Calcareous – Structures such as a seashell, secreted by an organism that consists of or contains calcium carbonate.
Calcite – Common, white mineral composed of calcium carbonate symbol CaCO3, and the principal constituent of limestone; whose crystals have a double image refraction property.
Caldera – Large, circular depression in a volcanic terrain, typically originating from collapse, explosion or erosion of a volcanic dome.
Calibration – Determination of the log values that correspond to environmental units, such as porosity or bulk density; calibration usually is carried out in pits or by comparison with laboratory analyses of core.
Cambrian – First period (542 to 488.3 mya) of the Paleozoic Era, during which most modern animal phyla developed.
Capital Expenditure – All expenditures not classified as operating costs.
Chalcocite – Mineral Cu2S.
Carbonate – General term used to describe a rock composed mainly of the carbonate minerals, calcite and dolomite (CaCO3).
Carbonate Platform – A submarine or intertidal shelf whose elevation is maintained by active shallow water carbonate deposition.
Carbonate Rock – Rock composed of carbonate minerals, especially limestone and dolomite.
Carbonates – Compounds containing the acid radical CO3.
Carbonic Acid – Weak acid H2CO3 formed by the dissolution of CO2 in water.
Carbon-in-Leach – Process step wherein granular activated carbon particles much larger than the ground ore particles are introduced into the ore pulp. Cyanide leaching and precious metals adsorption onto the activated carbon occur simultaneously. The loaded, activated carbon is mechanically screened to separate it from the barren ore pulp and processed to remove the precious metals and prepare it for reuse.
Carbon-in-Pulp – Process known as CIP in which granular activated particles much larger than the ground ore particles are added to a cyanide ore pulp after primary leaching in cyanide. Activated carbon and pulp are agitated together to enable the solubilised precious metals to become adsorbed onto the activated carbon. Precious metals adsorption occurs onto the activated carbon from the pregnant cyanide solution.
Care and Custody Hole – Drillhole placed for independent verification purposes in which secure handling procedures of rock samples are documented from drill rig to laboratory.
Care and Maintenance – Status of a mining operation when mining has been suspended but reclamation and closure of the property has not been commenced. The mill and associated equipment is being cared for and maintained until operations recommence or are dismantled.
Carolina Bays – Shallow elliptical depressions on unconsolidated ground whose major axis is oriented toward the Great Lakes Region. Carolina Bays have a width-to-length ratio of approximately 0.58 and occur within 1500 kilometers from the Great Lakes Region.
Casts – Fossils formed when water containing minerals leaks into a mold. The minerals harden to form a copy of the original structure or organism.
Cataclysm – Violent geologic change of the Earth’s surface.
Cataclastic Rock – Breccia of powdered rock formed by crushing and shearing during tectonic movements.
Cation – Atom or group of atoms with a positive electric charge.
Caliper Log – Continuous record of borehole diameter, usually made with a mechanical probe having from one to six arms.
Casing-Collar Locator – Electromagnetic device known as a CCL that usually is run with other logs to record the location of drill hole collars or other changes in casing or pipe.
Cementation Factor – Cementation exponent (m) in Archie’s equation relating formation-resistivity factor and porosity. The cementation factor as relates to many aspects of pore and grain geometry that affect permeability.
Cement Bond Log – Acoustic amplitude log that is used to determine the location of cement behind the casing and, under some conditions, the quality of the bonding to casing and rock.
Cenozoic, Caenozoic, Cainozoic – Current geologic era, which began 65.5 million years ago and continues to today.
Central Vent – Largest vent of a volcano, commonly situated at the center of its cone.
Centralizer – Device designed to maintain a probe in the center of a drill hole.
Chalcocite – Rims a weathered alteration rim on copper sulphide minerals.
Chalcopyrite – Common brassy yellow copper mineral composed of copper, iron and sulphur. This mineral is very similar to marcasite in its characteristics; it tarnishes easily; going from bronze or brassy yellow to yellowish or grayish brown, has a dark streak, and is lighter in weight and harder than gold. An important source of copper. The mineral CuFeS2.
Chalcopyrite Grains – Individual grains of the mineral CuFeS2.
Chalk – Soft compact calcite with varying amounts of silica, quartz, feldspar, or other mineral impurities. It is generally gray-white or yellow-white and derived chiefly from fossil seashells. The symbol is CaCO3.
ChannelA – Time gate during which measurements are made in time-domain EM, frequency-domain EM, or IP surveying. Measurements made during several time gates following a source pulse yield several channels of data.
Chargeability – Time domain IP surveys involve measurement of the magnitude of the polarization voltage ‘Vp’ that results from the injection of pulsed electric current into the ground. Polarization voltages primarily result from electrochemical action (ionic exchange) within the pores and pore fluids of the material being energised. The current is applied in the form of a square waveform, with the polarisation voltage being measured over a series of time intervals after each current cut-off using non-polarising electrodes. The measured value of ‘Vp’ is divided by the steady voltage as observed whilst the current is on to give the apparent chargeability of the ground. This provides qualitative information on the subsurface geology. TD-IP is primarily used in mineral exploration surveys.
