A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

R

Radioactivity       The property of spontaneously emitting alpha, beta or gamma rays by the decay of the nuclei of atoms.

Radon survey       A geochemical survey technique which detects traces of radon gas, a product of radioactivity.

Raise       A vertical or inclined underground working that has been excavated from the bottom upward. Or A secondary or tertiary inclined opening, vertical or near-vertical opening driven upward form a level to connect with the level above, or to explore the ground for a limited distance above one level.

Rake       Similar to plunge (see), being the trend of an orebody along the direction of its strike.

Ramp       A secondary or tertiary inclined opening, driven to connect levels, usually driven in a downward direction, and used for haulage.

Rank       The classification of coal by degree of hardness, moisture and heat content. "Anthracite" is hard coal, almost pure carbon, used mainly for heating homes. "Bituminous" is soft coal. It is the most common coal found in the United States and is used to generate electricity and to make coke for the steel industry. "Subbituminous" is a coal with a heating value between bituminous and lignite. It has low fixed carbon and high percentages of volatile matter and moisture. "Lignite" is the softest coal and has the highest moisture content. It is used for generating electricity and for conversion into synthetic gas. In terms of Btu or "heating" content, anthracite has the highest value, followed by bituminous, subbituminous and lignite.

Rare earth elements       Relatively scarce minerals such as scandium and ytrium.

Reaming       Enlarging the diameter of a hole.

Reaming shell       A component of a string of rods used in diamond drilling, it is set with diamonds and placed between the bit and the core barrel to maintain the gauge (or diameter) of the hole.

Reclamation       - The process of returning the land to another productive use after mining has been completed. Or The restoration of land and environmental values to a surface mine site after the coal is extracted. Reclamation operations are usually underway as soon as the coal has been removed from a mine site. The process includes restoring the land to its approximate original appearance by restoring topsoil and planting native grasses and ground covers.

Reconnaissance       A preliminary survey of ground.

Record date       The date by which a shareholder must be registered on the books of a company in order to receive a declared dividend, or to vote on company affairs.

Recovery       The percentage of valuable metal in the ore that is recovered by metallurgical treatment. Or The proportion or percentage of coal or ore mined from the original seam or deposit.

Red dog       A nonvolatile combustion product of the oxidation of coal or coal refuse. Most commonly applied to material resulting from in situ, uncontrolled burning of coal or coal refuse piles. It is similar to coal ash.

Reef       The reef is the seam of rock the gold comes from and reef gold depicts it as being located or recovered from the reef.

Refining       Extracting and purifying metals and minerals.

Refractory ore       Ore that resists the action of chemical reagents in the normal treatment processes and which may require pressure leaching or other means to effect the full recovery of the valuable minerals.

Regulator       Device (wall, door) used to control the volume of air in an air split.

Remediation       Relates to those actions taken to investigate, prevent, minimize or otherwise resolve the effects or potential effects on human health or the environment of a release or threatened release of a hazardous substance.

Replacement ore       Ore formed by a process during which certain minerals have passed into solution and have been carried away, while valuable minerals from the solution have been deposited in the place of those removed.