Appendix:Dictionary of Mining, Mineral, and Related Terms/F/3

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fleches d'amour

Acicular, hairlike crystals of rutile, TiO (sub 2) , embedded in quartz; a semiprecious gemstone. Also called love arrows, a literal translation. CF: rutilated quartz.


To scale or peel off suddenly; applies to shaley beds in the roof or to coal slab at the face.


Ger. A type of spotted slate characterized by minute flecks or spots of indeterminate material. See also: fruchtschiefer; garbenschiefer.


The movement of a rope sidewise when winding on a drum. See also: fleet angle.

fleet angle

a. The included angle between the rope, in its position of greatest travel across the drum, and a line drawn perpendicular to the drum shaft, passing through the center of the head sheave or head-sheave groove.

b. Of hoisting gear in mine shaft headworks, the angle between the sheave and extreme paying-off position on the winding drum; in good practice the angle is below 3 degrees . c. As used by diamond drillers and miners, the angle between the two ends of a hoist drum as a base and the sheave wheel in a drill tripod or derrick or the headframe pulley as the apex.

fleet wheel

a. A grooved wheel or sheave that serves as a drum and about which one or more coils of a hauling rope pass.

b. Surge wheel.


An isometric mineral, Pb (sub 3) Ge(SO (sub 4) ) (sub 2) (OH) (sub 6) .3H (sub 2) O ; linnaeite group; occurs in fibrous aggregates and crusts associated with cerussite, memetite, and plumbojarosite in the upper oxidation zone of the Tsumeb Mine, Namibia.

Fleissner process

A thermal drying, batch-type process, in which the action of high-pressure steam on a lump of lignite produces the following effects. The lump is heated inside and out to an approx. uniform temperature by its envelope of condensing steam. As the temperature rises and the pressure increases part of the colloidal water is expelled from the lump as a liquid. The lump shrinks as water leaves and the cells collapse, and when the pressure is lowered, more water leaves by evaporation caused by the sensible heat stored in the lump. When the pressure is lowered further by vacuum, additional moisture is evaporated, which cools the lump.


a. Capable of being flexed. Capable of being turned, bowed, or twisted without breaking.

b. Said of a mineral that can bend without breaking and will not return to its original shape; e.g., talc and chlorite. CF: elastic; malleable.

flexible ducts

See: ventilation ducts.

flexible guides

See: winding guide.

flexible joint

Any joint between two pipes that permits one of them to be deflected without disturbing the other pipe.

flexible sandstone

A fine-grained, thin-layered variety of itacolumite.

flexible silver ore

See: sternbergite.

flexible-type carrying idler

Consists of one or more idler rolls arranged to form a catenary trough. This may be accomplished by mounting a single roll on a flexible shaft or by linking a series of rolls with individual rigid shafts.


The bending of the conveyor belt that takes place as it wraps around the pulleys. The ply nearest the face of the pulley is under the minimum stress and the ply farthest from the face is under the maximum stress. Flexing stresses increase with a decrease in pulley diameters.


A patented circle brick, with book ends, used in domestic furnaces, cupola furnaces, and acid tank linings.

flexural center

With reference to a beam, the flexural center of any section is that point in the plane of the section through which a transverse load, applied at that section, must act if bending deflection only is to be produced, with no twist of the section. Also called shear center. CF: torsional center; elastic center; elastic axis.

flexural slip

The slipping of sedimentary strata along bedding planes during folding.


A general term for a fold, warp, or bend in rock strata. A flexure may be broad and open, or small and closely compressed. CF: monocline. Syn: hinge.

flexure correction

A correction necessary in pendulum observations of gravity. The vibrating pendulum produces oscillations of the receiver case, of the pillar, and of the surface soil. Rather complex, coupled vibration phenomena arise and the period of the pendulum itself changes. Numerous methods have been suggested to correct for this influence or to eliminate it. Since the correction is of the order of 10 x 10 (super -7) to 40 x 10 (super -7) s on solid rock or cement and may increase to as much as 500 x 10 (super -7) s on marshy ground, it must be determined accurately.

flexure-slip fold

A flexure fold in that the mechanism of folding is slip along bedding planes or along surfaces of foliation. There is no change in thickness of individual strata, and the resultant folds are parallel.


a. The metal strap or crossbar attached to the drag chain of a chain-and-flight conveyor.

b. A term sometimes applied to one conveyor in a tandem series.

flight conveyor

A type of conveyor comprising one or more endless propelling media, such as chain, to which flights are attached and a trough through which material is pushed by the flights. See also: grit collector; underground mine conveyor. Syn: bar flight conveyor.

flight line

A line drawn on a map or chart to represent the planned or actual track of an aircraft during the taking of aerial photographs.

flight pattern

In an aeromagnetic survey or in another airborne geophysical survey, the planned flying route used.

flinders diamond

A Tasmanian term for a variety of topaz.


a. A term that has been considered as a mineral name for a massive, very hard, somewhat impure variety of chalcedony (minute crystals of quartz with submicroscopic pores). It is usually black or of various shades of gray, breaking with a conchoidal fracture, and striking fire with steel. Mohs hardness, 7; and sp gr, 2.65. Syn: firestone. CF: chert.

b. Pulverized quartz of any type; e.g., "potters' flint" made by pulverizing flint pebbles into powder. c. A term that is widely used as a syn. of chert or for a homogeneous, dark gray or black variety of chert.

flint clay

A smooth, flintlike refractory clay rock composed dominantly of kaolin, which breaks with a pronounced conchoidal fracture and resists slaking in water. It becomes plastic upon prolonged grinding in water, as in an industrial wet-pan unit.

flint mill

A device, formerly used to provide light for miners at work, in which flints on a revolving wheel produce a shower of sparks incapable of igniting combustible gases. See also: steel mill.

Flintshire furnace

A reverberatory furnace with a depression, well, or crucible in the middle of the side of the hearth; used for the roasting and reaction process on lead ores.

Flintshire process

Method of smelting galena concentrates in a reverberatory furnace with a crucible well in its hearth.

flinty crush rock

See: ultramylonite.

flinty slate

A touchstone consisting of siliceous slate.

flipping turn

System of pulleys incorporated in the return-side tracking of a belt conveyor, which turns it through 180 degrees , so that any adherent abrasives do not come in contact with idler pulleys.


a. Widening of underground roadway by removing rock from sides.

b. The working of 2 to 5 yd (1.8 to 4.6 m) or more of the rib side coal in a narrow stall or heading. See also: skipping.


Collier who moves a coal cutter to a new working place; to flit is to shift equipment.

flitting wagon

A low truck or trolley used in pillar methods of working to transport face machines from one heading or bord to another.


a. A general term for loose fragments of ore or rock, esp. on a hillside below an outcropping ledge or vein. Syn: floater. CF: float mineral; float ore.

b. Fine gold that floats in panning and other operations and is lost. c. A timber platform, faced with boiler iron on both sides, and provided with rings at the corners for lifting. It is used in shaft work to prevent the crushing of the bottom timbers by flying fragments of rock. d. The tendency of the bit in a flat-angle borehole to follow an increasingly flat course as the depth of the borehole increases. e. In mineral concentration, the response of a specific mineral to the flotation process. f. The fine dust that does not settle out of the air current in the grinding mills but is filtered out by fine cloth bags. Also, the fine dust collecting on the roof and timbers in a mine. g. Metal particles so fine that they float on the surface of water in crushing or washing, as float gold. h. Various forms of ball-and-seat valves commonly inserted in casing and rod strings in such a manner as to keep drilling fluid out of the casing or rod string when lowered into a borehole. Also called float valve. i. To lift a material by the buoyant action of a strong current or flow of a liquid medium; also, that material buoyant enough to float on the surface of a liquid medium. j. The buoyant part of an apparatus for indicating the height of water in a steam boiler or of liquid in a tank.


In mineral concentration, word used in connection with response of a specific mineral to flotation process.

float-and-sink analysis

Use of a series of heavy liquids diminishing (or increasing) in density by accurately controlled stages for the purpose of dividing a sample of crushed coal into gravimetric fractions either equal-settling or equal-floating at each stage. The floats at a given specific gravity are defined as the percentage floating at that density and the sinks have a defined higher density. Each product (minus one density and plus another) is analyzed after weighing and the ash sulfur and Btu content is found. From this testing, a washability curve is drawn that relates density with ash sulfur and Btu content, in the form of cumulative float, sink, and specific gravity curves. The ash curve plots ash against density for successive fractions. The densimetric curve plots specific gravity against cumulative weight. The Mayer curve (M-curve) plots cumulative weight against that of a constituent (e.g., ash).

float coal

Small, irregularly shaped isolated deposits of coal imbedded in sandstone or in siltstone. They appear to have been removed from the original bed by washout during the peat stage and to have been carried a short distance and redeposited. Syn: raft.

float copper

Fine scales of metallic copper that do not readily settle in water.

float dust

Fine particles of coal suspended in the air.


