Geological Engineering E-Journal diterbitkan oleh Program Studi Teknik Geologi, Fakultas Teknik, Undip. Jurnal ini sebagai media publikasi karya ilmiah lulusan S1 jurusan Teknik Geologi Undip Artikel-artikel yang dipublikasi di jurnal ini sudah melalui proses review dari dosen Penguji.
Program Studi Teknik Geologi, Fakultas Teknik, Universitas Diponegoro
GEOLOGI, ALTERASI HIDROTERMAL, DAN MINERALISASI DAERAH ONTO DAN SEKITARNYA, KECAMATAN HU’U, KABUPATEN DOMPU, PROVINSI NUSA TENGGARA BARAT
The use of metallic minerals as raw materials is increasing. Therefore, Indonesia needs to improve metallic mineral reserves for the needs of the country and internationally to explore maximally. This can be done because some parts of Indonesia has huge reserves of metallic minerals.. This research purposed to learn about geological condition of research area involve morphology, lithology, and structure geology, determine alteration zone, and learn distribution of Copper (Cu) that contained in research area. Methodology used in this research is survey method and analysis method. Survey methos by doing surface geological mapping. Analytical method by doing petrology analyisis, petrography analysis, mineragraphy analysis, ASD analysis (Analytical Spectral Device) and sturcture geology analysis. Geomorphology of Onto and the surrounding divided into two units are volcanic very steep hill unit and volcanic steep hill unit. Lithology of research area from older to younger are tuff, volcanic breccia and breached by porphyrytic andesite. Structure geology in research area in the form of alignment pattern by Dem Map (Digital Elevation Model) in period I direction of structure is west-east and northwest-southeast, whereas in period III direction is north-south. The alteration zone of research area are divided into advanced argillic zone associated with dickite, alunite, and kaolinite minerals; argllic zone associated with kaolinite, palygorskite, and siderite minerals; and intermediet argillic associated with palygorskite and Chlorite minerals. Mineralization of research area is in the form of stockwork and disseminated whick mineralized by pyrite and chalcopyrite as ore mineral. Type of mineralization deposition in research area is Porphyry depoosition type. The value levels of Copper in research area are potential with 1132,79 ppm in tuff unit STA. 33, STA. 35 with value levels of copper is 130,01 ppm, STA. 55 is 390,37 ppm, STA. 56 is 499,9 ppm and STA. 73 is 288,95 ppm.
PERENCANAAN PERKUATAN LERENG PERUMAHAN CITRALAND MANADO, SULAWESI UTARA
Movement of soil often found in the State of Indonesia and is one of the natural disasters that can damage and harm humans each year. Indonesia most of the territory is hilly and mountainous, it is what makes our country vulnerable to catastrophic ground motion. This condition coupled with high rainfall as a trigger of ground motion. PT. Ciputra International is one company that is engaged in the development of housing. Housing development in the implementation problems encountered Citraland Manado local ground motion (local). Even landslides in Cluster 4 Eden Bridge damage homes and 6 people died. The cause of the avalanche is the presence of high rainfall and the presence of cracks in the rocks of the area. In anticipation of this problem, mapping and planning geotechnical slope reinforcement. Some of the data that is needed is the type of rock, heavy rock, fracture conditions, slope geometry, and rock mechanics of data. The lithology of the research sites is a tuff, sand gravel, volcanic breccias, soil embankment and sand. Based on the research generated sites prone to landslides for slope stability analysis is then performed using the software slides and phase2. The location of the Church of the Holy Kalam and Northern Hill still potentially complex landslide, being Cluster Eden Bridge is secure. At the location of the Church of the Holy Kalam, which meets the safety factor in both dry and water-saturated conditions are 1.423 and 1.349 which is a combination between the anchor and grouting grouting on the slopes and at the summit. While the location of the Northern Hill barrow, which meets the safety factor in both dry and water-saturated conditions are 1.505 and 1.494 which is the slope reinforcement using grouting.
GEOLOGI, ALTERASI HIDROTERMAL DAN MINERALISASI DAERAH CIURUG DAN SEKITARNYA, KECAMATAN NANGGUNG, KABUPATEN BOGOR, PROVINSI JAWA BARAT
The existence of metallic minerals in nature is closely related to geological conditions and hydrothermal alteration. hydrothermal alteration and mineralization occur due to hydrothermal solutions that change the physical and chemical properties of rocks and carrying metal elements which will be deposited on rock porosity and permeability have. hydrothermal alteration will make a special characteristic as an altered mineral association. Study of this alteration zone and mineralization will help us to make a plan for metal resources exploration. The purpose of this study was to determine the geological conditions study area include the morphology , lithology , structural geology , hydrothermal alteration zones , mineralization and determine the relationship between geology , hydrothermal alteration , and mineralization. Methods of research is using survey and analysis methods. Survey conducted by the method of data that collected in the field in the form of surface geological mapping. The analysis method was analysis of petrology, petrography, X-ray (XRD), and geological structure. Regional geomorphology of Ciurug Area classification based on Van Zuidam (1983) is divided into two units , namely units steep hilly volcanic landforms and volcanic landform units is very steep mountains. Lithology of the study area consists of older to younger andesite breccia , andesite lava, lapilli tuff , tuff , and andesite intrusion . Geological structure of the study area has a north-south direction . Hydrothermal alteration zones are present in the study area is the zone of argillic ( Illit - Kaolin ) , propylitic zone ( Smectite - Chlorite ) , and silicified zones ( Silica - Quartz ) . Mineralization in the area of research in the form of quartz veins and disseminated pyrite and chalcopyrite mineralization as ore deposits . Type of sediment deposition area of research is a low sulfidation epithermal type.
