Drain hole has an important role to reduce groundwater table on a slope of coalopen pit mine. Groundwater condition on acoal open pit mine slope with a homogeneous groundwater flow media is highly dependent on the type of lithology and the groundwater bearing-rocks. The drain hole on acoal open pit mine slope is very influential on the water discharge and the length of the drain hole. This paper presents a discussion on the effect of drain holeinstallation with an inclination angle of 65° and 90° on the discharge and drain hole length. The results show that the drain hole with an angle of 65° results in greater groundwater discharge than the 90° angle. In addition, the drain hole with inclination angle of 65° is shorter than that of the drain holeinstalled with an inclination angle of 90°, thus reducing the operating costs of the open pit mine slope drainages.

Carbon Forests Projects (CFPs) play a significant role in climate change mitigation strategies. Implementation of such projects should bring environmental benefits to companies, as well as contribute to improving the environmental management efficiency in the region. The aim of this paper is to analyze the possibility of developing CFPs as a tool to achieve carbon neutrality, taking into account its environmental and economic benefits. The analysis is undertaken on the example of the Bystrinsky Mining and Processing Plant (MPP), located at the Zabaykalsky Krai (southern Siberia, Russia). The ability of the forest lands to absorb greenhouse gas emissions is assessed using the ROBUL methodology. An important feature of CFPs is the ability to combine a positive environmental effect by contributing to climate change mitigation with strengthening the image of an environmentally friendly company. However, the analysis of CFPs implementation in the example of Bystrinsky MPP shows the excess of costs over benefits. In this regard, more effective projects can be proposed for regions with a high degree of forest cover, such as Zabaikalie. Reducing the risk of forest fires in such regions can have a more tangible environmental impact by preventing additional CO2 emissions. Identifying and comprehensively assessing the environmental and economic impacts of CFPs in the context of carbon neutrality facilitates the selection of the most relevant solutions.

Based on SNI 5015:2019, the estimation of coal resources is based on geological conditions, as well as the distance of information points for each geological condition and resource class. PT. AMNK is a coal mining company and has now started mining. The mines are divided into three blocks, north, middle, and south. Drilling activities have been carried out in the middle block, with 66 drilling points resulting in 4 main seams namely, H seam, I seam, J seam, and K seam. The average drill hole distance is 150 m. This type of coal deposit belongs to the moderate geological group characterized by the presence of a fault in the middle block. Further analysis of optimum drill hole distances is carried out as a basis for the estimation and classification of resources, which in 2024 will be used as an exploration target for the southern block. Analysis of the optimum drill hole distance based on the "relative error" value using the GEV (Global Estimation Variance) method and the size of the sill variogram. Based on the analysis of the K seam, the optimum borehole distances were 385 m, 750 m, and 1750 m, measured, indicated, and inferred categories, respectively.

Gold ore processing is carried out by amalgamation techniques where mercury (Hg) is used as a medium to bind gold which results in water pollution around the processing area, so it is necessary to remediate water. One way in managing mercury-contaminated water is phytoremediation of the use of water kale (ipomoea aquatica forsk) and to help the phytoremediation process, ingredients are needed that can help the growth of water kale in increasing the absorption of Hg concentrations, namely the addition of liquid NPK fertilizer. This study aims to analyze water kale without liquid NPK fertilizer, and use liquid NPK fertilizer against water kale in reducing the concentration of Hg, pH and TSS metals in water. This study used an experimental method with an experimental box (container) consisting of 4 treatments, then an Analysis of Variance (ANOVA) test of 5% and Duncan Multiple Rang Test were carried out. The results showed that liquid NPK fertilizer had an influence on reducing the concentration of Hg, pH and TSS in water. Based on the results of experiments using liquid NPK fertilizer, the best treatment results were obtained in mercury absorption by water kale and reducing Hg concentration in water, namely treatment D (contaminated water + water kale + liquid NPK fertilizer) on the 14th day, as evidenced by a decrease in Hg concentration in water by 0.56 mg / l to 0.00486 mg / l, pH 10.1 to 6.86 and TSS 1695 mg / l to 1 mg / l and an increase in nitrate levels, Phosphate and potassium in water can accelerate absorption by water kale.

Penangan air permukaan pada lokasi disposal tambang nikel merupakan hal yang pokok agar air tidak menjadi penghambat dari produksi dan lingkungan sekitar tambang. Tujuan dari penelitian ini ialah merancang sistem penyaliran pada disposal, sehingga air limpasan yang berasal dari daerah tangkapan hujan tidak langsung mengalir menuju sungai atau danau yang dapat mengakibatkan pencemaran lingkungan. Metode penelitian yang dipakai ialah curah hujan diolah dengan beberapa pendekatan alternatif yang bertujuan untuk merancang dimensi dari saluran terbuka dan kolam pengendapan. Hasil yang didapatkan rancangan dimensi saluran terbuka dan kolam pengendapan dengan menggunakan curah hujan rata-rata sudah dapat mengalirkan dan menampung air limpasan sebelum dialirkan menuju sungai dan danau. Kata kunci: Rancangan penyaliran, disposal, saluran terbuka, kolam pengendapan