Acid mine drainage is one of the most serious environmental problems that the coal and metal mining industry is currently facing. The generation of low pH drainage enhances the dissolution of heavy metals in water. The samples used in this research originated from three pits at mine dumps. In a study reported in this paper, three types of tests; namely static test, kinetic test and column test were conducted to estimate acid generation and acid neutralization reaction rates, and to predict the solubility of metals and their release rates. Static test showed that all samples had a pH of net acid generation (NAG pH) <4, a net acid producing potential (NAPP) >10 kg H2SO4tonne(-1), and a S-content >3%, which can be classified as a high acid-forming capacity. Simulated runoff in the column tests was equivalent to 5-year average rainfall in Indonesia, the resultant leachates showed acidic behaviour (pH < 3.5). Based on the results, it was found that high mobilization of heavy metals (Cr, Cu, Zn, Cd and Pb) takes place under strong acidic conditions (pH approximately equal 2).

The issue that surfaces from the digging of limonite and saprolite zones on nickel ore mining is the oxidation of chromium to chromium hexavalent. The aim of this research is to analyze the efficiency level of phytoremediation technology to reduce chromium hexavalent on waste water of nickel ore mining industry. This study was done in situ to observe the potential of Water Lettuce (Pistia stratiotes) using self-designed experimental devices.. This research was divided into three part, such as the variation of plant’s weight of 10grams, 20grams, 30grams, 60grams, 70grams, and 150grams with interval of an hour for five hours, variation of chromium hexavalent of 0.5ppm, 1ppm, 2ppm, 5ppm, and 7ppm with interval of 4 days for 20 days, and variation HRT 1.5 hours, 2 hours, and 3 hours with interval of 24 hours for 16 days. The result of this research shows the average of efficiency on observation one, two and three are 18.5%, 89%, and 28%. The usage of phytoremediation technology shows the potential to reduce chromium hexavalent pollutant.

Vegetation cover is a critical indicator and sensitive in degradation land. This study aims to explore the comparative analysis of vegetation index in the ex-mine reclamation area. The study is conducted on 2.03 ha area reclamation planted in 2017. The analysis is performed by measure Normalized Difference Vegetation Index (NDVI) from 2017 to 2020 using the Sentinel-2 satellite imagery dataset and processed by ArcGIS Pro 2.6 software. RGB drone photogrammetry acquired in April 2020 and vegetation photos featured with geotagging is used to validate vegetation index analysis. The result shows NDVI first and second-year revegetation demonstrates no significant improvement (less than 0.33), nevertheless third and fourth-year revegetation shows dramatically increase of NDVI, respectively 0.369 and 0.417 with the percentage of healthy vegetation 68.13% and 81.39%. This shows that NDVI and the percentage of vegetation health improve over the year.

The use of chemical-based wastewater treatment method may cause harm to the environment. The aim of this research is to identify the flow application of wastewater treatment using phytoremediation method and summarize the perspective from stakeholders regarding the application based on long-term and short-term categories. In-depth interview was done with expert stakeholders from the sectors of government, private and academics. Subsequently, the scenario of wastewater treatment and the result of phytoremediation research that will be applied on nickel ore extraction industry were confirmed. Finally, a summary of the in-depth interview is shown on a form of a figure. The result shows that this method application needs effort and decision making from the company’s part that become the short-term issue for the company. However, on long-term side, phytoremediation is able to benefit the environment, social, and economy.

This open-pit mining activity has a very helpful environmental potential, soil chemistry, erosion and sedimentation. Change in land use from mining actively after mining requires land and energy closure to ensure that the land is safe for and returned. In accordance with the local spatial pattern in Muara Enim, South Sumatra, the transfer of post-mining land after the dismissal of mining operations will be used as a conservation area managed by the mining community. The concept is an environmental addressing plan to determine the sustainability of various aspects of community life, including local sustainability, food environment, awareness, biodiversity, and sustainability. This study aims to ensure community sustainability after mining operations. The methodology that is an interview with Experts. The results of this research indicate that community empowerment in mining area can use one of the community's natural resource management strategies to ensure social sustainability with land use as agroforestry and integrated agricultural industries.