By Stuart Rosebrook
In the sixteenth century, the Spanish came north from New Spain in search of treasure, especially silver and gold. In 1540 Francisco Vazquez de Coronado led his famous expedition from the West Coast of Mexico to Northern New Spain, including Arizona and New Mexico, looking for “the seven cities of Cibola”. While cities of gold were never found, every generation of explorers and miners since Coronado have sought veins of precious metals across the Southwest.
In Arizona Spanish explorers Antonio de Espejo and Juan de Oñate ventured into the Verde Valley in the late 16th century, noting deposits of silver and copper. As the Spanish Empire sent missionaries and soldiers north, silver and gold were discovered and mined successfully in multiple locations, including the Santa Cruz River Valley and the Santa Rita Mountains south of present-day Tucson. In the 1750s, Spanish settlers mined copper in Ajo, southwest of Tucson, with limited success. In 1855 early American settlers discovered the Spanish copper mine and began reworking the rich deposit of ore. Little did they realize that copper would someday usurp gold and silver as the state’s most valuable ore.
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