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Nofrohu Retongga
Sumbawa University Of Technology
Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Computer Science & IT Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology Mechanical Engineering Physics Social Sciences Transportation

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ANALISIS KUALITAS INTRUSI ANDESIT SEBAGAI BAHAN BANGUNAN BERDASARKAN SIFAT KETEKNIKAN DI DAERAH BEJI, KECAMATAN UNGARAN TIMUR, KABUPATEN SEMARANG, JAWA TENGAH Retongga, Nofrohu; Purnamawati, Dwi Indah; Rakhman, Arie Noor
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscientia Vol 13 No 2 Februari 2021
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

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Abstract

This study aims to identify the quality of andesite intrusive rocks as a building material. The research location is in the Beji area, East Ungaran District, Semarang Regency, Central Java Province. Analysis of rock quality using data from the test results of engineering and petrographic properties. The andesite studied is an intrusion into basalt. Based on the quality standard requirements for natural stone for buildings (SNI 03-0394-1989) these rocks can be mined for building materials, especially medium to heavy building foundations (1,150.040 -1,421.621 kg/cm2). The middle andesite has a higher strength than the lower andesite. The strength of the rock is supported by resistant minerals in the form of plagioclase, which dominates up to 35%. However, in the andesite body getting down, olivine tends to decrease by 5%. The weathering of these minerals is influenced by the condition of the water in the rock where the water content is 0.391 to 0.412%. In water-saturated conditions, the degree of saturation of the lower rock can reach 100%, exceeding the rock above, 87.5%. The strength of the rock at the bottom is lower, making the slope potentially easy to collapse when the mining method is started from the bottom, especially the excavation is carried out on steep vertical slopes.
ANALISIS KUALITAS INTRUSI ANDESIT SEBAGAI BAHAN BANGUNAN BERDASARKAN SIFAT KETEKNIKAN DI DAERAH BEJI, KECAMATAN UNGARAN TIMUR, KABUPATEN SEMARANG, JAWA TENGAH Retongga, Nofrohu; Purnamawati, Dwi Indah; Rakhman, Arie Noor
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscientia Vol 13 No 2 Februari 2021
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

This study aims to identify the quality of andesite intrusive rocks as a building material. The research location is in the Beji area, East Ungaran District, Semarang Regency, Central Java Province. Analysis of rock quality using data from the test results of engineering and petrographic properties. The andesite studied is an intrusion into basalt. Based on the quality standard requirements for natural stone for buildings (SNI 03-0394-1989) these rocks can be mined for building materials, especially medium to heavy building foundations (1,150.040 -1,421.621 kg/cm2). The middle andesite has a higher strength than the lower andesite. The strength of the rock is supported by resistant minerals in the form of plagioclase, which dominates up to 35%. However, in the andesite body getting down, olivine tends to decrease by 5%. The weathering of these minerals is influenced by the condition of the water in the rock where the water content is 0.391 to 0.412%. In water-saturated conditions, the degree of saturation of the lower rock can reach 100%, exceeding the rock above, 87.5%. The strength of the rock at the bottom is lower, making the slope potentially easy to collapse when the mining method is started from the bottom, especially the excavation is carried out on steep vertical slopes.
Studi Provenance Batupasir Karbonatan Formasi Kerek Dengan Metode Point Counting Di Daerah Kandangan Kabupaten Semarang Nofrohu Retongga; Andika Gerardus Oratmangun; L. Muh. Fathur Rizki; Abdurrahman Saputra; Atikah Zahidah; Diana Septiani Roos; Rohmad Bagus Abadi; Oan Marcello Lukas Watania
Jurnal Teknologi Vol 14 No 2 (2021): Jurnal Teknologi
Publisher : Jurnal Teknologi, Fakultas Teknologi Industri, Institut Sains & Teknologi AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.34151/jurtek.v14i2.3728

