Appendix:Dictionary of Mining, Mineral, and Related Terms/I/1

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An orthorhombic mineral, (UO (sub 2) ) (sub 6) O (sub 2) (OH) (sub 8) .6H (sub 2) O ; acicular with perfect basal cleavage; in cavities, as an alteration product of uraninite at Kasolo, Congo, and Wolsendorf, Bavaria.

ice concrete

A dense frozen mixture of sand, rock fragments, and ice.

ice-laid drift

See: till.

Iceland agate

See: obsidian.

Iceland crystal

See: Iceland spar.

Iceland spar

A transparent, pure, optically clear variety of calcite principally in Iceland in vugs and cavities in basalt; formerly used in optical instruments such as nicol prisms, but has been replaced by artificial materials such as polaroid plates. Syn: Iceland crystal; optical calcite.

ice period

The period of time from freezeup to breakup of ice.

ice plug

An ice obstruction formed by a circulation medium freezing inside the drill-rod couplings while the rods are racked up or standing in the drill derrick or tripod in extremely cold weather. Such plugs may loosen when rods are lowered into the borehole and may be ejected from the open end of the rod with enough force to injure drill crewmembers severely.

ice run

See: debacle.

ice sheet

A glacier of considerable thickness and more than 50,000 km (super 2) in area, forming a continuous cover of ice and snow over a land surface, spreading outward in all directions and not confined by the underlying topography; a continental glacier. Ice sheets are now confined to polar regions (as on Greenland and Antarctica), but during the Pleistocene Epoch they covered large parts of North America and northern Europe.

ice spar

A white transparent variety of orthoclase. Syn: sanidine.

ice stone

See: cryolite.

ideal section

A geologic cross section that combines observed evidence on stratigraphy and/or structure with interpretation of what is not present. It may be the summation or average of several successive cross sections.

identified resources

Resources whose location, grade, quality, and quantity are known or estimated from specific geologic evidence. Identified resources include economic, marginally economic, and subeconomic components. To reflect varying degrees of geologic certainty, these economic divisions can be subdivided into measured resources, indicated resources, and inferred resources.


a. In X-ray crystallography, the distance along a crystallographic between like points in a lattice.

b. In geometrical crystallography, the completion of a sequence of symmetry operations, e.g., four rotations of 90 degrees each about a tetrad.


A mineral constituent of a metamorphic rock formed by recrystallization and bounded by its own crystal faces. It is a type of crystalloblast. The term was originated by Becke in 1903. CF: xenoblast.


Pertaining to an idioblast of a metamorphic rock. It is analogous to the term idiomorphic in igneous rocks.


Minerals in which a specific coloring agent is an essential constituent, e.g., copper in malachite, iron in olivine, manganese in rhodochrosite. CF: allochromatic.

idiochromatic mineral

Mineral in which the color is due to some essential constitutent of the stone, for example, malachite, peridot, and almandine. In contrast to allochromatic minerals, idiochromatic minerals have a limited range of color. See also: allochromatic mineral.


Suggested by Posepny for those ore deposits that are contemporaneous in origin with the wall rock. The word means of the same origin.


A syn. of automorphic, originally proposed by Rosenbusch in 1887 to describe individual euhedral crystals. Though the term lacks priority, it is now commonly applied to the igneous-rock texture characterized by such euhedral crystals, esp. in U.S. usage.

idler disk

A device used for holding the belt in proper position on certain types of boxcar loaders. See also: boxcar loader.

idler gear

a. A gear meshed with two other gears that does not transmit power to its shaft; used to reverse direction of rotation in a transmission.

b. Same as neutral gear.

idle wheel

a. A wheel interposed in a gear train, either to reverse rotation or to obtain the required spacing of centers, without affecting the ratio of the drive. Also called idler.

b. A pulley to guide a driving belt, to increase its tension, or to increase its arc of contact on one of the working pulleys.


See: vesuvianite.


An orthorhombic hydrocarbon mineral, 4[C (sub 22) H (sub 14) ] ; soft; greenish yellow to light brown with bluish fluorescence; mixed with clay, pyrite, and gypsum associated with cinnabar in the Idria region, Yugoslavia. Its combustibility gave rise to the term "inflammable cinnabar." Syn: inflammable cinnabar.


See: lueshite.

Igewsky's reagent

A solution consisting of 5% picric acid in absolute alcohol used as an etching reagent for carbon steels.


Said of a rock or mineral that solidified from molten or partly molten material, i.e., from a magma; also, applied to processes leading to, related to, or resulting from the formation of such rocks. Igneous rocks constitute one of the three main classes into which rocks are divided, the others being metamorphic and sedimentary. Etymol: Latin ignis, fire. See also: magmatic; plutonic; pyrogenic; hypabyssal; extrusive.

igneous breccia

a. A breccia that is composed of fragments of igneous rock.

b. Any breccia produced by igneous processes; e.g., volcanic breccia, intrusion breccia.

igneous complex

An assemblage of intimately associated and roughly contemporaneous igneous rocks differing in form or in petrographic type; it may consist of plutonic rocks, volcanic rocks, or both. See also: complex.

igneous cycle

The sequence of events in which volcanic activity is followed by major plutonic intrusions, and then minor intrusions (e.g., dikes).

igneous metamorphism

A high-temperature metamorphic process that includes the effects of magma on adjacent rocks as well as those due to injection pegmatitization (Lindgren, 1933). The term is no longer in common use. CF: pyrometamorphism.

igneous rock

Rock formed by the solidification of molten material that originated within the earth.

igneous-rock series

An assemblage of temporally and spatially related igneous rocks of the same general form of occurrence (plutonic, hypabyssal, or volcanic), characterized by possessing in common certain chemical, mineralogic, and textural features or properties so that the rocks together exhibit a continuous variation from one extremity of the series to the other. Syn: rock series. See also: series.


Applied to a mineral that sparks when struck with steel or iron; e.g., pyrite.


The rock formed by the widespread deposition and consolidation of ash flows and neues ardentes. CF: trass; welded tuff.


An assessment of the ease with which a coal can be ignited.

ignitability (dust cloud)

The relative ignitability of a dust cloud may be defined as the degree of ease with which it can be ignited.


a. A blasting fuse or other contrivance used to fire an explosive charge.

b. In mining, a metal cylinder that connects a main fuse with separate fuses that are only limited by the number of blasts to be fired. c. A device to relight safety lamps internally by friction. One type uses a waxed strip with igniting matches at intervals, while another type has a small burred wheel operating against a piece of cerium or something of a similar nature. Electrical devices are sometimes employed. d. One that ignites as (1) a charge, usually of black gunpowder, used to facilitate the ignition of a propelling charge and sometimes of a bursting charge; (2) a device for igniting fuel mixture (as in an internal combustion engine, a jet engine, or a rocket engine); (3) a separately energized electrode used for restriking the arc in an ignitron.

igniter cord

a. A cord that passes an intense flame along its length at a uniform rate to light safety fuses in succession.

b. Two types are manufactured: a fast cord having a nominal burning speed of 1 s/ft (3.3 s/m) and a slow cord having a nominal burning speed of 10 s/ft (33 s/m). The burning speeds are reliable and consistent even under adverse conditions, as, e.g., when burning underwater or in a direction opposite to a strong wind.


a. Percussion material or detonating powder.

b. The firing of an explosive mixture of gases, vapors, or other substances by means of an electrical or frictional spark. c. An outburst or fire or an explosion. d. The act of igniting, or the state of being ignited; specif., in mechanics, the act of exploding the charge of gases in the cylinder of an internal combustion engine.

ignition arch

entrance that promotes ignition by reflection of heat.

ignition charge

A small charge, usually of black powder, used to facilitate the ignition of the main charge.

ignition delay

Time interval between contact of an oxidant and a combustible and ignition.

ignition of combustible gases

See: gas ignition.

ignition point

a. Of solids and liquids, the minimum temperature at which combustion can occur, but at which it is not necessarily continuous.

b. Of combustible gases, the flashpoint.

ignition temperature

a. The ignition temperature of a substance is the temperature at which that substance starts to burn. The temperature of ignition varies greatly with different substances. All solid fuels must be heated to their ignition temperature before they will burn continuously by the process known as combustion.

b. The temperature required to effect ignition of a combustible-oxidant system at a specified pressure; in general, the minimum temperature is implied.

ignition tube

A heavy-walled test tube of hard glass for examining the behavior of heated substances.