ANALISIS FASIES BATUAN SEDIMEN SERTA HUBUNGANNYA DENGAN PARAMETER KUALITAS BATUBARA BERDASARKAN ANALISIS UJI PROKSIMAT PADA LAPANGAN EKSPLORASI PT ANUGERAH LUMBUNG ENERGI, TAMBANG KINTAP, KABUPATEN TANAH LAUT, PROVINSI KALIMANTAN SELATAN
Asam-asam Basin is one of the basins where to be found good quality coals in Kalimantan, especially in the the Eocene Tanjung Formation. The studies of Tanjung Formation have been done by other researchers, but study devoted to the Tanjung Formation of Asam-asam Basin has not been done yet. The purpose of this study was to determine the lithological characteristics found in the study sites, geological structure, sedimentary rock facies, as well as studies about the relationship between sedimentary rock facies with quality parameters of coal based on laboratory proximate test analysis. The study was conducted using descriptive methods include case study research and direct observation in the field through geological mapping and stratigraphic measurements, as well as analysis method include performed data processing as a result of field observation and other supporting data. The processed data is presented in the form of lithology columns, maps, and data of geological structure. After that performed the laboratory analysis includes analysis of sedimentary facies and structural analysis of geology. In the final stage is the interpretation of sedimentary facies and their relationship with quality parameters of coal based on proximate test analysis. Based on the results of research, it is known that geological structures that develop in area of research are systematical joints with main force direction North-Northeast (NNE) - South-Southwest (SSW), normal faults with a trending fault plane Southwest - Northeast , as well as the reverse fault with a trending fault plane Northwest - Southeast. From the facies analysis, rocks of older age at study sites are sedimented on transitional lower delta plain environment, with sub-environment includes swamp, interdistributary bay, distributary channels, and crevasse splay; whereas the younger rocks are sedimented in the lower delta plain environment, with sub-environment includes swamp, interdistributary bay, distributary channel, crevasse splay, and tidal flats. There are 11 coal seams exposed as the results of the field observations, from the oldest to the youngest age are seam L2, L1, L30, M25, M50, and M30 whose are sedimented in the transitional lower delta plain environment, also seam R1, R15, R2, R 3-1 and R 3-2 whose are sedimented in the lower delta plain environment. Based on the proximate analysis test, it is known that : ash values ranged 7-50%, classified as moderate to high (Graese, 1992); sulfur total values ranged from 0.34 to 1.06%, classified as moderate to high category (Hunt, 1984); and calorific value ranges from 2836 - 6693 kcal/kg, and the relatively low quality coal to high quality (Directorat General of Mineral and Coal, 2011; within Indonesian Coal Resources Development and Future Direction Of Coal Export). Based on the value of ash (ash content), total sulfur, and calorific value, it is known that in general, the coal seams whose sedimented at the transitional lower delta plain environment have better quality than the coal seams of lower delta plain environment.
PENYELIDIKAN GEOLOGI TEKNIK UNTUK PENENTUAN LOKASI PEMBANGUNAN AS BENDUNGAN PELOSIKA DI DESA ASINUA JAYA, KECAMATAN ASINUA, KABUPATEN KONAWE, PROVINSI SULAWESI TENGGARA
Development plan of Dam Pelosika is located in a river Konaweha, Asinua Jaya village, Asinua District, Konawe, Southeast Sulawesi Province. Konaweha river has a length of 127 km and has an Regional water bin area of 6,664 km2. The purpose of this research is to study the geology around the River Konaweha to determine the condition of the morphology and lithology of the area so it can be recommended as dam Pelosika construction site of several alternative locations. Then determine the engineering geology condition of the selected location. In addition, determine the spread and water level inundation. The research method used was a descriptive survey method engineering geological mapping. The descriptive method is collecting secondary data from topographic maps, regional geological maps, earth maps and technical data of dams. While the analytical survey method is analyze the data based on the geological conditions of the regional geology and geological engineering investigation of the data included surface geological conditions, core drilling and test results of geoelectric. Based on investigation in the field, the morphological conditions of the studyis divided into three units namely structural denudated steep hills landform unit, denudated structural undulating hills landform unit and plains of fluviall and denudated form unit. The lithology of the study area is a constituent of metamorphic rocks such as schist of Paleozoic Metamorphic Formation, conglomerates and sandstones of Pleistocene age Alangga Formation and deposition of clay to gravel-sized Alluvium Holocene age. Based on several parameters geology and geological engineering, so that from several alternative locations as dam development determined that 4th alternative locations is a selected location for construction Dam Pelosika. The foundation of the dam on the left side at elevation +121 m rests on weathering soil bedrock sandy silt-sized. The foundation of the center of the dam at elevation +16.9 m rests on clay silt layers firm. The foundation of the right of the dam at elevation +115 m rests on weathering soil bedrock sandy silt-sized. The inundation spread area is 165.98 km2, constrained by the topography of the area around the river. Inundation water levels is +180 m.
REKONSTRUKSI STRUKTUR GEOLOGI DAERAH SUPIORI TIMUR – SELATAN, KABUPATEN SUPIORI, PULAU BIAK, PAPUA
Papua and Papua New Guinea are had geology condition are very complex involving interaction between two plates, the Australian Plate and the Pacific Plate. New Guinea formed the result of the movement of oblique convergence (convergence oblique). The products of convergence are shrinkage and formed strike-slip structures and subduction which occur in Papua on 10 Ma. Sorendiweri Strait seen horizontal and vertical fault motion that separated the Biak Island and Supiori Island thar can be identified with the alignment on the satellite image. The purpose of this study was to determine the geological conditions in the study area, the pattern of structures, the main stress that formed the geological structure and reconstruct of geological structures in the study area. The Field research methods are field observation on Supiori track. Record the characteristics of the rock on each formation, measurement of geological structures such as bedding plane, joint and fault plane. Analysis methods such as analysis of alignment manually and visually interpreted on a satellite image DSM (Digital Surface Map). Stereographic analysis of geological structures, combining field data and analysis of alignment to determine the type of structure zone with rotated stress analysis and subsidiary structures method. Geological conditions consist of Oligocene clastic limestone Wainukendi Formation. and Miocene non-clastic limestones Wafordori Formation. Pattern geological structure on Wainukendi Formation., NE-SW normal faults, WSW-ENE strike-slip faults and NE-SW thrust fault. Wafordori Formation., NE-SW normal faults, NE-SW thrust fault. N-S trending major stress is the main primary stress, NE-SW and NW-SE sharpness trending are local stress. Reconstruction of geological structures of the study area began with N-S primary stress that formed E-W Maru reverse fault, NE-SW Soren sinisral fault and NW-SE Maruu, Yondonkir, Maryadori, Biniki dextral fault. The NE-SW trending secondary stress formed NW-SE Kepudari thrust fault, Yon reverse fault and Donkir reverse fault at south of the study area.