A single fragment of float. See also: float.

float gold

Particles of gold so small and thin that they float on water and may be carried off by it.


Said of large particles in a sedimentary rock that are not in contact with each other and are contained in a fine-grained matrix; e.g., quartz grains disseminated in limestone.

floating cable

In seismic operations in a watercovered area, a cable connecting geophones suspended by floats.

floating cone

A method of designing optimum extraction sequences for an open pit mine. "Cones" of material are built using an ore block as a base and economic net value of the cone is calculated. The process is repeated for each ore block in a deposit, considering cone overlaps. The term "floating" is derived from the "movement" of the cone throughout the model.

floating control system

As used in flotation, a system in that the rate of change of the manipulated variable is a continuous function of the actuating signal.

floating pipeline

A pipe supported on pontoons that is used for removing spoil from a suction dredger.

floating reef

An isolated, displaced rock mass in alluvium. CF: float.

floating strainer

A buoyant pump suction end that draws its water from near the surface of the free-water level and thus pumping almost clear water. Serves to decant. A floating strainer may be used in dealing with bodies of water other than in properly constructed sumps.

float mineral

Small fragments of any ore carried away from the ore bed by the action of water or by gravity alone, often leading to the discovery of mines; See also: floater; float ore; float.

float ore

Scattered fragments of vein material broken from outcrops and dispersed in soil; a type of float. See also: float; float mineral; shode.


Fractions with a defined upper limit of specific gravity and so described; e.g., floats, sp gr, 1.40.


a. A miners' term for cellular or honeycomb quartz detached from a lode.

b. A lightweight, porous, friable variety of opal that floats on water and occurs in white or grayish, spongy, and concretionary or tuberous masses; also spelled float stone. Syn: swimming stone. c. A carbonate rock containing a few bioclasts or other fragments more than 2 mm in diameter, widely spaced, and embedded in sand- or mud-size carbonate sediment that forms over 90% of a rock.

float sulfur

See: flake sulfur.

float valve

a. Syn. for a ball-and-seat type apparatus inserted in a pipe, casing, or drill-rod string being lowered into a borehole. See also: float.

b. A valve operated by a float.


a. A loose, open-structured mass formed in a suspension by the aggregation of minute (colloidal) particles.

b. A small aggregate of tiny sedimentary grains. c. A flocculent mass formed by the aggregation of a number of fine suspended particles. Syn: floccule.


a. To cause particles to aggregate in large particles. Usually accomplished with polymer, both natural or synthetic.

b. To thicken a clay suspension by addition of synthetic polymer. c. The addition of a suitable electrolyte to a clay suspension to cause the clay particles to agglomerate and settle. d. Something that has flocculated; a flocculent particle or mass; a floc; a floccule.


a. The thickening of the consistency of a slip by adding a suitable electrolyte.

b. The agglomeration of clay particles in a clay suspension by adding an electrolyte.

flocculating agent

A reagent added to a dispersion of solids in a liquid to bring together the fine particles to form flocs. These reagents usually consist of long chain polymers, both natural and synthetic.


The process by which a number of individual, minute suspended particles are tightly held together in clotlike masses, or are loosely aggregated or precipitated into small lumps, clusters, or granules; e.g., the joining of soil colloids into a small group of soil particles, or the deposition or settling out of suspension of clay particles in salt water. See also: coagulation; floc.


A small, loosely aggregated mass of material suspended in or precipitated from a liquid. One of the flakes of a flocculent precipitate. Syn: floc.


Coalescing and adhering in flocks. A cloudlike mass of precipitate in a solution. From the Latin floccus, meaning lock of wool.

flocculent deposit

An aggregate or precipitate of small lumps formed by chemical precipitation.

flocculent structure

An arrangement composed of flocs of soil particles instead of individual soil particles. See also: soil structure; honeycomb structure; single-grained structure.

Flodin process

A direct process for manufacturing steel, by means of which iron with a carbon content from 0.2% upwards can be produced by smelting, in a specially constructed electrical furnace, a mixture of hematite and coal, or charcoal, the process being continuous. The reduced metal accumulates at the bottom of the furnace, from which it is tapped. Both sulfur and phosphorus are reduced to a low figure without additional refining, while the manganese and silicon contents are controlled in the same way as in the ordinary open-hearth process.

floe rock

Rock occurring in or taken from a body of talus; usually refers to ganister.

flohmig amber

See: fatty amber.


See: flucan.

flood basalt

See: plateau basalt.


a. A gate for shutting out, admitting, releasing, or otherwise regulating a body of water, such as excess water in times of flood; specif. the lower gate of a lock. See also: sluice.

b. A stream stopped by or allowed to pass by a floodgate.

flood plain

The surface or strip of relatively smooth land adjacent to a river channel, constructed by the present river in its existing regimen and covered with water when the river overflows its banks. It is built of alluvium carried by the river during floods and deposited in the sluggish water beyond the influence of the swiftest current.


See: flucan.


a. The rock underlying a stratified or nearly horizontal ore deposit, corresponding to the footwall of more steeply dipping deposits.

b. The bottom of a coal seam or any other mineral deposit. CF: roof. c. Plank-covered, or steel-mesh-covered, level work area at the base of a drill tripod or derrick around the collar of a borehole in front of the drill. See also: platform. d. Loose plank laid parallel with rock drift at the heading before blasting a round of holes to facilitate the loading of broken rock. e. A horizontal, flat orebody. f. The bed or bottom of the ocean. A comparatively level valley bottom; any low-lying ground surface. g. That part of any underground gallery upon which a person walks or upon which a tramway is laid. h. A plank platform underground. i. The upper surface of the stratum underlying a coal seam.

floor break

The break or crack that separates a block of stone from the quarry floor. Also called floor cut.

floor burst

A type of outburst generally occurring in longwall faces and preceded by heavy weighting due to floor lift. Gas that evolved below the seam seems to collect beneath an impervious layer of rock, and a gas blister forms beneath the face, giving the observed floor lift. Later, the floor fractures and the combustible gases escape into the mine atmosphere. See also: outburst.

floor cut

a. A machine cut made in the floor dirt immediately below the coal seam. See also: undercutting; bottom cut.

b. A cut by means of which a block of stone is separated from the quarry floor. See also: floor break.

floor lift

The upward heave of the floor beds after a coal seam has been extracted. See also: creep.

floor sill

A large timber laid flat on the ground or in a level, shallow ditch to which are fastened the drill-platform boards or planking.

floor station

A survey station secured in the floor of a mine roadway or working face.

flop gate

An automatic gate used in placer mining when there is a shortage of water. This gate closes a reservoir until it is filled with water, when it automatically opens and allows the water to flow into the sluices. When the reservoir is empty the gate closes, and the operation is repeated. See also: boomer.


The entire plant population of a given area, environment, formation, or time span. CF: fauna.


A trigonal mineral, (La,Nd,Ce)Al (sub 3) (PO (sub 4) ) (sub 2) (OH) (sub 6) ; crandallite group; further speciated according to which rare-earth element predominates; weakly radioactive; pale yellow; in schists, carbonatites, pegmatites, and placer sands.


See: fluorite.

flos ferri

An arborescent variety of aragonite occurring in delicate white coralloid masses that commonly encrust hematite, forming picturesque snow-white pendants and branches.