See: copiapite.


A series of plutonic rocks containing nepheline and 30% to 60% mafic minerals, generally clinopyroxene, and including sphene, apatite, and melanite; also, any rock of that series. Melteigite and jacupirangite are more mafic members of the series; urtite is a type rich in nepheline. Named by Ramsay in 1891 for Ijola (Iivaara), Finland.


A trigonal mineral, Bi (sub 4) (S,Se) (sub 3) ; the selenium-rich analog of laitakarite, similar to jose#1.ite but containing no tellurium; at the Ikuno Mine, Hyogo Prefecture, Japan.


A monoclinic mineral, (Mn,Zn,Fe)SO (sub 4) .4H (sub 2) O ; rozenite group; a green, friable crystalline aggregate in Hall Valley, Park County, CO.


An amorphous mineral, Mo (sub 3) O (sub 8) .nH (sub 2) O(?) .

Ilgner flywheel

A heavy flywheel used in the Ward-Leonard control of winding engines in mine hoists. It is mounted on the shaft of a motor generator, which draws on this source of energy as the hoist starts to move.

Ilgner system

A modification of the Ward-Leonard system of speed control, in which a heavy flywheel is carried on the motor-generator shaft to smooth out peak loads, which would otherwise be taken from the power supply. The system is used on mine winding engines, etc. See also: Ward-Leonard control.

ill air

Scot. Noxious gas, as from underground fires or chokedamp; a stagnant state of the atmosphere underground.

illegal mine

A mine that has not obtained the necessary permits and licenses from the appropriate State and Federal agencies before commencement of mining.


A thin extraneous crust formed on minerals.


a. Melting or infusing.

b. Mixture of metallic and earthen substances.


A general term for a group of three-layer (14Aa), micalike clays (K,H (sub 3) O)(Al,Mg,Fe) (sub 2) (Si,Al) (sub 4) O (sub 10) [(OH) (sub 2) ,H (sub 2) O] ; widely distributed in argillaceous sediments and derived soils; intermediate in composition and structure between muscovite and montmorillonite; contains less potassium and more water than muscovite, but more potassium than kaolinite or montmorillonite; potassium is generally replaced by calcium and/or magnesium; named from studies by Grimm of shales and clays in Illinois. See also: muscovite. CF: pholidoide; phyllite. Syn: hydromica; hydromuscovite; glimmerton.


a. A trigonal mineral, FeTiO (sub 3) ; ilmenite group; forms two series with geikielite and with pyrophanite. Iron-black. Also called menaccanite; titanic iron ore. See also: zircon group.

b. The mineral group geikielite, ilmenite, and pyrophanite. See also: basonomelane.


A hypabyssal rock composed almost entirely of ilmenite, with accessory pyrite, chalcopyrite, pyrrhotite, hypersthene, and labradorite. CF: nelsonite.


A tetragonal mineral, (Ti,Nb,Fe) (sub 3) O (sub 6) ; forms a series with strueverite in which tantalum substitutes for niobium; black; sp gr, 5.14. Syn: iserine.


An orthorhombic and monoclinic mineral, CaFe (sub 2) FeSi (sub 2) O (sub 7) O(OH) ; in prisms with vertically striated faces; compact, massive, or fibrous; in some magnetite orebodies, in zinc and copper ores, in contact deposits in dolomitic limestone, and in sodalite syenite near Julianehaab, Greenland. Syn: elbaite; lievrite.


A rock composed of quartz and albite, formed by interaction between a nepheline-syenite magma and graywacke.


a. Formation of feldspathic minerals by penetration of alkaline solutions of magmatic origin into aluminum-rich metamorphic rocks.

b. The absorption of a fluid, usually water, by a granular rock or any other porous material, under the force of capillary attraction, and in the absence of pressure.

imbricate structure

a. A sedimentary structure characterized by imbrication of pebbles all tilted in the same direction, with their flat sides commonly displaying an upstream dip. Syn: shingle structure.

b. A tectonic structure displayed by a series of nearly parallel and overlapping minor thrust faults, high-angle reverse faults, or slides, and characterized by rock slices, sheets, plates, blocks, or wedges that are approx. equidistant and have the same displacement and that are all steeply inclined in the same direction (toward the source of stress).


See: synthetic stone; assembled stone.

Imlay table

See: end-bump table.

immediate roof

Lowest layer or layers of rock immediately above an underground opening. See also: roof; nether roof.

immersion cup

An accessory for a gemological microscope containing a liquid of high refractive index and designed to eliminate reflections from highly polished facets and thus to expedite the observation of determinative inclusions, growth lines, etc.

immersion method

In optical mineralogy, the determination of the refractive indices of a mineral by matching them with liquids of known refractive index. See also: index of refraction.

immersion objective

Oil-immersion lens used in microscopy to help concentrate light on the object under examination.

imminent danger

The existence of any condition or practice that could reasonably be expected to cause death or serious physical harm before such condition or practice can be abated.


Said of two or more phases that, at mutual equilibrium, cannot dissolve completely in one another; e.g., oil and water.


Collision between bodies, the velocity of one or both being changed. In direct impact, the velocity of the moving bodies is perpendicular to the bodies at the point of contact. The impact coefficient, known as the coefficient of restriction, is the ratio of the differences of velocities of the two bodies after impact to the same differences before impact.

impact breakers

The impact breaker or double impeller breaker uses the energy contained in falling stone, plus the power imparted by the massive impellers for complete stone reduction.

impact cast

Cast of marking produced by object striking the mud bottom. The steeply raised end of impact casts are always oriented downcurrent. Syn: prod mark; prod cast. See also: bounce cast.

impact crusher

Machine in which material is broken by sharp blows. See also: hammermill.

impact factor

The factor of from 1 to 2 by which the weight of a moving load is multiplied to calculate its full effect on the structural design of a floor or bridge.

impact glass

See: impactite.

impact grinding

Shattering of particles by direct fall upon them of crushing bodies or the use of a device that vibrates a metal object such as a shutter box.


a. A vesicular, glassy to finely crystalline material produced by fusion or partial fusion of target rock by the heat generated from the impact of a large meteorite, and occurring in and around the resulting crater, typically as individual bodies composed of mixtures of melt and rock fragments, often with traces of meteoritic material; a rock from a presumed impact site. Syn: impact slag; impact glass.

b. A term used incorrectly for any shock-metamorphosed rock.

impact loss

The head lost as a result of the impact of particles of water; included in and scarcely distinguishable from eddy loss.

impact mill

A crushing unit in which a rapidly moving rotor projects the charged material against steel plates; impact mills find use in the size reduction of such materials as coal, feldspar, perlite, etc. CF: disintegrator; hammermill.

impact screen

One in which the loaded screen is so suspended that it can be caused to swing or rock forward until it is abruptly checked on hitting a stop.

impact sensitivity

Sensitivity of an explosive to detonate when impacted. See: fallhammer test.

impact slag

Glassy material produced mainly by the melting of local sediment or rock where a meteorite has struck the earth. See also: impactite.


