TITLE:
The Ancient Quimbalete and Mercury Efficiency in Present-Day Small-Scale Gold Processing, Perú
AUTHORS:
William E. Brooks
KEYWORDS:
Quimbalete, Gold, Amalgamation, Comminution, Perú
JOURNAL NAME:
Archaeological Discovery,
Vol.13 No.2,
February
28,
2025
ABSTRACT: The quimbalete was used in pre-contact Perú and is still used today to process gold. It is a 1 - 2 ton, manually operated, artisanal stone crushing device used to release the gold from the ore as it is rocked back and forth on a water-lubricated, stone base to which mercury is added. The weight and the back-and-forth rocking motion forces the mm-sized gold grains and mercury together to form an amalgam that is recovered from the muddy slurry and then burned to produce an anthropogenic gold nugget. Spot geochemical sampling of: 1) the Au ore, 2) post-amalgamation mud, and 3) dried post-cyanide mud indicate that the ages-old mercury amalgamation process captures ~20% of the gold from the crushed ore and sodium cyanide is the final step to capture the remaining gold. Therefore, since mercury is used with quimbaletes to amalgamate gold at small-scale gold processing sites today in Perú, then, the documented use of quimbaletes in pre-contact Perú is evidence for and consistent with pre-contact use of mercury for gold amalgamation.