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A research about study of sandstone slope stability using the Bishop Simplified method in Uu Samarinda has been conducted. This study was conducted to analyze the rebound number values of sandstone slopes, evaluate their stability level, and calculate the safety factor using the Bishop method. The results showed that the rebound number values were 22.34 at point 1, 19.83 at point 2, and 18.07 at point 3. The Uniaxial Compressive Strength (UCS) values at the observation points were 1.90 MPa, 1.62 MPa, and 2.21 MPa, respectively. Geological Strength Index (GSI) evaluation indicated a rating of 80–85, demonstrating intact/massive rock structure, fresh and unweathered rock surfaces, and very good rock quality. Based on the Bishop method analysis, the slope factor of safety in 6.525  with a probability of failure is 0.000%, indicating that the sandstone slope in Ulu Samarinda is highly stable even under external pressures such as heavy rainfall or minor earthquakes. This study provides crucial information on the mechanical characteristics and stability of sandstone slopes in ulu Samarinda, which can serve as a reference for technical planning, geotechnical risk mitigation, and the sustainable development of safe areas.

This study aims to analyze the level of flood hazard in Baturaja Barat District, Ogan Komering Ulu Regency, by applying a spatial approach using Geographic Information Systems (GIS) through the overlay method. The analysis was carried out by integrating six main physical parameters, namely rainfall, land use, elevation, slope, river density, and soil type. Each parameter was assigned a score and weight according to its influence on flood potential and subsequently processed spatially to produce a flood hazard map. The results indicate that the Baturaja Barat District area is classified into three hazard levels: low (3.25%), moderate (70.64%), and high (25.84%). Areas with high hazard levels are predominantly characterized by densely populated settlements situated at low elevations and in close proximity to river networks, particularly in Tanjung Karang, Air Gading, Talang Jawa, Karang Agung, and surrounding villages. These findings highlight that land-use changes, topographic conditions, and the distribution of river networks play significant roles in increasing flood risk. The results of this study are expected to serve as a foundation for spatial planning, the strengthening of disaster mitigation policies, and the enhancement of community preparedness against flood hazards in the region.

The stability of slopes in open-pit coal mining in Indonesia is significantly influenced by geological faults, which are a major factor causing slope failures. This study aims to examine the impact of faults on slope stability by conducting a systematic literature review of 25 scientific publications from 2018 to 2025. The results indicate that faults and fault zones consistently reduce rock mass integrity through several mechanisms, including stress concentration in weak zones, the formation of preferential sliding surfaces, amplification of hydro-mechanical effects from groundwater and rainfall, and the reduction of rock strength parameters. Case studies in Kalimantan and Sumatra confirm these mechanisms with slope failures aligning with fault orientations. Kinematic and numerical analyses using the Limit Equilibrium Method (LEM), Finite Element Method (FEM), and Distinct Element Method (DEM) show a reduction in the safety factor (SF) by up to 36% on slopes affected by faults. Practical recommendations include continuous monitoring using Slope Stability Radar (SSR), optimization of slope geometry with angles < 18° in fault zones, groundwater control, reinforcement with anchors and bolting, and UAV-based discontinuity mapping for hazard zoning. This study concludes that managing slopes in fault zones requires an integrated approach combining detailed geological investigation, multi-method numerical analysis, real-time monitoring, and specific mitigation design.

Tax fairness has become a central concern in improving individual taxpayer compliance in Indonesia, particularly amid increasingly complex regulations and declining public trust in fiscal institutions. This study stems from the urgent need to understand how individual taxpayers interpret the notion of tax fairness and how these interpretations shape their willingness to comply. The primary objective is to explore the underlying dimensions of tax fairness procedural, distributive, and interactional and to explain how these dimensions relate to the development of voluntary compliance. Employing an interpretive qualitative approach, this research relies on in-depth interviews with 15 individual taxpayers located in Jakarta, Yogyakarta, and Medan, selected through purposive sampling. The data were examined using Interpretative Phenomenological Analysis (IPA) to uncover recurring themes and the subjective experiences shared by participants. Findings reveal that perceptions of procedural and interactional fairness exert the strongest influence on compliance behavior, while distributive fairness is often viewed negatively due to perceived inequality in public benefit allocation and the complexity of tax rules. Trust in government and social morality emerge as critical mediators linking fairness perceptions to voluntary compliance. The study contributes theoretically by integrating Equity Theory, Tax Morale Theory, and the Slippery Slope Framework within the Indonesian cultural context, emphasizing that tax fairness forms the moral foundation of voluntary compliance. Practical implications highlight the need for equitable public services, stronger fiscal transparency, and value-based tax education. Future research is encouraged to adopt mixed-methods designs to provide deeper quantitative insights into the relationship between fairness, trust, and tax compliance across diverse social settings.

