The mining operation is run by Peñoles, which has been controlled by Mexico City-based Grupo BAL since 1967.
[1] In 2004, Mina Proaño produced almost 32 million troy ounces (995,000 kg) of silver.
[2] As is quite common with long-running large-scale mining operations, especially silver mining, which uses large quantities of cyanide, there have been allegations of mine-related pollution including contamination of water sources, increased illness rates amongst cattle and people, and increased air pollution.
[citation needed] This particular mine has obtained ISO 14000 certification of its environmental management processes and equipment, and has received a "Clean Industry Registration" from Mexican authorities.
The mining company has also established an "ecological park", which is basically a sanctuary for over a hundred species of mammals, birds and reptiles.