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 dock steel chutes. These chutes project out over the water at a slight angle from the sides of the docks. The hinged chutes, which are lowered to drop ore from the pockets into ships, are located at twelve-foot intervals over the length of the dock. This spacing is not coincidental, as the docks and the lakers they could load evolved together, and laker hatch spacing is typically 12, or on center. Since the late 1800s, ore docks have been a common sight in many Lake Superior ports of Minnesota, Wisconsin and especially Michigan. Rich iron ore deposits were first discovered in