This literature study evaluates the accuracy of the Slope Mass Rating (SMR) method for coal mine slope stability in Indonesia through a systematic descriptive synthesis of 25 empirical studies from 2020 to 2025. The objectives of the study were to identify the level of SMR prediction accuracy, factors affecting the method's performance, and modifications required for local Indonesian conditions. The research method involved a systematic search with inclusion criteria for empirical studies reporting SMR and/or Safety Factor (SF) values ​​for coal mines and associated slopes in Indonesia. Quantitative analysis showed a range of reported SMR values ​​between 41 and 96 with a median of 72, while SF values ​​ranged from 1.137 to 4.09 for normal operational conditions. The synthesis results indicated that SMR provides a consistent stability classification for initial slope design and failure mode identification (planar, wedge, toppling), with historical validation showing a correlation of up to 91.23% between SMR-based hazard zoning and actual field events in some cases. Key limitations include dependence on discontinuity data quality, sensitivity to groundwater conditions and tropical weathering, and variation in the interpretation of adjustment factors F1-F4. Modifications such as NAAF23 and integration with numerical modeling have been shown to improve prediction reliability. It is recommended that coal mining practitioners combine SMR with kinematic analysis and limit equilibrium modeling as standard operating procedures, and develop adjustment factors specific to Indonesian geological conditions. Further research should focus on standardizing parameter reporting and cross-site quantitative validation to enable more robust statistical meta-analyses.  

This study formulates a design concept for the Beach Tourism Resort Area in Botubarani Village by applying tropical architecture that responds to coastal climatic conditions while enhancing the quality of visitor experiences. The research integrates principles of thermal comfort, environmental sustainability, and the ecological potential of coastal environments as the basis for creating climate-adaptive and environmentally responsive tourism areas. The methodology includes site analysis, field observation, climatological assessment, and a literature review related to tropical architecture and coastal tourism design. The collected data were used to determine building orientation, mass layout patterns, visitor capacity, materials, vegetation, and utility systems appropriate for humid tropical climates. The findings show that the site’s position between the sea and the mountains, combined with full-day sun exposure, requires design strategies that maximize cross-ventilation, utilize sloped roofs, provide natural shading, and apply local materials such as wood, bamboo, and red brick. The large spatial needs based on visitor capacity projections are accommodated through a flexible cluster layout that supports visual and functional connectivity between buildings while incorporating green open spaces to enhance microclimate comfort. The utility system is designed using sustainability principles through greywater–blackwater separation, infiltration wells, and recycling-based waste management. This study confirms that the application of tropical architecture in coastal tourism areas can improve thermal comfort, energy efficiency, and environmental sustainability. These findings guide developing tropical tourism area designs that are more adaptive to climate change and more responsive to visitor needs.

