The Fundão mine-tailing dam collapse in the Doce River on November 2015 was the most devastating natural hazard in Brazilian history, resulting in a loss of more than US$ 1 billion in property damage and the death of 20 people. In addition, it is estimated that 60 million m³ of toxic mud have reached the Atlantic Ocean after going through more than 600 km downstream. Almost three years after this disaster researchers are still addressing its environmental impacts. In this context, the present study aimed to identify the Doce River plume after the disaster, using Linear Spectral Unmixing Model (LSUM) coupled with images acquired by the CBERS-4 Multispectral Camera (MUX). The results are compared to the natural river plume during previous flood season and to the results obtained with Landsat-8 Operational Land Imager (OLI).