ANALISIS SENSITIVITAS PEMODELAN ANALOG SANDBOX UNTUK MENGETAHUI PERKEMBANGAN STRUKTUR SESAR NAIK
Pemodelan sandbox adalah salah satu jenis pemodelan analog dalam ilmu geologi yang memiliki tujuan utama yaitu simulasi gaya, deformasi dan evolusi struktur cekungan sedimen. Terbentuknya struktur geologi berupa sesar naik (thrust atau backthrust fault) diakibatkan oleh sistem tektonik konvergen dan dapat dimodelkan dengan pemodelan sandbox. Penelitian ini bertujuan untuk memahami mekanisme dan sekuen deformasi dari sistem sesar naik dengan mengetahui hasil deformasi yang berupa pola struktur geologi; mempelajari perkembangan morfologi, pola dan distribusi struktur pada sistem tektonik konvergen; mengetahui variabel pengujian dalam pembentukan deformasi pada pemodelan sandbox. Penelitian dilakukan dari tahap persiapan hingga pelaksanaan. Persiapan yang dilakukan adalah pewarnaan, pengeringan dan pengayakan bahan model yaitu pasir kuarsa Formasi Ngrayong dengan dua macam ukuran butir; kategori ukuran pasir kasar (30-50 mesh) dan kategori ukuran pasir halus (60-80 mesh). Selanjutnya melakukan uji konsistensi alat sandbox. Hingga terakhir menentukan kondisi batas pemodelan seperti ukuran butir, ketebalan dan basement. Pada tahap pelaksanaan, data yang dihasilkan yaitu; foto/ gambar hasil pemodelan, waktu pergerakan dan jumlah sesar yang terbentuk, jarak pemendekan dan perubahan dip sesar, serta perkembangan morfologinya. Struktur yang terbentuk yaitu thrust dan backthrust fault. Morfologi yang terbentuk merupakan sabuk sesar thrust yang perkembangannya ditandai oleh terbentuknya struktur-struktur sesar baru. Jumlah sesar bertambah dan sudut kemiringan sesar pun cenderung bertambah seiring dengan meningkatnya pemendekan. Semakin tebal lapisan pasir maka jumlah sesar yang terbentuk lebih sedikit sebaliknya semakin tipis lapisan maka jumlah sesar yang terbentuk lebih banyak. Perbedaan ukuran butir material akan menghasilkan pola struktur dan jumlah sesar yang berbeda pula.
ANALISIS SIKUEN STRATIGRAFI DAN PEMODELAN FASIES FORMASI TANJUNG BERDASARKAN DATA LOG SUMUR DAN DATA INTI BATUAN PADA LAPANGAN MIR CEKUNGAN BARITO, KALIMANTAN SELATAN
Increased consumption of energy resources of oil and gas, exploration and exploitation process results performed optimally. Interpretation of subsurface using well log data combined with geological disciplines becomes very important in increasing exploration. Location of the study lies in one of the field located in the Barito basin of South Kalimantan province owned by Pertamina UTC. This research was done in the implementation of the final project addressed the subject of mapping subsurface using sequence stratigraphic approachs. The purpose of this research is to determine the type of lithology, facies and depositional environment, sequence stratigraphy, distribution of sedimentation and facies modelling Tanjung Formation in the MIR field. This research is using descriptive method and analytical methods. Descriptive method is a method that does some literature review. While the analysis method is using qualitative analysis to determine the type of lithology, stratigraphy and facies modeling sequence. This analysis uses software petrel 2009 in an analysis of well logs in the distribution of lithology, stratigraphic marker horizon correlation, subsurface mapping and facies modelling. Based on the results of the data analysis and discussion, it can be interpreted that the Tanjung Formation in the MIR field has a type silisiklastik sandstone lithology (sandstone), shale (shale) and coal (coal) with depositional environment in estuarine area. The results of the analysis of stratigraphic marker is 2 MRS (Maximum Surface Regression), 5 FS (Flooding Surface), 2 MFS (Maximum Flooding Surface) and 1 SB (Sequence Boundary) with sequence stratigraphic unit 2 Lowstand System Track (LST), 2 Transgressive System Track (TST) and Highstand System Track 1 (HST). Direction of sedimentation cycles in Tanjung Formation sequence stratigraphy approach leads to Northwest – South east (NNW - SSE). Facies models are divided into two zones: the ZR1 zone and ZR2 zone, where the zone was conducted to calibrate the rock core data. Based on core analysis Estuary facies rocks have Chanel and Tidal flat on Keywell. According to core data support and electrofasies in the study site, there are 3 facies deposition environmental: Chanel Estuary , Tidal flat and Tidal Bars.
