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All Journal Indonesian Journal of Geography Jurnal Ilmiah MTG Proceeding Seminar LPPM UMP Tahun 2014 Techno LPPM Jurnal Ilmu Kebumian Teknologi Mineral (JIK TekMin) Jurnal Ilmiah Geologi pangea Journal of Geosciences and Applied Geology
Herry Riswandi
Department Of Geological Engineering, Faculty Of Mineral Technology, Universitas Pembangunan Nasional Veteran Yogyakarta, Indonesia
Civil Engineering, Building, Construction & Architecture Earth & Planetary Sciences Education Energy Engineering Environmental Science

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ALTERATION AND GOLD MINERALIZATION PANINGKABAN AREAS GUMELAR SUB-DISTRICT, BANYUMAS REGENCY, CENTRAL JAVA PROVINCE Purwanto, Heru Sigit; Riswandi, Herry
Journal TECHNO Vol. 1 No. 1 (2015)
Publisher : Universitas Pembangunan Nasional Veteran Yogayakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31315/journal techno.v1i1.1504

Abstract

The research location is located in Paningkaban area and its surrounding areas that included in the areaof Gumelar Subdistrict, Banyumas Regency, and Central Java Province. The objective of the researchwas to show the presence of any structural geology control on research area that affect the distributionpatterns of quartz vein and gold/ore mineralization.The methodology in this research begins with data collecting process, which this preliminary data is thenbeing compiled to determine the next phase of the study. This study covers the geomorphology,stratigraphy, any structural and alteration mineralization observation. The geomorphology of the studyarea composed of the four original forms: volcanic, structural, karsts and fluvial form. The stratigraphycomposed of seven unclassified litho units and two litodem, namely (from old - young): Halang volcanicbreccias unit, Halang sandstone unit, Kumbang andesite lava unit, Tapak volcanic breccias unit, Tapaksandstones, unit Tapak limestone unit, alluvial deposits, and andesite intrusion.Hydrothermal alterations formed in the research area are carefully grouped into three types of alterationzoning and they are argillic alteration, propylitic alteration, and sub-propylitic alteration. Themineralization then is carefully classified as pyrite (FeS2), chalcopyrite (CuFeS2), galena (Pbs), bornite(Cu5FeS4). The macroscopic analysis of the structure in the study area based on the alignment of allegedtraces of the geological structure in the form of fault, or directions of the fold axis alignment, obtainedthe general alignment directions trending N 305° E (NW - SE), and N 055° E (NE - SW).In the research area, the mineralization process is controlled by geological structure such as fault andjoint. The appearance of the mineralization is abundant and can be found many fulfilling the joint zonemainly shear joint trending Northeast - Southwest and Northwest - Southeast, the direction of jointsharpness measured in the field relatively trending North - South. This study will emphasize on themeasurement and detailed analysis to know more about the gold mineralization process and otherminerals controlled by structures patterns. The structural control analysis can really be a good helpinghand in locating the mineralized areas because basically the activity and geological structure controlprocess are corridor for magma and the its rest compound that brings minerals, so the methods ofmineral ores exploration by structure control can be used in determining ore gold mineralized depositsprecipitate on gold deposits system and other minerals on a different area.Keywords: lithostratigraphy, structure, zone of opening, zone of alteration, mineralization, metalminerals
Analisis Kestabilan Lereng Berdasarkan Mohr-Coulomb dan Generalized Hoek-Brown pada Tambang Terbuka Batubara, Desa Tegalrejo dan sekitarnya, Kabupaten Muara Enim, Provinsi Sumatra Selatan Siswanda, Faiza Melati; Riswandi, Herry
Jurnal Ilmiah Geologi PANGEA Vol. 11 No. 1 (2024): Jurnal Ilmiah Geologi Pangea
Publisher : PROGRAM STUDI TEKNIK GEOLOGI FAKULTAS TEKNOLOGI MINERAL UPN VETERAN YOGYAKARTA