Abstract

Carbonate sandstone in the study area was found around rivers and hills in the study area. Provenance of sandstones in the research area of interest to be examined, because not known provenance the sandstone rock formations karbonatan Kerek especially in the research area. The purpose of this study was to determine the provenance of Kerek carbonated sandstones in the study area using themethod point counting. The methodology used for the analysis of Provenance in the study area is using petrographic incisions. The results of the analysis of provenance on the five samples of carbonated sandstones of the Kerek Formation in the study area obtained data in the form of: rock types including lithic arenite (Pettijohn, 1975), the climate of the source area is semiarid (Nelson, 2007), the source rock type is plutonic rock (Tartosa, et al, 1991). ) and its tectonic setting is in the magmatic arc transitional arc sub-zone (Dickinson and Suczek, 1979). 
Analisis Kestabilan Lereng Menggunakan Metode Rock Mass Rating (RMR) dan Slope Mass Rating (SMR) untuk Menentukan Faktor Keamanan Lereng Pada Tambang Tuf Desa Candirejo, Kecamatan Semin, Kabupaten Gunungkidul, Daerah Istimewa Yogyakarta Marolop P Pangaribuan; Nofrohu Retongga
Jurnal Geosains dan Teknologi Vol 5, No 3 (2022): November 2022
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/jgt.5.3.2022.171-190

Abstract

Batuan yang tersingkap di permukaan bumi umumnya dapat dimanfaatkan untuk kebutuhan konstruksi bangunan. Masyarakat Desa Candirejo, Kecamatan Semin, Kabupaten Gunungkidul, Daerah Istimewa Yogyakarta mengambil batu dengan cara sederhana yaitu penambangan tuf menggunakan pahat dan palu besi. Tujuan dari penelitian ini adalah untuk menganalisis kestabilan lereng tambang tuf akibat aktifitas penambangan oleh masyarakat sekitar sehingga dapat mengetahui nilai faktor keamanan lereng pada tambang tuf di Desa Candirejo. Metode yang diguanakan adalah Rock Mass Rating (RMR) dan Slope Mass Rating (SMR). Hasil analisis hubungan nilai faktor keamanan lereng dan intensitas longsor berdasarkan nilai faktor keamanan <1,07 termasuk longsor sering terjadi (lereng labil), 1,07 < FK < 1,25 termasuk longsor pernah terjadi (lereng kritis) dan > 1,25 longsor jarang terjadi (lereng relatif stabil). Faktor keamanan yang dianalisis menggunakan bantuan software Rocscience Slide v.6.005 setelah dianalisis didapatkan nilai FK sebesar 4,775. Berdasarkan nilai FK 4,775 adalah longsor jarang terjadi (lereng relatif stabil). Faktor keamanan yang tinggi di pengaruhi oleh tingkat pelapukan batuan yang rendah, intensitas kekar yang sedikit, dan litologi yang di dominasi struktur masif.
Analisis Peran Sektor Pertambangan dalam Pembangunan Regional Berkelanjutan di Provinsi Sumatera Selatan dengan Menerapkan Pendekatan Analisis Model Input-Ouput Rizky Syaputra; Andyono Broto Santoso; Nofrohu Retongga; Lia Alfianita; Frida Rosidatul Mu’awanah; Nur Widi Astanto Agus Tri Heri
Jurnal Teknologi Vol 16 No 1 (2023): Jurnal Teknologi
Publisher : Jurnal Teknologi, Fakultas Teknologi Industri, Institut Sains & Teknologi AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.34151/jurtek.v16i1.4320

