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

Ceag Montlucon gas detector

This nonautomatic detector has the appearance of a mine official's electric hand lamp. It indicates on an illuminated scale percentages of methane from 0 to 3 in steps of 0.1. When a test for combustible gases is to be made, the projecting front piece is turned part of a revolution; this extinguishes the main light and lights up the illuminated scale. A sample of air is flushed into the detector by means of a small aspirator (or hand pump), the button switch at the side is operated, and the percentage of combustible gases, if any, is indicated on the illuminated scale.

cedarite

See: chemawinite.

ceiling concentration

The concentration of an airborne substance that shall not be exceeded during any part of the working exposure.

celadonite

The mineral monoclinic K(Mg,Fe)(Fe,Al)Si (sub 4) O (sub 10) (OH) (sub 2) ; mica group; soft; green or gray-green; earthy; generally occurs in cavities in basaltic rocks. Formerly called kmaite. Syn: svitalskite. CF: glauconite.

celestine

An orthorhombic mineral, 4 ; barite group; disseminated through limestone and sandstone; a source of strontium. Also called celestite.

celestite

See: celestine.

celite

A constituent of Portland cement clinkers. Also spelled celith. See also: brown millerite.

cell

a. A compartment in a flotation machine.

b. A single element of an electric battery, either primary or secondary. c. Battery unit consisting of two electrodes separately contacting an electrolyte so that there is a potential difference between them. d. See: galvanic cell; local cell.

cellar

Excavated area under a drill-derrick floor to provide headroom for casing and pipe connections required at the collar of a borehole, or to serve as a covered sump. See also: cave.

cell feed

The material supplied to the cell in the electrolytic production of metals.

cell texture

A network along grain boundaries, which may originate by segregation on exsolution. A similar texture may form by the replacement of organic forms, esp. cell walls, by ore minerals.

cellular

Said of the texture of a rock (e.g., a cellular dolomite) characterized by openings or cavities, which may or may not be connected. Although there are no specific size limitations, the term is usually applied to cavities larger than pores and smaller than caverns. The syn. vesicular is preferred when describing igneous rocks. CF: porous; cavernous; vesicular.

cellular cofferdam

A cofferdam, with a double wall, consisting of steel sheet piling arranged in intercepting rings about 50 ft (15 m) in diameter. The space between the lines of piling is filled with sand.

cellulose

A polymeric carbohydrate composed of glucose units, formula (C (sub 6) H (sub 10) O (sub 5) ) (sub x) , making it the most abundant carbohydrate, and with lignin, an important constituent of plant materials, from which coal is formed.

cellulose nitrate

See: nitrocellulose.

celsian

A rare monoclinic mineral, BaAl (sub 2) Si (sub 2) O (sub 8) ; feldspar group; the barium analog of anorthite; dimorphous with paracelsian.

Celsius

a. Designation of the degree on the International Practical Temperature Scale; also used for the name of the scale, as "Celsius Temperature Scale." Formerly (prior to 1948) called "Centigrade." The Celsius temperature scale is related to the International Kelvin Temperature Scale by the equation T (sub C) = T (sub K) - 273.16.

b. Symbol, C. Graduated to a scale of 100; of or pertaining to such a scale. On the centigrade thermometer the freezing point of water is 0 degrees (C) and its boiling point is 100 degrees (C). If any degree on the centigrade scale, either above or below 0 degrees C, is multiplied by 1.8, the result will be, in either case, the number of degrees above or below 32 degrees F, or the freezing point of Fahrenheit.

cement

a. A manufactured gray powder which when mixed with water makes a plastic mass that will set or harden. It is combined with aggregate to make concrete. Nearly all of today's production is portland cement. See also: cement rock.

b. To place cement in a borehole to seal off caves or fissures or to fill cavities or caverns encountered in drilling. c. Mineral material, usually chemically precipitated, that occurs in the spaces among the individual grains of a consolidated sedimentary rock, thereby binding the grains together as a rigid, coherent mass; it may be derived from the sediment or its entrapped waters, or it may be brought in by solution from outside sources. The most common cements are silica (quartz, opal, chalcedony), carbonates (calcite, dolomite, siderite), and various iron oxides. Others include clay minerals, barite, gypsum, anhydrite, and pyrite. Detrital clay minerals and other fine clastic particles may also serve as cements. d. A term used in gold-mining regions to describe various consolidated, fragmental aggregates, such as breccia, conglomerate, and the like, that are auriferous. e. A finely divided metal obtained by precipitation. The word in this sense is generally used in combination, such as, cement copper, cement gold, or cement silver.

cementation

a. The diagenetic process by which coarse clastic sediments become lithified or consolidated into hard, compact rocks, usually through deposition or precipitation of minerals in the spaces among the individual grains of the sediment. It may occur simultaneously with sedimentation or at a later time. Cementation may occur by secondary enlargement. Syn: agglutination.

b. Filling cavities or plugging a drill hole with cement or other material to stop loss of water or entrance of unwanted liquids, gas, or fragmented rock materials. Also called dental work. c. The process by which loose sediments or sands are consolidated into hard rock by injection of chemical solutions, thin cement slurries, or self-hardening plastic. Also called cementing. d. The introduction of one or more elements into the outer portion of a metal object by means of diffusion at high temperature. e. The precipitation of a more noble metal from solution by the introduction of a less noble metal. f. Usually, the process of raising the carbon content of steel by heating in a carbonaceous medium. Generally, any process in which the surface of a metal is impregnated by another substance. Also called casehardening; carburization; carbonization.

cementation sinking

A method of shaft sinking through water-bearing strata by injecting chemicals or liquid cement into the ground. A number of small-diameter boreholes are put down around the shaft--and about 80 ft (24 m) ahead of the shaft bottom#m-through which cement is forced by means of pumps. The cement, when set, seals the fissures and thus prevents water inflows during sinking. The method is most successful in strong fissured strata and least successful in loose alluvial deposits. See also: grouting; precementation process.

cementation steel

Steel made by a process in which bars of wrought iron are packed into a sealed furnace together with charcoal. The resulting material is blister steel. Syn: cement steel.

cementation water

Water containing dissolved copper or iron sulfates or other metal compounds.

cement clinker

Portland cement as it comes from the kiln.

cement copper

Copper precipitated by iron from copper sulfate in mine water.

cement deposit

Cambrian conglomerate occupying supposedly old beaches or channels. It is gold-bearing in the Black Hills, SD.