Extremely fine, so that no grains or grit can be felt.


The complex ratio of voltage to current in an electrical circuit, or the complex ratio of electric-field intensity to magnetic-field intensity in an electromagnetic field. It is the reciprocal of admittance. See also: acoustic impedance.

imperfect combustion

A term meaning that not all of the fuel is oxidized to its highest degree; e.g., if carbon monoxide is formed instead of carbon dioxide. CF: incomplete combustion.

imperial jade

A high-quality, semitransparent variety of jadeite.

Imperial screen

An oscillating or vibrating screen on which the ore is thrown upward, as well as moved forward on the screen.


Said of a rock that does not permit the passage of fluids under the pressure conditions ordinarily found in the subsurface. Ant: permeable. Syn: impervious. CF: vitreous.


See: impermeable.


Dust-sampling apparatus into which a measured volume of dusty mine air is drawn through a jet in such a way as to strike a wetted glass plate, to which dust particles adhere.


A bursting inward; sudden collapse; opposite of explosion.


a. A reservoir for impounding. Used in connection with the storage of tailings from ore-dressing plants and hydraulic mines.

b. To collect in a reservoir or sump provided near a borehole the water, drill cuttings, etc., ejected therefrom.

impounding dam

One in which tailings are collected and settled; also, a water-storage dam.


a. Said of a mineral deposit (esp. of metals) in which the minerals are epigenetic and diffused in the host rock. CF: interstitial.

b. Said of timber that has been soaked in various fluids to enable it better to resist the decomposing influences of the atmosphere. c. A metallic material in which fragments of diamond or other hard substances (in unflocculated distribution) are intermixed and embedded. See also: impregnated bit.

impregnated bit

A sintered, powder-metal matrix bit with fragmented bort or whole diamonds of selected screen sizes uniformly distributed throughout the entire crown section. As the matrix wears down, new, sharp diamond points are exposed; hence, the bit is used until the crown is consumed entirely. CF: multilayer bit. See also: impregnated.

impregnated timber

Timber that has been treated either to make it flame resistant or to protect it from destruction by fungi and insects. Cover boards used with steel arches are often vacuum-pressure impregnated with a flame-retardant preservative for safety and to comply with the flame-proofing requirements covering escape roadways.

impression block

A bell-shaped or hollow, tubular device filled with wax or other water-resistant plastic materials, which is lowered onto an article resting on the bottom of a borehole. The plastic material molds itself about the lost article, and by inspecting the impression so formed, the driller can determine which fishing tool is best fitted to recover the lost article.


In crystallography, any element or operation of symmetry involving a mirror or inversion resulting in a change of chirality of an asymmetric unit. CF: chirality; proper.

improved dial

A miner's dial in which a telescope replaces the usual sighting vanes.

Improved paragon

Trade name for nonrotating wire rope of 18 by 4 over 3 by 24 construction.

impulse turbine

a. A water turbine, such as the Pelton wheel, in which the driving force is provided more by the speed of the water than by a fall in its pressure. See also: Pelton wheel.

b. A turbine in which the steam is expanded in a series of stationary nozzles that it leaves at a very high velocity, perhaps 4,000 ft/s (1.2 km/s), and then gives up its kinetic energy to blades or buckets attached to the revolving disk that furnishes the power.


a. Eng. Toward the working face, or interior, of the mine; away from the shaft or entrance; from Newcastle coalfield. Also called in-over; inbye; inbyeside.

b. In a direction toward the face of the entry from the point indicated as the base or starting point. c. The direction from a haulage way to a working face. d. Opposite of outby.


Made luminous by heat; white or glowing with heat.


See: coalification.


The property of an igniting agent (e.g., spark, flame, or hot solid) whereby the agent can cause ignition.

inches of pressure

The height in inches of a column of water or of mercury as a measure of hydrostatic pressure.

inching starter

In one form, electrical gear that allows power to be applied gently to a stationary ball mill so as to avoid a high starting strain. The mill is said to be inched over as it begins slowly to rotate.

inch of water

A unit of pressure equivalent to 0.036136 psi (248.84 Pa).

inch pennyweights

In valuation of gold lodes, the product of the width of the exposure of ore, measured normal to the containing host rock, and the assay value in pennyweights of a true sample of the ore, cut evenly along the measured line. In evaluation of ore tonnages in base-metal mining, the equivalent measurement is the assay-foot or similar convenient combination across the exposed lode. Abbrev., in. dwt.


The work done in raising 1 lb, 1 in (0.179 kg, 1 cm); a unit of work or of energy. Abbrev.,

incidence rate

a. The rate of occurrence of accidents as determined by multiplying the actual number of injuries in any given period by 200,000 and dividing the product by the number of man-hours exposure. Syn: frequency rate.

b. A statistic used by the mining industries to measure safety performance and compare the performance of different groups or employers. The formula for determining the rate is: the number of injuries or illesses times 200,000 h divided by employee hours worked. The 200,000 hours represents 100 employees working 40 h/wk and 50 wk/yr. This number keeps the value that results from the formula small. The number of employee hours comes from company records. They represent hours worked; not vacation, sick leave, or holiday time.

incidental vein

A vein discovered after the original vein on which a claim is based.


a. The angular dip of a vein, a bed, etc., measured in degrees from the horizontal plane.

b. Angle between the direction of the magnetic field and the horizontal plane. Syn: declination.


Instrument to determine the inclination of the magnetic field.


a. A shaft not vertical; usually on the dip of a vein. See also: slope.

b. Any inclined plane, whether above or beneath the surface; usually applied to self-acting planes above ground, as in the bituminous coalfields. c. In mines, an inclined drift driven upwards at an angle from the horizontal. d. A sloping tunnel along which rails are laid from one level to another; a mechanically worked inclined haulageway in a coal mine. e. A slanting shaft. f. An opening driven up or down the pitch. Syn: inclined shaft.

incline bogie

Scot. A wheeled carriage for inclines, constructed with a horizontal platform so that cars can be run on it and be conveyed up and down the incline or slope.

inclined bedded formation

Any bedded formation of rock where the dip of the bedding planes is greater than 10 degrees .

inclined bedding

A type of bedding appearing commonly in sandy deposits; the strata, essentially intraformational, dip in the direction of the current flow. Syn: crossbedding; cross lamination; current bedding.

inclined borehole

A borehole drilled at an angle from the vertical not exceeding 45 degrees. The drilling technique is called angle drilling.

inclined cableway

A monocable cableway in which the track cable has a slope of about 1 in 4 over its whole length, sufficiently steep to allow the carrier to run down under its own weight.

inclined drilling

Drilling blastholes at an angle from the vertical. Also called angle drilling.

inclined extinction

Alignment of optical extinction at some angle other than 0 degrees , 45 degrees , or 90 degrees to a crystal face or cleavage trace. CF: extinction; extinction angle.

inclined fold

A fold, the axial plane of which is not vertical.

inclined gage

A common type of gage used with the pitot tube. A straight glass tube with connections at each end is mounted in an inclined position on an aluminum frame, and a scale is placed under the tube. In place of water, a colored oil is used, and the scale is graduated to read directly in inches of water.

inclined magnetic polarization

The inclination angle of the geomagnetic field.

inclined plane

a. A natural or artificial slope used for facilitating the ascent, descent, or transfer from one level to another of vehicles or other objects. See also: incline.