Abstract

Sustainable regional development aims to increase regional competitiveness, increase economic growth, reduce regional inequality, and improve people's lives. South Sumatra Province is one of the provinces in Indonesia with excellent coal mining potential and can encourage sustainable regional development. The development of a sector cannot be separated from the support of other sectors, so optimizing the allocation of routine and development budgets into the economic sector is essential. For this reason, it is necessary to calculate the output impact analysis and analysis of the impact of gross value added on government expenditure using the input-output model. The calculation through this input-output model shows how much influence the increase or decrease in output and gross value added has on government expenditure. The role of the coal mining sector with other sectors and the condition of its existence in the economy need to be studied using the input-output table to determine the part of the mining sector in the regional economy. It can be concluded that the coal mining sector is still one of the leading sectors in economic growth in South Sumatra Province.
Analisis Perbandingan Tipe Fluida Berdasarkan Kandungan Anion Cl-SO4-HCO3 Pada Mataair Panas Candi Gedong Songo Dan Mataair Panas Derekan Kabupaten Semarang Provinsi Jawa Tengah Nofrohu Retongga
Jurnal Ilmiah MTG Vol 14, No 1 (2023): Jurnal Ilmiah MTG Volume 14 No. 1 Tahun 2023
Publisher : Jurusan Teknik Geologi Fakultas Teknologi Mineral UPN "Veteran" Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31315/jmtg.v14i1.8358

Abstract

Lokasi penelitian terletak di daerah mataair panas Candi Gedong Songo dan mataair panas derekan, Kabupaten Semarang, Provinsi Jawa Tengah. Tujuan penelitian untuk mengidentifikasi perbandingan tipe fluida berdasarkan kandungan anion Cl-SO4-HCO3 pada mataair panas Gedong Songo dan mataair panas Derekan, Kabupaten Semarang, Provinsi Jawa Tengah. Analisis tipe fluida mataair panas menggunakan data hasil pengujian geokimia. Berdasarkan hasil analisis geokimia dan perhitungan persentase kadar  unsur  Cl, SO4 dan HCO3, yang kemudian diplotkan dalam diagram Ternary Plot kandungan fluida mataair panas yang terdapat pada daerah Gedong Songo merupakan fluida air Sulfat, dikarenakan dari hasil analisis kimia diketahui unsur SO4 (Sulfat) merupakan unsur yang paling dominan dan berada pada Volcanic Waters. Berdasarkan hasil analisis geokimia dan perhitungan persentase kadar  unsur  Cl, SO4 dan HCO3 , yang kemudian diplotkan dalam diagram Ternary Plot kandungan fluida mataair panas yang terdapat pada daerah Derekan merupakan fluida air Bikarbonat. Hal ini dikarenakan dari hasil analisis geokimia diketahui unsur HCO3 (Bikarbonat) merupakan unsur yang paling dominan dan berada pada Peripheral Water.
Model of Hydraulic Conductivity, Infiltration Rate, and Permeability at Gold Mine Waste Dump in North Sulawesi, Indonesia Friska Agustin; Landy Pratono; Rian Andriansyah; Nofrohu Retongga; Emi Prasetyawati Umar
Journal of Earth and Marine Technology (JEMT) Vol 4, No 1 (2023)
Publisher : Lembaga Penelititan dan Pengabdian kepada Masyarakat - Institut Teknologi Adhi Tama Suraba

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31284/j.jemt.2023.v4i1.4811

Abstract

The research area is a gold mine operating in North Sulawesi. The aim of the study was to analyze and calculate hydrological parameters, namely: hydraulic conductivity, infiltration rate, and permeability to find out how strong the soil cover is at one level of waste disposal. The method used is the Measurement of hydraulic conductivity, infiltration rate, and permeability in the field, analysis, and calculation of hydraulic conductivity, infiltration rate, and permeability based on field data. In the designated regions of the waste dump, specifically areas 1a, b, and c, we observed certain hydrological patterns that are worth noting. Firstly, the hydraulic conductivity in these areas, which is a crucial determinant of the rate at which water can move through the soil, consistently showcased low average values. This is further supported by the similarly slow infiltration rate identified in the same zones. The ability of the soil to transmit water, i.e., its permeability, also followed this trend, with values leaning towards the lower end of the scale, indicating very slow permeability. One major contributory factor to these patterns appears to be the soil's composition. Predominantly made up of sandy loam, the soil in these areas exhibits high water retention capabilities. Sandy loam, by its nature, binds and retains water effectively, which could potentially explain the observed hydrological behaviors in waste dump areas 1a, b, and c.
Relationship of Rock Geomechanics and Coal Mine Slope Safety Factor in South Sumatra Region, Indonesia Nofrohu Retongga; Rio Bagas Saputa; Friska Agustin; Rizky Syaputra; Muhammad Haikal Razi; Atikah Zahidah; Efrat N Nainggolan
Journal of Earth and Marine Technology (JEMT) Vol 4, No 1 (2023)
Publisher : Lembaga Penelititan dan Pengabdian kepada Masyarakat - Institut Teknologi Adhi Tama Suraba