cemented carbide

Generally, a mixture of powdered tungsten carbide and cobalt, subjected to pressure and heat to produce bit crowns, small plates, cubes, or cylinders of material having a much greater hardness than steel. Mixtures also may contain small amounts of titanium, columbium, or tantalum carbide. Cobalt may be replaced by powdered nickel. Also called sintered carbide. See also: carbide insert; sintered carbide.

cemented carbide tool

A tool made from pulverized carbides and fused into a hard tip for heavy-duty or high-speed cutting of metals.

cement gold

Gold precipitated in fine particles from solution by a more active metal.

cement grout

A pumpable thin slurry consisting primarily of a mixture of cement, sand, and water; injected into rock formations through boreholes as a sealant. Also called grout; grouting; cement grouting.

cement gun

A mechanical device for the application of cement, in the form of gunite, to the walls or roofs of mine openings or building walls. Also called gunite gun.

cementite

a. Identical with cohenite, a meteoritic material.

b. An orthorhombic FeC (sub 3) that occurs as a phase in steel and changes composition in the presence of manganese or other carbide-forming metals. See: cohenite.

cementitious

Having the property of or acting like cement, such as certain limestones and tuffs when used in the surfacing of roads.

cement-modified soil

The addition of small quantities of cement (1% to 2%) to fine-grained soils to reduce the liquid limit, plasticity index, and water-absorption tendency. The effect of the cement is to bring individual soil particles into aggregations, thus artificially adjusting the grading of the soil. See also: soil stabilization.

cement mortar

Made from four (or less) parts of sand, one of cement, and adequate water.

cement plug

Hardened cement material filling a portion of a borehole.

cement rock

a. Any rock that is capable of furnishing cement when properly treated.

b. Scot. Argillaceous limestone-magnesian. See also: hydraulic limestone.

cement silver

Silver precipitated from solution, usually by copper.

cement slurry

A pourable or pumpable mixture of water, cement, and fine sand-- having the consistency of a thick liquidlike heavy cream.

cement stabilization

The addition of cement to a soil, which acts as a binding agent and produces a weak form of concrete called soil cement. The quantity of cement to be added depends upon the type of soil. Cement can be used with most types of soil, providing the clay fraction is reasonably small and other specified impurities are not present. A small percentage of lime is usually added. With very poor soils, cement stabilization may be uneconomical or impracticable. See also: soil stabilization.

cement steel

See: cementation steel.

cement valve

A ball, flapper, or clack-type valve placed at the bottom of a string of casing, through which cement is pumped. When pumping ceases, the valve closes and prevents return of cement into the casing.

Cenozoic

An era of geologic time, from the beginning of the Tertiary period to the present. (Some authors do not include the Quaternary, considering it a separate era.) The Cenozoic is considered to have begun about 65 million years ago. Also spelled: Cainozoic; Kainozoic.

center

A temporary timber framework upon which the masonry of an arch of reinforced masonry lintel is supported until it becomes self-supporting. See also: centers.

center adjustment

In surveying, a system that allows accurate final centering of the theodolite above (or below) its station by sliding the whole instrument on its stand (tribrach). Important with short sights where small centering errors could introduce serious inaccuracy.

center brick

A special, hollow, refractory shape used at the base of the guide tubes in the bottom pouring of molten steel. The center brick has a hole in its upper face, and this is connected via the hollow center of the brick to holes in the faces (often six in number). The center brick distributes molten steel from the trumpet assembly to the lines of runner bricks. It is also sometimes known as a crown brick or spider.

center constant

In air velocity determination, the ratio of the mean velocity to the velocity measured at the center. This ratio is found to be dependent upon the Reynolds number. See also: Reynolds number.

center core method

A method of tunneling whereby the center is left to the last for excavation.

center country

Aust. The rock between the limbs of a saddle reef.

center drilling

Drilling a conical hole (pit) in one end of a workpiece.

centering of shaft

The fixing of the center spot of a proposed shaft at the site selected and the maintenance of the shaft sinking along this plumb line during its entire depth. See also: plumbing.

center-latch elevator and links

See: elevator.

centerline

a. A line marked on the roof of a mine roadway, or a plumbline, for controlling the direction in which the roadway is driven.

b. In U.S. public land surveys, the line connecting opposite quarter-section or sixteenth-section corners.

centerman

In anthracite and bituminous coal mining, one who locates the centerline of underground openings in a mine, such as entries, rooms, and haulageways, so that the miners can drive the openings in a straight line without calling the mine surveyor.

center of gravity

a. The center of mass of a cut or a fill.

b. That point in a body or system of bodies through which the resultant attraction of gravity acts when the body or system is in any position; that point from which the body can be suspended or poised in equilibrium in any position.

center of mass

a. The point that represents the mean position of the matter in a body.

b. The point in a body through which acts the resultant resisting force due to the body's inertia when it is accelerated. Coincident with the center of gravity. c. In a cut or a fill, a cross section line that divides its bulk into halves. d. Also called center of inertia.

center of shear

See: torsional center.

center of symmetry

In crystallography, an element of symmetry such that, for each and every lattice point, asymmetric unit, or crystal plane, there is another equidistant in the opposite direction. It is represented by i or by 1. Adj. centric or centrosymmetric. Syn: inversion.

center of torsion

See: torsional center.

center of twist

See: torsional center.

center prop

Eng. A prop set temporarily under the center of a plank to support it before props are set at the ends of the plank. Syn: middle prop.

centers

a. Framed supports, usually arch shaped, upon which are placed the lagging boards used, in building an arch, for supporting the roof of a tunnel. See also: center.

b. Linear distance between coal-mine entries or crosscuts.

center shot

A shot in the center of the face of a room or entry. Also called center cut.

center spinning

A method of casting molten metal, in which the molds are spun and centrifugal force helps to fill them.

center-trace time

One of two approaches used in plotting seismic reflection data on time cross sections. Center-trace times are the times picked on the two traces from the respective detector groups nearest the shot and on opposite sides. The average of the two times for each reflection is plotted at the shot-point position. The points thus plotted for adjacent shot points are connected by straight lines. CF: trace-by-trace plotting.

centigrade

See: Celsius.

centipoise

The one-hundredth part of a poise, an absolute unit of fluid viscosity. Viscosity of drill-mud fluid is sometimes expressed in centipoise or millipascal-second units. See also: poise.

central breaker

A breaker where the coal from a number of mines in a district is prepared. Central breakers, representing the last word in mining technology, make it economical for operators to abandon many local breakers.

centralizer

A device that lines up a drill steel or string between the mast and the hole.