PENYELIDIKAN ZONA AKUIFER MENGGUNAKAN GEOLISTRIK METODE SCHLUMBERGER DI SEKITAR PANTAI UTARA KECAMATAN KRAMAT, SURADADI DAN WARUREJA KABUPATEN TEGAL, JAWA TENGAH
Salah satu permasalahan yang sering terjadi di kecamatan Kramat, Suradadi, dan Warureja, Kabupaten Tegal adalah sulitnya masyarakat mendapatkan air bersih untuk kebutuhan industri maupun kebutuhan sehari-hari. Kesulitan tersebut disebabkan karena belum adanya data pendukung untuk dilakukannya pengeboran airtanah sehingga tentunya masyarakat merugi bila hasil pengeboran airtanah mereka belum kunjung menemukan sumber air bersih. Tujuan dari penelitian adalah menentukan zona akuifer, jenis akuifer dan arah aliran airtanah berdasarkan pemetaan hidrogeologi dan pengolahan data geolistrik metode Schlumberger. Geolistrik merupakan metode geofisika yang digunakan untuk mengetahui kondisi geologi bawah permukaan berdasarkan variasi nilai resistivitas jenis batuannya. Metode yang digunakan pada penelitian ini adalah geolistrik metode Schlumberger, dengan 16 titik pengukuran geolistrik yang tersebar di sekitar pantai utara Kabupaten Tegal. Proses pengolahan data dilakukan menggunakan software IPI2win untuk mengetahui nilai resistivitas sebenarnya beserta kedalamannya. Hasil interpretasi litologi berdasarkan nilai resistivitas batuan, dapat dikelompokkan menjadi lempung air Asin (0,06-0,27 Ωm), lempung air Payau (0,4-0,99 Ωm), lempung air tawar (1,057-9,714 Ωm), lempung pasiran (10,18-19,87 Ωm), pasir (20,44-119,7 Ωm) dan gravel (≥ 124,3 Ωm). Litologi akuifer pada daerah penelitian berupa pasir yang memiliki sifat permeabilitas dan porositas yang baik. Hasil dari nilai resistivitas dibuat penampang geolistrik dan dikorelasikan untuk menentukan letak, dimensi dan jenis akuifer yang terdapat pada daerah penelitian. Jenis akuifer yang terlihat dari hasil korelasi adalah akuifer bebas, akuifer bocor dan akuifer tertekan. Debit aliran airtanah pada akuifer tertekan pada wilayah penelitian ini adalah 4090,82 m3/hari. Nilai tersebut setara dengan 47,35 liter/detik atau setara dengan 1.493.149,3 m3/tahun.
IDENTIFIKASI PENYEBAB GERAKANTANAH DENGAN PENYELIDIKAN GEOLOGI TEKNIK DAN PENGUKURAN GEOLISTRIK METODE WENNER PADA PERUMAHAN TAMAN SENTOSA DAN SEKITARNYA KELURAHAN SUKOREJO KECAMATAN GUNUNG PATI KOTA SEMARANG
Salah satu permasalahan yang terjadi di Perumahan Taman Sentosa, Kecamatan Gunung Pati, Kota Semarang dan sekitarnya adalah gerakantanah yang terjadi pada lokasi tersebut yang menjadi lokasi penelitian. Kejadian gerakantanah yang terjadi cukup mengganggu aktifitas masyarakat dan merusak infrastruktur bangunan serta jalan yang ada. Penyebab dan klasifikasi gerakantanah tersebut perlu diketahui secara baik sehingga dapat dilakukan penanggulangan gerakantanah yang tepat terhadap lokasi penelitian. Tujuan dari penelitian ini adalah menentukan litologi lokasi penelitian, klasifikasi gerakantanah, dan penyebab gerakantanah yang terjadi berdasarkan analisis pengukuran geolistrik metode Wenner dan pemetaan geologi teknik. Geolistrik merupakan metode geofisika yang digunakan untuk mengetahui kondisi geologi bawah permukaan berdasarkan variasi nilai resistivitas jenis batuannya. Metode yang digunakan pada penelitian ini adalah geolistrik metode Wenner, dengan 4 titik pengukuran geolistrik yang tersebar di sekitar lokasi penelitian. Proses pengolahan data dilakukan menggunakan software IPI2win untuk mengetahui nilai resistivitas batuan. Sedangkan pemetaan geologi teknik adalah penyelidikan material permukaan menggunakan peta kontur dengan memperhatikan sifat geologi teknik material dengan hasil akhir berupa peta geologi teknik. Hasil interpretasi litologi berdasarkan nilai resistivitas batuan, dapat dikelompokkan menjadi batulempung (< 10 Ωm) dan batupasir (10-100 Ωm) dan tidak ditemukan adanya ketidakmenerusan litologi yang menjadi penciri keberadaan struktur geologi. Sedangkan hasil penyelidikan geologi teknik permukaan ditemukan pada lokasi penelitian batulempung sisipan batupasir dan lempung kepasiran dan tidak ditemukan adanya struktur geologi. Batulempung sisipan batupasir 75% komposisinya memiliki ukuran butir 0,06 mm dan 25% dibawah 0,02 mm. Sedangkan lempung kepasiran terdiri dari 90% komposisi lempung dengan ukuran butir dibawah 0,02 mm dan 10% pasir dengan ukuran butir 0,06 mm. Setelah dilakukan analisis terhadap data-data geolistrik dan geologi teknik yang didapat diketahui bahwa jenis gerakantanah yang terjadi pada lokasi penelitian adalah rayapan (creep) yang disebabkan oleh keberadaan material lempung pada lokasi penelitian.
