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Feldspar mine may cause environmental problem. Post-mining lake water pollute the environment because it has a low pH containing heavy metals such as aluminium (Al). The research objective was to analyze the effectiveness of water quality changes using Eichorniasp and Thypaangustifolia plants with organic substrates, and to analyze the results of water quality management based on wastewater quality standards. The results showed that the treatment using water from pit lake + material pit lake + clumps of Thypaangustifolia + organic substrate was declared effective in increasing pH and reducing TSS and dissolved metals at 15 days of treatment, indicated by a pH value of 6.7-7.04, a TSS value of 1,710 mg/l to 108 mg/l, and decreased grade Al from 233.0975 mg/l to 190.77 mg/l. The quality standard for Al dissolved metal management has not reached the waste water quality standard, while the results of pH and TSS management are in accordance with the quality standards stipulated with the provisions concerning the wastewater quality standard.

This research aims to review the theoretical study of contingency theory and the concept of entrepreneurship in the context of submitting research prepositions about antecedent  factors  and  the consequences  of  management  patterns  of  eco-village tourism. Observations are planned to be carried out using a sample of 11 tourist villages in Bantul Regency and data collection is carried out by in-depth interview techniques with 25 research participants including community leaders, business people and government officials who manage Small and Medium Enterprises (SME). More detailed this paper explores the external and internal environmental factors that have a significant influence on the managerial pattern of eco-friendly tourism villages. Managerial pattern dimensions include the intensity of innovation, pro- active behavior and business agility are also predicted to determine the success of the management of environmentally friendly tourism villages.

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The resource classification system helps protect producers and consumers from ambiguous reporting of mineral resources. Classification systems have been introduced in many countries, but they are often general, so they are not easy to apply in the field. Geostatistical approaches are often inaccurate on data with high nugget values. The system requires sophisticated knowledge and takes time to understand, while field practitioners are eager to immediately get mineral resource classification results. This study aims to introduce the average distance from the borehole as a mineral resource classification parameter. In this study, modeling and grade estimation uses a block model with nearest-neighbor polygon and inverse distance weighing techniques as grade estimation techniques. The highest weight in the NNP estimation technique is the closest sample, while the IDW weight depends on the distance; therefore the NNP and IDW techniques use distance considerations only. Based on the histogram of the average distance, the populations in the graph show the classification as inferred resources, indicated resources, and measured resources. The application of the average distance technique for the classification of laterite nickel resources uses the block model.