In the Andean mining tradition , or is the hand selection of rock fragments with ore for further processing. Usually, is done in piles of discarded material with little planning, randomly and without authorization. However, historically in places like Potosàand Pulacayo in Bolivia, has been regarded as an integral part of the mining operation. has the benefit that it can allow for high âÂÂor over-all increasedâ ore grades to be processed. In some places the selected rocks are sold to the local mining company, but this model has the drawback that it could incentivize smuggling of ore from the mine to make it pass as recovered through .
The term and are derived . Those that practice are variously referred to as , , , and, in Bolivia, . In some places like La Rinconada in Peru, this activity is primarily made by women known as , as they are otherwise not allowed to work inside the mines. For artisan miners known as , is a secondary activity to proper mining.
The work of and can be physically demanding given uncomfortable stances and â in the high Andes â also because of the cold climate.
Historically, the term applied sometimes also to any independent miner of surface ores, similar to what is today understood as a , and they were important agents of mineral exploration.