White cast iron for converting into steel.

floss hole

a. A small door provided at the bottom of a flue or chimney for ash removal.

b. A tap hole.


a. Ore lying between the beds or at certain definite horizons in the strata.

b. Eng. Veins that branch off laterally, Alston Moor lead mines.


a. See: froth flotation. b. The method of mineral separation in that a froth created by a variety of reagents floats some finely crushed minerals, whereas other minerals sink. Formerly the term flotation with descriptive adjectives was used for all processes of concentration in which levitation in water of particles heavier than water was obtained. Thus, if some particles were retained in an oil layer or at the interface between an oil layer and a water layer, the process was spoken of as bulk-oil flotation; if the particles were retained at a free water surface as a layer one particle deep, the process was skin flotation; and if the particles were retained in a foamy layer several inches thick, the process was froth flotation. Froth flotation is the process that has survived the test of time, and the term flotation is now used universally to describe froth flotation. See also: bulk oil flotation; film flotation; selective flotation; skin flotation. Syn: flotation process.

flotation agent

A substance or chemical that alters the surface tension of water or that makes it froth easily. See also: surface activity; depressant.

flotation cell

Appliance in which froth flotation of ores is performed. It has provision for receiving conditioned pulp, aerating this pulp and for separate discharge of the resulting mineralized froth and impoverished tailings. Types of cell include (1) agitation (impeller, and splashing, now obsolete); (2) pneumatic (in which air blown in agitates pulp), such as Hallimond laboratory cell, Callow, McIntosh, Forrester, Southwestern, and Britannia; (3) vacuum cells (Elmore and Clemens, obsolescent); (4) subaeration with mechanized stirring and pressure-input air (M.S. cell, Agitair); (5) subaeration, self-aerating mechanized cell (Fagergren, Denver, M.S.S.A., Humboldt, Boliden, K.B., etc.)

flotation conditioning time

In ore processing, the period during which pulp is agitated with a given chemical, or combination of chemicals, in the series of conditioning operations that precede separation of various minerals in the ore by froth flotation.

flotation middlings

Intermediate flotation products that may be re-treated.

flotation of crystals

See: crystal flotation.

flotation oil

Oil, such as creosote oil, pine oil, or turpentine. Used to wet a particular component of a powdered material and cause it to concentrate in an airy froth.

flotation plane

Plane of a liquid surface in which a body floats.

flotation process

See: flotation; oil flotation.

flotation reagent

Any of several reagents used in the froth flotation process. They include pH regulators, slime dispersants, resurfacing agents, wetting agents, conditioning agents, collectors, and frothers.

flotation regulator

An acid or an alkali used to control the pH of flotation solutions.

flotation time

The time necessary to make the separation into concentrate and tailing depends on such factors as particle size and reagents used, and must be known for determination of the size and number of flotation cells in the plant.


A synthetic reagent of the general nature of pine oil; used as frother in flotation process.

flour agate

a. Any moss agate.

b. A term applied to any moss agate or mocha stone with flowerlike markings. c. Translucent chalcedony from Oregon containing inclusions of minerals, some red, brown, or yellow and green, arranged in flowerlike forms, commonly both red and green.

flour copper

Very fine scaly native copper that floats on water and is very difficult to save in milling. See also: float copper.


The finely granulated condition of quicksilver, produced to a greater or lesser extent by its agitation during the amalgamation process. The coating of quicksilver with what appears to be a thin film of some sulfide, so that when it is separated into globules these refuse to reunite. Also called flouring. See: sickening.

flour gold

See: float gold.

flour gypsum

See: gypsum.

flour salt

Very fine-grained vacuum pan salt.

floury alumina

Fine-grained, highly calcined, powdery textured alumina; also dusty, easily airborne. Traditionally produced by European Bayer plants.


a. The plastic deformation of solids: flowage; solid flow; rock flowage; plastic flow. CF: fracture.

b. That which flows or results from flowing. A mass of matter moving, or that has moved in a stream, such as a lava flow. Syn: current. c. The movement of a fluid, such as air, water, or magma (lava). d. A tabular-shaped body of lava that consolidated from magma on the surface of the Earth. e. In ceramics, the flux used to cause color to run and blend in firing. f. A mass movement of unconsolidated material that exhibits a continuity of motion and a plastic or semifluid behavior resembling that of a viscous fluid; e.g., creep; solifluction; earthflow; mudflow; debris flow; sturzstrom. Water is usually required for most types of flow movement. g. The mass of material moved by a flow. The smallest formal lithostratigraphic unit of volcanic flow rocks. A flow is a discrete, extrusive, volcanic body distinguishable by texture, composition, order of superposition, paleomagnetism, or other objective criteria. It is part of a member and thus is equivalent in rank to a bed or beds of sedimentary-rock classification. Many flows are informal units. Designation of flows as formal units should be limited to those that are distinctive and widespread.


See: flow.

flowage differentiation

a. The retarding effect produced by walls on the movement under the influence of pressure of a mush of crystals in a magmatic liquid, which may give rise to magmatic differentiation and also to the concentration of ore minerals.

b. The tendency of suspended crystals to concentrate in the high-velocity zone of a magma that is moving by laminar flow.

flowage fold

A minor fold that is the result of the flowage of rocks toward a synclinal axis, toward which the minor folds are overturned.

flowage structure

See: flow structure.

flow banding

A structure of igneous rocks that is esp. common in silicic lava flows. It results from movement or flow, and is an alternation of mineralogically unlike layers.

flow breccia

A breccia that is formed contemporaneously with the movement of a lava flow; the cooling crust becomes fragmented while the flow is still in motion.

flow characteristic

The rate at which a metal powder will flow through an orifice in a standard instrument, and/or according to a specified procedure.

flow cleavage

A syn. of slaty cleavage, so called because of the assumption that recrystallization of the platy minerals is accompanied by rock flowage. CF: fracture cleavage.

flower of iron

See: flos ferri.

flowers of sulfur

A light-yellow, pulverulent modification of sulfur formed when sulfur vapor is condensed.

flow folding

Folding in incompetent beds that offer so little resistance to deformation that they assume any shape impressed upon them by the more rigid rocks surrounding them or by the general stress pattern of the deformed zone. CF: ptygmatic folding. Syn: incompetent folding.

flow gneiss

A gneiss with a structure produced by flowage in an igneous mass before complete solidification.

flow gradient

A drainageway slope determined by the evelation and distance of the inlet and outlet, and by required volume and velocity.

flowing film concentration

In metallurgy, a concentration based on the fact that liquid films in laminar flow possess a velocity that is not the same in all depths of the film. There is no flow at the bottom but maximum at or very near the top resulting from the internal friction of one layer upon another. By this principle, lighter particles are washed off while the heavier particles accumulate and are intermittently removed. This is basis of the stationary table, which has been known for thousands of years. Vanners and round tables have been developed from this basic principle, whereas bumping and shaking tables jointly utilize flowing film and other principles.

flow layer

An igneous-rock layer, differing mineralogically or structurally from the adjacent layers, which was produced by flowage before the complete solidification of the magma. CF: flow line; schlieren.

flow line

A lineation of crystals, mineral streaks, or inclusions in an igneous rock, indicating the direction of flow before consolidation. CF: flow layer.


a. A device installed in a drilling-fluid circulation system that registers the number of gallons (liters) of liquid circulated per minute and also indicates when the flow past the bit ceases.

b. A device which registers rate of flow, and perhaps quantity, of gases, liquids, and fluid pulps. Used in mineral dressing to measure rates and quantities of pregnant solutions in cyanide and to control liquid additions to pulps.

flow rate

Weight of dry air flowing per unit time. Measured in kilograms per second.

flow roll

A rounded, pillowlike body or mass of sandstone occurring within or just above finer-grained sediment or commonly within the basal part of a sandstone overlying shale or mudstone. Its shape approaches that of an elongate, flattened ellipsoid (short axis more or less vertical), and is presumed to have formed by deformation, such as by large-scale load casting or mud flowage accompanied by subaqueous slump or foundering of sand channels.


A diagram showing the progress of material through a preparation or treatment plant. It shows the crushing, screening, cleaning, or refining processes to which the material is subjected from the run-of-mine state to the clean and sized products. The size range at the various stages may also be shown.

flow stretching

The orientation and possible deformation of crystals with their long axes in the direction of plastic flow in metamorphic rocks.

flow structure

a. A structure of igneous rocks, generally but not necessarily volcanic rocks, in which the stream lines or flow lines of the magma are revealed (1) by alternating bands or layers of differing composition, crystallinity, or texture, or (2) by subparallel arrangement of prismatic or tabular crystals. Syn: flow texture; fluidal structure; fluxion structure.

b. A primary sedimentary structure resulting from subaqueous slump or flow.

flow texture

See: flow structure; fluidal texture.

flow unit

One of the nearly contemporaneous subdivisions of a lava flow (usually basaltic) that consists of two or more parts that were poured one over the other during the course of a single eruption.


In Great Britain, tests of every type of apparatus are made in explosive atmospheres before it is approved and allowed to use the official letters F.L.P. (flameproof).


A narrow band of crushed rock or clayey material found along a fault zone or vein of ore. See also: breccia; gouge; selvage; pug. Also spelled fluccan; flookan; flukan; floocan.


a. S. Wales. A furnace, such as a large coal fire at or near the bottom of an upcast shaft for producing a current of air for ventilating the mine.

b. A tube or passageway in a steam boiler for hot gases or water (depending on whether the boiler is a fire-tube or water-tube boiler). c. A passage or channel through which the products of combustion of a boiler or other furnace are taken to the chimney. d. Lanc. Shale.

flue dust

Dust passing into the flues of a smelter or metallurgical furnace and which, unless caught, passes out into the atmosphere. It is composed of particles of unchanged or oxidized ore, volatilized lead that has been converted into oxide, carbonate and sulfate ash, fuel, and volatilized products of arsenic, zinc, bismuth, etc.