centrifugal brake

A safety device on a mine hoist drum that applies a brake if the drum speed exceeds the set limit.

centrifugal casting

Casting molten metals in a rapidly revolving mold.

centrifugal clutch

Consists of a driving hub having one or more weighted sections fitted with friction lining on the outer radial surfaces that contact a driven hub having a flange covering that portion of the driving hub containing the radial elements. Upon starting, the radial elements of the driving hub have no appreciable drag, but upon accelerating to the operating speed the force produced by the centrifugal action increases rapidly as the square of the speed and the elements grip the driven element, thereby causing it to speed up to the required speed of the driving hub.

centrifugal discharge bucket elevator

A type of bucket elevator using centrifugal discharge elevator buckets suitably spaced to permit the free discharge of bulk materials. See also: bucket elevator; centrifugal discharge elevator bucket.

centrifugal discharge elevator bucket

A bucket designed to scoop material from the boot of an elevator and discharge by reason of the combined effect of centrifugal force and gravity.

centrifugal fan

a. A type of fan often used in mines and ventilation activities in which an impeller, generally consisting of numerous blades, discharges the air radially into an expanding scroll casing while imparting an increase in pressure to the air.

b. See: radial-flow fan.

centrifugal filter

See: filter.

centrifugal pump

a. A form of pump in which water is drawn through the eye of a rotating impeller and discharged from its periphery into a chamber containing a series of passages of gradually increasing cross section. The kinetic energy given to the water by its centrifugal discharge is thus largely converted to pressure energy. CF: duplex pump.

b. See: turbine pump.

centrifugal replacement

Mineral replacement in which the host mineral is replaced from its center outward. CF: centripetal replacement.

centrifugal separation

a. The separation of different particles by centrifugal action as used in cyclone separators and centrifuges.

b. The use of centrifugal force to increase the apparent density of finely divided particles so as to accelerate their movement with respect to ambient fluid. c. Accelerated settlement of finely divided particles from pulp, removal of moisture, or classification into relatively coarse and fine fractions by centrifuging. Performed on a laboratory scale in small batches and commercially in a hydrocyclone or centrifugal classifier. See also: cyclone; cyclone washer.

centrifugal ventilation

A mine ventilation system in which the air is led through a shaft in the middle of the field into the mine and out again at the periphery of the mining field.

centrifuge

a. A centrifugal device for dewatering, usually conical or bowl-shaped, in which the containing surface is imperforated. The greater density of the solid particles causes them to collect preferentially in contact with the inside of the containing surface where they are discharged mechanically; the water usually overflows from a position nearer to the axis.

b. A rotating device for separating liquids of different specific gravities or for separating suspended colloidal particles, such as clay particles in an aqueous suspension, according to particle-size fractions, by centrifugal force. Colloidal particles that cannot be deposited from suspension by gravity can be deposited by centrifugal force in a supercentrifuge. See also: cyclone. Syn: hydroextractor.

centrifuging

Dewatering of clean coal or refuse with the aid of centrifugal force. See also: centrifugal separation.

centripetal drainage

Drainage more or less radially inward toward a center.

centripetal pump

A pump with a rotating mechanism that gathers a fluid at or near the circumference of radial tubes and discharges it at the axis.

centripetal replacement

Mineral replacement in which the host mineral is replaced from its periphery inward. CF: centrifugal replacement.

centrocline

Said of strata and structures that dip toward a common center. Ant: quaquaversal. CF: periclinal. See also: centrocline. 0� [�� ��� _�� � � ��DICTIONARY TERMS:centrocline An equidimensional basin characteristic An equidimensional basin characteristic of cratonic areas, in which the strata dip toward a central low point. The term is little used in the United States. CF: pericline. Ant: quaquaversal. See also: centroclinal.

centrosphere

See: barysphere; core of the Earth.

centrosymmetrical

Having a center of symmetry. Centrosymmetric crystal structures cannot exhibit pyroelectricity or piezoelectricity.

ceramet

Substance formed of a mixture of metal and ceramic, to give the requisite conductivity to the latter.

ceramic

a. As a singular or plural noun, any of a class of inorganic, nonmetallic products that are subjected to a high temperature during manufacture or use.

b. As an adj., of or pertaining to (1) ceramic--that is, inorganic or nonmetallic as opposed to organic or metallic; (2) products manufactured from inorganic nonmetallic substances, which are subjected to a high temperature during manufacture or use; (3) the manufacture or use of such articles or materials, such as ceramic process or ceramic science.

ceramic cone

See: pyrometric cone.

cerargyrite

A former name for chlorargyrite, AgCl. Also spelled kerargyrite.

cerhomilite

Borosilicate of calcium, beryllium, iron, thorium, and rare earths.

cerianite

An isometric mineral (Ce,Th)O (sub 2) ; forms minute greenish-yellow grains; named for its relationship to thorianite and uraninite.

cerite

A trigonal mineral, (Ce,Ca) (sub 10) (SiO (sub 4) ) (sub 6) (OH,F) (sub 5); generally brown, massive.

cerium

One of the most abundant of the rare earth metals. Symbol, Ce. The minerals monazite and bastnasite are presently its two most important sources. It is used in the manufacture of pyrophoric alloy. The oxide is a constituent of incandescent gas mantles and is emerging as a catalyst in self-cleaning ovens. The sulfate is used as an oxidizing agent in quantitative analysis. Other cerium compounds are used in the manufacture of glass, as a polishing agent, and in carbon-arc lighting, petroleum refining, and metallurgical and nuclear applications.

cermet

A material or body consisting of ceramic particles bonded with a metal. According to the American Society for Testing and Materials, the ceramic phase must be present in 15% or more of the body. A ceramic foam or porous ceramic is not a cermet because the bonding of the ceramic structure is not dependent on or due to the metal.

cerolite

See: kerolite.

cerro

A term used in the Southwestern United States for a hill, esp. a craggy or rocky eminence of moderate height. Etymol: Spanish.

certified

a. A certified employee is one who has been granted a State certificate of competency for a given job.

b. Evaluated and listed as permissible by the National Institute for Occupational Safety and Health or the Mine Safety and Health Administration.