Tujuan penelitian ini adalah untuk mengetahui hubungan analisis Rasio Keuangan terhadap Perubahan SHU pada Koperasi Kredit Tuke Jung berdasarkan analisis Rasio Keuangan yaitu Rasio Likuiditas ditinjau dari Current Ratio, Rasio Profitabilitas ditinjau dari Return on Equity, Rasio Solvabilitas ditinjau dari Total Debt to Equity Ratio, dan Rasio Aktivitas ditinjau dari Receivable Turn Over. Metode penelitian yang digunakan adalah asosiatif kuantitatif. Analisis data yang digunakan adalah Analisis Rasio Keuangan, Analisis Perubahan SHU, dan Analisis Statistik yaitu menggunakan Korelasi Pruduct Moment. Data yang digunakan adalah laporan keuangan Koperasi Kredit Tuke Jung yaitu Neraca tahun 2014 – 2015 dan Laporan Laba Rugi tahun 2014 – 2015. Teknik pengumpulan data yang dilakukan adalah dengan metode dokumentasi. Hasil dari penelitian menunjukan bahwa : (1) Berdasarkan analisis rasio keuangan diperoleh hasil sebagai berikut : Current ratio sebesar 288%, Return on Equity sebesar 30 %, Total Debt to Equity Ratio sebesar 288 %, Receivable Turn Over sebesar 0,20 kali. (2) Berdasarkan analisis perubahan SHU memperoleh hasil yaitu perubahan SHU sebesar 4,18 %. (3) Sedangkan analisis statistik memperoleh hasil yaitu korelasi product moment sebesar 0,93 %, artinya tingkat hubungan antara analisis rasio keuangan dan perubahan SHU pada Koperasi Kredit Tuke Jung di kategorikan sangat kuat dan disebut sebagai korelasi sempurna atau hubungan linear sempurna dengan kemiringan (slope) negatif.

Slope stability is a key concern in open-pit mining due to its impact on safety and operational efficiency. Mine X, located in Kalimantan Island, faces landslide risks on its high wall slopes. This study aims to model slope stability and determine safe and economical slope geometry. The analysis was performed using the Limit Equilibrium Method (Bishop Simplified), both analytically and numerically, through Slide 6.0 software by Rockscience Inc. Input data were obtained from five geotechnical investigation points provided by PT.X, including cohesion, internal friction angle, and saturated unit weight. Two lithologies were analyzed—claystone and sandstone—with slope height variations (5 m, 10 m, 15 m) and angles (26°, 45°, 51°, 59°), under dry and saturated conditions. Simulation results show that the factor of safety (SF) decreases with increasing slope height and angle, especially under saturated conditions. Sandstone demonstrates better stability than claystone. The recommended optimal slope geometry is 10 meters in height with a 59° angle, yielding a SF ≥ 1.25 and aligning with the PC-400 excavator's cutting capability. This study provides a technical reference for designing safe slopes that support mining productivity.

Rock stability and service life in geotechnical and mining engineering are highly dependent on the rock's mechanical and physical parameters, where the variation in sandstone grain size is a crucial intrinsic factor. This study aims to comprehensively analyze the correlation between sandstone grain size with uniaxial compressive strength (UCS) and resistance to weathering (Slake Durability Index) in samples taken from the Balikpapan and Pulau Balang Formations in the Samarinda area, East Kalimantan. The research methodology involved a series of standard laboratory tests, including rock physical properties analysis, grain size distribution analysis, UCS testing, and slake durability testing through three cycles. The test results show a significant correlation: sandstone with finer grain sizes and higher density consistently demonstrates greater UCS values and a higher Durability Index, indicating superior mechanical and physical resistance. Specifically, the Pulau Balang Formation exhibits a more compact structure and finer grain size, resulting in better durability values compared to the Balikpapan Formation. These findings are important as a geomechanical data basis for slope design planning, rock mass stability analysis, and material selection in infrastructure projects or mining operations involving both formations.

The purpose of this study was to determine the effect of pulley angle variations of 13.5ᵒ and 14ᵒ and roller weight variations of 12 g, 14 g, and 16 g on the torque of a 150 cm3 automatic motorcycle. The method with a quantitative approach the method used is the experimental method. For the sample of this research is a type of pulley and 3 types of rollers with different slopes and weights where the angle varies to test the 150 cm3 matic motorcycle torque used. From the results of this study results in a value where the Fcount value is greater than the Ftable means that the null hypothesis (H02) is rejected and the alternative hypothesis (H22) is accepted or the mass of the roller has an influence on torque, the Fcount value is greater than the Ftable means that the hypothesis (H01) is rejected and the alternative hypothesis (H11) is accepted or the mass of the roller has an influence on torque, and that the interaction between pulley angle and roller mass does not affect, and the Ftable value is lower than the Fcount value that the hypothesis (H03) is accepted and the alternative hypothesis (H33) is rejected, roller mass affects torque.