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31284/j.jemt.2023.v4i1.4852

Abstract

The research location is in the coal mine area South Sumatera region, Indonesia. This study aims to determine the geomechanics relationship of the rock which includes the physical properties of the rock: bulk density, and mechanical properties of the rock (shear strength), cohesion and internal shear angle to the safety factor of the coal mine slopes in the study area. Field research is carried out by observing and measuring directly in the field in the following ways: (a) Measuring slope azimuth, slope, dip direction and slope height and width using a measuring tape and geological compass. (b) Rock description based on physical characteristics (megascopic) and rock sampling for testing the physical and mechanical properties of the rock in the laboratory. (c) Observing the general condition of water from rock slopes (dry, moist, watery, wet or flowing) and slope vegetation. 2. Cohesion values and internal shear angles are secondary data obtained from PT. X which has been analyzed in the laboratory. 3. Slope modeling was carried out using Rocscience Slide software. This shows that the smaller the rock density value, the greater the rock cohesion value. The greater the cohesion value of the rock, the smaller the value of the shear angle on the rock. The smaller the value of the shear angle in the rock, the greater the value of the safety factor of the rock slope.
Mitigasi Bencana Longsor Sebagai Dasar Penurunan Risiko Bencana di Sepanjang Jalan Karanganyar - Karanggayam, Kabupaten Kebumen Nofrohu Retongga
Jurnal Pengabdian kepada Masyarakat Nusantara Vol. 5 No. 1 (2024): Jurnal Pengabdian kepada Masyarakat Nusantara (JPkMN)
Publisher : Sistem Informasi dan Teknologi (Sisfokomtek)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55338/jpkmn.v5i1.2665

Abstract

Longsor adalah bencana selalu terjadi di Kabupaten Kebumen. Berdasarkan data dari Badan Penanggulangan Bencana Daerah (BPBD) Kabupaten Kebumen dari tahun 2011 - 2020 sudah terjadi 1335 kejadian bencana, 477 atau (35,7%) kejadian adalah bencana longsor. Bencana longsor merupakan kejadian yang paling banyak terjadi di Kecamatan Karanggayam dengan 43 kejadian. Bencana longsor dapat disebabkan oleh kondisi geomorfologi seperti bentuklahan, kelerengan, jenis batuan, proses pelapukan, bidang-bidang diskontinuitas, curah hujan yang tinggi, penggunaan lahan, kondisi hidrologi dan vegetasi. Mitigasi struktural longsor, yaitu pembangunan dinding penahan yang di buat menggunakan sistem drainase dan pembangunan terasering menggunakan penguatan bronjong. Metode pengabdian ini menggunakan metode pemetaan langsung di lapangan dengan mengamati langsung pada lereng jalan, meliputi: intensitas longsor, besar atau kecilnya longsoran, kelerengan, jenis batuan, tingkat pelapukan batuan, ketebalan tanah, kondisi air tanah, dan vegetasi di daerah rawan bencana longsor, khususnya di jalan lintas utama Karanganyar ke Karanggayam. Mitigasi non-struktural, yaitu pemasangan sistem peringatan dini, terdapat jalur dan tanda arah jalur evakuasi, sosialisasi tentang bencana longsor, dan pembuatan papan peringatan daerah rawan bencana longsor. 
Sosialisasi Pentingnya Soft Skill Sebagai Dasar Menghadapi Industri Pertambangan Setelah Lulus Sarjana Bagi Mahasiswa Baru Teknik Pertambangan Universitas Teknologi Sumbawa Nofrohu Retongga; Sayidatina Hayatuzzahra; Adella Ulyandana Jayatri; Samsun Samsun; Rizaldi Rizaldi; Muhammad Jihad; Aghib Dirgantara; Ahmad Husnul Fiqri; Aqmal Septian Hakim; Budiman Budiman; Veri Irshapratama; Alfal Gilang Ramadhan; M. Haris; Dandy Firdiansyah
Jurnal Pengabdian kepada Masyarakat Nusantara Vol. 5 No. 2 (2024): Jurnal Pengabdian kepada Masyarakat Nusantara (JPkMN)
Publisher : Sistem Informasi dan Teknologi (Sisfokomtek)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55338/jpkmn.v5i2.2837

