New Almaden hydrothermal deposition of cinnabar from deep within the earth is found in a gangue of silica-carbonate rock formed locally by hydrothermal alteration of serpentine. The Guadalupe mine produced about 10% as much mercury as the New Almaden. There are several smaller mines in the mining district, but their ore production was not significant. The only significant quicksilver ore is cinnabar; other sulfides are present in small quantities. Mining, other than a single placer deposit of cinnabar, was underground. There is a high probability of undiscovered high-grade ore which could be found and exploited using modern techniques. Mining operations resulted in
Ore shoot for hundreds or thousands of feet horizontally and vertically. Such a structure could contain an area of enhanced metal content extending horizontally and vertically. This would be termed an "ore shoot." The existence of the ore shoot could be recognized visually in a tunnel or "drift" excavated along the structure, or by the assaying of rock samples cut from the walls and roof of the tunnel. Ore shoot In mining and geology, an ore shoot is a long seam of mineral or metal bearing rock that can be profitable to extract. The term may have originated in the 17th and