Qualitative analysis: 

Determining which metals are present in a sample.

Quantitative analysis: 

Determining how much of a metal is present.


Fourth period of time, from present back to the end of the tertiary period.


Common rock-forming mineral consisting of silicon and oxygen.


A metamorphic rock formed by the transformation of a sandstone rock by heat and pressure.

Quartz porphyry: 

Common gold mine lithology.


Another name for Mercury.


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.


The track which ore car ride.


A vertical or inclined underground working that has been excavated from the bottom upward.


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


An inclined underground tunnel which provides access for exploration or a connection between levels of a mine.

Rare earth elements: 

Relatively scarce minerals such as scandium and yttrium.


A chemical used in the mineral recovery process.


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.


The process by which lands disturbed as a result of mining activity are reclaimed back to a beneficial land use. Reclamation activity includes the removal of buildings, equipment, machinery and other physical remnants of mining, closure of tailings impoundments, leach pads and other mine features, and contouring, covering and re-vegetation of waste rock piles and other disturbed areas.


A preliminary survey of ground.

Recovery rate: 

A term used in process metallurgy to indicate the proportion of valuable material obtained in the processing of an ore. It is generally stated as a percentage of the material recovered compared to the total material present.


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.

Regional metamorphism: 

see Ore Reserves.


The process of filing a new location on a claim which was previously located by the same locator for reasons beyond those allowed by amendments to the existing location.

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.


That part of a mineral deposit which could be economically and legally extracted or produced at the time of the reserve determination. Reserves are customarily stated in terms of ore when dealing with metalliferous minerals. There are three categories of reserves:

1) Proven ore - material for which tonnage and grade are computed from dimensions revealed in outcrops, trenches, underground workings or drill holes; grade is computed from the results of adequate sampling; and the sites for inspection, sampling and measurement are so spaced and the geological character so well-defined that size, shape and mineral content are established.

2) Probable ore - material for which tonnage and grade are computed partly from specific measurements, samples or production data and partly from projection for a reasonable distance on geological evidence; and for which the sites available for inspection, measurement and sampling are too widely or otherwise inappropriately spaced to outline the material completely or to establish its grade throughout.

3) Possible ore - material for which quantitative estimates are based largely on broad knowledge of the geological characteristics of the deposit and for which there are few samples or measurements.

Reserves - Geologic: 

The tonnage and grade of a mineral deposit based upon geological interpretation, but on which more data are needed before mineable reserves may be established.

Reserves - Mineable: 

The tonnage and grade of that part of a mineral deposit expected to be mineable economically under present and anticipated conditions.


Left over; eroded in place.

Resistivity survey: 

A geophysical technique used to measure the resistance of a rock formation to an electric current.


There are three categories of resource.

1) Inferred mineral resource - a mineral resource inferred from geoscientific evidence, drill holes, underground openings, or other sampling procedures where the lack of data is such that continuity cannot be predicted with confidence and where geoscientific data may not be known with a reasonable level of confidence.

2) Indicated mineral resource - a mineral resource sampled by drill holes, underground openings or other sampling procedures at locations too widely spaced to ensure continuity but close enough to give a reasonable indication of continuity and where geoscientific data are known with a reasonable level of reliability. An indicated mineral resource estimate will be based on more data, and therefore will be more reliable, than an inferred mineral resource estimate. Leads to probable ore reserves.

3) Measured mineral resource - a mineral resource intersected and tested by drill holes, underground openings and or other sampling procedures at locations which are spaced closely enough to confirm continuity and where geoscientific data are reliably known. A measured mineral resource estimate will be based on a substantial amount of reliable data, interpretation and evaluation of which allows clear determination to be made of shapes, sizes, densities and grades. Leads to a proven ore reserve.


A method of stoping in narrow-vein deposits whereby the wall rock on one side of the vein is blasted first and then the ore.


Process of recovering gold from Mercury by heating in a retorter.

Reverberatory furnace: 

A long, flat furnace used to slag gangue minerals and produce a matte.

Reverse circulation drilling: 

A drilling method employing double walled drill rods. The drilling fluid (usually water) is pushed down the shaft around the rods and the cuttings are blown up the middle.


A fine-grained (extrusive) igneous rock which has the same chemical composition as granite.

Rib samples: 

Ore taken from rib pillars in a mine to determine metal content.


A groove or ridge in the bottom of a stream channel; a slat or block of wood or metal placed across a sluice box or other placer unit.


To heat an ore to drive off volatile substances or oxidize the ore.


Any natural combination of minerals; part of the Earth's crust.


The act of supporting openings in rock with steel bolts anchored in holes drilled especially for this purpose.


A violent release of energy resulting in the sudden failure of walls or pillars in a mine, caused by the weight or pressure of the surrounding rocks.

Rock factor: 

The number of cubic meters of a particular rock type required to make up one tonne of the material. One tonne of a highly siliceous ore may occupy 0.40 cu m while a tonne of dense sulfide ore may occupy only 0.25 cu m.

Rock mechanics: 

The study of the mechanical properties of rocks, which includes stress conditions around mine openings and the ability of rocks and underground structures to withstand these stresses.

Rod mill: 

A rotating steel cylinder that uses steel rods as a means of grinding ore.

Room-and-pillar mining: 

A method of mining flat-lying ore deposits in which the mined- out area, or rooms, are separated by pillars of approximately the same size.

Rotary drill: 

A machine that drills holes by rotating a rigid, tubular string of drill rods to which is attached a bit. Commonly used for drilling large-diameter blastholes in open pit mines.


An amount of money paid at regular intervals by the lessee or operator of an exploration or mining property to the owner of the ground. Generally based on a certain amount per ton or a percentage of the total production or profits. Also, the fee paid for the right to use a patented process.


A loose term used to describe ore of average grade.

Run-of-mine ore: 

Uncrushed ore in its natural state just as it is when blasted.