This study examines the reclamation plan of PT. Z for the 2023–2027 period with the aim of assessing the technical feasibility, ecological effectiveness, and alignment with national reclamation regulations. A descriptive-quantitative approach was employed through field observations, analysis of geomorphological conditions, evaluation of topsoil management, assessment of revegetation performance, and review of key environmental documents. The planned land disturbance reaches 138.53 ha, with reclamation focused on the disposal and topsoil areas covering 29.67 ha, as the mining pit remains active. Reclamation activities include land recontouring, topsoil spreading, erosion control, establishment of Legume Cover Crops (LCC), and planting of local species such as Rukam. The results indicate that the implemented strategies effectively enhance soil stability, improve vegetation cover, and support ecosystem recovery. Furthermore, the reclamation program meets the key performance criteria set by the Ministry of Energy and Mineral Resources, with vegetation cover exceeding 90% and stable slope conditions. Challenges remain, particularly related to sedimentation management and the absence of pit reclamation during the active mining phase. Overall, the study concludes that PT. Z has developed and executed a reclamation plan that reflects good mining practices and environmental stewardship, contributing to the long-term sustainability of post-mining land use.

Kaloran Village is an area characterized by steep slope topography that makes it vulnerable to landslides, especially during the rainy season with high rainfall intensity. Although the landslide risk level in this village is still relatively low and has never caused any casualties, the potential for material losses and psychosocial impacts that may arise still need to be seriously anticipated. Disaster risk reduction efforts in Kaloran Village are carried out through the Disaster Resilient Village Work Program (Destana), which aims to increase the capacity and capability of the community in facing disaster threats. The program implementation method consists of three main stages: preparation through focus group discussions (FGDs) and interviews with stakeholders, preparation of the Destana document containing mitigation strategies and steps, and community empowerment through socialization activities and preparedness training. The results of the study indicate that Kaloran Village is categorized as a Medium Resilient Village with a resilience score of 68.97. This achievement serves as an important basis for strengthening the village preparedness system, which is followed up with the establishment of the Disaster Risk Reduction Forum (FPRB) "Kaloran Tangguh Rescue" as a community coordination forum. In addition, evacuation route maps were produced, which serve as technical guidance in the event of a disaster, and the development of the Destana (Disaster Preparedness and Disaster Management) and Contingency Plan (Renkon) documents, which serve as official guidelines for disaster mitigation and management efforts at the village level. This program demonstrates that active community participation, collaboration between stakeholders, and the development of strategic documents can strengthen village preparedness for the threat of landslides.

Lau Kawar Lake, a natural tourism area located on the slopes of Mount Sinabung in Karo Regency, North Sumatra, holds significant potential for the development of nature and culture-based tourism. However, the growth in tourist visits has not yet met expectations due to limited accessibility across various dimensions. This study aims to formulate strategies for improving physical, informational, and institutional accessibility in support of sustainable regional development.The research adopts a mixed methods approach, emphasizing primary data collection through field observations, interviews with key stakeholders and village officials, as well as surveys of 60 tourist respondents. Findings reveal that, overall, the three dimensions of accessibility are still rated as "fair," with average scores ranging from 3.28 to 3.36. The main barriers identified include inadequate road infra-structure within the area, lack of dedicated public transportation for tourists, limited official digital promotional content, and weak institutional coordination in area management. A synthesis of the quantitative and qualitative results indicates that the development of Lau Kawar Lake requires an integrative approach that combines spatial planning, community-based governance, and local policy interventions.Based on these findings, several strategic recommendations are proposed: (1) improvement of access roads and landslide-prone areas through Special Allocation Fund (DAK) for infrastructure; (2) provision of dedicated public transportation for tourists with fixed routes and schedules from the nearest city center; (3) installation of directional signs and visual information boards in aesthetically pleasing formats and bilingual language; (4) establishment of a Digital Promotion Team involving local actors and institutions; (5) capacity-building programs for the community in tourism services, home stay management, and culinary entrepreneurship; and (6) formation of a Cross-Sectoral Accessibility Coordination Forum for Lau Kawar Tourism as a medium-term planning and monitoring platform.This study contributes contextually to strengthening the accessibility dimension as a key prerequisite for advancing local tourism destinations towards sustainable, inclusive, and locally grounded development.