An orthorhombic mineral, Al (sub 2) (PO (sub 4) )F (sub 2) (OH).7H (sub 2) O ; has one distinct cleavage; occurs with secondary iron phosphate minerals in pegmatites. Formerly called kreuzbergite.


a. The quality, state, or degree of being fluid: a liquid or gaseous state. CF: gas.

b. The physical property of a substance that enables it to flow and that is a measure of the rate at which it is deformed by a shearing stress, as contrasted with viscosity: the reciprocal of viscosity. c. In mineral transport, the term is not confined to liquids and slurries, but is also used for finely divided solids that flow readily in air currents, fluosolids reactors, or through dry ball mills.

fluidal structure

See: flow structure.

fluidal texture

a. See: flow texture.

b. A metamorphic texture in which narrow stripes or lenticles of a mineral, present as grains approx. 0.01 mm in diameter, are connected with porphyroclasts of the same mineral and extend across regions in which another mineral shows a dominantly mosaic texture. This texture has been given a specific genetic connotation relating to superplasticity (Harte, 1977).

fluid-bed reactor

A single or multi-stage reactor, generally used for gas-solid contacting, in which the solid component is a reactant or a catalyst and is in a continuous fluidized state. The gas is injected into the reactor to provide rapid and uniform mixing for reactants to facilitate heat transfer and completion of the reaction.

fluid column

The number of feet of drilling fluid standing in a borehole while the drill is operating and/or the number of feet of drilling fluid remaining in a borehole with the drill string withdrawn.

fluid conveyor coupling

A device for overcoming the starting resistance of a conveyor fed by a constant-speed motor. It is used to allow the motor to reach full speed before starting the conveyor.

fluid cut

See: fluid wash.

fluid energy mill

A size-reduction unit depending for its action on collisions between the particles being ground, the energy being supplied by a compressed fluid, (e.g., air or steam) that enters the grinding chamber at high speed. Such mills will give a product of 5 mu m or less; they have been used for the fine grinding of frits, kaolin, zircon, titania, and calcined alumina, but the energy consumed per ton of milled product is high.

fluid inclusion

A cavity, with or without negative crystal faces, containing one or two fluid phases, and possibly one or more minute crystals, in a host crystal. If two fluid phases are present, the vapor phase (bubble) may show Brownian motion. See also: inclusion; negative crystal.

fluidized bed dryer

A coal dryer that depends on a mass of particles being fluidized by passing a stream of hot air through it. As a result of the fluidization, intense turbulence is created in the mass, including a rapid drying action. The dry coal is withdrawn from the opposite side of the chamber. Fine particles in the feed become entrained in the air and are recovered in a cyclone, while the finest particles may need removal by dry filters or wet scrubbers. The dryer has a high capacity and many are in use in the United States. See also: cascade coal dryer; flash coal dryer; thermal drying.

fluidized roasting

Oxidation of finely ground ore minerals by means of upward currents of air, blown through a reaction vessel with sufficient force to cause the bed of material to become fluid. Reaction between mineral and air is maintained at a desired exothermic level by control of oxygen entry, by admission of cooling water, or by added fuel. Fluidized beds are used in the mineral industry for a number of concentrates, including copper, lead, zinc, and carbonaceous gold ores.

fluid lubricated

The core barrelhead bearings and/or other rotating members in a drill string cooled and lubricated by water or mud-laden fluid circulated as the drilling fluid.

fluid pressure

a. The force, expressed in pounds per square inch, exerted by the weight of the column of drilling fluid measured at any given depth in a borehole. CF: bottom-hole pressure.

b. The pressure exerted by fluid contained in rock.

fluid ton

Thirty-two ft (super 3) (0.9 m (super 3) ) of fluid. A unit to correspond with the short ton of 2,000 lb (908 kg), and of sufficient accuracy for many hydrometallurgical, hydraulic, and other industrial purposes, it being assumed that the water or other liquid under consideration weighs 62.5 lb/ft (super 3) (1,002.7 kg/m (super 3) ).

fluid volume

The amount of drilling fluid circulated through the drill string, generally expressed in gallons per minute.

fluid wash

The wearing away of core and parts of a drill string or bit exposed to the erosive forces of the rapid passage of the circulated drilling fluid. Also called fluid cut.


See: flucan.


A rod used for cleaning drill holes before they are charged with explosives.


a. Corn. See: gouge clay.

b. A crossvein composed of clay.


a. An artificial inclined channel used for conveying water for industrial purposes, such as irrigation, transportation, mining, logging, or power production; or for diverting the water of a stream from its channel for the purpose of washing or dredging the sand and gravel in the dry bed or to aid in engineering construction.

b. An inclined channel, usually of wood and often supported on a trestle, for conveying water from a distance to be utilized for power, transportation, etc., as in placer mining, logging, etc. Syn: sluice; race. c. To divert by a flume, such as the waters of a stream, in order to lay bare the auriferous sand and gravel forming the bed. CF: ditch.


The transportation of solids by suspension or flotation in flowing water.


A smooth porcellanous rock resembling porridge in color and texture; Carboniferous limestone, Hunts quarry, Porthywaen, and Vale of Clwyd, north Wales. Also called flummery stone.


A compact mixture of fluorite and barytes.


A hexagonal mineral, Mg (sub 3) (BO (sub 3) )(F,OH) (sub 3) ; colorless; occurs as fibrous masses of small prisms in skarns and veinlets in massive franklinite ore at Sterling Hill, NJ; also at Norberg, Sweden; Nocera, Italy; and Broadford, Scotland. Formerly called nocerite.


A hexagonal mineral, (Ce,La)F (sub 3) ; further speciated on the basis of the dominant rare-earth element; weakly radioactive; in pegmatites associated with gadolinite, allanite, and bastnaesite in the Front Ranges, CO.


See: fluorimetry.


a. The original spelling of fluorite; still used chiefly in Great Britain.

b. A prefix to mineral names indicating that some or all of the hydroxyl radical in its composition has been replaced by fluoride; e.g., micas and amphiboles. See also: fluorite; fluormica.


Artificial amphibole with fluorine replacing the hydroxyl of hydroxyl amphibole.


A hexagonal mineral, Ca (sub 5) (PO (sub 4) ) (sub 3) F ; apatite group; variably colored; commonly fluorescent or phosphorescent; defines 5 on the Mohs hardness scale; a common accessory mineral in igneous and metamorphic rocks, pegmatites, veins, and carbonate rocks; an ore of phosphate in phosphorites. Syn: apatite.


See: fluoramphibole.


An organic compound formed through the burning of pyritous shale in Bohemia, former Czechoslovakia. Later renamed kratochvilite.


a. The emission of visible light by a substance exposed to ultraviolet light. It is a useful property in examining well cuttings for oil shows and in prospecting for some minerals.

b. The absorption of radiation at one wavelength, or a range of wavelengths, and its reemission as radiation of longer, visible wavelengths. c. A type of luminescence in which the emission of light ceases when the external stimulus ceases; also, the light so produced. d. Quantized electromagnetic radiation as a material drops from a higher to a lower energy state. Fluorescence stops when the excitation energy stops. CF: phosphorescence; luminescence.


Having the property to produce fluorescence.

fluorescent lamp

a. Commonly and improperly designates an electric lamplike device emitting ultraviolet radiations or black light. CF: black light, lamp.

b. A glass globe or tube, the inner surface of which is coated with a fluorescent substance that produces visible light when excited by an electric current.

fluorescent penetrant inspection

A type of nondestructive testing wherein a penetrating type of oil or other liquid combined with fluorescent material particles is applied over a surface and flowed into cracks, crevices, or other surface defects or irregularities; the excess is then removed, and the article is examined under ultraviolet light.


A variety of hectorite in which fluorine partially replaces hydroxyl. CF: montmorillonite; smectite; saponite.


A mineral with fluorine as its chief anion.


Method of analysis based on the intensity of fluorescence measured when using ultraviolet light.


A nonmetallic element, the lightest of the halogens; it is a pale yellow, corrosive gas, that is highly toxic. Symbol, F. It is the most electronegative and reactive of all the elements. Fluorine occurs chiefly in fluorite (CaF (sub 2) ) and cryolite (Na (sub 2) AIF (sub 6) ), but is widely distributed in other minerals. Used in producing uranium and many high-temperature plastics.


