Search

Mining operations lead to the production of large quantities of mineral waste, such as fluid fine tailings whose disposal is rather challenging. In Brazil, tailings disposal is facing a critical situation due to the large accidents that took place in the last couple of years. As a response to these accidents, the Brazilian Mining Agency became stricter on licensing mining complexes and issued an interruption on activities on 56 tailings dams. In this paper, the authors propose a promising approach to minimize risks on the existing tailings dams hoping that the industry succeeds at mining avoiding social harms and environmental damages. The results presented herein showed that in situ electrical dewatering is a promising technology that offers many benefits. It can significantly increase the solids content of liquefiable tailings stratum within a short time. This leads to tailings masses possessing higher shear strength. As a consequence, this technology might well lead to safe tailing dams in Brazil bringing socio-economic and environmental benefits. [ABSTRACT FROM AUTHOR]

Croplands, occupying approximately 13% of the Earth's land surface, can dramatically alter surface temperature via multiple biophysical processes. However, it remains unclear whether and to what extent croplands warm or cool the land surface globally. Here we present new evidence of the temperature effects of global croplands based on high-resolution satellite observations of land surface temperature (LST). We find general daytime warming and nighttime cooling of crop-dominated lands (cropland intensity ≥90%) relative to other vegetation cover, with net daily cooling in the arid zone and net daily warming in all other areas. On a per-pixel basis, however, nearly half of the crop-dominated lands cool daytime LST and/or warm nighttime LST. The temperature effects vary greatly by location and season. The per-pixel intensity can exceed 10 °C likely due to the changes in surface evapotranspiration, albedo, and background climate. By extending the LST changes of crop-dominated lands to the full land surface, we find that croplands make large contributions to regional and global land surface warming. Daytime warming can reach 0.56 °C in Europe during spring. Nationally, China, India, and Brazil lead the warming due to their large cropland areas and strong local climate effects. Our results highlight the importance of accounting for the biophysical effects of croplands for projecting climate change and formulating adaptation and mitigation strategies. • Biophysical climate effects of global croplands are quantified with MODIS LST data. • We find general daytime warming and nighttime cooling with a net daily warming. • The LST effects vary greatly by location likely due to changes in ET and albedo. • Croplands contribute largely to regional and global land surface warming. • China, India, and Brazil lead the land surface warming effect of global croplands. [ABSTRACT FROM AUTHOR]