Glossary of Natural Resources Terms

This comprehensive directory of terms and their definitions makes it easier for everyone to learn about automated mineralogy as it relates to the natural resources industry.

Alteration : A change in the mineralogy of the country rock or ore as a result of a chemical reaction with hydrothermal solutions. For example, mafic minerals such as hornblende or biotite may alter to chlorite and feldspars may alter to clay. An alteration zone describes rocks which have been altered to a specific group of secondary or alteration minerals, usually around the perimeter of a mineral deposit.

Applied Mineralogy : Application of mineralogical information.

Automated Mineralogy : A generic term describing a range of analytical solutions, areas of commercial enterprise, and a growing field of scientific research and engineering applications involving largely automated and quantitative analysis of minerals, rocks and man-made materials.

Base Metals : Industrial non-ferrous metals such as nickel, copper, lead zinc, excluding precious metals.

Breccia : Angular fragments of rock produced by movement along a fault or explosive igneous activity. The material which surrounds the fragments and cements them together is called matrix and might be vein minerals, igneous material or very fine rock fragments.

Chimney : Also referred to as a pipe, this is a vertically oriented, cylindrical body, often a breccia, of vein or replacement mineralization.

Concentrator : The plant, on or near a mine site, where comminution, sizing and concentration of ore occurs.

Concordant : Any geologic body, such as an ore deposit, which lies within or parallel to volcanic or sedimentary bedding and does not cut across the bedding structures. (Also conformable ).

Core : A cylindrical sample of rock.

Country Rock : The rock which surrounds the ore deposit. Also referred to as wall-rock, in particular that rock on either side of a vein.

Cuttings : Small pieces of rock that break away due to the action of the drill bit teeth.

Cut-off : The cut-off grade is the arbitrarily defined lowest grade which will be mined from an ore deposit, and usually defines the boundary of the deposit. For example, if the average grade of a porphyry deposit is 0.5% Cu, the cut-off might be 0.2% Cu. Any rock with a grade below 0.2% Cu would therefore be considered waste.

Concentrate : The residue of valuable metal from which most of the waste rock has been removed. The residue metal becomes the raw material for smelting.

Discordant : A geologic body, such as a dyke or vein, which cuts across primary rock structures such as bedding.

Epigenetic : If a mineral deposit formed much later than the rocks which enclose it, it is said to be epigenetic. An example is a vein.

Fault : A planar feature or fracture zone along which displacement has occurred.

Field/Frame : An area scanned by the electron beam during automated measurement.

Field Size : The size of the field scanned during automated measurement.

Froth Flotation : Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic ones. This is used in several processing industries. Historically this was first used in the mining industry.

Footwall : The lower contact of an inclined vein, or the wall rock which lies on the lower side of a dipping vein.

Gangue : Those minerals which occur with the ore minerals but which have no commercial value, such as quartz, calcite or pyrite.

Geology : Study of the Earth as a whole, its origin, structure, composition, and history, and the nature of the processes which have given rise to its present state.

Geoscience : An umbrella term for the sciences related to planet Earth such geology, geophysics, geochemistry. (Also known as Geosciences, Earth Science or the Earth Sciences).

Gossan : A rusty, surficial weathering zone which is caused by the oxidation of pyrite to produce secondary iron oxide minerals. Since pyrite is often associated with ore deposits, gossans can be a guide to ore.

Grade : The concentration of each metal in a rock sample, usually given as weight percent. If concentrations are extremely low, as with Au, Ag, Pt and others, the concentration may be given in grams per tonne (g/t). The average grade of an ore deposit is calculated, often employing very sophisticated statistical procedures, as an average of the grades of a very large number of samples collected from throughout the deposit.

Grain : An individual mineral grain.

Grain size : An area within the measured image comprising a single mineral.

Hangingwall : The upper contact of an inclined vein.

Host rock : The rock within which the ore deposit occurs.

Hydrothermal : Hot water or hydrothermal solutions have actually been observed forming mineral deposits, for example, the "black smokers" on the sea floor. The ore constituents, such as Cu, Pb, Au or other metals are dissolved in a hot aqueous solution along with other deposit constituents such as Si, S and Fe. These elements are deposited to form the ore and gangue minerals in response to a change in the solution, very often a sharp decrease in temperature.