Compressive strength is one of the mechanical properties of rock behavior. This study focuses on the Balikpapan and Kampungbaru Formations located in the Kutai Kartanegara area, East Kalimantan. The Schmidt Hammer testing method was applied due to the lack of previous studies utilizing this tool to evaluate rock hardness in correlation with compressive strength. The research site is situated in the Kutai Kartanegara area, specifically in the districts of Muara Badak, Muara Jawa, and Sanga-Sanga. Field observations revealed the presence of claystone slopes at predetermined locations. Based on the test results, the uniaxial compressive strength (UCS) values for the Balikpapan Formation range from 3.453 MPa to 5.454 MPa, while the Kampungbaru Formation ranges from 3.317 MPa to 8.571 MPa. The Schmidt Hammer rebound number (RN) values for the Balikpapan Formation range from 17 to 19.6, and for the Kampungbaru Formation from 15 to 23.7. A negative correlation was found between the rebound number and UCS, where higher RN values tend to correspond with lower UCS values. This is supported by the linear regression analysis showing a negative coefficient (-0.450).  

In the Kutai Basin area, seasonal changes such as high rainfall can significantly increase groundwater content, so that the effect of water content on the shear strength of claystone, increasing water content in rocks tends to decrease shear strength. Water in the pores or fractures can increase pore water pressure and reduce effective normal stress. Shear strength is one of the most important mechanical parameters used to assess soil and rock stability, this parameter is very important in slope stability analysis, foundation planning, and various civil engineering and mining applications. Therefore, this study was conducted to determine whether the water content in rocks can affect the strength of rocks in receiving shear forces. The method used in this study is more quantitative and specific to the effect of water content on the shear strength of claystone in this area. Increasing water content in rocks tends to reduce shear strength. This study was conducted by taking claystone samples from several locations in the Kutai Basin. Data collection in the form of primary data and secondary data for testing physical properties and testing mechanical properties, in testing physical properties, the water content value will be taken as supporting data which is one of the factors that affect rock strength, in testing mechanical properties, claystone shear strength data will be taken. From the results of the physical properties test calculations, the air content in each Formation is obtained, namely, in the Kampungbaru Formation the minimum air content value is 15.54% and the maximum is 20.17%, in the Balikpapan Formation the minimum air content value is 10.21% and the maximum is 12,88%, in the Palaubalang Formation the minimum air content value is 10.49% and the maximum is 22.87%. The results of the strength of the claystone in receiving shear forces in the Kutai Basin are the Muara Jawa location 0.486MPa, Tanah Datar location 0.500 MPa, Sanga-sanga location 0.333 MPa, Muara Badak location 0.269, Air Putih location 0.711MPa, Mugirejo location 0.021 MPa and Lempake location 0.092 MPa.

Durability is defined as a measure of a rock's resistance to weathering and disintegration when the rock undergoes weathering processes over a short period of time. The susceptibility of rocks to disintegration is related to their low durability. Rock durability is often measured using the slake durability test. The slake durability test is widely used to assess physical changes resulting from wetting-drying processes (Franklin and Chandra, 1972). Therefore, slake durability testing is conducted to understand the weathering of rocks caused by heat and water, particularly clay stones which are one of the constituent rocks on a slope. The sampling location is around Sanga-sanga and Muara Badak. Sampling was conducted with coordinate points and the Balikpapan and Kampungbaru formations. The claystone samples taken were then brought to the Mineral and Coal Technology Laboratory of the Engineering Faculty of Mulawarman University for Slake Durability tests. In this study, the lowest index value obtained was 45.7% and the highest value was 93%, indicating high to very high durability. The difference in the durability index values of claystone at the research locations indicates the presence of variables that can affect the slake durability index values of the claystone in the Balikpapan and Kampungbaru formations, including grain size and mineral content as well as geological conditions at the research site. Based on the results of the claystone durability tests, the durability index value (Id2) was obtained, indicating that the sandstone at the research location falls into the classification of high to low.

