The implementation of coal mining activities with an open pit system at the end of its activities will leave behind the remains of former mining holes. Control of acid mine water is something that needs to be done during mining activities until the end of the mining process because acid mine water can cause a decrease in the quality of surface water and groundwater and have an impact on the survival of humans and biota that live on land and water. The initial characteristics of water using the floating treatment method of wetland, the pH, TSS, Fe, and Mn values ??of ex-mining lake water do not meet the quality standards of the Government Regulation of the Republic of Indonesia Number 22 of 2021. The ability of water hyacinth plants to increase pH for 25 days is quite good with an initial pH value of 4.13 to 7.34. For 25 days, the TSS parameter of water hyacinth plants is also good at reducing TSS levels with an initial value of 6 mg/L to 3 mg/L, the Fe parameter of water hyacinth plants is also good at reducing iron levels with an initial value of 1.06 mg/L to 0.34 mg/L, while the Mn parameter of water hyacinth plants is quite good at reducing manganese levels with an initial value of 1.13 mg/L to 0.32 mg/L.

Stockpiles are accumulations of materials such as coal or ore stored at specific locations. Accurate stockpile volume measurement is crucial in the mining and logistics industries for inventory management and cost efficiency. Conventional methods like Real-Time Kinematic (RTK) GPS rely on surface coordinate measurements but require numerous points, especially for irregular-shaped objects. Newer technologies like Terrestrial Laser Scanners (TLS) offer high-precision alternatives by capturing thousands of points per second, expediting and enhancing the resolution of volume measurements. This study compares TLS and RTK GPS methods in measuring the volume of andesite rock stockpiles at PT Bara Tabang. This research uses a quantitative approach, involving six Ground Control Points (GCPs) measured using the Sokkia GRX2 RTK GPS on October 24, 2024. TLS generated over 8.6 million point cloud data filtered down to 35,197 points, while RTK GPS yielded 2,276 coordinates. Accuracy testing showed very small RMSE values (RMSEr: 0.008 m; RMSEz: 0.007 m), and both LE90 and CE90 demonstrated 90% confidence within a 0.012 m range. Volume calculation using Surpac software with the cut and fill method showed TLS produced a volume of 18,766 bcm (51,982 tons/m³), while RTK GPS resulted in 18,694 bcm (51,782 tons/m³), with a difference of 72 bcm or 0.211%.These results indicate that both methods offer acceptable accuracy; however, TLS provides greater data density, efficiency, and precision, particularly for complex or large-scale stockpile objects. Therefore, TLS is recommended for high-accuracy volume measurement in mining operations that require efficiency and detailed analysis.

Mining roads play an important role in supporting the smooth running of mining activities, especially in the process of transporting materials. The bearing capacity of the soil as a road subgrade greatly affects the stability and resistance of the road to heavy equipment loads. This study aims to analyze the effect of the plasticity index and compaction parameters on the California Bearing Ratio (CBR) value, as well as to determine the thickness of the road layer based on the laboratory CBR value. Testing was carried out at the South Pit of PT. Bina Sarana Sukses site PT. Baramulti Suksessarana with a field test method using the Dynamic Cone Penetrometer (DCP) and laboratory tests such as proctor tests, Atterberg limit tests, and CBR tests on various variations of clay and sand soil mixtures. The results showed that increasing the plasticity index decreased the CBR value, while increasing the maximum dry density and decreasing the optimum water content increased the CBR value. Based on the laboratory CBR value, recommendations were obtained for the appropriate road layer thickness to ensure optimal bearing capacity for heavy equipment passing through the research area.

Using a descriptive method with a triangulation approach including observation, document analysis, and interviews this study ensures data reliability. Daily monitoring is conducted on wastewater flow and pH levels, while monthly laboratory analysis covers eight key parameters: Total Suspended Solids (TSS), iron (Fe), copper (Cu), zinc (Zn), total chromium (Cr), phosphate (PO³), oil and grease, and pH to evaluate the perfomance of the treatment system. The treatment process begins with the inflow of 960 m³ of wastewater per day into the storage pond, where aeration is applied to ensure homogenization before being transferred to the neutralization unit. pH adjustment is carried out by adding NaOH or HCl before the wastewater undergoes coagulation and flocculation stages. The study’s findings indicate that the WWTP meets the environmental quality standards established in accordance with the Decree of the Head of the Investment Coordinating Board of the Republic of Indonesia (2020), Number SK.214/1/KLHK/2020 concerning the Permit for Wastewater Disposal into the Sea on Behalf of PT Pembangkit Jawa Bali Unit Pembangkitan Gresik. This study emphasizes the importance of systematic monitoring and treatment in wastewater management.