An isometric mineral, CaF (sub 2) ; perfect octahedral cleavage; transparent to translucent; defines 4 on the Mohs hardness scale; in veins as a gangue mineral; in carbonate rocks; an accessory in igneous rocks. Syn: fluorspar; fluor; Derbyshire spar.


A group name for the fluorite-rich micas, natural or artificial. See: fluor.


A device for measuring the intensity of fluorescence.


An instrument consisting of a fluorescent screen and a source of ionizing radiation. Used to examine the image formed by opaque objects placed in the beam.


An inspection procedure in which the radiographic image of the subject is viewed on a fluorescent screen; normally limited to low-density materials or to thin sections of metals because of the low-light output of the fluorescent screen at safe levels of radiation.


See: fluor.


See: fluorite.


See: fluor.

fluosolids system

A method of roasting, applied to finely divided material, in which air with sufficient strength is blown through a heated bed of mineral to keep it fluid, while reaction is controlled by continuous adjustment of rate of feed, cooling water, and added fuel (including oxygen in air). Train of appliances includes instrument controls, air compressor, dust-collecting cyclones, and feed pump.


a. To operate a placer mine, where the continuous supply of water is insufficient, by holding back the water and releasing it periodically in a flood.

b. To fill underground spaces, as in coal mines, with material carried by water, which after drainage forms a compact mass. c. See: hydraulic mine filling.


a. A drilling method in that water or some other thicker liquid, such as a mixture of water and clay, is driven into the borehole through the rod and bit. The water rises along the rod on its outer side, between the walls of the borehole and the rod, with such a velocity that the broken rock fragments are carried up by this water current (direct flushing). Alternatively, water enters the borehole around the rod and issues upwards through the rod (indirect flushing).

b. In a colliery, diversion of ventilation to clear foul atmosphere (a dangerous method.) c. See: hydraulic stowing. d. In oil-well production, use of gravitated ground water to force oil or gas to the surface.

flushing fluid

See: flush.

flush-joint casing

Lengths (usually 10 ft or 3 m) of steel tubing provided with a box thread at one end and a matching pin thread on the opposite end. Coupled, the lengths form a continuous tube having uniform inside and outside diameters throughout its entire length. Syn: casing.

flush water

CF: top water.


a. A groove parallel or nearly parallel to the axis of a cylindrical piece, such as the grooves of a split-ring core lifter or the grooves in a core-barrel stabilizer ring. Also applied to grooves or webs following a corkscrewlike course around the outside surface of a cylindrical object, like the spiraled webs on an auger stem or rod.

b. A primary sedimentary structure, commonly seen as a flute cast, consisting of a discontinuous scoop-shaped or lobate depression or groove generally 2 to 10 cm in length, usually formed by the scouring action of a turbulent, sediment-laden current of water flowing over a muddy bottom, and having a steep or abrupt upcurrent end where the depth of the mark tends to be the greatest. Its long axis is generally parallel to the current. CF: facet.

fluted core

Core, the outside surface of which is spirally grooved or fluted. Syn: corkscrew core.


A peculiar method of surface decay by which granite or granite gneisses are left with a corrugated or fluted surface. In a large subangular fragment of granite, one side contains a dozen of these little channels, from 1 to 4 in (2.5 to 10.2 cm) deep and from 3 to 10 in (7.6 to 25.4 cm) apart from center to center. These channels run straight down the face of the rock.


a. Of or pertaining to a river or rivers.

b. Existing, growing, or living in or about a stream or river. c. Produced by the action of a stream or river; e.g., sand and gravel deposits. Syn: fluviatile. Etymol. Latin fluvius, river.


See: fluvial. Geologists tend to use the term for the results of river action (e.g., fluviatile dam, or fluviatile sands) and for river life (e.g., fluviatile fauna).


See: glaciofluvial.


Of or pertaining to sedimentation partly in lake water and partly in streams, or to deposits laid down under alternating or overlapping lacustrine and fluviatile conditions.


Consisting of or pertaining to the land and its streams.


a. See: fluxstone.

b. To cause to become fluid; to treat with a flux, esp. to promote fusion; to become fluid. Syn: flow. See also: current. c. Any chemical or rock added to an ore to assist in its reduction by heat; e.g., limestone with iron ore in a blast furnace. d. In metal refining, a material used to remove undesirable substances; e.g., sand, ash, or dirt, as a molten mixture.

fluxed pellet

An iron-ore pellet made by mixing minor amounts of a ground flux (forsterite, calcite, dolomite, or lime) with the magnetite or hematite concentrate to decrease smelting times and coke consumption.

flux fusion

A method of growing refractory crystals; similar in many respects to crystallization for aqueous solutions, but the fluxes are salts with relatively high melting temperatures.

flux-gate magnetometer

An instrument used for detailed studies of the Earth's magnetic field on a local basis that uses the flux-gate, which consists of two identical saturable cores of high permeability, with identical, but oppositely wound, coils. An alternating current in these coils magnetizes them first with one polarity, then in the opposite sense. If an additional field is present, such as the Earth's field, it will add to the flux in one coil while decreasing that in the other, resulting in different voltage drops across the two coils. This difference is proportional to the unvarying field, which can be measured by noting the average voltage difference between the two halves of the flux gate. In use, a part of the Earth's field is balanced out by an additional winding surrounding both cores and carrying direct current. In airborne use, the recording flux gate is kept aligned with the magnetic field by the use of two additional flux gates. When these are at right angles to the Earth's field, they generate no voltage, but if they depart from this position, they can generate voltages which operate motors returning them to proper alignment. In this fashion, the recording element is held always parallel to the total field.


Fusion or melting of a substance as a result of chemical action.

fluxing lime

Lump or pebble quicklime used for fluxing in steel manufacture. The term may be applied more broadly to include fluxing of nonferrous metals and glass. It is a type of chemical lime.

fluxing ore

An ore containing an appreciable amount of valuable metal, but smelted mainly because it contains fluxing agents that are required in the reduction of richer ores.

fluxing stone

Consists of pure limestone or sometimes dolomite and is used in iron blast furnaces and foundries. Usually material below 2 in (5.1 cm) in diameter is eliminated. The most desirable size is between 4 in and 6 in (10 cm and 15 cm).

fluxion banding

Banding in rock consisting of flow layers.

fluxion structure

See: flow structure.

flux spoon

A small ladle for dipping up a sample of molten metal for testing.


a. Limestone, dolomite, or other rock or mineral used in metallurgical processes to lower the fusion temperature of the ore, combine with impurities, and make a fluid slag. Syn: flux.

b. Crushed limestone or dolomite used as a flux in the smelting of iron ore. c. In iron-ore pelletizing, a mixture of ground limestone and dolomite added to the iron ore before the concentrate is rolled into green balls and fired at 1,315 degrees C in a pelletizing furnace. Also spelled fluxing stone; flux stone.

fly gate

a. An opening in a chute that can be opened or closed at will. In a chute for coal, a fly gate may be inserted so that if rock is deposited in the chute, it may be trapped out by opening the fly gate.

b. An opening or bypass in a chute or hopper that can be opened or closed at will for diverting ore, rock, or coal from one bin or conveyor to another. Sometimes called "to fly."

Flygt pump

A submersible pump developed in Sweden.

flying cradle

Eng. See: cradle.

flying reef

Aust. A broken, discontinuous, irregular vein.

flying veins

A pattern of mineral-deposit veins overlapping and intersecting in a branchlike pattern.


Rocks propelled from the blast area by the force of an explosion. See also: throw.


a. A marine sedimentary facies characterized by a thick sequence of poorly fossiliferous, thinly bedded, graded deposits composed chiefly of marls, sandy and calcareous shales, and muds, rhythmically interbedded with conglomerates, coarse sandstones, and graywackes.

b. An extensive, preorogenic sedimentary formation representing the totality of the facies deposited in different troughs, by rapid erosion of an adjacent and rising mountain belt at a time directly previous to the main paroxysmal (diastrophic) phase of the orogeny; specif., the Flysch strata of late Cretaceous to Oligocene age along the borders of the Alps, deposited before the main phase (Miocene) of the Alpine orogeny. c. A term that has been loosely applied to any sediment with most of the lithologic and stratigraphic characteristics of a flysch, such as almost any turbidite. Ethymol. dialectal term of German origin used in Switzerland for a crumbly or fissile material that slides or flows. CF: molasse.