Liberation : A term used by applied mineralogists and metallurgists to describe the textural make-up of particles in various streams within mineral processing plants. Liberation is typically studied, estimated and quantified using 2D sections of particles, and this is best achieved by setting them in epoxy and exposing their cross-sectional geometry by combinations of cutting, grinding and polishing. Examination of images of particles allows for the classification of each particle in terms of whether it is ‘pure’, ‘barren’ or ‘locked’. This classification of particles is typically based on the volume of the mineral of interest in each particle

Line Spacing : The physical distance (in micron) between scan lines in an automated SEM measurement.

Lode, shoot : Refers to mineralized zones within a fault or shear zone, or a vein fissure or stringer structure.

Magmatic : Some mineral deposits, particularly those containing Ni, Cr and Pt, form by the separation of the metal sulphide or oxides in the molten form, within an igneous melt before it crystallizes. These are known as magmatic deposits. They occur within the igneous rock from which they were derived, such as a gabbro. The ore metals concentrated as liquid in much the same manner as metals are purified in a smelter or blast furnace. The heavier metal-rich liquids sink and concentrate at the base of the intrusive body, while lighter silicate liquid and crystals tend to rise, the same as the slag in a blast furnace.

Manto : This is a horizontally oriented chimney-like structure, usually of replacement mineralization.

Massive sulphide : A stratiform, usually lens-shaped, mineral deposit consisting of at least 60% sulphide minerals.

Micro/Micrometer : A micrometre (also known unofficially as a "micron") is one millionth of a metre, or equivalently one thousandth of a millimetre or one thousand nanometres.

By way of example, a strand of human hair is about 100 μm wide. Red blood cells are approx. 8 μm in diameter.

Micro-CT : Micro-computed tomography, or micro-ct, micro-computer tomography, or high resolution x-ray tomography.

Mineralogy : Branch of geology that studies minerals - their structure and properties, and the ways of distinguishing them.

Mineral : A structurally homogeneous solid of definite chemical composition formed by natural inorganic processes.

Mineral Processing : Mineral processing, otherwise known as mineral dressing, is the practice of beneficiating valuable minerals from their ores.

Mineraloid : A mineral-like substance, natural or man-made, which does not have a distinct crystallinity, and posses chemical compositions that vary beyond the generally accepted ranges for specific minerals (examples include volcanic glass, opaline silica).

Mineralization : A general term which usually refers to ore minerals but which often may refer to other metallic minerals such as pyrite.

Mississippi Valley : Named after the region where they were first described, these deposits formed within porous carbonate rocks (limestone reefs or caves). Typically Pb-Zn deposits with low Ag values.

Nanometer : A nanometre is a unit of length in the metric system, equal to one billionth of a metre, and equals ten Ångström, an internationally recognised non-SI unit of length.

Natural Resource : Materials, either actual or potential, occurring in a natural state that are necessary or useful to humans, and are of economic interest.

Natural Reserves are that part of a Natural Resource which have been fully evaluated, and are deemed to be commercially viable to extract, and have valid permission for extraction.

Ore : A mineral or aggregate of minerals that form a rock which can be mined at a profit.

Particle : An agglomeration of mineral grains, such as a cutting.

Permeability : The ability, or measurement of a rock's ability, to transmit fluids, typically measured in darcies or millidarcies. Absolute permeability is the measurement of the permeability conducted when a single fluid, or phase, is present in the rock. Effective permeability is the ability to preferentially flow or transmit a particular fluid through a rock when other immiscible fluids are present in the reservoir (for example, effective permeability of gas in a gas-water reservoir).

Petrogenesis : The origin of rocks.

Petrography : Systematic description of rocks.

Petrology : Study of rocks in all aspects - including mineralogy, textures, structures, origins, and relationships.

Pixel : In digital imaging, a pixel (or picture element) is a single point in a raster image. The word pixel is based on a contraction of pix ("pictures") and el (for "element"); similar formations with el for "element" include the words: voxel and texel.

Pixel Spacing : The distance between electron beam measurement sampling points when scanning, which can be varied and therefore defines the resolution of the resulting image.

Placer : Formed within sediments by the concentration of heavy resistant minerals (Au, diamond, cassiterite) by stream or wave action.

Platinum Group Minerals : Minerals containing primarily platinum & platinum group metals, as native metals, sulphides or oxides, often abbreviated as PGM.

Porphyry : Large, low grade deposits usually associated with a porphyritic intrusive body.

Porosity : The percentage of pore volume or void space, or that volume within rock that can contain fluids. Porosity can be a relic of deposition (primary porosity, such as space between grains that were not compacted together completely) or can develop through alteration of the rock (secondary porosity, such as when feldspar grains or fossils are preferentially dissolved from sandstones).Porosity can also be generated by the development of fractures, in which case it is called fracture porosity.

