• Energy Research

Research on coal mining that uses an open pit system shows that during the rainy season with extreme rainfall intensity causes water puddles in the mining area that cannot be flowed out of the area. The purpose of this study is to analyze rainfall and study and design a system of mine flow every mine progress. The method used to calculate plan rainfall, and runoff water flow into open channels, sumps, and settling ponds, using the Modification Gumbell, Mononobe, Empirical and Rational methods. Based on the results of the study, the planned rainfall is 285.03 mm with a return period of 8 years of rain and the hydrological risk is 86.51%. The catchment area and runoff water flow every year is getting bigger because the opening of the mine area is getting wider. Water entering the mining area is accommodated using sumps and then flowed using a pump through an open channel to the settling pond. The planning pump used is Multiflo 420EX, with a maximum discharge capacity of 440 l/sec. The need for pumps and sumps every mine progress continues to grow because the incoming runoff water flow is getting bigger.

The objective of the research was to analyze both internal and external factors influencing the strategy of sustainable soybean development to increase soybean needs in North Sumatera. SWOT analysis was used as the method of the research through identifying internal factors in the development of sustainable soybean the strategy to increase soybean production in research area is aggressive strategy or strategy of SO (Strengths - Oppurtunities) that is using force to exploit existing opportunity with activities as follows: (1). Use certified seeds in accordance with government regulations and policies. (2). Utilizing the level of soil fertility and cropping patterns to be able to meet the demand for soybeans. (3). Utilizing human resources by becoming a member of farmer groups.

Styrax sp. is a valuable latex-producing plant in North Sumatra Province, Indonesia, which requires sustainable land use practices to maintain its production and ecological value. This study aimed to assess the land characteristics and suitability of Styrax sp. in Humbang Hasundutan Regency, North Sumatra Province, to support the development of sustainable land use practices for the cultivation of this plant. The study employed a survey method to collect soil samples and evaluated the land suitability using a matching method and Geographic Information System (GIS) techniques. The results showed that Styrax sp. had moderately suitable land suitability in three villages in Humbang Hasundutan Regency. The limiting factors for land suitability were identified as rooting media, nutrient retention, water availability, and erosion hazard. These findings have important implications for the development of sustainable land use practices for Styrax sp. cultivation in the region, which can contribute to the conservation of this valuable plant species and the maintenance of ecological balance. Overall, this study provides valuable insights into the land characteristics and suitability of Styrax sp. in North Sumatra Province and highlights the importance of sustainable land use practices for the conservation of valuable plant species.