KAJIAN DAERAH RAWAN BENCANA ALAM GERAKAN TANAH BERDASARKAN ANALISIS FAKTOR PENGONTROL DI WILAYAH KECAMATAN CILONGOK, KABUPATEN BANYUMAS, JAWA TENGAH
Kecamatan Cilongok merupakan salah satu kecamatan di Kabupaten Banyumas yang berada di lereng selatan Gunung Slamet. Kecamatan ini memiliki daerah-daerah rawan bencana alam gerakan tanah yang dikontrol oleh faktor kondisi geologi (litologi), kemiringan lereng, dan tata guna lahan. Tujuan penelitian ini yaitu untuk mengetahui zona kerentanan gerakan tanah dan mengetahui cara untuk mengurangi gerakan tanah. Metode penelitian meliputi pengamatan lapangan yang dilanjutkan dengan metode analisis. Pengamatan lapangan meliputi pemetaan lokasi gerakan tanah dan pemetaan faktor-faktor penyebab gerakan tanah (litologi, kelerengan, dan tata guna lahan). Setelah melakukan pengamatan lapangan, data lapangan dianalisis sehingga menghasilkan peta geologi, peta kelerengan, peta tata guna lahan. Kemudian analisis dilanjutkan dengan melakukan pembobotan faktor-faktor pengontrol gerakan tanah dilakukan sehingga menghasilkan nilai bobot setiap faktor pengontrol. Langkah selanjutnya yaitu menumpangtindihkan (overlaying) ketiga peta faktor pengontrol (dengan nilai bobot masing-masing) sehingga menghasilkan peta tingkat kerentanan gerakan tanah. Berdasarkan peta tingkat kerentanan gerakan tanah, Kecamatan Cilongok dapat dibagi menjadi tiga zona tingkat kerentanan gerakan tanah, yaitu zona tingkat kerentanan tinggi (luas mencakup + 35% peta), zona tingkat kerentanan sedang (luas mencakup + 15% peta), dan zona tingkat kerentanan rendah (luas mencakup + 50% peta). Peta zona tingkat kerentanan gerakan tanah dapat digunakan untuk skala prioritas mitigasi bencana alam gerakan tanah berdasarkan zona tingkat kerentanan. Untuk mengendalikan gerakan tanah, dapat dilakukan tindakan yang tepat berdasarkan faktor pengontrol gerakan tanah di masing-masing daerah.
MODEL KONSEPTUAL PERKEMBANGAN DELTA SEPINGGAN, INTERVAL “MFS 1-MFS 5”, BLOK SOUTH MAHAKAM, CEKUNGAN KUTAI, KALIMANTAN TIMUR
The energy demand are growing by day, especially in Indonesia, whereas these needs are not matched by the number of oil and gas production in Indonesia. This case is evidenced by the release of Indonesia as a member of an organization of oil exporting countries on October 9-10, 2008 in Vienna (Kompas, 10 October 2008). Thus required a study on the potential of producing hydrocarbon basin that will be expected to meet the energy demand of the oil and gas in Indonesia. One of the basins in Indonesia is the Kutai Basin which is the largest and widest Tertiary Basin in western Indonesia. The study area is located at the South Mahakam, Kutai Basin, East Kalimantan. This study aims to make conceptual model of delta Sepinggan development. The method included analysis of well log analysis method, 2D seismic analysis method, method of data analysis of rock core and biostratigraphic data analysis method. Based on analysis results can be obtained in the form of variations in lithology information on Sepinggan Zone deltaic sequence at intervals of MFS 1-MFS 5 marker are coal, sandstone, shale and limestone. Process on Sepinggan Delta are regretion process dominated on Early Miocene – Middle Miocene (N4-N14), and transgretion process on Middle Miocene –Late Miocene (N14-N16). Sedimentation process influenced by East Manpatu Fault that increasing accomodation space in Rocky Field area, so sediment layer in Rocky Field area is thicker 60-150 meter than Zahra-Zidane Field area.
ANALISIS PROVENANCE, DIAGENESIS DAN LINGKUNGAN PENGENDAPAN SERTA PENGARUH TERHADAP KUALITAS RESERVOIR BATUPASIR FORMASI TALANG AKAR, SUMUR FA-21, CEKUNGAN JAWA BARAT UTARA
The necessary of technology at this time resulted the necessary of energy resources will increasing, and it also result the scarcity of energy resources. One of the energy resources that is still used as a major energy resource is oil and gas. To overcome these problems, exploration activities at this time needs to be further improved. In the field of exploration, one of the most important things to know is reservoir. Reservoir quality is important for us to know so that we can determine whether an area has hydrocarbon potential to be developed or not. The main parameters of reservoir quality are porosity and permeability. In this study discussed the analysis of provenance, diagenetic and depositional environment of the sandstone reservoir of Talang Akar Formation, North West Java Basin and from the results of the analysis will be associated with the effect on reservoir quality. To determine the reservoir quality based on these parameters, can be done by several methods such as petrographic, cores, SEM and XRD analysis. From the analysis that has been done can be seen that the provenance of Talang Akar sandstone is Granite. So it can be seen that the Talang Akar sandstone which the provenance is Granite has good reservoir quality, with porosity values ranging from 19.04% to 24.28% and permeability ranging between 30-674 mD or belonging to the class good - very good (Koesoemadinata, 1980). Then the diagenetic process that occurs is compaction, cementation, replacement and dissolution. The process of compaction, cementation and replacement leads to reduced rock porosity values ranging from 2.25 to 11.5%, while the dissolution process resulting in increased rock porosity is about 1.5 - 2%. The depositional environment of the Talang Akar Sandstone is Upper Delta front. Rock facies in the upper delta front has good reservoir quality, with porosity values range from 19.04% to 24.28% and permeability range between 30-674 mD or belonging to the class is good - very good (Koesoemadinata, 1980).