Certified Blaster

A blaster certified by a government agency to prepare, execute, and supervise blasting.

cerulene

a. A trade name for a form of calcium carbonate colored green and blue by malachite or azurite, and used as a gemstone. From Bimbowrie, south Australia.

b. A term used less correctly for a blue variety of satin spar.

ceruleofibrite

A former name for connellite. Also spelled caeruleofibrite.

cerussite

An orthorhombic mineral, 4 ; aragonite group; adamantine; sp gr, 6.55; in oxidized and carbonated parts of lead-ore veins; a source of lead. Syn: white ore; white lead ore; lead carbonate; lead spar.

cervantite

An orthorhombic mineral, Sb (super 3+) Sb (super 5) O (sub 4) ; may be confused with stibiconite.

cesium

A silvery white, soft and ductile alkaline element, of the rare-earth metals. Symbol, Cs. Occurs in lepidolite and pollucite. Reacts explosively with cold water. Because of its great affinity for oxygen, the metal is used as a "getter" in electron tubes and as a catalyst in the hydrogenation of certain organic compounds; it has recently found application in ion propulsion systems.

cetane number

An indication of diesel fuel ignition quality. The cetane number of a fuel is the percentage by volume of cetane in a mixture of cetane and alpha methylnaphthalene, which matches the unknown fuel in ignition quality. American diesel oil usually ranges from 30 to 60 cetane.

ceylanite

Original spelling of ceylonite. See also: ceylonite.

Ceylonese peridot

The trade name for a yellowish-green variety of tourmaline, approaching olivine in color; used as a semiprecious gemstone. Syn: peridot of Ceylon.

ceylonite

A dark-green, brown, or black variety of spinel containing iron. Syn: pleonaste; candite; ceylanite; zeylanite.

C-frame

An angling bulldozer lift and push frame.

chabazite

A trigonal mineral, 1 ; zeolite group; pseudocubic cleavage; occurs in cavities in basalts and hydrothermal veins and as alteration of silicic vitreous tuffs in alkaline saline lake deposits.

chadacryst

See: xenocryst. Also spelled cadacryst.

chain

a. A measuring instrument that consists of 100 links joined together by rings and is used in surveying. See also: Gunter's chain.

b. A unit of length prescribed by law for the survey of U.S. public lands and equal to 66 ft (20.12 m) or 4 rods. It is a convenient length for land measurement because 10 square chains equal 1 acre (0.4 ha).

chain block

A combination of sheaves over which chains are arranged in the same manner as the rope in a block and tackle. Also called chain hoist.

chain brow way

An underground inclined plane worked by an endless chain.

chain bucket dredger

A dredger with a bucket ladder.

chain bucket loader

A mobile loader that uses a series of small buckets on a roller chain to elevate spoil to the dumping point. Also called bucket loader.

chain casing

See: chain guard.

chain coal cutter

A coal cutter that cuts a groove in the coal by an endless chain traveling around a flat plate called a jib. The chain consists of a number of pick boxes. Each box holds a cutter pick fastened into the box by a set screw or similar device. The coal cutter pulls itself along the face by means of a rope at a speed ranging from 7 in/min (17.8 cm/min) to 5 ft/min (1.5 m/min) or more. The chain travels around the jib at a speed ranging from 320 to 650 ft/min (97.6 to 198.2 m/min). The cut in the coal ranges from 3-1/2 to 7-1/2 in (8.9 to 19.1 cm) high and up to 8-1/2 ft (2.59 m) in length. See also: coal-cutter pick.

chain conveyor

a. A conveyor comprising one or two endless linked chains with crossbars or flights at intervals to move the coal or mineral. The loaded side of the conveyor runs in a metal trough, while the empty side returns along guides underneath. The material is transported on the conveyor partly by riding on the chain and flights and partly by being scraped along in the trough. The chain conveyor is widely used in coal mines, and capacities range up to 100 st/h (90.7 t/h) with lengths of about 100 yd (91 m). See also: armored flexible conveyor.

b. See: drag-chain conveyor.

chain driller

See: chain-machine operator.

chain-driven belt

A conveyor similar in design to those driven by ropes, the essential difference being that the tension is taken by chains, either under or alongside the carrying belt.

chain elevator

See: bucket elevator.

chain feeder

See: conveyor-type feeder.

chain-feeder operator

See: mill feeder.

chain guard

An open guard of sheet metal, expanded metal, or similar construction around a chain drive.

chain hoist

a. A block and tackle in which chain is used instead of rope.

b. See: chain block.

chain lacing

The arrangement of block positions in a cutter chain so that bits inserted in these blocks will occupy certain positions while cutting.

chain machine

Coal-cutting machine that cuts coal with a series of steel bits set in an endless chain moved continuously in one direction either by an electric or a compressed-air motor. These machines may be divided into four classes, known as breast machines, shortwall machines, longwall machines, and overcutting machines.

chain-machine operator

In bituminous coal mining, one who operates a chain-driven machine to undercut coal preparatory to blasting it loose from the working face with explosives. Also called chain driller.

chain pillar

A pillar left to protect the gangway and airway, and extending parallel to these passages.

chain pitch

For a roller chain, the distance in inches between the centers of adjacent joint members. For a silent chain, the distance in inches between the centers of the holes in a link plate.

chain road

Main underground haulage road through which tubs are hauled by an endless chain.

chain-selvage belt

A belt in which the carrying section may be made up of rubber or fabric, woven metal, or other material and along each edge of which is fastened an endless chain with a suitable attachment. The chains carry the driving tension. The center part functions only as a loading supporting medium.

chain silicate

Silicate mineral with silica tetrahedra linked by shared oxygens into infinite one-dimensional chains. Single chains characterize pyroxenes; double chains characterize amphiboles; and wider chains grade toward sheet structures.

chain structure

A structure or texture found in a number of chromite occurrences, consisting of a series of connected chromite crystals somewhat resembling a chain.

chain surveying

The simplest method of surveying, which has the advantage that the equipment required is inexpensive and hard wearing. It is the ideal method for small areas and has been employed successfully for large surveys. Nevertheless, it has definite limitations when applied to surveys of enclosed or built-up areas.

chain takeup

An idler sprocket, or similar device, mounted on an adjustable bracket to adjust the slack in a chain drive. See: takeup.

chain tension

The actual force existing at any point in a conveyor chain.

chain-type conveyor

A conveyor using a driven endless chain or chains, equipped with flights that operate in a trough and move material along the trough.

chainwall

a. A method of mining coal in which the roof is supported by pillars of coal between which the coal is mined away.

b. Scot. A system of working by means of wide rooms and long, narrow pillars, sometimes called "room and rance." c. Scot. A long, narrow strip of mineral left unworked; e.g., along the low side of a level.

chain width

For a roller chain, the distance between the link plates of a roller link. This is not the overall width of the chain. For a silent chain, the width over the working-link plates of the chain, exclusive of pinheads, washers, or other fastening devices.