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Abstract

Abstrak – Pemilihan penggunaan kriteria keruntuhan yang tepat dalam analisis kestabilan lereng dapat mengurangi ketidaktepatan hasil analisis dalam memperoleh nilai Faktor Keamanan (FK) dari desain lereng yang dibuat, sehingga dibutuhkan dasar dalam pemilihan penggunaan kriteria keruntuhan yang tepat. Limit Equilibrium Methods (LEM) dan Morgenstren-Price merupakan metode yang digunakan dalam analisis ini. Klasifikasi massa batuan yang digunakan yaitu Rock Mass Rating (RMR) dan dari hasil analisisnya tergolong sedang hingga baik. Hasil perbandingan kriteria keruntuhan Generalized Hoek-Brown dengan maupun tanpa damage region menunjukkan nilai FK yang lebih kecil dibandingkan pada kriteria keruntuhan Mohr-Coulomb. Nilai FK pada Mohr-Coulomb berkisar dari 1,463-1,830 sedangkan nilai FK pada Generalized Hoek-Brown tanpa damage region sebesar 1,024-1,438 nilai FK pada Generalized Hoek-Brown dengan damage region sebesar 1,110-1,875. Hasil nilai Probabilitas Kelongsoran (PK) menunjukkan nilai yang sama yaitu 0%. Nilai FK Generalized Hoek-Brown dengan maupun tanpa damage region yang lebih kecil dibandingkan Mohr-Coulomb dipengaruhi oleh variabel pada litologi seperti struktur dan kondisi bidang diskontinuitas serta nilai disturbance factor (D) sebagai dampak dari aktivitas penggalian dan peledakan yang mereduksi nilai FK sehingga lebih memvisualisasi kondisi aktual di lapangan sedangkan kriteria keruntuhan Mohr-Coloumb tidak dipengaruhi oleh kondisi tersebut dan secara sederhana hanya melibatkan nilai material properties dari batuan itu sendiri. Kata Kunci: Generalized Hoek-Brown, kestabilan lereng, klasifikasi massa batuan, Mohr-Coulomb, Muara Enim Abstract – Determining the appropriate use of failure criteria in slope stability analysis can reduce the inaccuracy of analysis results in obtaining the Safety Factor (SF) value from the slope design created so that a basis is needed for determining the appropriate use of failure criteria. Limit Equilibrium Methods (LEM) and Morgenstren-Price are the methods used in this analysis. The rock mass classification used is Rock Mass Rating (RMR) and the analysis results are classified as moderate to good. The comparasion result of the Generalized Hoek-Brown failure criteria with and without damage region show a smaller SF value compared to the Mohr-Coulomb failure criteria. The SF value on Mohr-Coulomb ranges from 1,463-1,830 while the SF value on Generalized Hoek-Brown without damage region is 1,024-1,438 and the SF value on Generalized Hoek-Brown with damage region is 1,110-1,875. The results of the Probability of Failure (PoF) value show the same value 0%. The SF value of Generalized Hoek-Brown with and without damage ragion is smaller than the Mohr-Coloumb are influenced by variables in lithology such as the structure and condition of discontinuity as well as the disturbance factor (D) value as the impact of excavation and blasting activities which reduces the SF value and it can better visualizes the actual conditions in the field. Meanwhile, the Mohr-Columb failure criteria are not influenced by those conditions and simply involve the value of the material properties of the rock itself. Keywords: Generalized Hoek-Brown, safety factor, rock mass rating, Mohr-Coulomb, Muara Enim
Geologi dan Pengaruh Struktur Kekar Terhadap Kestabilan Lereng Desain Pit Pada Tambang Terbuka Batubara Kecamatan Lawang Kidul, Kabupaten Muaraenim, Sumatra Selatan Riswandi, Herry; Fitri, Arnia
Jurnal Ilmiah Geologi PANGEA Vol. 11 No. 2 (2024): Jurnal Ilmiah Geologi Pangea
Publisher : PROGRAM STUDI TEKNIK GEOLOGI FAKULTAS TEKNOLOGI MINERAL UPN VETERAN YOGYAKARTA

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31315/jigp.v11i2.12939

Abstract

Open pit mining system is one of the systems used to exploitation coal resources by stripping the overburden to produce slopes. Unstable slopes will result in landslides. Fractures are one of the causes of landslides. The purpose of the study was to determine the geological and geotechnical conditions of the area to create an optimal and safe slope design. The research area is administratively located in Tanjung Lalang, Lawang Kidul District, Muara Enim Regency, South Sumatra Province, which is a mining business permit (IUP) area of PT Bukit Asam Tbk. Geographically located at the geographical coordinates 103° 49'0 "BT - 103° 50'20" BT and 3° 50'59" LS - 3° 50'9" LS. The research methods used are literature studies, geological mapping, profiles, Scanlines, data analysis, rock mass rating, RQD, RMR, SMR, GSI, kinematic analysis, and quantitative analysis to determine the FK (Safety Factor) value. The research area is included in the South Sumatra basin which is included in the Muara Enim Formation which consist of Muara Enim mudstone units aged Middle - Late Miocene, and Alluvial units aged Holocene in the form of loose material accumulation. The geological structure that developed in the research area is a left slip fault with SE-NW emphasis and fractures that have NE-SW direction emphasis. At observation location 7 has an RQD value of 22.2543%, RMR 48.4210, SMR 46.81, GSI 40.8654, at observation location 10 has an RQD value of 35.1343%, RMR 52.642 8, SMR 49.17, GSI 48.2671, at observation location 24 has an RQD value of 57.2979, RMR 64.375, SMR 61.27 and GSI 60.836 at observation location 2 has a GSI value of 30 and at observation location 16 has a GSI value of 25. Based on the results of the analysis of the FK value without the influence of fractures on Section A-A' 2.364, section B-B' 1.889 and section C-C' 2.546, the FK value with fractures on section A-A' 2.326, section B-B' 1.172 and section C-C' 1.389 based on the results of linear analysis of the influence of fractures on the decrease in FK value has a determination value of R² = 0.5836 (moderate) and the effect of the number of fractures on the decrease in FK value has a determination value of R² = 0.6948 (Strong). Based on the results of kinematic analysis on sections A-A' and C-C' have a Wedge Landslide Potential type while on section B-B' has a Toppling landslide potential type. Recommendations for increasing slope stability at LP 7 by changing the slope direction N 288ºE and slope 55º, at LP 10 slope direction N 325ºE and slope 62º, LP 24 slope direction N 005ºE and slope 44º. Positive geological potential in the research area is in the form of economical coal mines and PLTU, negative geological potential in the research area is in the form of landslides, acid mine water, air pollution and bare forests.
Co-Authors Dina Tania Dina Tania Emi Sukiyah Eni Muryani Fitri, Arnia Heru Sigit Purwanto Puji Pratiknyo Sari Bahagiarti Kusumayudha Sari Bahagiarti Kusumayudha Siswanda, Faiza Melati