b. A slope used to change the direction and speed-power ratio of a force.

inclined polarization

Polarization that is inclined to the linear dimensions of a magnetized body, or to the plumb line or the horizon.

inclined railroad operator

See: inclined railway operator.

inclined railway operator

In metal mining, one who operates the machinery that drives the haulage cable along a power incline railway used for hauling cars, supplies, workers, and materials to and from one level to another on a steep slope. Also called inclined railroad operator; tramway operator.

inclined shaft

See: incline.

inclined traverser

A traverser that moves mine cars laterally and vertically by traveling on an inclined plane. It is sometimes used at the pit bottom for the transfer of cars from a higher decking level to a lower decking level on the opposite side rail track. The cars are held upright in a frame and can handle loaded or empty cars to and from the two levels. See also: traverser.

inclined water gage

A sensitive form of water gage, giving readings of greater accuracy. It is used mainly for ventilation surveys. See also: water gage.

incline engine

A stationary haulage engine at the top of an incline.

incline hole

See: angle hole.

incline man

In mining, a laborer who controls the movement of cars on a self-acting incline (loaded car going down one track pulls empty cars up on other), hooking cable to loaded or empty cars, starting them down the incline, and applying brake to cable drum by a lever to control their speed of descent. Also called dilly boy; drum runner; monitor operator; plane man; wheel runner; jinnier.

incline repairman

In mining, a person who oils, greases, repairs, and replaces pulleys or rollers which support the cable on a haulage slope or plane (incline) underground and at the mine surface. Also called rolley man. Syn: incline trackman.

incline shaft

A shaft sunk at an inclination from the vertical, usually following the dip of a lode. See also: turned vertical shaft; underlay shaft.

incline trackman

See: incline repairman.


a. An instrument for measuring the inclination or slope, as of the ground, Syn: clinometer.

b. Any of various instruments for measuring the departure of a drill hole from the vertical; a driftmeter. c. An instrument that measures magnetic inclination.

included angle

Either of the two angles formed at the station by the intersection of the two survey lines.


a. Any size fragment of another rock enclosed in an igneous rock. Syn: xenolith.

b. A particle of nonmetallic material retained in a solid metal or alloy. Such inclusions are generally oxides, sulfides, or silicates of the host metal, but may also be particles of refractory materials picked up from a furnace or ladle lining. c. A crystal, aggregate, or minute cavity filled with one or two fluid phases and with or without a crystal phase enclosed in a host crystal. See also: fluid inclusion; three-phase inclusion; negative crystal.


a. A term applied to crystals and anhedra of one mineral involved in another; and to fragments of one rock inclosed in another, as when a volcanic flow picks up portions of its conduit.

b. Particles of foreign matter, solid, liquid, or gaseous, enclosed within a gem stone. The nature of such inclusions provides a powerful clue to the origin of a stone and enables natural stones to be distinguished from their synthetic counterparts.


a. The process of coal formation that begins after peat formation is completed without there being any sharp boundary between the two processes. From the German inkohlung.

b. See: coalification.


a. Said of a rock or deposit that is loose or unconsolidated.

b. Said of electromagnetic radiation (EMR) having a broad spectrum of frequencies; e.g., incoherent (sunlight) EMR vs. coherent (laser) EMR.


a. Applies to substances that will not burn.

b. Any building material that contains no matter subject to rapid oxidation within the temperature limits of a standard fire test of not less than 2�-h duration. Materials that continue to burn after this time period are termed combustible. c. See: noncombustible.


a. Applied to strata, a formation, a rock, or a rock structure not combining sufficient firmness and flexibility to transmit a thrust and to lift a load by bending; consequently, admitting only the deformation of flowage. See also: competent.

b. Soft or fragmented rocks in which an opening, such as a borehole or an underground working place, cannot be maintained unless artificially supported by casing, cementing, or timbering.

incompetent bed

A bed that, in a particular case of folding, has yielded to the lateral pressure by plastic adjustment and flow. This may result in the bedding being thrown into complex structures or in the development of more regular internal structures, particularly drag folds and fracture cleavage. The bed tends to thicken toward the hinges, and to thin in the limbs, of the folds. See also: competent bed.

incompetent folding

See: flow folding.

incomplete combustion

A term applied to combustion in which all of the fuel is not burned; e.g., leaving unburned carbon in ashes. CF: imperfect combustion.

incongruent melting

a. Melting accompanied by decomposition or by reaction with the liquid, so that one solid phase is converted into another; melting to give a liquid different in composition from the original solid. An example is orthoclase melting incongruently to give leucite and a liquid richer in silica than the original orthoclase. CF: congruent melting.

b. A crystalline compound that dissociates into another compound and a melt of different composition upon heating. CF: congruent melting.


A process by which material contributing to coal formation responds to diagenetic and metamorphic agencies of coalification and becomes a part of the coal without undergoing any material modification. See also: coalification. CF: vitrinization; fusinization.


The quantity of coal or coke taken by a single sweep of the sampling instrument.


A former outcrop concealed by or buried beneath younger unconformable strata.


See: encrustation.

independent subsidence

The condition in sedimentation in which each floc or particle settles freely; i.e., its movement is not influenced in any way by other flocs or particles in suspension.

independent wire rope core

This core may be 6 by 7, 7 by 7, 6 by 19, or 7 by 19 (number of strands laid together and ropes twisted together) construction, and the individual wires shall be of an appropriate grade of steel in accordance with the best practice and design, either bright (uncoated), galvanized, or drawn galvanized wire. See also: wire-strand core.


Hydrous calcium and magnesium borate mineral, CaMg[B (sub 3) O (sub 3) (OH) (sub 5) ] (sub 2) .6H (sub 2) O , as monoclinic crystals from the Inder borate deposits, Kazakhstan. Named from locality. See also: metahydroboracite.


A monoclinic mineral, MgB (sub 3) O (sub 3) (OH) (sub 5) .5H (sub 2) O ; forms nodular aggregates or acicular crystals; named from the locality, Inder, Kazakhstan.

index bed

See: key bed.

index contour

A contour line shown on a map in a distinctive manner for ease of identification, being printed more heavily than other contour lines and generally labeled with a value (such as figure of elevation) along its course. It appears at regular intervals, such as every fifth or sometimes every fourth contour line (depending on the contour interval). Syn: accented contour.

index fossil

A fossil that, because of its wide geographic distribution and restricted time range, can be used to identify and date the strata in which it occurs. CF: guide fossil.

index horizon

A structural surface used as a reference in analyzing the geologic structure of an area.

index mineral

A mineral developed under a particular set of temperature and pressure conditions, thus characterizing a particular degree of metamorphism. When dealing with progressive metamorphism, it is a mineral whose first appearance (in passing from low to higher grades of metamorphism) marks the outer limit of the zone in question. CF: typomorphic mineral.

index of liquidity

This is found by the formula: water content of test sample-water content at plastic limit/index of plasticity. This gives a value of 100% for clay at the liquid limit, and zero at the plastic limit, and is the reverse of the consistency index.

index of plasticity

The difference between the water content of clay at its liquid and plastic limits, showing the range of water contents over which the clay is plastic.

index of refraction

A number n found by dividing the velocity of light in a vacuum c by the velocity of light in a transparent substance. Isometric crystals are isotropic and have one index of refraction; all other symmetries are anisotropic. Hexagonal, trigonal, and tetragonal crystals have two principal indices; orthorhombic, monoclinic, and triclinic crystals have three principal indices. Determination of indices of refraction of a mineral is a major means of mineral identification. See also: dispersion; interference. Syn: immersion method; optical mineralogy; refractive index. CF: transmitted light.

index properties

Properties that can be used to identify the soil type. The properties are of two kinds: (1) soil grain properties and (2) soil aggregate properties.

index property tests

Tests to determine index properties that in turn serve to identify the soil type and indicate its consistency.