chair

a. Movable support for a cage, arranged to hold it at the landing when desired. See also: catch; dog; rests.

b. Projection that can be set into a guide so that the skip or cage descending in the mine shaft is brought to rest at the correct level. c. A cast-iron support bolted to a timber or concrete railway sleeper used to hold a bullhead rail in position.

chalcanthite

a. A triclinic mineral 2 ; azure blue; metallic taste; occurs in the oxidized supergene zone above copper sulfides in arid regions; a minor ore of copper. Syn: blue vitriol; copper sulfate; copper chalcanthite; copper vitriol; bluestone; cyanosite.

b. The mineral group chalcanthite, jokokuite, pentahydrite, and siderotil.

chalcedonite

Fibrous quartz with a negative elongation. See also: chalcedony.

chalcedony

a. A fine-grained or cryptocrystalline variety of quartz; commonly microscopically fibrous; translucent or semitransparent, with a nearly waxlike luster; has lower density and indices of refraction than ordinary quartz. Chalcedony is the material of much chert, flint, and jasper; commonly an aqueous deposit filling or lining cavities in rocks. In the gem trade, the name refers specif. to the light blue-gray or common variety of chalcedony. Varieties include carnelian, sard, chrysoprase, prase, plasma, bloodstone, onyx, and sardonyx. See also: agate. Syn: calcedony, chalcedonite; white agate.

b. A general name for crystalline silica that forms concretionary masses with radial-fibrous and concentric structure and that is optically negative (unlike true quartz). c. A trade name for a natural blue onyx.

chalchuite

A blue or green variety of turquoise.

chalco-

(prefix) A combining form meaning copper.

chalcoalumite

A monoclinic mineral, CuAl (sub 4) (SO (sub 4) )(OH) (sub 12) .3H (sub 2) O .

chalcocite

A monoclinic mineral, 96 ; pseudohexagonal, metallic gray-black with blue to green tarnish; sp gr, 5.5 to 5.8; a secondary vein mineral; an important source of copper. Syn: redruthite; copper glance; chalcosine; beta chalcocite; vitreous copper; vitreous copper ore.

chalcocyanite

An orthorhombic mineral, CuSO (sub 4) ; white; it becomes blue upon hydration, thus formerly called hydrocyanite.

chalcodite

See: stilpnomelane.

chalcogene

Said of ore deposits, such as those of copper, connected with a phase of mountain building and plutonism.

chalcolite

See: torbernite.

chalcomenite

An orthorhombic mineral, CuSeO (sub 3) .2H (sub 2) O ; dimorphous with clinochalcomenite.

chalcomiklite

See: bornite.

chalcophanite

A trigonal mineral, (Zn,Fe,Mn)Mn (sub 4) O (sub 7) .3H (sub 2) O . Formerly called hydrofranklinite.

chalcophile

Said of an element tending to concentrate in sulfide minerals and ores. Such elements have intermediate electrode potentials and are soluble in iron monosulfide. Examples are S, Se, As, Fe, Pb, Zn, Cd, Cu, and Ag. CF: lithophile.

chalcophyllite

A trigonal mineral, Cu (sub 18) Al (sub 2) (AsO (sub 4) ) (sub 3) (SO (sub 4) ) (sub 3) (OH) (sub 27) .33H (sub 2) O ; green; forms tabular crystals and foliated masses.

chalcopyrite

a. A tetragonal mineral, CuFeS (sub 2) ; brass-yellow with bluish tarnish; massive; softer than pyrite; occurs in late magmatic hydrothermal veins and secondary enrichment zones; the most important source of copper. Syn: copper pyrite; cupriferous pyrite; yellow copper ore; yellow ore; yellow pyrite; yellow copper.

b. The mineral group chalcopyrite, eskebornite, gallite, and roquesite.

chalcopyrrhotite

A former name for cubanite.

chalcosiderite

A triclinic mineral, CuFe (sub 6) (PO (sub 4) ) (sub 4) (OH) (sub 8) .4H (sub 2) O ; turquoise group; occurs in sheaflike crystalline incrustations; forms a series with turquoise.

chalcosine

See: chalcocite.

chalcostibite

A lead-gray copper-antimony sulfide, CuSbS (sub 2) . Also called wolfsbergite. Syn: rosite; antimonial copper.

chalcotrichite

A capillary variety of cuprite in fine, slender interlacing fibrous crystals. Syn: cuprite; plush copper ore; hair copper.

chalk

A soft, earthy, fine-textured, usually white to light-gray or buff limestone of marine origin. It consists almost wholly (90% to 99%) of calcite, formed mainly by shallow-water accumulation of calcareous remains of floating microorganisms (chiefly foraminifers) and of comminuted remains of calcareous algae, set in a structureless matrix of very finely crystalline calcite. The rock is porous, somewhat friable, and only slightly coherent.

chalk rock

Any soft, milky-colored rock resembling white chalk, such as talc, calcareous tufa, diatomaceous shale, volcanic tuff, or white limestone.

chalky chert

A commonly dull or earthy, soft to hard, sometimes finely porous chert of essentially uniform composition, having an uneven or rough fracture surface, and resembling chalk. Syn: dead chert. Obsolete syn: cotton chert. CF: granular chert.

challenge feeder

Ore feeder used with stamp batteries to regulate the rate of entry of ore to a mortar box. A horizontal plate is turned by linkages operated when the central stamp falls below a prefixed point; it then draws ore from feeding bin.

chalmersite

A former name for cubanite.

chalybite

See: siderite.

chamber

a. A miner's working place, sometimes referred to as a room or breast.

b. A large irregular or rounded body of ore, occurring alone or as an expansion of a vein. c. A body of ore with definite boundaries, apparently filling a preexisting cavern. d. A powder-storage room in a mine. e. To enlarge the bottom of a drill hole by the use of explosives, so that a sufficient blasting charge may be loaded for the final shot. Syn: spring. f. A space or gallery excavated in a quarry or underground mine to receive a large explosive charge. See also: heading blast.

chamber-and-pillar

See: breast-and-pillar.

chamber-and-pillar system

A modification of sublevel stoping by which a series of sublevels are successively caved. See also: sublevel stoping.

chamber blast

A large-scale blast in which explosives in bulk are placed in excavated subterranean chambers. Also called coyote blast; gopher-hole blast.

chambered lode

A portion of the wall of a lode that is fissured and filled with ore. See also: chamber.