PENENTUAN ZONA PROSPEK RESERVOIR HIDROKARBON PADA TAHAP EKSPLORASI DENGAN ANALSIS PETROFISIKA FORMASI BATURAJA LAPANGAN “IRFA” BLOK SEKAYU CEKUNGAN SUMATERA SELATAN
South Sumatera basin is one of the basin area in Indonesia that has considerable hydrocarbon potential, particularly in the field by IRFA well as the research of the physical properties of a reservoir characteristics including type of lithology, shale volume, porosity, permeability and water saturation value which is fundamental to the activities of oil and gas exploration. The purpose of this research was to determine the physical properties of the reservoir that developed in the areas include shale volume (Vsh), porosity (Ф), permeability (K), water saturation (Sw) zone which in turn can be determined that there is the prospect of hydrocarbon reservoir in the reservoir-3 on the well IRFA-1. The method used is descriptive method is a method that is done from multiple libraries. While the analytical methods used are qualitative analysis and quantitative. Qualitative analysis is to conduct research lithology and correlation of 7 wells located in the study area, while for the quantitative analysis was conducted on the calculation of reservoir petrophysical properties among other shale volume, porosity, permeability and water saturation then be determined net pay identified as areas reservoir will know where is hydrocarbon prospects and the prospects for the determination of hydrocarbon reservoir zones in this study is supported by the chromatograph of analysis done by knowing the value of the total gas C1, C2, C3, iC4, nC4 IRFA-1 well. Based on data analysis and discussion of reservoir-3 well IRFA-1 has a value of shale volume average of 22%, porosity 26%, permeability 371 mD, water saturation of 38%. This calculation is obtained by using a cutoff value for the volume of shale reservoirs <50%, effective porosity >9%, water saturation <60%. The results of the calculation of the average value cromatograph C1 / C2 = 4.14 ppm, C1 / C3 = 7.34 ppm, C1 / C4 = 18.46 ppm, C2 / C3 X 10 = 17.8 ppm. From the results of the data analysis and discussion can be interpreted that the reservoir-3 well IRFA-1 at a depth of 4298.3 to 4353 feet of a reservoir zone with oil prospects.
MIKROFASIES BATUGAMPING FORMASI BULU DAN KUALITAS BAHAN BAKU SEMEN, PADA LAPANGAN GUNUNG “PAYUNG”, KECAMATAN BOGOREJO, KABUPATEN BLORA JAWA TENGAH
Bulu Formation is one of formation which is sedimented at Tertiary age in The North East Java Basin. Bulu Formation has a lithological composition of limestones with kalkarenit. Bulu Formation is located in Gandu village, Tahunan Village, and the surrounding areas, District Bogorejo, Blora, Central Java, with a particular study on the "Gunung Payung". The study aimed to determine microfasies, facies zone, the relative age, and standart of quality limestone as materials cement on data petrographic, paleontologist, and chemical analysis of limestone samples in the study area. Development of Limestone Bulu Formation Unit microfacies is Bioclast Red Algae Packstone, Bioclast Large Foram Grainstone, Bioclast Large Foram Packstone, Bioclast Planktonic Foram Packstone, Bioclast Grainstone with dolomitation, Planktonic Forams Grainstone, Planktonic Wackstone, Peloidal Wackestone, Packstone with dolomitation, Bioclast Wackstone with microspar, Bioclast Planktonic Foram Wackstone, Bioclast Wackstone with dolomitation, Bioclast Packstone with dolomitation, and Dolomite limestone. Based on the analysis microfacies and foraminifera on the areas of research, there are 3 types of facies zoning based on the model of Wilson (1975), namely: FZ 5 Platform - Margin Reefs, Marine Open 7 FZ, FZ 8 Platform and Interior - Restricted to the age of rocks between N9 to N12 is the Middle Miocene. From the chemical analysis, the potential limestones in the study area can be used as raw material for cement and relationships microfacies analysis and chemical analysis showed that the pitch "Gunung Payung" has a great potential in terms of good quality which is spread of West to East direction. The west area of “Gunung Payung” has better quality of limestone as a raw material for cement than east area.
KAJIAN KLASIFIKASI MASSA BATUAN DAN ANALISIS STEREOGRAFIS TERHADAP STABILITAS LERENG PADA OPERASI PENAMBANGAN TAMBANG BATUBARA AIR LAYA, DESA TANJUNG ENIM, KABUPATEN MUARA ENIM, SUMATERA SELATAN
Slope stability problems on an open pit mine is a very important issue because it involves issues of human safety, mining equipment, and other infrastructure that is located around the excavation slopes. PT. Pamapersada is a coal mining contractor company that uses open pit system. Based on experience, sometimes avalanches or cracks occur in excavated slopes. To determine the relationship between the classification of the rock mass and slope stability slope forming material is necessary to do a research on the matter. Research sites located in Tambang Air Laya pit. This is because the TAL Pit excavation area that has considerable variation in complex geological structures. Geological mapping carried out to determine the distribution of lithology and geological structures contained in the Tambang Air Laya Pit. Geotechnical mapping carried out to classify the rock mass based on Rock Mass Rating. From the field observations, the study area was divided geologically into four lithologic units, sandstone, mudstone, andesite, and coal. Based on the classification of the rock mass, the study area was divided into 4 types of rock mass: Type 1 rock mass composed of andesite with RMR value of 92 (very good rock), rock mass composed of type 2 rather weathered sandstone with RMR value of 80 (good rock), rock mass type 3 is composed of moderately weathered sandstone 50-70 RMR value (fair rock), type 4 is composed of claystone with 44-62 RMR value (fair rock). Slope stability analysis using the program Slide Ver. 5, was conducted to determine the stability of existing slopes, changes in slope geometry, and simulated slopes formed by a type of rock mass. The results of the analysis showed that the TAL Pit slope design is in a state unsafe with Fk between 1:19 - 1,248.
