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Yusi Firmansyah
Fakultas Teknik Geologi - Universitas Padjadjaran
Earth & Planetary Sciences Engineering

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Determination of Maximum Unsupported Span and Stand Up Time Value using Q-System Method (Case Study: Pongkor Area, Nanggung Subdistrict, Bogor District, West Java Province) Alisah Alisah; Irvan Sophian; Zufialdy Zakaria; Ryan Pratama; Yusi Firmansyah
Journal of Geological Sciences and Applied Geology Vol 2, No 4 (2018): Journal of Geological Sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v4i2.18235

Abstract

Epithermal deposit might be a potential economic mining source. One kind of this deposit is the low-sulphidation epithermal with the quartz vein which can be found in the study area. However, the high intensity number of the alteration process will affect the rock mass quality in the area of interest which also will influence the safety of underground mining process, ecspecially while the tunnel reinforcement is being set. Therefore, maximum unsupported span and stand up time value need to be determined.Study area is Nanggung Subdistrict, Bogor District, West Java Province. This study is conducted at some fronts in Ciguha tunnel, using the Q system methode. After the rock mass has been classified, the maximum unsupported span and stand up time value can be calculated.The result shows that maximum unsupported span value has a variety number from 8 hours to 1 year extend. At the other side, stand up time value also has a variety number from 1 to 4 meters span. Both shows a value depends on their own rock mass quality. Keyword: Q- System, Stand up time, Maximum unsupported span
STRATIGRAPHIC ANALYSIS : RAJAMANDALA FORMATION AND CITARUM FORMATION BASED ON OUTCROPS DATA Reza Mohamad Ganjar Gani; Yusi Firmansyah; Satrio Fajar Pamengkas
Journal of Geological Sciences and Applied Geology Vol 4, No 1 (2020): Journal of Geological Science and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v4i1.29112

Abstract

The location of study area is in Padalarang, West Java with Rajamandala Formation and Citarum Formation outcrop as observation object. Rajamandala Formation is characterized by shallow marine deposit and carbonate sedimentary rock. Meanwhile, Citarum Formation is identified as deep marine deposit and consists of clastic sedimentary rock. The methods used in this study are fieldwork, laboratory analysis, data interpretation, and stratigraphic analysis. Laboratory analysis consists of petrographic analysis and foraminiferal analysis. The contact between these formations is not identified in study area. Outcrop observation exposes improper data to determine the stratigraphic relation, since covered by debris materials of limestone. Foraminiferal analysis data shows that Rajamandala Formation is formed in Late Oligocene (Lower Te/P20 – P22/N1 – N3) and Citarum Formation is formed in Middle Miocene (N9 – N13). It shows gap of time from N3 until N9. It determines an uncorformity stratigraphic relation between these two formations. The depositional environment changes significantly from shallow marine to deep marine. Study area exposes outcrops data which represent these formations and other additional data needed. It offers a good opportunity to determine the stratigraphic relation between these two formation. Furthermore, it can be used as analogue in determining stratigraphic relation.
Lithology Units Padaherang Area and Surrounding, Ciamis District, West Java Province Reza Mohammad Ganjar Gani; Yusi Firmansyah
Journal of Geological Sciences and Applied Geology Vol 5, No 2 (2021): Journal of Geological Science and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v5i2.35035

Abstract

Administratively, Padaherang region and surrounding is included to kecamatan Padaherang, Ciamis Regency, West Java. The reason why this area is a research area is partly because the author feels that the area in Ciamis Regency is a southern mountainous area that is influenced by volcanism and sedimentation processes and other geological processes. In addition, there are still many geological problems that have not been fully revealed, so the author feels the need to conduct further and more detailed research. Objects to be studied in the field include rocks (description, sampling, direction of moves and slopes), indications of geological structures, and landscape appearances accompanied by sketch photos and additional data deemed to support the research results, The research steps carried out included several stages of work, namely the preparation stage, field work, laboratory research, and the stage of preparing reports. The trajectory that is traced in the field research that has been determined at the preparatory stage. If the trajectory is deemed inadequate, a search for additional trajectories is carried out. There are three methods used in geological mapping, namely the field orientation method, the compass trajectory method, the measuring tape method and the compass. In this mapping, the methods used are the field orientation method and the measuring tape and compass method. Threre are  five lithology units which is arrange at research area, these units of lithologi from the older to the younger is breccias unit, sandstone units,  claystone. Geology activity at research area predicted begun at Oligocen till Holocen era. first in Oligocen the volcanic activity is strong enough where the eruption produced the breccia and sandstone unit, this process stop at lower Miosen. And at the middle Miosen there is the tectonic activity hapenned. Limestone unit was diendapkan at middle Miocen, and claystone unit at upper Miocen, and quartery deposit is the younger unit at research area
LITHOLOGIC ORDER MAPPING AND ROCK RESOURCES INVENTORY OF KUTAWARINGIN QUADRANGLE, WEST JAVA Reza Mohammad Ganjar Gani; Yusi Firmansyah; Aji Nurdrajat
Journal of Geological Sciences and Applied Geology Vol 2, No 4 (2018): Journal of Geological Sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v4i2.18377

