Judul: Valuasi Ekonomi Kegiatan Pertambangan Emas dan Persepsi Masyarakat Terhadap Dampak Sosial di Kecamatan Huta Bargot, Sumatera Utara
Abstrak: Mandailing Natal is one of the regencies in North Sumatra which is rich in natural resources. The natural resource which has been managed is gold mining. Huta Bargot is one of the sub-districts in the regency where there is Illegal Gold Mining (PETI). The existence of this illegal gold mining has socio-economic impact on the people involved in the mining activities either directly or indirectly, which can be positive or negative. This study aimed to analyze the economic impact through economic valuation with cost-benefit analysis, people’s perceptions of social changes due to the gold mining, and the form of community wisdom on the utilization of natural resources. This study used secondary data and primary data. The secondary data was obtained from written documents either in the form of scientific papers or official documents from the relevant authorities. The primary data was obtained from direct observation at the study site and through interviews (in-depth and structured). The determination of the respondents in the study used purposive sampling method, which was based on the research need appropriate to the research objectives. The respondents included 30 miners and 30 non-miners, with 9 key persons consisting of 3 religious leaders, 3 adat leaders and 3 village heads. The data analysis of economic valuation used Net Present Value (NPV) and Benefit Cost Ratio (BCR) with a period of 20 years and an interest rate of 8%. The data analysis of the people’s perceptions used perception index. The data analysis of local wisdom was conducted descriptively. The cost analysis obtained from mining costs due to the forest degradation (as producer firewood, animals, medicinal plants, erosion-flood control) amounted to Rp. 1 966 086 740 per year. The cost of water resource reduction (water availability and fish production) was Rp 275,676,000 per year. The cost of ladang production decline was Rp. 530 596 800 per year. The cost of people’s health deterioration amounted to Rp. 19 936 000 per year. The benefit value derived from the increase in revenues was Rp. 128 679 996 per year. Based on the costbenefit analysis, the NPV obtained was Rp. -21 606 438 873 and the BCR was 0.055. The NPV indicated that the land conversion—from the forest land to the mine land—resulted in a loss of Rp. -21 606 438 873, so that the people’s gold mining was not feasible to continue. The BCR showed that every Rp 1 000 spent by the people only brought benefit to a group of people from mining activities amounting to Rp 55. Social changes had occurred in the form of increased crime, social jealousy and an increasingly consumptive community.There was a perception gap between miners and non-miners on the social impacts in terms of increased crime, social jealousy, an increasingly consumptive community, and those who should rehabilitate the post-mining land. The people were concerned about the impacts which would continue to increase due to the absence of land rehabilitation. According to the local wisdom in Bargot Huta, people should utilize the natural resources wisely and they must have the awareness of maintaining the quantity and quality
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Judul: Kerugian Ekonomi akibat Konversi Lahan Perkebunan Kelapa Sawit menjadi Pertambangan Emas (Studi Kasus: Desa Daya Murni, Kecamatan Pelepat Ilir, Kabupaten Bungo, Provinsi Jambi)
Abstrak: The increasing of people amount will effect on the demand, to fulfill those needs it increase the extraction towards resources in some more amount. one of the economic activities to fulfill those needs is a mining business are carried out by converting oil palm plantation. The mining activities are mining without authorization (PETI). This research objective were to identify the perception of multistakeholder about PETI activity, to estimate the economic loss because land convertion, and to analyze the willingness to pay (WTP) for of miner society. This research used descriptive analysis, loss of earning method, contingent valuation method (CVM), and multiple linear regression. The result showed that the multi stakeholder perception related to PETI from the aspect of social, economic, and environmental. The impact socio-ekonomic aspect are opening job, increase income, mining accidents, and the constriction plantation. While the impact of environmental aspect is the destruction of soil structure, reduce soil fertility, land became irreguler, and the destruction of village and plantation roads caused by sund truck. Economic loss from production of palm oil is Rp 2066 333.3/people/month. The total value of WTP miner is Rp 315 000 with an average of Rp 10 150. The factors affect on the WTP were the amount of amenability, income, soil quality, the dummy mine work and other work.
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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