By the start of the seventeenth century, Spanish colonizers accumulated and appropriated much knowledge about the location and abundance of salt resources north of Mexico. After becoming governor of New Mexico in 1598, Juan de Oñate leveraged this information to legitimize his effort to colonize and control local peoples and resources. “The wealth of the abundant salines,” Oñate reported in 1599, was among a few “very great treasures”—including some silver mines, Native laborers, and their material tribute payments—that might fill royal coffers. To verify salt’s abundance and its commercial viability, Oñate explained to imperial officials that “salt is the universal article of traffic of all these barbarians.” “Indian herdsmen” from the Salinas district often travelled northwest to Taos and Picuris, “where they sell meat, hides, tallow, suit, and salt in exchange for cotton blankets, pottery, maize, and some small green stones.” The sellers most certainly provisioned their salt from the lakes in the Estancia Valley, which according to Oñate “consist of white salt [and] . . . are seven or eight leagues in circumference.” Salt harvesting could be strenuous, but labor would be no issue; Oñate assured the viceroy that “the said pueblos of the salines and Xumanas [Jumanos] all rendered obedience to his majesty.”
Through the seventeenth century, Spanish officials mobilized the Spanish crown’s absolute sovereignty to incorporate salt resources into the imperial economy. To work these resources, officials used the encomienda, a system of land and labor redistribution that extracted tribute from Native peoples. Between 1659 and 1660, New Mexico governor Bernardo Lόpez de Mendizábal ordered Tewas and Tompiros living in the Salinas district to haul salt from the Estancia Valley’s lakes to the Rio Grande and eventually to northern Mexico—shipments and labor that went uncompensated by the Spanish state, presumably by virtue of the legalities surrounding mineral resources within Spanish territorial claims. Harvesting and hauling salt—especially commercial quantities—demanded long hours of physical labor, often conducted during warmer, dryer months when salt lakes and flats reached peak evaporation. Even after Lόpez’s especially exploitative tenure ended, salt trafficking between the Estancia Valley and northern Mexico seemed to have continued through at least 1668. In Parral and at other silver manufactories across northern Mexico, New Mexican salt was used as one of several chemical additives to refine silver ores.