POTENSI SITUS-SITUS WARISAN GEOLOGI DI AREA KARS GUNUNG SEWU SEBAGAI PENDUKUNG DAN PELUANG PENGEMBANGAN GEOPARK DI INDONESIA UNTUK ASET GEOWISATA KREATIF
Kars Gunung Sewu yang melingkupi wilayah Gunungkidul, Wonogiri dan Pacitan merupakan salah satu kawasan Kars yang paling terkenal di Jawa karena kekhasan dan keunikan Karsnya. Gunung sewu secara geologi terbentuk dari batugamping berumur Neogen (Miosen Tengah) dengan ketebalan mencapai lebih dari 200 m. Karena ciri khas morfologinya menjadikan Gunung Sewu terpilih sebagai kandidat Geopark (Taman Bumi) di Indonesia. Geopark merupakan suatu konsep manajemen pengembangan kawasan secara berkelanjutan, yang memadu-serasikan tiga keragaman alam, yaitu keragaman geologi (geodiversity), keragaman hayati (biodiversity), dan keragaman budaya (cultural diversity), dengan tujuan untuk pembangunan serta pengembangan ekonomi kerakyatan yang berbasis pada asas perlindungan (konservasi) terhadap ketiga keragaman tersebut. Sebanyak 30 geological heritage dan 3 non-geological heritage yang berada di Kawasan Kars Gunung Sewu yang diakui sebagai geopark atau taman geologi nasional oleh Badan Geologi Kementerian Energi Sumber Daya Mineral. Situs-situs ini ditargetkan akan dikelola oleh masyarakat dengan berbasis pemberdayaan masyarakat. Berdasarkan hasil analisis citra landsat Area Kars Gunung Sewu dikelompokkan menjadi 4 Satuan yaitu : Unit K1 Dataran Tinggi Kars, Unit K5 Dataran Alluvial Kars, Unit K6 Doline dan Unit K8 Lembah Kering (Brahmantyo B, 2006). Hasil analisis SWOT dan scoring self-assesment yang melingkupi Keadaan Geologi, Struktur Manajemen, Edukasi Lingkungan, Geotourism dan Perkembangan Ekonomi Daerah secara berkelanjutan didapat nilai 73,25%, angka tersebut (lebih dari 50 %) yang berarti Kawasan Kars Gunung Sewu sangat layak untuk bergabung ke dalam Jaringan Global Geopark National oleh UNESCO. Sebab, pengembangan kawasan geopark memiliki dampak yang sangat besar untuk pariwisata yang mendorong pertumbuhan ekonomi masyarakat setempat juga kebutuhan Negara.
EVALUASI DESAIN TAHAP 1 DISPOSAL SWD 11 PIT 116 TAMBANG BATUBARA DISTRIK BAYA DESA SEPARI, KECAMATAN TENGGARONG SEBERANG, KABUPATEN KUTAI KARTANEGARA, KALIMANTAN TIMUR
Kegiatan eksploitasi batubara dengan sistem penambangan terbuka melakukan kegiatan pengambilan batubara dan batuan yang tidak digunakan seperti material overburden dan interburden. Kemudian, material yang tidak digunakan tersebut ditimbun kembali di disposal. Pembuatan disposal harus dilakukan dengan baik, apabila tidak, akan timbul adanya tanah longsor yang akan mengganggu aktivitas eksploitasi batubara. Selain itu pembuatan disposal harus mencukupi target kapasitas timbunan. Penelitian tugas akhir ini bermaksud untuk menganalisis kestabilan lereng, mengevaluasi, dan melakukan perhitungan kapasitas desain awal dan desain baru (redesign) disposal SWD 11 yang terletak di site Baya, Kalimantan Timur. Metode yang dilakukan adalah penyelidikan langsung lapangan yang bersifat deskriptif ke disposal SWD 11 untuk mengetahui geometri lereng serta tipe longsoran dan kegiatan laboratorium untuk mengetahui bobot isi (g), kohesi (c) serta sudut geser (f) dalam timbunan tanah pada disposal NED 2 sebagai acuan. Analisis kestabilan lereng unuk menentukan nilai faktor keamanan dari lereng disposal. Metode analisis kestabilan lereng menggunakan metode Bishop simplified dan Janbu simplified. Analisis kestabilan dan permodelan lereng disposal menggunakan bantuan perangkat lunak Slide 6.0 serta permodelan desain disposal menggunakan perangkat lunak AutoCad dan Minescape. Berdasarkan hasil evaluasi desain awal disposal SWD 11 memiliki nilai faktor keamanan £ 1,2 sehingga termasuk kedalam kondisi tidak aman. Untuk menghasilkan nilai faktor keamanan ³ 1,2 perlu adanya konstruksi counter weight pada kaki lereng disposal, serta untuk mengoptimalkan kapasitas disposal dilakukan penggeseran timbunan dan counter weight menjauhi kolam lumpur (sump) dan mengubah lereng tunggal timbunan disposal dari 37° menjadi 40°. Kapasitas disposal SWD 11 mengalami peningkatan sebesar 1.016.342,3 ton atau setara dengan peningkatan 5% setelah dilakukan perubahan menjadi desain baru. Pengaruh parameter sifat fisik dan mekanik tanah yang mempengaruhi kestabilan lereng disposal SWD 11 antaralain unit weight (γ), kohesi (c), sudut geser dalam (f). Semakin besar nilai unit weight (γ) maka nilai faktor keamanan mengalami penurunan rata-rata 4,4%, semakin besar nilai kohesi (c) maka nilai faktor keamanan mengalami kenaikan rata-rata 8,4%, semakin besar sudut geser dalam (f) maka nilai faktor keamanan mengalami kenaikan rata-rata 15,3%.
