Timbers laid at right angles to each other to create a vertical or horizontal support structure
Timbers laid at right angles to each other to create a vertical or horizontal support structure
A wide crack, fissure or opening in rock
A period existing 146-65 million years ago
A stabilized part of the Earth’s crust, usually centrally attached to the continents
A circular depression created by a sunken volcanic vent in the ground, or meteoric impact
The mass of rock adjacent to, or hosting an orebody
A chemical used to dissolve gold and silver
An ore of copper, CuS
Extracting gold or silver by dissolving it in cyanide solution
A trigonal metallic mineral, Al2O3