A hexagonal mineral, Mg (sub 2) Al (sub 4) Si (sub 5) O (sub 18) ; the high-temperature polymorph of cordierite; in sediments fused by a burning coal seam in India. Named for the locality.


A style of diamond cutting, usually of Indian or other Oriental origin, in which the table is usually double the size of the culet; such stones are generally recut for European or American requirements.

Indian jade

Aventurine quartz containing inclusions of chromian muscovite. Syn: regal jade.

Indian title

An Indian's right to occupancy of land, and that right recognized by the United States, constitutes Indian title.

India steel

A fine natural steel from southern India made directly from the ore; wootz.

indicated ore

Ore for which tonnage and grade are computed from information similar to that used for measured resources, but the sites for inspection, measurement, and sampling are farther apart or otherwise less adequately spaced. The degree of assurance is high enough to assume continuity between points of observation.

indicated resources

Resources from which the quantity and grade and/or quality are computed from information similar to that used for measured resources, but the sites for inspection, sampling, and measurement are farther apart or are otherwise less adequately spaced. The degree of assurance, although lower than that for measured resources, is high enough to assume continuity between points of observation.


a. A geologic or other feature that suggests the presence of a mineral deposit, such as a geochemical anomaly, a carbonaceous shale indicative of coal, or a pyrite-bearing bed that may lead to gold ore at its intersection with a quartz vein. A plant or animal peculiar to a specific environment, which can therefore be used to identify that environment. See also: pencil mark.

b. See: marker bed; marker.

indicator plant

a. Some plants develop peculiar diagnostic symptoms that can be interpreted directly in terms of probable excesses of a particular element in the soil. Geobotanical indicators are either plant species or characteristic variations in the growth habits of plant species that are restricted in their distribution to rocks or soils of definite physical or chemical properties. They have been used in locating and mapping ground water, saline deposits, hydrocarbons, and rock types, as well as ores.

b. A plant whose occurrence is broadly indicative of the soil of an area; e.g., its salinity or alkalinity, level of zone of saturation, and other soil conditions.

indicator vein

A vein that is not metalliferous itself, but may lead to an ore deposit.

indices of a crystal face

The numbers that define the position of a crystal face in space with reference to crystallographic axes. Miller and Bravais-Miller indices, those in current use, are the reciprocals, cleared of fractions, of the intercepts the face makes with the crystallographic axes. Syn: Miller indices. CF: crystal systems; intercept.


A blue variety of elbaite tourmaline.

indigenous limonite

Sulfide-derived limonite that remains fixed at the site of the parent sulfide, often as boxworks or other encrustation. CF: exotic limonite; relief limonite.

indigo copper

See: covellite; copper sulfide.

indirect flushing

Flushing in which the water enters the borehole around the rod and issues upwards through the rod.

indirect initiation

See: inverse initiation.

indirect priming

Placement of the blasting cap in the first cartridge going into the borehole with the business end pointing toward the collar. Recommended method of priming charges of permissible dynamite.


An isometric mineral, FeIn (sub 2) S (sub 4) ; linnaeite group; in minute iron-black grains in cassiterite from the Dzhalind deposit, Little Khingan ridge, the former U.S.S.R.


a. A tetragonal mineral. Symbol, In; native; metallic silvery white; sp gr, 7.31; in meteorites and as a trace constituent in the minerals of other metals, principally zinc, lead, tin, tungsten, and iron minerals; principal source is sphalerite concentrates that may contain up to 10,000 ppm.

b. Used in making bearing alloys, germanium transistors, rectifiers, thermistors, and photoconductors.

individually screened trailing cable

A trailing cable with a screen of metallic covering over each power conductor. This is the type now adopted in British coal mines. See also: trailing cable.

individual reduction ratio

In crushing practice, this term may be expressed as: Size most abundant in feed/mean size of grading band concerned.

indoor catches

Beams that catch the walking beam of the Cornish pump or engine on its down piston stroke if the string of tools being moved should break. The indoor stroke is the lifting stroke of such a pump.

indoor stroke

Eng. That stroke of a Cornish pump that lifts the water at the bottom or drawing lift.


The act of drawing in, or that which is drawn in; an inward flow; such as an indraft of air.

induced breaks

The fine breaks or cracks that occur in the nether roof of a coal seam following the holing of the coal or its removal, and having the same general direction as that of the coal face itself.

induced bursts

Rock bursts caused by stoping operations to distinguish them from development bursts, which are called inherent.

induced caving

In the block caving mining method, the ore zone is undercut until the ore material breaks apart and falls under gravity load into draw points. If the ore zone is reluctant to fall under gravity loading, the fall is sometimes induced with explosives set in boreholes drilled into the orebody. This induced caving is generally accomplished from drifts above the ore zone.

induced cleavage

See: induced fracture.

induced current

See: induction.

induced fracture

Fracture formed in a roof bed as a result of mining operations. For example, on longwall faces fractures are formed in a shale roof parallel to and along successive lines of face. They are induced after coal cutting and become intensified at the end of the loading shift. The distance between the fractures coincides, roughly, with the depth of cut. See also: break. Syn: induced cleavage.

induced magnetization

The magnetic field spontaneously induced in a volume of rock by the uniform action of an applied field. Its direction and magnitude are parallel and proportional, respectively, to the applied field. In the absence of remanent magnetization, induced magnetization is the magnetic moment per unit volume. See also: remanent magnetization.

induced polarization

The production of a double layer of charge at a mineral interface, or production of changes in double-layer density of charge, brought about by application of an electric or magnetic field (induced electrical or magnetic polarization). Induced electrical polarization is manifested either by a decay of voltage in the Earth following the cessation of an excitation current pulse, or by a frequency dependence of the apparent resistivity of the Earth. Abbrev: IP.


The production of magnetization or electrification in a body by the mere proximity of magnetized or electrified bodies, or of an electric current in a conductor by the variation of the magnetic field in its vicinity. Syn: induced current.

induction balance

An apparatus for measuring changes of conductivity, detecting the proximity of metallic bodies, etc., by noting extremely minute changes in an electric current.

induction furnace

An alternating-current electric furnace in which the primary conductor is coiled and generates, by electromagnetic induction, a secondary current that develops heat within the metal charge.

induction hardening

Quench hardening in which the heat is generated by electrical induction.

induction log

A continuous record of the conductivity of strata traversed by a borehole as a function of depth.

induction period

A term used with reference to instantaneous caps to describe the time between the bridge break and the detonation of the base charge.

induction time

The interval between the bursting and lag times of a detonator.

inductively coupled plasma spectroscopy

An atomic emission spectroscopy analytical technique where liquid solutions are passed through a quartz tube surrounded by a high-frequency induction coil for heating the sample to high temperatures. It is an important method for measuring trace element concentrations.

inductive method

An electrical exploration method in which electric current is introduced into the ground by means of electromagnetic induction and in which the magnetic field associated with the current is determined.


