Mining in river channels provides a living for millions of people across the globe, particularly in the tropics. However, because this mining involves deforestation, excavating, dredging, and other work directly in or next to river channels, ecosystems are intensively degraded. Soils and river sediments excavated during mining are processed to extract the precious mineral of interest, usually gold, then discarded. Often the excess sand, silt, and clay is washed downstream by rivers, muddying river water for as much as 1,000 km downstream of mining sites. 

During the past 20 years, mining in rivers has increased dramatically, particularly during the Global Financial Crisis in 2008–09 when the price of gold increased significantly. Despite the human and ecological importance of mining-related environmental degradation, no global documentation of its environmental footprint exists. For the first time these environmental impacts were quantified through the use of satellite imagery and on-the-ground measurements, documenting more than 400 mining areas in 49 countries, mostly in the tropics. We show that the effects of mining have altered 173 rivers, which collectively represent 5–7% of large river length globally. In the tropical countries with river mining, on average nearly one-quarter of large river length is altered by river mining. 

Abstract Available online The recent rise of mining in rivers is a global crisis (Evan Dethier et al, 2022)