chambered vein

a. A vein in which the walls, particularly the hanging wall, are irregular and brecciated, owing to the formation of the vein under low pressure at shallow depth. See also: chambered lode.

b. Stockwork.

chambering

a. The process of enlarging a portion of a blast hole (usually the bottom) by firing a series of small explosive charges. It can also be done by mechanical or thermal methods.

b. The enlarging of the bottom of a quarry blasting hole by the repeated firing of small explosive charges. The enlarged hole or chamber is then loaded with the proper explosive charge, stemmed, and fired to break down the quarry face. See also: concentrated charge. c. A borehole in which portions of the sidewalls are breaking away and forming cavities or small chambers.

chambersite

An orthorhombic mineral, Mn (sub 3) B (sub 7) O (sub 13) Cl ; the manganese analogue of boracite; occurs in brines.

chambers without filling

See: sublevel stoping.

chameleonite

A rare variety of tourmaline, olive green in daylight, changing to brownish-red in most artificial light. Syn: alexandritelike tourmaline.

chamfer

To bevel or slope an edge or corner. Also spelled chanfer.

chamoisite

See: chamosite.

chamosite

A monoclinic mineral, 2 ; chlorite group; a constituent of oolitic iron ores and sedimentary ironstones. Also spelled chamoisite.

chamotte

The refractory portion of a mixture used in the manufacture of firebrick, composed of calcined clay or of reground bricks.

Champlain forge

A forge for the direct production of wrought iron, generally used in the United States instead of the Catalan forge, from which it differs in using only finely crushed ore and in working continuously. Syn: American forge.

chance

a. In coal mining, the opportunity a shot has to break the coal.

b. The opportunity to put in a shot in a good position.

Chance cone

See: cone classifier.

Chance sand-flotation process

A dense-media process in which coal is separated from refuse in an artificial dense medium of sand suspended in water. The specific gravity of this medium is such that the merchantable coal floats while the refuse sinks to the bottom, the separation being analogous to that of a float-and-sink separation with a heavy liquidlike zinc chloride. Named after Thomas M. Chance, U.S. mining engineer.

changehouse

A special building at a mine where workers may wash themselves or change from street to work clothes and vice versa. Also called changing house; dry; dryhouse. CF: doghouse.

changing bronze

The process of changing tuyeres, plates, monkey, etc., at blast furnaces.

changing house

See: changehouse.

changkol

Malay. A heavy Chinese hoe with an eye in which the handle fits; used in cutting soft rock and earth and for stirring gravel in sluice boxes, etc.

channeler

a. A powerful quarrying machine capable of cutting slots in stone at any angle. It is used for cutting dimension stone off the quarry face without explosives. See also: broaching. Syn: channeling machine.

b. A machine that cuts a deep groove in rock, ordinarily to free dimension stone from the mass, or to make a smooth side for a canal or other excavation in rock. Cutting is accomplished by a group of reciprocating chisel-pointed bars, operated by steam or compressed air while the machine carrying them travels back and forth on a track. Ordinarily used only in the softer rocks, such as limestone, soapstone, or slate. Also called track channeler; bar channeler.

channeling

a. In ion-exchange, fixed-bed work, development of passages in a resin column through which the liquors flow preferentially so that the resin is unequally loaded.

b. In cyanide sand leaching, cracks in the sand bed through which cyanide solution runs without proper percolating contact with a mass of particles. c. The action of a blast furnace in opening up irregular openings for the blast.

channeling machine

See: channeler.

channeling-machine operator

a. In bituminous coal mining, one who operates a coal-cutting machine to cut channels (a few inches wide) in coal, after the overlying ground has been removed, to partly detach coal in blocks so that it may be broken loose more easily by blasting. Also called channeler-machine operator; channel-machine operator.

b. In the quarry industry, one who sets up and operates a track-mounted machine that cuts (drills) vertical channels (a few inches wide) in quarrystone in which wedges are driven to crack off a block from the mass. Also called channeler-machine operator; channeler runner; channel-machine operator; channel-machine runner.

channel man

In ore dressing, smelting, and refining, one who installs new channel irons to form a supporting framework for a continuous anode.

channel sample

Material from a level groove cut across an ore exposure to obtain a true cross section of it. Syn: groove sample; strip sample.

channel sampling

See: trench sampling.

channel sand

A sand or a sandstone deposited in a stream bed, or some other channel eroded into the underlying rock; it frequently contains oil, gold, or other valuable minerals.

channel slide rail

One of a pair of rails used in a method of temporary rail-track advance at a tunnel face. The rails comprise a pair of specially made channels with ramp ends. They fit over the rail section in use and are pushed forward periodically as a power loader clears the rock ahead. The permanent track is extended as space becomes available.

channel terrace

A contour ridge, built of soil moved from its uphill side, that serves to divert surface water from a field.

channelway

An opening or passage in a rock through which mineral-bearing solutions or gases may move.

chapeau de fer

a. Scot. A customary and rough mode of judging, by sound, of the thickness of coal between two working places, by knocking with a hammer on the solid coal.

b. To examine the face of the coal, etc., for the sake of safety, by knocking on it lightly. c. Scot. A blow, rap, knock, or stroke. See also: chapping; sounding. �� �L� �N� �A8�� � A DICTIONARY TERMS:chapeau de fer A French term for gossan or iron hat A French term for gossan or iron hat.

chapelet

a. A machine for raising water, or for dredging, by buckets of an endless chain passing between two rotating sprocket wheels.

b. A chain pump having buttons or disks at intervals along its chain; paternoster pump. c. A device for holding the end of heavy work, such as a cannon, in a turning lathe.

Chapman-Jouget plane

In a detonating explosive column, the plane that defines the rear boundary of the primary reaction zone. The plane is the point within the reaction at which all thermodynamic properties of temperature, pressure, energy, gas, volume, and density are measured and calculated. Syn: C-J plane.

Chapman process

A method of gold recovery in which cyanidation dissolves the metal from an ore pulp and the aurocyanide is simultaneously absorbed by activated carbon. This last is then retrieved by froth flotation.