Said of a rock or soil hardened or consolidated by pressure, cementation, or heat.


a. The hardening of a rock or rock material by heat, pressure, or the introduction of cementing material; esp. the process by which relatively consolidated rock is made harder or more compact. See also: lithification.

b. The hardening of a soil horizon by chemical action to form a hardpan.

industrial calorific value

The calorific value obtained when coal is burned under a boiler.

industrial degree-day

A degree-day unit based on a (usually) 45 degrees F or 55 degrees F (7.2 degrees C or 12.9 degrees C) mean daily temperature so as to be applicable to industrial buildings maintained at relatively low temperatures.

industrial diamonds

a. Crystalline and/or cryptocrystalline diamonds having color, shape, size, crystal form, imperfections, or other physical characteristics that make them unfit for use as gems. Industrial diamonds usually are grouped as toolstones, drill diamonds, fragmented bort, ballas, and carbons. Also called industrials; industrial stones. See also: diamond.

b. Impure diamond used in borehole drilling and the grinding industry. Also called black diamond; bort; boart; carbonado.

industrial minerals

Rocks and minerals not produced as sources of the metals, but excluding mineral fuels. See also: non-metallic minerals.


See: heterogranular.


Uranium is soluble in acid waters and tends to be removed in solution, but radium is much less soluble and its compounds tend to remain behind in the leached outcrop. Therefore, the outcrop may be radioactive due to the presence of the gamma-emitting elements RaC and RaD, even though much of the uranium has been lost in solution. In this case a radiometric assay may indicate a high counter reading, but the uranium content may be low. Uranium minerals deposited less than a million years ago may be in inequilibrium because daughter products have not accumulated in their equilibrium amounts. Hence, counter readings may indicate less uranium than is actually present. See also: radiometric assay.

inert anode

An anode that is insoluble in the electrolyte under the conditions obtained in the electrolysis.

inert dust

a. Any dust that contains only a small amount of combustible material.

b. Dust that has no harmful effect.

inert gas

a. A gas that is normally chemically inactive, esp. in not supporting combustion.

b. One of the helium group of gases comprising helium, neon, argon, krypton, xenon, and sometimes radon. Also called a noble gas; a rare gas.


The reluctance of a body to change its state of rest or of uniform velocity in a straight line. Inertia is measured by mass when linear velocities and accelerations are considered and by moment of inertia for angular motions (that is, rotations about an axis).


A coal maceral group including micrinite, macrinite, sclerotinite, fusinite, semifusinite, and inertodetrinite. They are characterized by a relatively high carbon content and a reflectance higher than that of vitrinite. They are relatively inert during the carbonization process. Syn: inerts.

inert primer

A cylinder of inert material that enshrouds a detonator, but that does not interfere with the detonation of the explosive charge.


Constituents of a coal that decrease its efficiency in use; e.g., mineral matter (ash) and moisture in fuel for combustion or fusain in coal for carbonization. Syn: inertinite.


A triclinic mineral, Ca (sub 2) Mn (sub 7) Si (sub 10) O (sub 28) (OH) (sub 2) .5H (sub 2) O ; forms small prismatic crystals, fibers, or radial aggregates; associated with some manganese deposits; although related to zeolites, contains no aluminum.

infective jaundice

Mine workers served by drifts and adits are subject to occasional attacks of this disease, which is often fatal. It is caused by a micro-organism, the principal carrier of which is the sewer rat. If the skin is scratched, the germ can enter the bloodstream of the miner. Preventive measures include clearing up of all stores, food, and other waste to deprive the rats of food and of a systematic extermination by a pest control officer. Also known as Weil's disease. See also: mining disease.

inferred ore

Ore for which estimates are based on an assumed continuity beyond measured and/or indicated ore. Inferred resources may or may not be supported by samples or measurements.

inferred reserve base

The in-place part of an identified resource from which inferred reserves are estimated. Quantitative estimates are based largely on knowledge of the geologic character of a deposit for which there may be no samples or measurements. The estimates are based on an assumed continuity beyond the reserve base, for which there is geologic evidence.

inferred resources

Resources from which estimates are based on an assumed continuity beyond measured and/or indicated resources, for which there is geologic evidence. Inferred resources may or may not be supported by samples or measurements.


a. Material used for filling in; filling.

b. Material, such as hardcore, used for making up levels; e.g., under floors.


The flow of a fluid into a solid substance through pores or small openings; specif. the movement of water into soil or porous rock. CF: percolation.

infiltration vein

An interstitial mineral deposit formed by the action of percolating waters. CF: segregated vein.

inflammable cinnabar

See: idrialite.

inflatable seal

A seal made from polyvinyl chloride reinforced with glass fiber. It is inflated by compressed air and can cover or seal roadways up to 12 ft wide and 10� ft in height (about 4 m wide and 3 m in height). It is used to isolate a fire, or heating, and reduce the volume of smoke and gases so that erection of stoppings can proceed in respirable air without workers being hampered by breathing apparatus.


See: tumescence.

influence line

An influence line usually pertains to a particular section of a beam, and is a curve so drawn that its ordinate at any point represents the value of the reaction, vertical shear, bending moment, or deflection produced at the particular section by a unit load applied at the point where the ordinate is measured. An influence line may be used to show the effect of load position on any quantity dependent thereon, such as the stress in a given truss member, the deflection of a truss, the twisting moment in a shaft, etc.

in fork

a. Eng. When pumps are working after the water has receded below some of the holes of the windbore, they are said to be in fork.

b. Of mine pumps, sucking air and water.


Pertaining to or designating that part of the electromagnetic spectrum ranging in wavelength from 0.7 mu m to about 1 mm. CF: visible light.

infrared gas analyzer

An instrument used for routine gas analysis for the determination of methane and other gases. The results are accurate to 0.1%.

infrared photography

This technique is employed in air survey during misty weather, using special film that is more sensitive to infrared rays than to light rays. See also: photogrammetry.


An apparatus for sizing air elutriation of very fine particles. See also: air classification.


a. Structure produced at a deep crustal level, in a plutonic environment, under conditions of elevated temperature and pressure, which is characterized by plastic folding, and the emplacement of granite and other migmatitic and magmatic rocks. This environment occurs in the internal parts of most orogenic belts, but the term is used esp. where the infrastructure contrasts with an overlying, less disturbed layer, or superstructure.

b. The basic facilities, equipment, roads, and installations needed for the functioning of a system.


Said of a mineral crystal or fragment that will not melt in the hottest flame produced by a hand-held blowpipe or blowtorch, i.e., around 1,500 degrees C. The bronzite variety of pyroxene, e.g., has a melt point of approx. 1,400 degrees C and is said to be practically infusible; quartz, with a melt point of about 1,710 degrees C, is infusible.

infusion gun

See: water infusion gun.

infusion shot firing

A technique of shot firing in which an explosive charge is fired in a shothole, which is filled with water under pressure and in which the strata around the shothole have been infused with water.

infusorial earth

An obsolete syn. of diatomite. Syn: infusorial silica.

infusorial silica

See: infusorial earth.


The point of entrance from a shaft to a level in a coal mine. See also: inset.


a. A mass of cast metal as it comes from a mold or crucible; specif., a bar of gold or silver for assaying, coining, or export. CF: pig.

b. A mold in which an ingot may be cast. c. A casting suitable for working or remelting.

ingot header

In ore dressing, smelting, and refining, one who pours molten aluminum, copper, or other nonferrous metals into solidifying ingots to compensate for shrinkage that occurs when ingots cool in their molds. Also called billet header; casting header; header; ingot pipe filler; pipe-out man.

ingot iron

Iron of comparatively high purity, produced, in the same way as steel, in the open-hearth furnace, but under conditions that keep down the carbon, manganese, and silicon content. See also: iron. CF: wrought iron.