A landslide that occurred on May 24, 2024, in Pekon Datarajan, Ulubelu District, Tanggamus, Lampung, caused significant disruption to provincial road access and resulted in material losses. This study aims to assess the post-failure slope stability through field geotechnical investigation and numerical analysis using the Limit Equilibrium Method (LEM), and to propose immediate countermeasures. The slope materials consist of MH (inorganic silt) and ML (elastic silt) with high moisture content and moderate to high swelling potential. The lithology is dominated by montmorillonite clay, which has hygroscopic characteristics, making it highly vulnerable to water infiltration that reduces shear strength and increases the risk of slope failure. Stability analysis indicates a post-failure factor of safety (FoS) of 1.36 (static loading) and 1.03 (dynamic loading), which decreases to 1.07 beneath raised groundwater conditions. Recommended immediate mitigation includes surface runoff control, the construction of impermeable drainage systems, the sealing of cracks using impermeable materials, and the installation of temporary slope reinforcements such as sheet piles. The implementation of these measures increased the FoS to 1.61 (static loading) and 1.16 (dynamic loading). This study provides a technical basis for the rapid and effective mitigation of landslides in areas with similar geological and hydrological conditions.

Disposal area is an area at an open pit mine that is used as a place to store or dispose of worthless materials. Disposal must also follow the specified safety factor standards, if the disposal design is not safe after being analyzed by a geotechnical engineer, the design must be redesigned to achieve the desired safety factor value. One way to increase the fk value is to make a Counterweight plan in making disposal. Where Counterweight is a fill material that is made with special treatment so that the soil bearing capacity increases which functions to withstand the load on it. Landslides on disposal slopes are one of the serious problems faced in mining activities, especially in areas with vulnerable geological and topographic conditions. PT Jembayan Muarabara, which operates in Marangkayu District, Kutai Kartanegara Regency, East Kalimantan Province, is no exception to this challenge. The A–A’ cross section shows a safety factor value of 1.118 in saturated conditions, which indicates that the slope is at a stable limit and needs to be improved through engineering such as adding counterweights. The B–B’ cross-section has a safety factor value of 2.332, which is included in the safe category and has met the provisions of the ESDM Ministerial Decree No. 1827 K/30/MEM/2018. The C-C’ cross-section has a safety factor value of 1.511, which is included in the safe category and has met the provisions of the ESDM Ministerial Decree No. 1827 K/30/MEM/2018.

Putra Muba Coal is one of the subsidiaries under the MNC Group, operating in the coal mining sector with an IUP (Mining Business Permit) area covering 2,947 hectares. During its mining operations at the Pandu Pit, PT. Putra Muba Coal experienced a landslide incident on the highwall side. Therefore, a back-analysis using the deterministic method was conducted to determine the material property values that led to the slope failure in the mining area. The slope material consists of claystone and siltstone layers, each with a cohesion value of 192.3 kN/m² and 157.0 kN/m², and internal friction angles of 25.3° and 24.4°, respectively. Based on the back-analysis results, it was found that there was a decrease in material property values, with cohesion reduced by 91% and the internal friction angle reduced by 29%. This reduction in material properties suggests that the decrease in cohesion was the primary factor causing the highwall slope failure, as indicated by the back-analysis of slope stability which resulted in a safety factor of (SF = 1.008).

Landslides or commonly called landslides are a disaster that often hits areas with tropical climates. The damage caused by landslides is most dominantly structural damage such as damaged road sections that are cut off. At the research location, there was a landslide that resulted in the obstruction of the road flow which was originally two lanes to one lane, it is feared that landslides will occur again, so one of the landslide prevention techniques is to use retaining walls. Based on this, this study is deemed necessary to determine the slope safety factor and to determine the safety of the slope after using retaining walls. The purpose of this study was to determine the level of slope safety without being given a load, the level of slope safety after being given a load of 25 Kpa and the level of slope safety after being given a load of 25 kpa and the addition of a retaining wall on the research slope using a Retaining Wall. In this study using the Finite Element Method in the calculation to find the level of safety of a slope, the researcher used the help of Plaxis 2D V20 Software, and the results of the calculation obtained a slope safety factor of 1.31, after being given a load of 25 kpa the slope safety factor was 1.14 and after being given a retaining wall the slope safety factor increased to 2.46.