ANALISIS GEOKIMIA FLUIDA UNTUK PENENTUAN POTENSI SUMBERDAYA PANASBUMI LAPANGAN ZW, KABUPATEN GARUT, PROVINSI JAWA BARAT
Daerah Lapangan panasbumi ZW terletak pada Provinsi Jawa Barat menunjukkan keadaan Geologi yang memungkinkan untuk terdapatnya sumberdaya panasbumi. Posisinya terletak pada jalur pegunungan api sehingga memungkinkan terbentuknya suatu sistem panasbumi. Pada daerah ini ditemukan manifestasi panasbumi berupa mataair panas dan fumarol. Kimia fluida di daerah panasbumi mengandung informasi penting mengenai kondisi reservoir, sehingga dilakukan anilisis kimia fluida untuk menentukan karakteristik geokimia dan potensi sumberdaya dari lapangan panasbumi ZW. Metode yang digunakan dalam penelitian ini adalah metode deskriptif dan analisis dari data kimia fluida panabumi. Hasil data diperoleh dari pengambilah 5 contoh air panas dari 12 manifestasi yang muncul disekitar lokasi penelitian. Contoh air panas yang diambil berasal dari mataair panas Cipayung, Citeduh, Cibeuning, Siun dan kawah Basah. Berdasarkan hubungan rasio unsur kimia dan plotting pada diagram segitiga Giggenbach (Giggenbach, 1988) terhadap suatu sistem panasbumi, Berdasarkan analisis sifat fisik dan analisis geokimia maka Manifestasi Kawah Citeduh, Cipayung, kawah Basah dan Cibeuning berada pada zona upflow. Sedangkan Mataair Panas Siun berada pada zona outflow (Nicholson, 1993). Dalam pengeplotan diagram segitiga Giggenbach (Giggenbach, 1988) juga menunjukkan informasi bahwa Mata air Citeduh merupakan mata air Sulphat, Mataair Siun merupakan air Bikarbonat. Sementara kawah Cipayung, Cibeuning dan Basah memiliki sampel yang encer sehingga analisis geoindikator tidak valid. Berdasarkan perhitungan Geothermometer Gas yang digunakan, temperatur reservoir panasbumi lapangan ZW adalah 246,6oC, Termasuk dalam sistem panasbumi berentalpi tinggi (Hochstein, 1990). Adapun potensi berdasarkan perhitungan panas yang hilang/heat loss secara Konveksi adalah 49,2 MWe. Sementara dari perhitungan dengan metode volumetrik adalah 625,5 MWe, memungkinkan untuk dilakukan eksplorasi lebih lanjut sehingga dapat dimanfaatkan sebagai pembangkit listrik dan pemanfaatan langsung.
ANALISIS KESTABILAN LERENG UNTUK PENANGANAN GERAKAN TANAH DENGAN METODE GROUTING DI PERUMAHAN BUKIT MANYARAN PERMAI (BMP) KOTA SEMARANG
Build an infrastructure must consider the aspects of geology in order to get maximum results. One of the geological aspects that must be considered is the condition of lithology. If the lithology is not sturdy, it will frequently moves or called landslide. This land movement can have negative impacts on existing communities in the vicinity. In this study, the author took the theme, slope stability analysis, which is located in Bukit Manyaran Permai Housing (BMP), Semarang. The housing have high intensity of damage due to soil movement. The housing is standing on ground that is dominated by clay. Clay has a low degree of friction angle and low cohesion so it will easily move if given more weight than the carrying capacity of the lithology. The methodology is using slope stability analysis computionally. The first step of research conducted by geotechnical mapping to determine the distribution of the existing surface lithology and clasify the damage of infrastructure caused by the movement of existing soil. Then drill in two different drill point where each point was drilled to a depth of 10 m. From the drilling results will be obtained samples to be used in laboratory testing, including unit testing and direct shear weight. From both test, the results will be obtained are the value of the unit weight, cohesion and friction angle which we can use for making modeling and computational search for the safety factor. In doing modeling and find the value of the safety factor of the location of the study authors using Slide 6.0 software which is very helpful in determining the value of the safety factor on the ground. From the computational analysis found that is worth the value of the safety factor of less than 1.5, it indicates the condition of the slopes of the potential occurrence of landslide. Therefore, at the end of this final report the authors provide proper recommendations handling of landslide in accordance with the results of laboratory analysis and the existing conditions in the field.
IDENTIFIKASI KARAKTERISTIK ALTERASI HIDROTERMAL DAN MINERALISASI ENDAPAN EMAS EPITERMAL DAERAH PROSPEK RAMADA, KECAMATAN CIMANGGU, KABUPATEN PANDEGLANG, PROVINSI BANTEN
Cibaliung Gold Project area is one of the largest primary gold deposits mineralization prospect areas in the western part of Java island which is controlled by PT. Antam (Persero) Tbk.. The research area is part of the Cibaliung Gold Project area called Ramada Prospect. Administratively, Ramada Prospect located in Cimanggu Subdistrict, Pandeglang District, Banten Province. Research conducted aimed to determine the geological condition, characteristics of hydrothermal alteration and gold deposition mineralization, as well as predicting the environmental conditions of hydrothermal constituent. Research conducted with descriptive and qualitative analysis approach. The research method used consists of literature study, field observation, and laboratory test. In the literature study methods conducted assessment of the theoretical basis and previous research. Field survey methods consists of geological mapping, mapping of alteration and mineralization, as well as description and identification of rock core drilling results. In the laboratory test method conducted descriptions and identifications of petrographic, mineragraphy, and X-Ray Diffraction (XRD) to some rock samples and veins, as well as analysis of geological structure stereographic method. The research was also supported by secondary data such as AAS (Atomic Absorption Spectrometry) test results. Lithology of research area consists of tuff rock units, pyroclastic breccia rock units, and andesite lava flow rock units. Pyroclastic breccias rock units and andesite lava flow rock units are interpreted as pre-mineralization rocks, whereas tuff rock units are interpreted as post-mineralization rocks. Based on the analysis of geological structure there is interpreted strike-slip fault has affected geological conditions of the research area. Hydrothermal alteration in the research area can be divided into alteration facies of kaolinite-smectite-chlorite±quartz±carbonate-pyrite replacement-infill strong intensity and alteration facies of chlorite±epidote±sericite±quartz±carbonate-pyrite replacement-infill moderate-strong intensity. Gold deposition mineralization (Au) in the research area predominantly formed on quartz±carbonate veins. The presence of gold associated with silver (Ag) and pyrite (FeS2). The main prospect gold deposits mineralization in the research area contained in "Ramada" veins. Hydrothermal environment in research area interpreted as a low sulfidation epithermal deposition system that developed in the ancient depths of 120 m - 340 m with temperatures around 175 °C - 225 °C.