Chemical Sediment – One that is formed at or near its place of deposition by chemical precipitation, usually from seawater.
Chemical Weathering – Total set of all chemical reactions that act on rock exposed to water and atmosphere and thus change its minerals to stable forms.
Chert – Compact and dense sedimentary rock. It is a glass-like siliceous rock composed of silica of various types (opaline or chalcedonic).
Chi-Factor – Ratio of data-misfit to the number of data and controls the degree to which the data are fit during an inversion. A Chi-factor of less than one would over-fit the data while a Chi-factor of greater than one would under-fit the data.
Chilled Margins – Edge of dyke or other intrusive body where magma has cooled quickly in contact with relatively cold wall rock. Crystals close to margin are much smaller than those farther inside the body.
Chlorite – Dark green, soft, flaky mineral similar to mica. Common as an alteration or metamorphic mineral formed from ferromagnetism minerals.
C-Horizon – Lowest layer of soil, consisting of fragments of rock and their chemically weathered products.
Chronostratigraphy – Establishment of time relations in stratified rocks. Term is generally restricted to deposition-related processes in which the super-positional properties but can be used to establish a detailed historical record.
Chrysocolla – Mineral Cu2H2Si2O5(OH)4.
Cinder Cone – Steep, conical hill built up above a volcanic vent and composed of coarse pyroclasts expelled from the vent by escaping gases.
Circuit – Processing facility for removing valuable minerals from the ore so that it can be processed and sold.
Cirque – Bowl-shaped depression formed at the head of glacial valleys by frost wedging and ice plucking. Usually in the form of one half of an inverted cone with the upper edges having the steepest slopes, often approaching vertical, and the base possibly flat or hollowed out and occupied by a small lake or pond.
Claim Permit or Concession – Designated area that confers mineral exploration or exploitation rights to the registered holder under the laws of the governing jurisdiction.
Clast – Individual grain, rock or sediment composed mainly of fragments of preexisting rocks or minerals that have been transported some distance from their place of origin.
Clastic – Fragments of minerals, rocks, or organic structures that have been moved individually from their places of origin.
Clay – Hydrous aluminosilicate minerals formed by weathering and hydration of other silicates, as well as any mineral fragment smaller than 1/255 mm.
Cleavage – Tendency of a mineral or rock to break along a preferred direction in smooth parallel planes. In metamorphic rocks, this is also called foliation or schistosity.
Cline – Suffix specifying a form of slope or gradation such as anticline, monocline or syncline.
Coal – Metamorphic product of stratified plant remains which contains more than 50 percent carbon compounds and burns readily.
Coastal Plain – Low plain of little relief adjacent to the ocean and covered with gently dipping sediments.
Coherence – Measure of the similarity of two oscillating functions.
Collimation – Technique for forcing radiation, like gamma photons, into a beam.
Columnar Jointing – System of polygonal fractures, resulting from cooling of molten magma that splits a rock body into long prisms or columns. It is characteristic of lava flows and shallow intrusive igneous rocks.
Common Earth Model – Explicit, quantitative model of the Earth consistent with all data, testable by drilling, and subject to editing and refinement as the collection of new data proceeds.
Compactions – Fossils that have undergone some degree of flattening of their 3-dimensional structure.
Complex Number – Comprised of a real and imaginary part.
Complex Resistivity – CR is a geophysical effect in which polarization within the medium results in the voltage and applied current being out of phase; that is, their ratio is complex. Also known as Spectral IP. Induced Polarization (IP) is a form of complex resistivity.
Composite Cone – Volcanic cone of a stratovolcano, composed of both cinders and lava flows.
Compression – Fossil formed when an organism is flattened by compression and a thin film of organic material from its body is left in the rock.
Compressibility – Relative volume reduction that geological material can undergo when a force is applied or water is removed from the area by pumping.
Compressional Wave – Compressional acoustic waves (P) are propagated in the same direction as particle displacement. They are faster than shear waves and are used for measuring acoustic velocity or transit time.
Concentrator – Industrial plant designed to mechanically separate minerals and produce a mineral concentrate.
Concretion – Hard, rounded mass, commonly of silica, calcite, dolomite, iron oxide, pyrite, or gypsum, that formed within a rock from the precipitation of these minerals around a nucleus, such as a leaf, bone, shell, or fossil, and ranging in diameter from centimeters to meters.
Conductance – Product of conductivity and thickness [Siemens].
Conduction Currents – Electrical current resulting from the movement of electrons under applied potential.
Conductivity – Ability of a material to conduct electrical current. In an isotropic material it is the reciprocal of resistivity. Measured in units of Siemens per meter.
Conglomerate – Coarse-grained sedimentary rock, with rounded clasts larger than 2 mm, composed of rounded fragments which may vary in size from pebbles to boulders. Differentiated from breccias, which consist of angular clasts.
Consolidated – Condition of sediments when they have hardened into rock from their original, soft state.
Constrained Modelling – Modelling using geologic or physical property information such as drill-holes, geologic maps, outcrop physical property samples, as a constraint on the inversion process. Produces more reliable models that are consistent with multiple datasets.
