Temporal Variability Evaluation of a Mine Tailings Dump from Surface Coal Mining Through Remote Sensing

Abstract Through the remote sensing technique (Landsat), the study analyzed the temporal variability on the mine tailings dump located on Valea Motrului, Șteic – Valea Perilor, Gorj County, Romania. Satellite images were taken in ten years from 1988 – 2016. The NDVI and NBR indices were calculated in the ten years. An increasing, statistically significant trend was recorded in the data series for the NDVI index (S = 116115, Z = 18,394, p = 1.4786E-75), and a decreasing, statistically significant trend in the data series for the NBR index (S = −16043, Z = −2.5412, p = 0.011047). Statistically significant differences were recorded for the NDVI and NBR indices between most of the years considered in the study. In the multivariate analysis (PCA), independent positioning of the years 1988 and 1999 (primary area of the dump) and the years 2002, 2007 and 2014 was recorded, with reduced values of NDVI and NBR indices. The cluster analysis facilitated the association of years in clusters based on similarity, in relation to the NDVI and NBR indices values. The year 2011 was highlighted with the highest level for the NDVI and NBR indices. High level of similarity was recorded between 2010 and 2016, SDI = 0.0314.