Chapman shield

A pair of vertical plates of sheet iron or steel arranged with a ladle between them, which can be moved longitudinally along the front of a furnace; it is mainly used to protect laborers from furnace heat.

chapping

Rough guess of distance separating two approaching drives underground made by knocking with a heavy hammer. See also: chap.

chapra

A term used in Bihar, India, for a kind of hoe used in mines for scraping waste debris into pans for carrying or loading cars.

char

The solid carbonaceous residue that results from incomplete combustion of organic material. It can be burned for heat, or, if pure, processed for production of activated carbon for use as a filtering medium. See also: coke.

characteristic ash curve

The curve obtained from the results of a float-and-sink analysis showing, for any yield of floats (sinks), the ash content of the highest density (lowest density) fraction passing into these floats (sinks), the yield being plotted on the ordinate and the ash content on the abscissa.

characteristic curve

In general, a curve that defines one or more of the characteristics or properties of a piece of machinery, such as a fan, pump, motor, etc. See also: mine-ventilation fan characteristics.

characteristic impedance

a. Of an explosive, the amount of energy transferred to a given rock is a linear function of the product of density and rate of detonation.

b. For rock, density times velocity of longitudinal waves in the rock.

characteristic radiation

High-intensity, single-wavelength X-rays, characteristic of the element emitting the rays, that appear in addition to the continuous white radiation whenever the voltage of an X-ray tube is increased beyond a critical value.

characterizing accessory mineral

See: varietal mineral.

charcoal blacking

Charcoal used in pulverized form as dry blacking or in suspension with clay as a black wash; either dusted or coated on the surface of molds to improve the surface.

charcoal iron

Sulfur-free pig iron made in a charcoal furnace; it has higher quality, higher density, and closer structure than other iron.

charcoal tinplate

Tinplate with a relatively heavy coating of tin (higher than the coke tinplate grades).

charge

a. The liquid and solid materials fed into a furnace for its operation or prepared for further processing.

b. The explosive loaded into a borehole for blasting; also, any unit of an explosive, such as a charge of nitroglycerin or a charge of detonating composition in a blasting cap. c. To put an explosive into a hole, to arrange the fuse or squib, and to tamp it. CF: load.

charged hole

Hole to be blasted that contains explosive material and a detonator; for blasting operations under the jurisdiction of the Mine Safety and Health Administration (MSHA), charged holes must be detonated within 72 h of charging unless prior approval has been obtained from MSHA (CFR 30, 1988 - 56.6094).

charge limit

For an explosion, the maximum weight of charge that can be fired without causing an ignition in gallery tests.

chargeman

a. A stallman.

b. A laborer who moves a mixture of concentrate, slag, and fluxing ingredients through a hopper into charge pipes opening into a reverberatory furnace where smelting takes place, using an air-pressure hose. Also called feeder.

charger

a. A remotely controlled device for moving single wagons at a mine surface over a short distance. The device runs on a narrow-gage track alongside the main rails and uses a pair of roller arms, which extend to engage on either side of a wagon wheel. Propelled by a guided chain engaging a power-drive chain wheel, the charger can position a wagon exactly where required.

b. In the iron and steel industry, one who loads steel ingots into a furnace for heating, withdraws white-hot ingots from the furnace, and positions them on the bed of a mill for rolling, using a traveling electric charging machine. c. See: lidman.

charge weigher

In ore dressing, smelting, and refining, one who weighs out specified amounts of coke, limestone, and copper-bearing scrap materials to make furnace charges for recovery of copper from plant refuse.

charging

a. The loading of a borehole with explosives.

b. The arranging of a fuse or squib, and the tamping of the hole with stemming material. c. Feeding raw material into an apparatus, such as a furnace, for treatment or conversion.

charging box

A box in which ore, scrap, pig iron, fluxes, etc., are conveyed to a furnace by means of a charging machine.

charging machine

A machine for delivering coal, ore, or metals to a furnace, gas retort, coke oven, or other reactor.

charging peel

A long arm or extension attached to a charging machine for conveying and dumping scrap into an open-hearth furnace.

charging person

A laborer who charges an electric-arc furnace with metals, alloys, and other materials. Also called furnace feeder. See also: furnace charger.

charging rack

A device used for holding batteries for mining lamps and for connecting them to a power supply while the batteries are being recharged.

charging scale

A scale for weighing the various materials used in a blast furnace.

chark

a. To burn to charcoal or coke.

b. Charcoal; coke; cinder.

charred peat

Peat artificially dried at a temperature that causes partial decomposition.

chart

A base map conveying information about something other than the purely geographic; also, a special-purpose map; esp. one designed for purposes of navigation, such as a hydrographic chart or a bathymetric chart.

chart datum

The plane to which soundings on a chart are referred, usually low water.

chaser

An edge wheel revolving in a trough for crushing asbestos mineral, without destroying the fiber, and for fine crushing of ore.

chaser mill

a. This type of mill usually consists of a cylindrical steel tank that is lined with wooden blocks laid with the end grain up. The rollers are usually wooden--with a speed of 15 to 30 rpm.

b. Occasionally synonymous with an edge-runner mill.

chasing

Following a vein by its range or direction.

chasing the vein

Derb. Following a vein along the surface by means of cast holes or prospect pits.

chasm

A yawning hollow or rent, as in the Earth's surface; any wide and deep gap; a cleft; fissure. See also: abyss.

chasovrite

A variety of clay mineral (glinite) from the Chasovyar deposit in the Ukraine.

chat

The finely crushed gangue remaining after the extraction of lead and zinc minerals in the Tri-State District of Missouri, Kansas, and Oklahoma. The term is derived from chert. See also: chats.

chatoyance

See: chatoyancy.

chatoyancy

An optical phenomenon, possessed by certain minerals in reflected light, in which a movable wavy or silky sheen is concentrated in a narrow band of light that changes its position as a mineral is turned. It results from the reflection of light from minute, parallel fibers, cavities or tubes, or needlelike inclusions within the mineral. The effect may be seen on a cabochon-cut gemstone, either distinct and well defined (such as the narrow, light-colored streak in a fine chrysoberyl cat's-eye) or less distinct (such as in the usual tourmaline or beryl cat's-eye). Syn: chatoyance.

chatoyant

a. Having a luster resembling the changing luster of the eye of a cat as seen at night. See also: cat's-eye.

b. adj. Said of a mineral or gemstone possessing chatoyancy or having a changeable luster or color marked by a narrow band of light. c. A chatoyant gem.

chatroller

An ore-crushing machine, consisting of a pair of cast-iron rollers, for grinding roasted ore.

chats

a. Northumb. Small pieces of stone with ore.

b. Eng. A low grade of lead ore. Also, middlings that are to be crushed and subjected to further treatment. The mineral and rocks mixed together that must be crushed and cleaned before being sold as mineral. Chats are not the same as tailings, as the latter are not thrown aside to keep for future milling. c. See: chat. d. Eng. Bowse when broken up on the knockstone ready for the hotchin tubs; Yorkshire lead mines. e. A quarrying term for cherty rock used as an abrasive.