Contact – Surface separating two different rock types or bodies.
Contact Metamorphism – Mineralogical and textural changes and deformation of rock resulting from the heat and pressure of an igneous intrusion in the near vicinity.
Continental Crust – Earth’s crust that includes both the continents and the continental shelves.
Continental Margin – Ocean floor from the shore of continents to the abyssal plain.
Continental Rise – Part of the continental margin encompassing the ocean floor from the continental slope to the abyssal plain. The continental rise generally has a gentle slope and smooth topography.
Continental Shelf – Part of the continental margin from the coastal shore to the continental slope; usually extending to a depth of about 200 meters and with a very slight slope, roughly 0.1 degrees. It includes continental and oceanic sediments down to the ocean floor.
Continental Slope – Part of the continental margin from the continental shelf to the continental rise or oceanic trench. Usually to a depth of about 200 meters. The continental slope typically has a relatively steep grade, from 3 to 6 degrees.
Contour Map – Map showing elevations and surface configuration by means of contour lines through points of equal elevation.
Converter – Operator of a facility licensed to receive, store and transform U3O8 into another chemical form suitable for subsequent processing.
Copal – Brittle aromatic yellow to red resins of recent or fossil origin, obtained from tropical trees.
Copper-Carbonates – Class of minerals, such as azurite and malachite that contain copper and carbonate.
Copper-Oxides – Class of mineral compounds that contain copper and elemental oxygen.
Copper-Silicates – Class of mineral compounds that contain copper and a silicon-oxygen radical.
Coprolite – Fossilized feces.
Coral – Bottom-dwelling, reef-building marine invertebrate organism.
Core – Portion of the interior of the earth that lies beneath the mantle and goes all the way to the center. The earth’s core is very dense, rich in iron and the source of the magnetic field.
Core – a long cylindrical rock sample, about an inch and a half in diameter, produced by drilling with hollow drill tubes.
Core Drilling – Act of collecting subsurface rock samples by utilizing hollow tube drill shafts.
Correlation – Determination of the position of stratigraphically equivalent rock units in different drill holes, often done by matching the character of geophysical logs; also the matching of variables, such as log response and core analyses.
Country Rock – Rock intruded by and surrounding an igneous intrusion.
Covellite – Mineral CuS.
Crag and Tail – Elongated hill or ridge resulting from glaciation, having at the stoss end a steep often precipitous face or knob of ice smoothed bedrock (crag) obstructing the movement of the glacier and at the lee end a tapering, streamlined, gentle slope (tail) of till.
Craton – Part of the earth’s crust that has attained stability and has been little deformed for a long period of time; refers only to the earth’s continents.
Cretaceous – Period spanning 145 to 65.5 million years ago and divided into two epochs. The Early Cretaceous Epoch had six Ages: Cenomanian, Turonian, Coniacian, Santonian, Campanian, and Maastrichtian. The Late Cretaceous Epoch had six Ages: Berriasian, Valanginian, Hauterivian, Barremian, Aptian, and Albian.
Crinoid – Marine animal related to modern starfish and sea urchins that lives attached to the seafloor by a stalk.
Cross-Bedding – Arrangement of sedimentary beds tilted at different angles to each other. Bedding that was inclined when originally deposited. It formed by variable current or wave action, or by wind such as common sand dunes.
Cross-Hole – Geophysical methods carried out between boreholes.
Crossplot – Term used in log analysis for a plot of one parameter versus another. Usually two different types of logs. Useful in the identification of lithology.
Crushing – Breaking of ore from the size delivered from the mine into smaller and more amenable fragments to be then fed to grinding mills or to a leach pad for further processing.
Crust – Outermost layer of the Earth, varying in thickness from about 10 kilometers (6 miles) below the oceans, to 65 kilometers (about 40 miles) below the continents. It represents less than 1 percent of the Earth’s volume.
Crystal – Solid material bounded by natural flat surfaces that result from a regular internal arrangement of atoms. Almost all minerals can form crystals but in most rocks the flat surfaces do not have room to develop.
Cu – Chemical symbol for copper.
Cultural Environment – Part of the environment which represents man-made features such as roads, buildings, canals, and bridges, as opposed to natural features.
Cuprite – Mineral Cu2O.
Curie – Quantity of any radionuclide that produces 3.70 x 1010 disintegrations per second.
Curie-Point – Temperature at which certain magnetic materials undergo a sharp change in their magnetic properties. Also commonly referred to as the Curie temperature.
Current Channeling or Gathering – Channeling is a restriction of current flow due to an insulating barrier or narrowing of a conductor. Current gathering is a concentration of current in a locally, more conductive zone. The disproportionate influence of lakes and swamps on VLF surveys is a well-known example.
Current Density – Measure of current flow through a given orientated area.
Cyanidation – Method of extracting exposed gold or silver grains from crushed or ground ore by dissolving the contained gold and silver in a weak cyanide solution. May be carried out in tanks inside a mill or in heaps of ore outdoors.
Cycle Skip – Cycle skips are caused, in acoustic velocity logging, by only one of a pair of receivers being triggered by an arriving wave, which causes sharp deflections on the log.