In mining activities, there is often a discrepancy between the plan and the actual conditions in the field, this discrepancy was found after reconciliation at the end of the progress (month). From the mining activities carried out by PT. Jembayan Muarabara (JMB), coal roof floor data was obtained from the survey which was then used to find survey tonnage, model tonnage data and actual tonnage scales. Then from this data it can be used to obtain coal recovery, coal looses in coal cleaning, loading, and coal transportation. The results of the study obtained tonnage data from the survey of 26,201.50 tons, a model of 26,488.50 tons and an actual tonnage of 24,885.09 tons. From the data obtained, the coal recovery value at the research location was 94.98% with coal losses in coal cleaning activities of 4.52% or 1196.39 tons and in loading activities of 0.5% or 120.02 tons with a tonnage discrepancy between planning and actual in the field of 1603.41 tons.

This study analyzes the morphological form and development characteristics of the Petrosea City Park green open space in Mimika Regency, Central Papua. Using qualitative descriptive-analytical methods, this research examines road patterns, spatial configurations, and architectural elements as well as the physical, economic, and socio-cultural characteristics of park development. The results show that the park implements a radial pattern centered on a roundabout with clear hierarchical zoning, integrating Kamoro cultural landmarks through bronze statues. However, infrastructure limitations and underutilized economic potential indicate the need for integrated development to optimize the function of green open spaces in the context of mining cities in Eastern Indonesia.

Handling natural disaster victims requires a fast, precise, and fair aid distribution process. In this context, expert systems can be utilized as a decision-making tool in determining the type and amount of aid that should be given to victims. This article develops a desktop-based expert system using the Java programming language, which is able to calculate the type of aid based on the condition of the victim, the level of damage, and the number of affected family members. The method used is a rule-based expert system with if-then logic. The results show that this system can assist field officers in accelerating the calculation and distribution of aid.

Organic waste management is an important issue in addressing environmental problems. One potential solution is bioconversion technology using Black Soldier Fly (BSF) maggots that can break down organic waste and produce larvae with economic value as animal feed. To increase the selling value and extend the shelf life, BSF larvae need to be dried using tools such as rotary dryers. This study aims to design and analyse the strength of a rotary dryer machine frame for maggot drying with a Finite Element Analysis (FEA) approach based on SolidWorks software. Simulations were carried out on several materials: ASTM A36, AISI 1020 Steel, and AISI 1045 Steel. The analysis results show that all materials are within safe limits based on Von Mises stress, deformation, and safety factor. AISI 1045 steel material gives the best performance with Von Mises stress of 14.238 MPa, deformation of 0.59 mm, and safety factor of 7.2. These results show that AISI 1045 steel is the most recommended material for the rotary dryer frame.

Compensation is an effort to reduce the pollution load from other sectors to replace the wastewater load that will be discharged by businesses and/or activities due to river water quality being exceeded. Currently, most large rivers in Indonesia have exceeded the water quality standards set by the government. The one of the hospitals in Jember plans to discharge wastewater into the Bedadung River. However, the Biochemical Oxygen Demand (BOD) quality standard for the Bedadung River has been exceeded. Therefore, alternative compensation activities are needed to reduce the BOD levels of the Bedadung River. Bathing, Washing, and Toilet (MCK) facilities with biofilter septic tanks were chosen. This technology is considered to be able to effectively reduce the BOD concentration of domestic waste before being discharged into the environment. This study aims to calculate the potential for reducing the BOD pollutant load in Bedadung River water if compensation is carried out through the construction of MCK with a biofilter septic tank system, so that it is expected to provide a significant contribution to improving river water quality while supporting the sustainability of hospital activities.

Indonesia, which is located on the equator, has great potential to utilize solar energy, with an average solar radiation reaching 4.80 kWh/m² per day. This provides an advantage in the development of Solar Power Plants (SPP), one of which is through the installation of rooftop on the roof of the building as a source of electrical energy. This study aims to analyze the feasibility of SPP development by considering the techno-economic aspects of the Pondok Juice cafe. The total real electrical energy consumption required by the Pondok Juice cafe is 32,548 Wh/day. Assuming a system loss of 15%, the total electrical energy requirement that must be supplied by the SPP is 37,430.2 Wh/day. The initial investment projection is IDR 204,265,197, with operational and maintenance costs for 25 years of IDR 105,760,028. The investment feasibility analysis shows NPV of IDR 441,523,820.10, BCR 4.11, DPP ±5 years, and IRR 15.55%, which proves that this SPP planning is feasible to implement.