PERU, 2012

Water contaminated by pollutants from the large open-pit mine in Cerro de Pasco

Van Houtryve

© Tomas van Houtryve / VII / Redux

 

A large part of the objects we use are made of metals found in the Earth’s crust, such as aluminium, zinc, copper, iron and many others. To extract them means building mines, but these can seriously damage the ecosystem and environment. Their construction alone disfigures the land, with their tunnels, extraction shafts and various kinds of excavation.
The chemical and mechanical processes required to extract the specific metals release a fluid composed of various types of mining waste and this is then collected in facilities for treatment and disposal. But mining processes are never 100% efficient and metal residues can end up in the waste slurry, thus aggravating the ecological impact of mining by contaminating the soil and surface and ground water. One way to alleviate this problem would be through wastewater storage and recycling systems, more expensive than leaving the liquid to stagnate in special pools, but useful, considering that about 70% of mines are located in areas where water resources are scarce, such as Africa and Latin America.
Fortunately, there is now a move to revalue old mining residues or secondary metals deriving from mining processes, an operation that would also allow large mining companies to make money by reutilising waste products, thus encouraging their possible ecological conversion.

Andrea Pozzobon