Effective porosity is the interconnected pore volume in a rock that contributes to fluid flow in a reservoir. It excludes isolated pores.

Total porosity is the total void space in the rock whether or not it contributes to fluid flow. Thus, effective porosity is typically less than total porosity. Shale gas reservoirs tend to have relatively high porosity, but the alignment of platy grains such as clays makes their permeability very low.

Process Mineralogy : Application of mineralogical information to mineral processing and smelting in order to: improve understanding of an ore or product, solve mineral processing problems, and improve the efficiency of mineral extraction.

Replacement :

A chemical process whereby hydrothermal fluids, passing through permeable rocks, react with the rocks to dissolve original minerals and relace them with ore and/or other gangue minerals.

Reserves : The amount of ore in a given deposit, usually quoted as the number of tonnes available at a specific average grade.

Reservoir : A subsurface body of rock having sufficient porosity and permeability to store and transmit fluids. Sedimentary rocks are the most common reservoir rocks because they have more porosity than most igneous and metamorphic rocks and form under temperature conditions at which hydrocarbons can be preserved. A reservoir is a critical component of a complete petroleum system.

Sedimentary Massive Sulphide (Sedex) : These are formed by hydrothermal emanations on or near the sea floor in association with the deposition of sedimentary rocks.

Shear Zone : A planar zone of weakness, similar to a fault, but consisting of several parallel displacement zones usually over a greater width than a single fault.

Skarn : Mineral deposits formed by replacement of limestone by ore and calc-silicate minerals, usually adjacent to a felsic or granitic intrusive body.

Smelter : Plants for the production of metal from ore.

Stockwork : A large number of small, closely spaced veins, often with many different orientations, is referred to as a stockwork and sometimes as a stringer zone.

Stratabound : A mineral deposit which occurs within a specific stratigraphic bed or horizon, but which does not comprise the entire bed.

Stratiform : A mineral deposit which occurs as a specific stratigraphic (or sedimentary) bed.

Syngenetic : A syngenetic mineral deposit is a deposit which formed at the same time as the rocks that enclose it. Magmatic deposits are syngenetic in that the ore minerals crystallize from the same magma that produced the silicate minerals which form the bulk of the intrusive - they crystallize more or less simultaneously as the melt cools. Deposits which form on the earth's surface in the form of a sedimentary layer are also syngenetic. The rocks which they lie upon were deposited just prior to the mineralizing event, while the overlying rocks were deposited just after - all three layers being deposited at essentially the same time in terms of the geological time frame.

Tailings : Also known as slimes, tailings pile, tails, leach residue, or slickens, tailings are the materials left over after the process of separating the valuable fraction from the worthless fraction (gangue) of an ore.

Texture : Texture is the relationship between the grains of minerals forming a rock in terms of their size, shape, arrangement, and pattern, both the megascopic and microscopic feature level.

Tomography : The word was derived from the Greek word tomos which means "volume", representing the idea of "a section", "a slice" or "a cutting". Tomography is imaging by sections or sectioning, through the use of waves of energy. A device used in tomography is called a tomograph, while the image produced is a tomogram. The method is used in radiology, archaeology, biology, geophysics, oceanography, materials science, astrophysics and other sciences. In most cases it is based on the mathematical procedure called tomographic reconstruction.

Vein : Fracture filling deposits which often have great lateral and/or depth extent but which are usually very narrow (mm-cm scale).

Volcanic Massive Sulphide (VMS) : These deposits formed as massive (over 60% sulphide) lens-like accumulations on or near the sea floor in association with volcanic activity.

Voxel : A voxel (volumetric pixel or, more correctly, Volumetric Picture Element) is a volume element, representing a value on a regular grid in three dimensional space. This is analogous to a pixel, which represents 2D image data in a bitmap.

Waste : Rock which is not ore. Usually referred to that rock which has to be removed during the normal course of mining in order to get at the ore.

Wettability : The preference of a solid to contact one liquid or gas, known as the wetting phase, rather than another. Wettability affects relative permeability, electrical properties, nuclear magnetic resonance relaxation times and saturation profiles in the reservoir.

Explore Applications & Solutions

Explore our comprehensive suite of solutions for Automated Mineralogy applications.

Find an Authorized Service Provider or University Partner

Have questions about our products and solutions? View a list of knowledgeable and helpful service providers and university partners.

See a list of Service Providers and University Partners »