"The Huanzala Mine is situated in central Peru, about 250km north of Lima.
(It) is part of the steep Andean range, 3,900 to 4,500m above sea level. The
deposit was discovered at the time of the Spanish colonization. Since 1964 it
has been managed by the Compania Minera Santa Luisa S. A., in cooperation with
the Mitsui Mining and Smelting Company." (Economic Geology, 80:p.461)
Here is a picture of the mining operation from Matrix Magazine with 'piritos' in the foreground. Piritos ride the bus into Lima with the next batch of specimens for the worldwide market.