A heavy wheel used in a rotating system to reduce surges of power input or demand by storing and releasing kinetic energy as it changes its rate of rotation.

foam drilling

A method of dust suppression in which thick foam is forced through the drill by means of compressed air and the foam and dust mixture emerges from the mouth of the hole in the form of a thick sludge. With this method the amount of dust dispersed into the atmosphere is almost negligible and the amount of water used is about 1 gal/h (3.8 L/h). Approx. 30 to 50 ft (9 to 15 m) of drilling can be done with one filling of the unit.

foaming agent

A material that tends to stabilize a foam. See: frothing agent.

foaming earth

Soft or earthy aphrite. See also: earth foam.

foam injection

The injection of foam into shotholes and connecting breaks to displace any combustible gases present and to minimize further combustible gases emission into the shotholes, thereby reducing the risk of ignition of the gas during shot firing.

foam plug

A secondary method of fighting underground fires, devloped in Great Britain in 1956. It consists of filling the fire area with soap bubbles which are moved forward by the air current. The foam is produced by passing the air current through a cotton net, saturated with a dilute solution of detergent, which is stretched across the mine roadway. The air passing through the net forms bubbles 1/2 to 1-1/2 in (1.3 to 3.8 cm) in diameter which honeycomb and form a plug of foam that tends to quench the fire and reduce its temperature to a point where it can be attacked directly and without protective clothing. See also: high-expansion foam.

foam spar

See: aphrite.

foamy amber

Frothy amber. Almost opaque chalky white amber. Will not take a polish.


See: free on board.

focal sphere

An arbitrary reference sphere drawn about the hypocenter or focus of an earthquake, to which body waves recorded at the Earth's surface are projected for studies of earthquake mechanisms.


a. The initial rupture point of an earthquake, where strain energy is first converted to elastic wave energy; the point within the Earth which is the center of an earthquake. Syn: hypocenter.

b. The point at which rays of light converge to form an image after passing through a lens or optical system or after reflection by a mirror.

focused logging device

Logging device designed to focus lines of current flow.


Eight pigs of cast iron.

fog quenching

Quenching in a fine vapor or mist.


A term proposed by Johannsen; derived by contracting the word feldspathoid; used in his classification of igneous rocks to indicate one of the feldspathoidal group of minerals. CF: feldspathoid.


A crack or a break in the roof.


a. A curve or bend of a planar structure such as rock strata, bedding planes, foliation, or cleavage. A fold is usually a product of deformation, although its definition is descriptive and not genetic and may include primary structures. CF: anticline; syncline; monocline.

b. In crystallography, refers to the number of repetitions about a crystallographic axis to return to identity; i.e., equal to a complete rotation of 360 degrees . Modern usage refers to a six-fold axis as a hexad, a four-fold axis as a tetrad, three-fold as triad, two-fold as diad, and one-fold as monad.

fold axis

See: axis.

fold breccia

A local tectonic breccia composed of angular fragments resulting from the sharp folding of thin-bedded, brittle rock layers between which are incompetent ductile beds; e.g., a breccia formed where interbedded chert and shale are sharply folded. CF: tectonic breccia.

fold fault

A fault formed in causal connection with folding.


The formation of folds in rocks.

fold mountain

A mountain resulting chiefly from large-scale folding of the Earth's crust.

fold system

A group of folds showing common characteristics and trends and presumably of common origin.


Thin, leaflike layers or laminae; specif., those of gneissic or schistose rocks. Singular form is folium.


A general term for any foliated rock. Adj. of foliation.


Adj. of foliation.


A general term for a planar arrangement of textural or structural features in any type of rock; esp., the planar structure that results from flattening of the constituent grains of a metamorphic rock. Adj. foliate; foliated. CF: schistosity.

follower chart

A table showing (1) the size of casing or pipe that should be placed in a borehole drilled with a specific-size bit and (2) which sizes of casing or pipe can be nested inside each other.

follower rail

The follower rail of a mine switch is the rail on the other side of the turnout corresponding to the lead rail.

following dirt

A thin bed of unconsolidated dirt; a parting between the top of coal seam and the roof. See also: pug.

followup tag

The cardboard tag placed in the cartons, boxes, or cases of blasting supplies; used for identifying the date and place of manufacture.

Follsain process

A method for the sintering of the raw materials for the burden of blast furnaces in which continuous sintering is carried out in a rotating tube furnace; at the discharge end a special tuyere is arranged comprising two concentric close-ended tubes parallel to the furnace axis, the outer tube having one nozzle near its closed extremity, the other having a number of nozzles protruding through the outer tube. The inner tube supplies air heated to 650 to 800 degrees C; the outer one carries cold air, which keeps the inner tube from softening and becoming deformed and itself becomes somewhat heated by the time it emerges from the nozzle. These jets are directed upon the material to be sintered. The fine iron-bearing material is mixed with a proportion of fuel; under the intensive action of the hot air blast, the fuel raises the temperature of the mixture sufficiently for sintering to occur, whereupon the material is discharged from the furnace.

fool's gold

See: pyrite.


a. The bottom of a slope, grade, or declivity. The lower part of any elevated landform; e.g., the foot of a hill, the foot of a mountain, etc.

b. The lower bend of a fold or structural terrace. CF: head. Syn: lower break. c. See: footwall. d. The foot is 12 in (30.5 cm) in length on the vein, including its entire width, whether 6 in (15.2 cm) or 60 ft (18.3 m), and its whole depth down toward the Earth's center. e. Corn. An ancient measure containing 2 gal or 60 lb of black tin. f. That portion of the displaced material of a landslide that lies downslope from the toe of the surface of rupture (Varnes, 1978).


See: acre-foot.

footage block

See: marker block.

footage per bit

The average number of feet of borehole specific types of drill bits can be expected to drill in a certain rock before the bit becomes dulled and is replaced, discarded, resharpened, or reset.

foot clamp

See: safety clamp.


See: connellite.

foot hole

Any of the holes cut in the sides of shafts or winzes to enable miners to ascend and descend.


a. A relatively shallow foundation by which concentrated loads of a structure are distributed directly to the supporting soil or rock through an enlargement of the base of a column or wall. Its ratio of base width to depth of foundation commonly exceeds unity. CF: pier.

b. The characteristics of the material directly beneath the base of a drill tripod, a derrick, or mast uprights. Also, the material placed under such members to produce a firm base on which they may be set.


In salt production, a laborer who adjusts the height of the gate in the chute leading from the crusher by means of a lever, to regulate flow of crushed rock salt into vibrating screens that separate salt into various sizes prior to shipment or refining.


See: marker block.

foot rod

Scot. An iron rod at the foot of pump rods to which the bucket is attached.


a. The underlying side of a fault, orebody, or mine working; esp. the wall rock beneath an inclined vein or fault. Syn: heading wall; heading side; lower plate; foot. CF: hanging wall. See also: wall; walls.

b. The wall or rock under a vein. It is called the floor in bedded deposits. c. Opposite wall from hanging wall. d. S. Afr. The wall on the lower side of a reef, lode, or fault. e. Can. The underside of a vein or lens in relation to the dip of an ore deposit. f. In metal mining, the part of the country rock that lies below the ore deposit.

footwall of a fault

The lower wall of an inclined fault plane.

footwall shaft

See: underlay shaft.


In Pennsylvania, a miner's measurement of length, such as the distance a working face is advanced. With the heel of one foot on a mark, a short step is taken and the tip of the forward toe marks the foot-yard. The next measurement is taken by placing the first foot against the toe of the second and repeating the first step and so on. The foreperson checks measurements with a rule.

Foraky boring method

A percussive boring system comprising a closed-in derrick over the crown pulley of which a steel rope is passed from its containing drum. The boring tools are suspended from the end of the rope and are moved in the hole as required by means of the drum. A walking beam, operated by a driving mechanism, gives the boring tools a rapid vibrational motion.

Foraky freezing process

One of the original freezing methods of shaft sinking through heavily watered sands. Although the principle is the same today, the process has been improved in many respects. See also: freezing method.


See: foraminifer.


Any protozoan belonging to the subclass Sarcodina, order Foraminifera, characterized by the presence of a test (shell) of one to many chambers composed of secreted calcite (rarely silica or aragonite) or of agglutinated particles. Most foraminifers are marine but freshwater forms are known. They are important microfossils in well logging. Range, Cambrian to present. Syn: foram. Plural, foraminifera.


Plural of foraminifer.


A mixture of annabergite and arsenolite.


Four lengths of drill rod or drill pipe connected to form a section, which is handled and stacked in a drill tripod or derrick as a single unit on borehole round trips. Also spelled fourble. CF: treble.


