Archaeological research carried out in the altiplano locale of Escaramayu (in the community of Escara, Potosí, Bolivia), revealed a prehispanic metallurgical establishment (ninth to fifteenth centuries AD) for the extractive processing of copper ores and, to a lesser extent, lead-silver ore exploited at the nearby Pulacayo mine. The number and variety of metallurgical equipment identified in this establishment for smelting metallic ore and for refining the metal indicate a deep level of technological experience and experimentation among the resident Escaramayu metalworkers during the Middle Horizon (MH) and Late Intermediate periods (LIP). In Escaramayu we find the first known antecedents of Andean wind furnaces (wayras) and a model of a prehispanic reverberatory furnace that was widely used in the southern Andean altiplano during the colonial period.

We examined copper production at the archaeological site of El Manchón, located in the Sierra Madre del Sur of Guerrero, using archaeological, historical, ethnographic, and materials engineering data. Thirty-six AMS wood charcoal samples from El Manchón, analyzed using Bayseian statistics, date the two domestic sectors of El Manchón from cal AD 1250–1440 (Sector 1) and cal AD 1280–1680 (Sector 3). The smelting sector (Sector 2) contains copper ore and slag and dates to cal AD 1630–1825. Historical sources show that the Spanish had no experience smelting copper metal and were forced to negotiate with indigenous specialists to acquire smelted copper. These specialists provided it in return for tax exemptions and other economic privileges. The indigenous specialists requested iron tools for mining; the Spanish suggested introducing bellows to smelt copper in volume. In the smelting sector we excavated the stone foundations and a slag cake that conform to the dimensions of a hand-powered bellows-driven furnace in which the copper ore was smelted in a circular depression known as a cendrada. Thus far, this furnace design has only been excavated at El Manchón. This bellows-powered furnace was likely operated by indigenous Manchón specialists, who probably initially smelted copper using the more ancient blowpipe technology. The dates for the smelting and occupation of El Manchón overlap.