Abstract

In general, the southern part of Bandung is composed of rocks produced by volcanic activity. Research in this region based on the want to understand the geology of volcanoes in Bandung and surrounding areas including the origin of the formation of the Bandung Basin (Bronto & Hartono, 2006). The Bandung basin is almost surrounded by volcanoes; even in the midst there is also volcanic rock (Silitonga, 1973, Alzwar drr., 1992). Information about why and how the area of Bandung to be controlled by volcanic rocks is needed to find out more potential resources as well as geological disasters due to volcanic activity. This study aims to decide the history of volcanism in South Bandung. I want to represent a complex area seen from the diversity of geological and rock environment conditions. This diversity condition controls the landscape and geological conditions observed at this time. The purpose of the preparation of this study is to be used to develop the Stratigraphic order and inventory of minerals.Keywords: Kutawaringin, stratigraphy, resource potential
LITHOLOGY UNITS PENGKOL AREA AND SURROUNDING, GUNUNG KIDUL DISTRICT, YOGYAKARTA PROVINCE. Reza Mohammad Ganjar Gani; Yusi Firmansyah; Rifky Nurdeani
Journal of Geological Sciences and Applied Geology Vol 4, No 2 (2021): Journal of Geological Science and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v4i2.31820

Abstract

The research area is located sub-district Nglipar,District of Gunnung Kidul,Yogyakarta Province. Accessibility to the research location by train Bandung - Yogyakarta, followed by a minibus to Nglipar District Gunung Kidul. Purpose Of this Research is to understanding geological conditions of the research area reviewed from litohologic units and  its stratigraphic order. The lithostratigraphy of the research area is divided into 3 lithologic units, Breccia Unit, Sandstone Unit and Limestone Unit. namely the naming of the rock units based on observable physical characteristics, including rock type, uniformity lithology symptoms and their stratigraphic position. Geological history at the location of this study is the eruption of Mount Ngalanggran and deposited volcanic breccia units. Early Miocene deposited units sandstone. At that time there was a decrease in sea level which caused the diagenesis of the sedimentary material into limestone material. On Middle Miocene limestone deposited. Keyword: Lithologic units, stratigraphic order, Gunung Kidul District.
LITOFASIES ANALYSIS IN THE CIPAMINGKIS RIVER ROCK FORMATION JATILUHUR, BOGOR, WEST JAVA. Reza Mohammad Ganjar Gani; Yusi Firmansyah; Nurdrajat Nurdrajat; Muhammad Kayis Fathin
Journal of Geological Sciences and Applied Geology Vol 5, No 3 (2021): Journal of Geological Science and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v5i3.38253

Abstract

The Sedimentary rocks result from the breakdown of previously transported rocks deposited and lithified. Sedimentary rocks cover almost 80% of the earth's crust (Folk, 1974). The research was conducted in the Cipamingkis River, Jonggol District, Bogor Regency, West Java. The research area is included in the Cianjur Regional Geological Map Sheet (Sudjatmiko, 1972) and is included in the Dayeuhkaum Earth Map (1209 – 233) published by the Geospatial Information Agency (BIG). The Jonggol District, Bogor Regency, West Java, has a large river, the Cipamingkis R,iver, stretching from the northeast to the southwest of the study area. This river is included in the Jatiluhur Formation (Sudjatmiko, 1972). The facies is a rock body with a different combination of physical, chemical and biological characteristics from the surrounding rock body, which reflects its original conditions, namely the way it was transported and the way it was deposited. Two bodies of rock deposited simultaneously have different facies if they have differences in their physical, chemical and biological characteristics. Units and sediment structure components in the study area are grouped into six lithofacies: (1) Thin-Medium Sandstone Layer, (2) Massive Claystone, (3) Alternating Sandstone and Claystone, (4) Thick Sandstone Layer, (5) Alternating Fine Sandstone and Very Fine Sandstone, and (6) Slump Deposit. Description of facies by limiting physical and chemical characteristics is called lithofacies, and lithofacies is a facies analysis method by considering information about physical and chemical characteristics of rock layers (Nichols, 2009).
Co-Authors Aji Nurdrajat Alisah Alisah Irvan Sophian Muhammad Kayis Fathin Nurdrajat Nurdrajat Reza Mohamad Ganjar Gani Reza Mohammad Ganjar Gani REZA MOHAMMAD GANJAR GANI Rifky Nurdeani Ryan Pratama Satrio Fajar Pamengkas Zufialdy Zakaria