Abstract

Data Smeru Research Institute jika diuraikan lebih lanjut presentase tingkat penganggur di Indonesia yang berusia muda atau usia siap bekerja lebih banyak daripada jumlah penganggur di usia muda di dunia. Salah satu faktor penyebabnya adalah masih rendahnya soft skill atau keahlian yang dimiliki oleh calon tenaga kerja di usia muda siap bekerja tersebut. Metode pengabdian terdiri dari 3 tahap, yaitu tahap persiapan, tahap penyampaian sosialisasi dan materi pengabdian, serta tanya jawab dengan mahasiswa baru. Sosialisasi ini sebagai wadah untuk memberi gambaran, pemahaman dan melatih 20 soft skill yang harus dimiliki oleh mahasiswa Teknik Pertambangan Universitas Teknologi Sumbawa seperti meningkatkan kemampuan komunikasi, integritas yang baik, kemampuan bekerjasama, etos kerja yang baik, memiliki motivasi yang baik, kemampuan beradaptasi, kemampuan analitik, kemampuan software pertambangan, kemampuan berorganisasi, berorientasi kepada hal yang detail, kemampuan memimpin, kepercayaan diri yang baik, berkepribadian yang ramah, sopan, bijaksana, indek prestasi yang memuaskan, kreatif, humoris, dan kemampuan berwirausaha bagi mahasiswa baru sampai dengan lulus sarjana S-1 sebagai sebagai dasar untuk mencapai kesuksesan dalam bekerja di industri pertambangan, industri di luar pertambangan, maupun akan menjadi Dosen Teknik Pertambangan kedepannya.
Co-Authors Abdurrahman Saputra Adella Ulyandana Jayatri Aghib Dirgantara Agus Munandar Ahmad Husnul Fiqri Alfal Gilang Ramadhan Andika Gerardus Oratmangun Andyono Broto Santoso Aqmal Septian Hakim Ardian Anwar Arie Noor Rakhman Atikah Zahidah Atikah Zahidah Bayu Syakiran Budiman Budiman Dandy Firdiansyah Diana Septiani Roos Dwi Indah Purnamawati, Dwi Indah Efrat N Nainggolan Emi Prasetyawati Umar Frida Rosidatul Mu’awanah Friska Agustin Friska Agustin Indah Aprianti L. Muh. Fathur Rizki Landy Pratono Lia Alfianita M. Haris Marolop P Pangaribuan Muhammad Haikal Razi Muhammad Jihad Muhammad Rivai Nur Widi Astanto Agus Tri Heri Nurhikmah Putri Wijaya Oan Marcello Lukas Watania Popi Jolia Salia Rian Andriansyah Rio Bagas Saputa Rizaldi Rizaldi Rizky Syaputra Rohmad Bagus Abadi Samsun Samsun Sayidatina Hayatuzzahra Veri Irshapratama