dan segi efisiensi biaya, yang bermuara pada pengambilan keputusan dalam teknis eksploitasi cadangan yang bernilai ekonomis. Tujuan penelitian ini adalah untuk mengetahui karakteristik batubara didaerah penelitian, mengetahui pola sebaran lapisan batubara, serta mengetahui besaran sumber daya tereka, tertunjuk dan terukur pada PT. Jhonlin Baratama di IUP GAJ Kecamatan Sebamban, Kabupaten Tanah Bumbu, Provinsi Kalimantan Selatan. Berdasarkan data geologi regional daerah penelitian, termasuk ke dalam cekungan Barito dan termasuk ke dalam Formasi Warukin berumur Miosen Tengah sampai Miosen Akhir.Metode yang digunakan dalam perhitungan sumber daya batubara adalah metode Poligon Donut dengan menggunakan aplikasi Ventyx Minescape 5.7. Data yang digunakan yaitu data pemboran sebanyak 38 titik bor, data survei, serta data litologi. Data hasil pemboran yang telah didapatkan kemudian diolah menggunakan aplikasi Ventyx Minescape 5.7 sehingga diperoleh luas area sebesar 1229,32 Ha, dan hasil estimasi sumber daya tereka sebesar 4,326,355 ton, sumber daya tertunjuk sebesar  3,891,293 ton, dan sumber daya terukur sebesar 115,700,907 ton.
Assessment of Ground Deformation and Landslide Susceptibility Using InSAR and Hypsometric Data in Jayapura City, Papua Anas, Nur Ayu; Hasudungan, Harsan Ingot; Indrajati, Rahmat; Yonas, Marcelino N.; Hutami, Harnanti Y.
JURNAL GEOCELEBES Vol. 9 No. 2: October 2025
Publisher : Departemen Geofisika, FMIPA - Universitas Hasanuddin, Makassar

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.70561/geocelebes.v9i2.45404

Abstract

Ground deformation and landslides are major geohazards affecting Jayapura City, Papua, due to its active tectonic setting and steep topography. This study aims to assess the correlation between surface deformation and landslide susceptibility using a combination of Interferometric Synthetic Aperture Radar (InSAR) and hypsometric analysis. Sentinel-1A SAR data from ascending and descending tracks, combined with DEMNAS elevation data, were used to detect deformation patterns and evaluate geomorphological maturity through hypsometric parameters. The results reveal significant deformation patterns, including subsidence up to –0.77 m and uplift up to +0.25 m, predominantly concentrated in sub-watersheds Sw2, Sw3, and Sw4. Hypsometric analysis indicates that most sub-watersheds are in the mature geomorphological stage (HI between 0.476 and 0.495), except Sw14, which is classified as young (HI = 0.501). Validation with the landslide inventory further confirms this correlation: 75% of documented landslides occurred in areas of high deformation, while 25% were associated with moderate deformation, and none in low or stable zones. These findings provide essential insights for disaster risk reduction, highlighting priority areas for slope stabilization, land-use management, and early warning systems.
MINERALOGICAL ANALYSIS OF ROCK WEATHERING AND ITS INFLUENCE ON SLOPE FAILURE ALONG THE JAYAPURA CITY RING ROAD Karapa, Enos; Joni, Joni; Hartiningsih, Endang; Yonas, Marcelino Novryanto; Indrajati, Rahmat; Patabang, Djuarensi; Anas, Nur Ayu
Jurnal Ilmiah Ilmu Terapan Universitas Jambi Vol. 10 No. 2 (2026): Volume 10, Nomor 2, April 2026
Publisher : LPPM Universitas Jambi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22437/jiituj.v10i2.54453

Abstract

Slope failure along the Jayapura City Ring Road persisted despite shotcrete reinforcement, indicating that instability is not controlled solely by slope geometry or surface confinement. Field evidence points to weakening within foliated metamorphic rocks affected by tropical weathering, where mineral alteration progressively modifies the internal structure. This study examines how mineralogical transformations govern subsurface degradation and contribute to failure beneath reinforced slopes. A case study approach was applied using two representative samples (ST-01 and ST-02) obtained directly from the failure zone. Petrographic analysis of ~30 μm thin sections was conducted to evaluate mineral textures, fabric orientation, and alteration pathways. X-ray diffraction (XRD) was used to identify and semi-quantify the mineral phases, including albite, quartz, chlorite, muscovite, sericite, and magnetite. Subsurface conditions were assessed using ADMT resistivity profiling across a frequency range of 0.0001–10,000 Hz, reaching depths of approximately 300 m. The results indicate a mineralogical transition from a wollastonite–actinolite–chlorite assemblage in ST-01 to a chlorite–muscovite–sericite-dominated system in ST-02. The XRD data show a decrease in albite from ~19.74% to ~11.61%, while an unresolved fraction exceeding ~20% suggests the presence of poorly crystalline phases. Petrographic observations revealed that chlorite and sericite were concentrated along foliation and microfractures. The resistivity data identified a low-resistivity zone (10–20 Ωm) at depths of ~10–60 m, corresponding to altered and fluid-influenced domains. These findings indicate that weathering reduces cohesion along structurally controlled planes while preserving partial framework integrity, shifting the locus of failure to the subsurface beneath the shotcrete layer.
Co-Authors Anas, Nur Ayu Dzulfikar, Trio Endang Hartiningsih Hasudungan, Harsan Ingot Hutami, Harnanti Y. Joni Karapa, Enos Marcelino N. Yonas Nahumury, Bevie Patabang, Djuarensi Tandy, Lia Medy Yonas, Marcelino Novryanto