Mining Glossary

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Open-Cut (Pit) Mining - A form of operation designed to extract minerals that lie near the surface. Waste, or overburden, is first removed, and the mineral is broken and loaded, as in a stone quarry. Important chiefly in the mining of ores of iron and copper. The mining of metalliferous ores by surface-mining methods is commonly designated as "open-pit mining" as distinguished from the "strip mining" of coal and the "quarrying" of other nonmetallic materials such as limestone, building stone, etc.

Opening - A short heading driven between two or more parallel headings or levels for ventilation.

Outcrop - A term used in connection with a vein or lode as an essential part of the definition of apex. It does not necessarily imply the visible presentation of the mineral on the surface of the earth, but includes those deposits that are so near to the surface as to be found easily by digging.

Overburden - Used by geologists and engineers in several different senses. By some, it is used to designate material of any nature, consolidated or unconsolidated, that overlies a deposit of useful materials, ores, or coal, especially those deposits that are mined from the surface by open cuts. By others, overburden designates only loose soil, sand, gravel, etc., that lies above the bedrock. The term should not be used without specific definition. Also called burden, cover, drift, mantle, surface.

Overriding Royalty - The term applied to a royalty reserved in a sublease or assignment over and above that reserved in the original lease.