That which tends to put a stationary body in motion or to change the direction or speed of a moving body.

forced auxiliary ventilation

A system in which the duct delivers the intake air to the face. The forcing system may be used with flexible ducting and simplifies arrangements for protecting the duct from blasting. The forcing system has the added advantage that the fan motor always works in intake air, and no special arrangements about fan drives are necessary. See also: auxiliary ventilation.

forced-caving system

A stoping system in which the ore is broken down by large blasts into the stopes, which are kept partly full of broken ore. The large blasts break ore directly into the stopes and have the further effect of shattering additional ore, part of which then caves.

forced ventilation

A system of ventilation in which the fan forces air through the workings under pressure.

force lines

Stress fields can be represented by lines, each of which represents a definite force, so that their distance apart is a measure of the intensity of stress. The concept is similar to that of a magnetic field represented by lines of force.

force majeure

a. The clause in a metal supply contract which allows the seller not to deliver or the buyer not to take delivery of the metal concentrate or scrap under the contract because of events beyond the seller's control.

b. An unexpected occurrence beyond the control of parties to a contract, such as an earthquake preventing the timely delivery promised by a metal supply contract, that typically relieves a party from contract performance. The language of the contract, as well as applicable State or Federal laws, determine the applicability of this legal mechanism in any given situation. Also called an Act of God.

force of blow

The effective diameter of the piston or hammer, its weight, distance of travel, and the air pressure during the forward movement. The energy of the blow in foot-pounds is equal to: 1/2 mv (super 2) = w X v (super 2) / 64.4, where m = the mass; w = the weight in pounds; v = the velocity of the hammer in feet per second.

force of crystallization

See: crystallizing force.

force oscillator

An instrument to determine the mechanical resonant frequency of a whole crystal or cut crystal plate. A slowly varying frequency is applied to the crystal from a signal generator, and the resonant frequency voltage developed across the crystal is measured with a voltmeter. Also called drive oscillator.

force pump

a. A pump consisting of a plunger or ram, the up-stroke of which causes the suction valve to open and the water to rise in the suction pipe. On the down-stroke of the plunger, the suction valve closes and the contained water is forced through the delivery valve into the rising main or discharge pipe.

b. A pump that forces water above its valves. c. A pump in which the water is lifted by the force due to atmospheric pressure acting against a vacuum.


a. A small hand pump used in Cornish mining.

b. The solid piston of a force pump.


An orange-yellow opal colored with orpiment.

forcing fan

A fan which blows or forces the intake air into the mine workings, as opposed to an exhaust fan. A mine exhaust fan may become a forcing fan (with reduced efficiency) when the ventilation is reversed in an emergency.

forcing lift

Scot. A set of pumps raising water by a plunger; a ram pump. Also called forcing set.

forcing set

A pump for forcing water to a higher level or to the surface.


a. A reservoir or pond at the head of a penstock or pipeline.

b. The water immediately upstream of any structure.


An auxiliary combination for gas-fired boilers that provides an incandescent surface for lighting gas instantly when turned on after being shut off for any reason. Also called Dutch oven; doghouse.

fore drift

The one of a pair of parallel headings that is kept a short distance in advance of the other.


a. A projecting bay in the front of a blast furnace hearth under the tymp. In open-front furnaces, it is from the forehearth that cinder is tapped.

b. An independent settling reservoir into which is discarded the molten material from a furnace and which is heated from an independent source. The heavy metal settles to the bottom and the light slag rises to the surface. c. A section of a furnace, in one of several forms, from which glass is taken for forming.

foreign coal

Coal received at a preparation plant from a source other than that to which the plant is attached.


Dark, ovoid inclusion of country rock in granite. Syn: furrener.

foreign inclusion

A fragment of country rock enclosed in an igneous rock. Syn: xenolith.


A stable area marginal to an orogenic belt, toward which the rocks of the belt were thrust or overfolded. Generally the foreland is a continental part of the crust, and is the edge of the craton or platform area.


The steeper of the two limbs of an asymmetrical anticlinal fold.

forelimb thrust

A thrust fault cutting strata on the steeply dipping flank of an asymmetrical anticline.


See: troctolite.

Forel scale

The basic scale for measuring seawater color. See also: water color.


The head person; esp., the overseer of a group of workers. See also: mine foreman; boss.


A pointed board or steel strap with a sharp edge, that is driven ahead in loose ground for support purposes. See also: spile; spill.


a. A method of advancing a mine working or tunnel in loose, caving, or watery ground, such as quicksand, by driving sharp-pointed poles, timbers, sections of steel, or slabs into the ground ahead of, or simultaneously with, the excavating; a method of supporting a very weak roof. It is useful in tunneling and in extracting coal from under shale or clay. See also: close timbering; cribbing; poling; running ground.

b. A method of securing loose ground by driving poles, planks, etc., ahead of and on the top and sides of the timbers. See also: spile.

forepoling girder

One of two or more heavy straight girders set over and in advance of the last permanent support in a tunnel. They provide protection to the worker until there is space to erect another support.


a. To set a prop under the fore or coal-face end of a bar.

b. Timber set used at the working face for roof support. Also called force piece. c. Temporary forward support; a middle prop under a bar.

foreshaft sinking

The first 150 ft (46 m) or so of shaft sinking from the surface, during which time the plant and services for the main shaft sinking are installed. Sometimes, the main sinking contract does not commence until the foreshaft has been completed.


a. In coal mining, first or morning shift.

b. Eng. The first shift of hewers (miners) who go into the mine from 2 to 3 h before the drivers and loaders.


a. One of the initiating shocks preceding the principal earthquake.

b. An earthquake that precedes a larger earthquake within a fairly short time interval (a few days or weeks), and which originates at or near the focus of the larger earthquake. c. A small tremor that commonly precedes a larger earthquake or main shock by an interval ranging from seconds to weeks and that originates at or near the focus of the larger earthquake. CF: aftershock.


a. A sight on a new survey point, taken in a forward direction and made in order to determine its bearing and elevation. Also, a sight on a previously established survey point, taken to close a circuit.

b. A reading taken on a level rod to determine the elevation of the point on which the rod rests. Syn: minus sight. Abbrev. FS. CF: backsight.

foresight hub

A stake or mark placed by a responsible individual some distance in front of a drill; used by a driller to point and line up a drill to drill a borehole in a specific direction. Also called front hub. See also: picket.

forest marble

See: landscape marble.

forest moss peat

Peat formed in forested swamps.

forest peat

Peat consisting mainly of the remains of trees that grew in low wet areas.


Penalty incurred in accordance with governing laws and regulations when mining concessions, claims leases, rights, are not adequately, safely, and consistently developed and exploited. CF: abandonment.


a. An open fireplace or hearth with forced draft, for heating iron, steel, etc.; e.g., a blacksmith's forge.

b. A hearth or furnace for making wrought iron directly from ore; a bloomery. c. To form by heating in a forge and hammering; to beat into some particular shape, as a mass of metal. d. A plant where forging is carried out. e. Eng. That part of an ironworks where balls are squeezed and hammered and then drawn out into puddle bars by grooved rolls.

forge cinder

The dross or slag from a forge.

forge iron

Pig iron used for the charge of a puddling furnace.

forge pigs

Pig iron suitable for the manufacture of wrought iron.

forge roll

One of the train of rolls by which a slab or bloom of metal is converted into puddled bars.

forge train

In iron puddling, the series of two pairs of rolls by means of which the slab or bloom is converted into bars.

forge welding

A group of welding processes in which the parts to be joined are heated to a plastic condition in a forge or other furnace and are welded together by applying pressure or blows.


a. An appliance used in free-fall drilling that serves to hold up the string of tools during connection and disconnection of the rods.

b. A double-pronged clip on a tub or wagon for the haulage rope or chain. c. A two-pronged lever used to slide the flat belt from a powerdrive over to an idler pulley (loose pulley). d. Corn. Bottom of a drainage sump. e. Derb. A piece of wood supporting the side of an excavation in soft ground, esp. if it has a Y-shaped end. f. Scot. A tool used for changing buckets, or for loading lump coal. g. To pump water out of a mine. A mine is said to be in fork, or a pump to have the water in fork, when all the water is drawn out of the mine.


Aust. Coal filled into skips with a fork, having the prongs about 1-1/4 in (3.2 cm) apart. This separates the bulk of the slack from the round coal. The course product should not contain more than 10% of fine coal. See also: box filling.


a. In crystallography, all the crystal faces having a like position relative to the elements of symmetry of a point group; e.g., mirror planes and rotation axes. A form is closed if it encloses a volume, such as a cube or a rhombohedron; it is open if additional forms are necessary to enclose a volume, such as a prism or a pinacoid. A single crystal may exhibit faces of two or more crystal forms which supplement one another, such as a prism and a basal pinacoid; or truncate one another's edges or corners, such as a dodecahedron and a trapezohedron.

b. In geomorphology, a syn. of landform. c. Those aspects of a particle shape that are not expressed by sphericity or roundness. Form can be described as ratios of the long, intermediate, and short axes, which can be combined into various "form indices," and by terms such as platy, bladed, elongate, or compact.