A defect common to almost all metal ingots in which metal crystals (dendrites) tend to grow at right angles to the walls of the mold and form planes of weakness at their junctions; these make the ingot tender and it tends to tear apart when rolled.

ingot mold

The mold or container in which molten metal is cast and allowed to solidify in order to form an ingot.

ingot pitch

The chemical condition in which metal is fit to be cast into ingots.

ingot saw

A saw that is run at a high rate of speed and has a fusing action at its cutting edge; used in cutting hot ingots.

ingot structure

The general arrangement of crystals in an ingot, which consists typically of chill, columnar, and equiaxed crystals. According to the relations between the mass and the temperature of the molten metal and mold, respectively, one or two types of crystals may be absent.


The primary and higher order reactants of the resins and the chemical constituents of the molding compound, such as plasticizer, lubricant, solvent, catalyst, stabilizer, fire retardant, hardener, and coloring material.


a. A place for entering; a way of entrance.

b. In underground bituminous mining there are three methods of ingress--by drift, shaft, or slope. Drift mines are opened by driving horizontally from the side of an elevation into the seam; shaft mines by sinking a vertical shaft through the overlying strata into the seam; and slope mines by driving an inclined entry through the overlying strata through the surface into the seam.

inhabited building

(As in the American Table of Distances for storage of explosives). A building regularly used in whole or in part as a habitation for human beings, or any church, schoolhouse, railroad station, store, or other structure where people are accustomed to assemble, except any building or structure occupied in connection with the manufacture, transportation, storage, or use of explosive materials.

inhaul cable

In a cable excavator, the line that pulls the bucket to dig and bring in soil. Also called digging line.

inherent ash

Widely used to designate the part of the ash content of a coal that is structurally part of the coal itself and cannot be separated from it by any mechanical means, usually amounts to about 1%. Also called dirt; fixed ash; constitutional ash. Opposite of free ash. See also: ash; ash yield; extraneous ash.

inherent floatability

Property considered by some physicists to be possessed by certain naturally occurring minerals, which readily respond without pretreatment to levitation by the froth-flotation process; by other workers considered due to slight surficial contamination during mining and transport.

inherent mineral matter

The portion of the mineral matter of coal organically combined with the coal. It contains elements that have been assimilated by the living plant, such as iron, phosphorus, sulfur, calcium, potassium, and magnesium.

inherent moisture

a. In general, the moisture that is present in the coal in the bed.

b. Of coal, that remaining after natural drying in air. c. Maximum moisture that a sample of coal will hold at 100% humidity and atmospheric pressure. d. See: moisture content.

inherited structure

An original structural feature of the country rock that has been faithfully preserved after replacement by ore.


a. In drilling, a substance that, when added to cement, has the capacity to slow down or lengthen the normal time required for that specific cement to set; also, a substance added to drilling mud to check or slow down organic or chemical deterioration or change in the physical characteristics of the drilling mud.

b. A substance that when present in an environment substantially decreases corrosion.

initial depression

The total water gage actually produced by a mine fan. See also: theoretical depression.

initial dip

See: original dip.

initial face

In quarrying, the face formed by the blasting of the slope.

initial impulse

See: first arrival.


The process of causing a high explosive to detonate. The initiation of an explosive charge requires an initiating point, which is usually a primer and electric detonator, or a primer and a detonating cord or fuse.


A detonator or detonating cord used to start detonation or deflagration in an explosive material; can refer to a blasting cap or primer.

injected hole

A borehole into which a cement slurry or grout has been forced by high-pressure pumps and allowed to harden.


a. The process of emplacement of magma in preexisting rocks; magmatic activity; also, the igneous rock mass so formed.

b. The forcing, under abnormal pressure, of sedimentary material (downward, upward, or laterally) into a preexisting deposit or rock, either along some plane of weakness or into a crack or fissure, producing structures such as sandstone dikes.

injection gneiss

A composite rock whose banding is wholly or partly caused by lit-par-lit injection of granitic magma into layered rock. See also: composite gneiss. CF: migmatite; lit-par-lit.

injection metamorphism

Metamorphism accompanied by intimate injection of sheets and streaks of liquid magma (usually granitic) in zones near deep-seated intrusive contacts. CF: plutonic metamorphism; lit-par-lit.

injection pressure

The total amount of pressure required to force a liquid or grout into cracks, cavities, and pores in rocks or other substance.


a. Any apparatus used to force, under pressure, material into an opening in another material.

b. A device used to force-feed water into a boiler by the direct action of steam. See also: inspirator. c. Mechanism used for spraying fuel oil into the combustion-type engine or to spray a fine oil mist into a stream of air or steam. See also: air mover.


a. Native copperas (melanterite), or a stone containing it. Used in inkmaking.

b. A stone slab used in preparing India ink for use.


An area or group of rocks surrounded by rocks of younger age; e.g., an eroded anticlinal crest. CF: outlier.

in-line valve

A valve that proves the cage is in the correct position relative to the decking level.


Being at a point, place, or position farthest from the exterior; deepest within; innermost; such as, the inmost depths of a mine.

inner core

The central part of the Earth's core, extending from a depth of about 5,100 km to the center (6,371 km) of the Earth; its radius is about one-third of the whole core. The inner core is probably solid, as evidenced by the observation of S waves that are propagated in it, and because compressional waves travel noticeably faster through it than through the outer core. Density ranges from 10.5 to 15.5 g/cm (super 3) . It is equivalent to the G layer. CF: outer core. Syn: siderosphere.

inner mantle

The lower part of the mantle.

innermost isoseismal

The isoseismal line surrounding the area experiencing the greatest damage to manmade structures during an earthquake.


The addition of a material to molten metal to form nuclei for crystallization.


Pertaining or relating to a compound that contains no carbon. CF: organic.


See: inby.

in-pit crusher

A crushing system that can be a fully mobile unit or a permanently fixed unit at the point of mining so that the mined material can be transported out of the pit by a conveyor system.


In bullion assay, dissolution of silver from associated gold by use of nitric acid.

inrush of water

A sudden and often overwhelming flow of water into mine workings. Inrushes of water may be caused by striking unsuspected waterlogged old workings that possibly were shown inaccurately on the mine plans. Faults have also been responsible for serious inflows of water. A fault may retain large volumes of water above or at the same level as workings approaching it. It is usual to drive exploring headings in the direction of the suspected water danger. See also: mud rush; old working; inundation; stopping; tapping; tapping old workings; water inrush; waterlogged.


A prominent isolated residual knob, hill, or small mountain rising abruptly from an extensive erosion surface in a hot, dry region (as in the deserts of southern Africa or Arabia), generally bare and rocky, although partly buried by the debris derived from its slopes. Etymol: German Inselberg, island mountain. CF: monadnock.


Formed pieces of sintered cobalt-tungsten carbide mixture (in which diamonds may be inset), brazed into slots or holes in drilling bits or into grooves on the outside surface of a reaming shell to act as cutting points, reaming surfaces, or wear-resistant pads or surfaces of reaming shells or outside surfaces of other pieces of drilling equipment or fittings. Also called inserts. See also: insert bit; insert set. CF: slug.

insert bit

A bit into which inset cutting points of various preshaped pieces of hard metal (usually a sintered, tungsten carbide-cobalt powder alloy) are brazed or hand-peened into slots or holes cut or drilled into a blank bit. Hard-metal inserts may or may not contain diamonds. Also called slug bit. See also: insert.

inserted rod-type pick

See: sintered carbide-tipped pick.

insert reaming shell

A reaming shell, the reaming diamonds of which are inset in shaped, hard, metal plates brazed into grooves cut into the outside surface of the shell.

insert set

Bits or reaming shells set with inserts. See also: insert.


a. The entrance to underground roads from the shaft; a landing. See also: ingate.

b. See: phenocryst. c. The opening from the mine shaft to a seam of coal. d. A surface into which diamonds or other cutting points are embedded or set; also, the act or process of embedding such materials in a surface.


