Underground hard-rock mining
Underground hard-rock mining refers to various underground mining techniques used to excavate "hard" minerals, usually those containing metals, such as ore containing gold, silver, iron, copper, zinc, nickel, tin, and lead. It also involves the same techniques used to excavate ores of gems, such as diamonds and rubies. Soft-rock mining refers to the excavation of softer minerals, such as salt, coal, and oil sands.
A 3D diagram of a modern underground mine with shaft access
Decline portal
Door for directing ventilation in an old lead mine. The ore hopper at the front is not part of the ventilation.
A metal is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically ductile and malleable. These properties are the result of the metallic bond between the atoms or molecules of the metal.
Iron, shown here as fragments and a 1 cm3 cube, is an example of a chemical element that is a metal.
A metal in the form of a gravy boat made from stainless steel, an alloy largely composed of iron, carbon, and chromium
Gallium crystals
A metal rod with a hot-worked eyelet. Hot-working exploits the capacity of metal to be plastically deformed.