A tetragonal mineral, YTaO (sub 4) ; dimorphous with yttrotantalite; forms a series with fergusonite; in granite pegmatites and placer deposits.


An informal rock stratigraphic unit bounded by marker horizons believed to be isochronous surfaces that can be traced across facies changes, particularly in the subsurface; useful for correlations between areas where the stratigraphic section is divided into different formations that do not correspond in time value. See also: marker.


a. A persistent body of igneous, sedimentary, or metamorphic rock, having easily recognizable boundaries that can be traced in the field without recourse to detailed paleontologic or petrologic analysis, and large enough to be represented on a geologic map as a practical or convenient unit for mapping and description; the basic cartographic unit in geologic mapping. Syn: rock formation.

b. A body of sedimentary rock identified by lithic characteristics and stratigraphic position; it is prevailing but not necessarily tabular, and is mappable at the Earth's surface or traceable in the subsurface. The formation is the fundamental unit in lithostratigraphic classification. c. A general term applied by drillers to a sedimentary rock that can be described by certain drilling or reservoir characteristics; e.g. hard formation, cherty formation, or porous formation. d. A naturally formed topographic feature, commonly differing conspicuously from adjacent objects or material, or being noteworthy for some other reason; esp. a striking erosional form on the land surface. Syn: geologic formation.

formation drilling

Boreholes drilled primarily to determine the structural, petrologic, and geologic characteristics of the overburden and rock strata penetrated. Also called formation testing.

formation level

Level of the ground surface after completion of excavation.

formation resistivity factor

a. In geophysical borehole logging, the ratio of the conductivity of an electrolyte to the conductivity of a rock saturated with that electrolyte. Symbol, F.

b. The ratio of the resistivity of the saturated rock to the resistivity of the saturating water in a completely water-saturated clean rock.

formation striae

Color bands in synthetic corundum or spinel which, because they are invariably distinctive and generally curved, differ from the straight color zones in natural minerals. Also called formation striations.

formation water

Water present in a water-bearing formation under natural conditions, as opposed to introduced fluids, such as drilling mud. Syn: native water. CF: connate water.

form contour

A topographic contour determined (1) by stereoscopic study of aerial photographs without ground control or (2) by other means not involving conventional surveying.

form energy

The potentiality of a mineral to develop its own crystal form against the resistance of the surrounding solid medium (Eskola, 1939).

formosa marble

A high grade of marble; dark gray and white, variously mottled and blotched with yellow and red; from Nassau and Germany.


A monoclinic mineral, (Pb,Cu) (sub 3) [(Cr,As)O (sub 4) ] (sub 2) (OH) ; forms prismatic crystals on dioptase. Also spelled furnacite.


An orthorhombic mineral, 4[Mg (sub 2) SiO (sub 4) ] ; olivine group, with magnesium replaced by iron toward fayalite; trimorphous with ringwoodite and wadsleyite; in dunite and metamorphosed dolomitic limestones.

forsterite refractories

Semibasic refractories made from olivine and magnesia; consist essentially of forsterite, including about 50% magnesia, 39% silica, 6% ferrous oxide, and 5% of other oxides.


Derb. Light waste left after washing ore. Also called forstid ore.


The purchase or sale of metal for delivery at a specified future date. Hence "forward price," "forward contract."

forward dealing

Purchase of stocks, notably metals, for delivery at an agreed future date and price.


A triclinic mineral, Ca (sub 4) Si (sub 3) O (sub 9) (OH) (sub 2) ; forms compact fibrous vein filling associated with vesuvianite and blue calcite at Crestmore, Riverside County, CA.


A monoclinic mineral, Ca (sub 3) Si (sub 2) O (sub 7) .3H (sub 2) O(?) ; occurs on the Kola peninsula, Russia, where it is related to foshagite and centrallassite and named from a combination of those names. Also spelled foshallasite.


a. Aust. To work out the pillars of abandoned claims, or work over waste heaps in hope of finding gold.

b. Eng. In gold mining, to undermine another's digging.


a. Person who searches for small amounts of mineral.

b. One who picks over old mine workings. Fossicking is casual and unsystematic mining. c. Aust. A sort of mining gleaner who overhauls old workings and refuse heaps for gold that may be contained therein.

fossil copal

See: copalite.

fossil erosion surface

An erosion surface that was buried by younger sediments and was later exposed by their removal. Sometimes used as a syn. of buried erosion surface.

fossil flour

See: diatomite.

fossil fuel

Coal, petroleum, or natural gas.

fossil ice

a. Ice formed in, and remaining from, the geologically recent past. It is preserved in cold regions, such as the coastal plains of northern Siberia, where remains of Pleistocene ice have been found.

b. Relatively old "ground ice" in a permafrost region. Also, underground ice in a region where present-day temperatures are not low enough to create it. c. Crystal of selenite.

fossilized wood

See: silicified wood.

fossil ore

An iron-bearing sedimentary deposit, in which shell fragments have been replaced and cemented together by hematite and carbonate. CF: flaxseed ore.

fossil paper

See: mountain paper; mountain leather.

fossil pineapple

Opal pseudomorph after glauberite; from New South Wales.

fossil resin

Any of various natural resins found in geologic deposits as exudates of long-buried plant life; e.g., amber, retinite, and copal.

fossil salt

See: rock salt.

fossil turquoise

See: odontolite.

fossil wax

See: ozocerite.


Any of the various units of weight for lead; esp. a unit equal to 19.5 hundredweight (885 kg).


a. A condition of the atmosphere of a mine so contaminated by gases as to be unfit for respiration. Impure.

b. In a coal seam, a place where the seam was washed out during deposition, leaving a barren area.

foul-air duct

A suction line in a tunnel ventilation system.

foul gas

Coke-oven gas or natural gas containing appreciable amounts of hydrogen sulfide and similar contaminants.


The assemblage of marine organisms that attach to and grow upon underwater objects.

fouling position

The point on any rail beyond which a wagon or mine car cannot proceed without becoming an obstruction to another wagon or car traveling on the intersecting rail.


a. Eng. A condition in which seams of coal disappear for a certain space and are replaced by some foreign matter. See also: fault.

b. The cutting out of portions of the coal seam by wash outs or barren ground.


a. To form in a mold, such as articles of cast iron, by melting the metal and pouring; cast.

b. The name for the melting operation that the raw materials undergo in a furnace.

foundation bolt

A fastener for connecting a structure or machine to a permanent base. See also: anchor bolt.

foundation curb

A construction in a sinking shaft that will provide support for the concrete lining. It consists of a wedge-shaped excavation around the shaft in solid ground that is filled up completely with wet concrete. Steel shuttering is used and the concrete is filled in behind. Also called foundation canch; foundation crib; walling curb. See also: curb; permanent shaft support.

foundation investigation

A branch of soil mechanics involving the drilling and testing of the deposits underlying a proposed foundation. It includes the estimation of bearing capacities, settlements, and the most suitable type of foundation for the prevailing soil conditions. See also: bearing capacity; depth of soil exploration.

foundation testing

Testing in which boreholes are drilled for the purpose of obtaining samples by means of which the characteristics of overburden and/or the rock on which the foundation of a structure will rest can be determined.

founder breccia

See: collapse breccia.


The act or process of casting metals.

foundry sand

Sand used by founders in making molds for castings. See also: fire sand.

four-cutter bit

See: roller rock bit.


An axis of symmetry requiring four repetitions to complete 360 degrees and return to identity. Syn: tetrad.

four-high mill

A mill that contains four rolls arranged one above the other; i.e., two small-diameter working rolls supported by larger diameter back-up rolls above and below.


A crystal twin consisting of four individuals; characteristic twinning exhibited by some varieties of authigenic microcline. CF: trilling; fiveling; eightling.


An orthorhombic mineral, PbU (sub 4) O (sub 13) .4H (sub 2) O ; strongly radioactive; in pegmatites as an alteration product of uraninite.

four-piece set

Squared timber frame used in underground driving to give all around support to weak ground. A cap is supported by two posts on a sill-piece or sill. See also: timber set; three-piece set.

four-way dip

In seismic operations, a dip determined by spreads placed in four directions from a shot point. Three are essential, and the fourth serves as a check.


A variety of rhodonite containing up to 10% zinc.


See: iron pan.


A nepheline syenite with predominant orthoclase and a trachytic texture. Not a name in the I.U.G.S. classification of plutonic rocks. Syn: midalkalite. See also: nepheline syenite.