The Main Tunnel

The Beginning of New Almaden’s Rich History Just ahead lies the original site of mining activity in New Almaden’s rich history, where Ohlone Indians extracted cinnabar ore from a red cave in 1845, while visiting Mission Santa Clara, Mexican soldier Andres Castillero observed Ohlones using crushed cinnabar as a paint pigment. He recognized the significance of such a find and followed the Ohlones to this site.Castillero claimed his discovery and began mining the cinnabar ore, which was known to contain mercury,a valuable liquid metal needed by Mexico to process silver and gold. This Main Tunnel was the principal entrance to the New Almaden Mine, which would grow to become the richest mining area in all of California.