A term often used to designate the interior of a mine.

inside angling

See: angling.

inside clearance

The difference between the outside diameter of a core and the inside diameter of the core-barrel parts through which the core passes or enters; also, the annular space between the inner and outer tubes in a double-tube core barrel. See also: clearance.

inside face

That part of the bit crown nearest to and/or parallel with the inside wall of an annular or coring bit.

inside gage

The inside diameter of a bit as measured between the cutting points, such as between inset diamonds on the inside-wall surface of a core bit.

inside-gage stone

A diamond set in the inside-wall surface of the crown of a diamond core bit so that it cuts sufficient inside clearance to permit the core to pass through the bit shank and into the core barrel without binding. Syn: inside kicker; inside reamer; inside stone.

inside-haulage engineer

In bituminous coal mining, one who operates a mine locomotive to haul trains of cars along underground haulageways in a mine.

inside kicker

See: inside-gage stone.

inside parting

A side track or parting some distance from the beginning of a long entry, at which cars are left by a gathering driver. Also called a swing parting.

inside reamer

See: inside-gage stone.

inside slope

a. A slope on which coal is raised from a lower to a higher entry, but not to the surface.

b. An inside slope is a passage in the mine driven through the seam by which coal is brought up from a lower level.

inside stone

See: inside-gage stone.

inside upset

A tubular piece having ends that are thickened for a short distance on the inside. See also: upset.

inside work

a. The drilling of boreholes in underground workplaces; also applied to work done on the surface with the drill machine and tripod completely housed.

b. Any work in the mines. Most commonly used in bituminous coal mining.

in situ

a. In the natural or original position. Applied to a rock, soil, or fossil occurring in the situation in which it was originally formed or deposited. See also: place.

b. Said of tests done on a rock or soil in place, as compared with collecting discrete samples for testing in the laboratory. c. See: solution mining.

in situ autoclave

A six-sided in situ vat containing liquid or gas for ore treatment and recovery of mineral values requiring elevated temperatures and pressure, usually for long periods of time.

in situ gasification

Process that can recover the energy of coal seams without the extensive use of traditional mining operations. The primary product brought from underground is hot fully combusted flue gas, 1,100 to 1,800 degrees F (approx. 600 to 1,000 degrees C), whose sensible heat contains most of the heating value of the coal, 5,000 to 13,000 Btu/lb (11.6 to 30.2 MJ/kg). Particularly applicable to coal deposits that are not economically or technically feasible to mine by conventional methods because of seam quality or quantity, depth, dip, strata integrity, overburden thickness, etc.

in situ leaching

a. A hydrometallurgical process that treats ore for the recovery of mineral values while the ore is in place. It is a true mining technique in that the ore is not extracted from the ground and no mine waste piles or tailings impoundments are created.

b. A leaching technique in which ore is leached in place by solution injected into the deposit through wells. CF: solution mining.

in situ liner

A water, gas, or aqueous, chemically impermeable material placed in artificially constructed underground channels, crevices, or slices.

in situ origin theory

The theory of the origin of coal that holds that a coal was formed at the place where the plants from which it was derived grew. See also: autochthonous coal.

in situ processes

Activities conducted on the surface or underground in connection with in-place distillation, retorting, leaching, or other chemical or physical processing of coal or ore. The term includes, but is not limited to, in situ gasification, in situ leaching, slurry mining, solution mining, borehole mining, and fluid recovery mining.

in situ soil tests

Tests carried out on the ground, in a borehole, trial pit, or tunnel, as opposed to a laboratory test. An in situ soil test may be a vane test, dynamic penetration test, etc.

in situ vat

A five- or six-sided enclosure constructed in the earth by backfilling cuts around an orebody or orebody zone with material that is impervious to solutions so that aqueous leaching can be conducted for the extraction of mineral values from the isolated ore.


a. Incapable of being dissolved in a particular liquid.

b. Term used of solid that does not dissolve under specified attack. No known substance is completely insoluble, so the term refers to systems characterized by very low solubility. c. As used in smelter contracts, the terms "insoluble" and "silica" are often used interchangeably, but they are different things. Silica is determined by a special fusion assay. Insoluble is the residue left after the ore has been digested with acid in the course of assaying for some of the metals. The insoluble is generally silica plus something else, often alumina, since this substance is not always dissolved by acids.

insoluble anode

An anode that does not dissolve during electrolysis.


One employed to make examinations of and to report upon mines and surface plants relative to compliance with mining laws, rules and regulations, safety methods, etc. State inspectors have authority to enforce State laws regulating the working of the mines. Federal inspectors have authority to enforce Federal laws in coal mines. See also: mine inspector.


A kind of injector for forcing water by steam. See also: injector.

instantaneous charge weight

The weight of explosive detonated at any one precise time.

instantaneous cuts

Cuts characterized by the drilling and ignition being done so that all the holes can cooperate and break smaller top angles. They are called instantaneous cuts because they are preferably ignited by instantaneous detonators to ensure a simultaneous detonation of all the charges in the cut. Some examples are Blasjo cut; WP-cut.

instantaneous detonator

A detonator in which there is no designed delay period between the passage of an electric current through the detonator and its explosion.

instantaneous fuse

Term used to distinguish rapid burning from slow fuse. Ignition rate is several thousand feet per minute, but slower than that of detonating fuse.

Institution of Mining and Metallurgy

The London Institution of Mining and Metallurgy is the central British organization for regulating the professional affairs of suitably qualified mining engineers engaged in production and treatment of nonferrous metals and rare earths. Related bodies are those of Canada (Can. I.M.M.), Australia (Aust. I.M.M.), and Republic of South Africa (Rep. S. Af. I.M.M.).

Institution of Mining and Metallurgy screen scale

Laboratory screens of usual 8-in-round (20-cm-round) size, in which the diameter of each new wire is equal to the distance between successive parallel wires. Therefore, in a 60-mesh screen (having 60 wires/in (152 wires/cm) measured along either the warp or the woof) the aperture is a square measuring 1/120 in (0.21 mm) on the side. The meshes used are 5, 8, 10, 12, 16, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 150, and 200.


The right to raise or take ore from a leased mine through the shaft or tunnel of an adjoining mine.

instrumentalities of mining

The true meaning of such expressions as shafts, tunnels, levels, uprises, crosscuts, inclines, and sump when applied to mines signifies instrumentalities whereby and through which such mines are opened, developed, prospected, and worked.


Control by servomechanisms. Use of signaling devices originating with the process to indicate, vary, or regulate performance.


An injector for forcing air into a furnace.

insular shelf

The zone surrounding an island extending from the line of permanent immersion to about 100 fathoms (600 ft or 183 m) of depth, where a marked or rather steep descent toward the great depths occurs.

insular slope

The declivity from the offshore border of the insular shelf at depths of from 50 to 100 fathoms (300 to 600 ft or 91 to 183 m) to oceanic depths. It is characterized by a marked increase in gradient.


To separate or to shield (a conductor) from conducting bodies by means of nonconductors, so as to prevent transfer of electricity, heat, or sound.

insulating water bottle

In oceanography, an instrument used for the accurate determination of the temperature of the sea at moderate depths. Also called Nansen-Pettersson water bottle.

insulator-tube header

One who forms heads on porcelain tube insulators by means of hand capping press, inserting clay tube in machine and pulling lever to form the head.

insurance and freight cost

Term showing that these items have been paid by the shipper of concentrates, metal, etc.