chatter

a. Rapid vibrations caused by overfeeding a bit and/or by drill rods rubbing against the sidewalls of a borehole.

b. In grinding, a vibration of the tool, wheel, or workpiece producing a wavy surface on the work. c. The finish produced by such vibrations during grinding.

chattermark

A spiral or flutelike, round-topped ridge, sometimes seen on the outside surface of a drill core.

check

a. Applied to slit canvas or brattice cloth placed across a passage to prevent the flow of air while still permitting the passage of personnel and equipment. See also: check curtain.

b. A brass disk with a miner's lamp number punched on it that a person exchanges for a lamp at the lamp room every time the person enters or leaves the mine.

check battery

A battery to close the lower part of a chute acting as a check to the flow of coal, and as a stopping to keep air in the breasts.

check board

A board usually posted at the entrance to a mine or to a section of a mine on which (1) miners hang their identification checks to show whether they are in or out, or (2) the miners' loading checks are hung.

checkboarding

To divide property in a manner so that two parties acquire title to alternating and equal-size square sections of land.

check curtain

a. See: curtain.

b. Ventilation control consisting of jute or nylon material fastened to the roof and placed across an entry or a crosscut. It is used to direct the air to the working place, yet allow the passage of equipment and persons.

check dam

A dam that divides a drainageway into two sections with reduced slopes.

checker arch

One of the firebrick supports built of arch brick or keys to support the checker work on the second, third, or fourth pass of hot-blast stoves.

checkerboard drilling

See: checkerboarded.

checkerboarded

An area in which boreholes have been placed at the intersections of equally spaced parallel lines laid out on a square grid or checkerboard pattern.

checkerboard system

See: bord-and-pillar method.

checking

Temporarily reducing the temperature or the volume of the air blast on a blast furnace.

checkout

Scot. The meeting of the roof and floor, the coal seam being thereby cut off; to pinch out.

check screen

See: oversize control screen.

checksheet

A sheet on which are printed illustrations of various drilling equipment assemblies with the component items shown in their relative operating positions; used as a guide in making up a list of the units necessary to do various routine drilling jobs.

check survey

A survey made to confirm the positions of established survey stations in a mine.

check viewer

In bituminous coal mining, one who inspects and checks portions of a mine that have been leased to workers to see that the terms of lease, such as mining within specified limits, safety precautions, and production rate, are duly observed.

checkweigher

In mining, one who checks, in the interest of miners, the weighing of coal in mine cars or other containers by the company weighmaster. The person estimates the amount of slate, dirt, rock, and other foreign matter in the coal and sees that only authorized deductions are made. Also called check-docking boss; check measurer; checkweighman; justiceman.

checkweighman

See: checkweigher.

cheeking

The removal of the side or sides of a roadway to increase its width.

cheeks

a. The sides or walls of a vein.

b. Extensions of the sides of the eye of a hammer or pick. c. The refractory sidewalls of the ports of a fuel-fired furnace.

chelate compound

The compound formed by the combination of a chelating agent and a metal ion.

chelating agent

A substance that contains two or more electron donor groups and will combine with a metal ion so that one or more rings are formed.

chelation

The reaction between a metallic ion and a complexing agent, generally organic, with the formation of a ring structure and the effective removal of the metallic ion from the system. It is significant in chemical weathering.

cheleutite

a. A ferruginous, nickeliferous, and slightly cupriferous smaltite. See also: smaltite.

b. A copper-bearing variety of smaltite.

Chelsea color filter

An effective dichromatic color filter transmitting light of only two wavelength regions--one in the deep red, the other in the yellow green. Useful for discriminating between emerald and its imitations and for detecting synthetic spinels and pastes colored blue with cobalt.

chemawinite

A pale-yellow to dark-brown variety of retinite (amber) in decayed wood at Cedar Lake, MB, Canada. Syn: cedarite. See also: amber.

chemechol

A method of breaking down coal similar to Hydrox and applied on the same lines as air shooting.

chemical adsorption

Surface adherence, accompanied by the formation of primary bonds.

chemical affinity

a. The force that binds atoms together in molecules.

b. The tendency of one substance to form a chemical compound with another.

chemical analysis

A method of determining the composition of a material employing chemical techniques by which the various elements are quantitatively separated.

chemical brick

See: chemical stoneware.

chemical-clay grout

A typical grout of this class used in Great Britain is bentonite-sodium silicate, in which the silicate is used to render irreversible the thixotropic nature of the bentonite suspension. The gel is stronger than pure bentonite and is permanent, in that local vibration cannot cause it to liquefy again. Setting time can be controlled by adjustment of the chemical content.

chemical combination

Change in which permanent alteration of properties occurs, accompanied by intake or release of energy. Reaction is governed by laws of mass conservation, definite and multiple proportions, equivalence, and volumetric reaction.

chemical composition

The weight percent of the elements (generally expressed as certain oxide molecules) in a rock.

chemical constitution of coal

The elements or component parts of coal. These are determined by chemical analyses that may be performed in different ways. An ultimate analysis provides exact information as to the percentages of the various elements (such as carbon, oxygen, and hydrogen) present in the coal. Another method is by proximate analysis, which determines the relative percentages of carbon, moisture, volatile matter (such as gas and tar), sulfur, and ash.

chemical denudation

The processes in which the salts or the soluble minerals in the Earth are dissolved by water and carried to the sea.

chemical deposition

The precipitation or plating-out of a metal from a solution of its salts through the introduction of another metal or a reagent into the solution.

chemical engineering

Developing, building, and operating plants in which materials are chemically worked up to desired end products.

chemical equilibrium

A state of balance between two opposing chemical reactions. The amount of any substance being built up is exactly counterbalanced by the amount being used up in the other reaction, so that concentrations of all participating substances remain constant.

chemical erosion

See: corrosion.

chemical extraction

Term taking the place of hydrometallurgy; embraces leaching (acid, alkaline, and pressure), ion exchange, solvation precipitation, and calcination. See also: leaching.

chemical lead

Lead of more than 99.9% purity, with traces of copper and silver, as originally obtained from the ore; used for manufacturing storage battery plates and chemical piping.

chemical limestone

A limestone formed by direct chemical precipitation or by consolidation of calcareous ooze.

chemically precipitated metal powder

Powder produced by the reduction of a metal from a solution of its salts either by the addition of another metal higher in the electromotive series or by other reducing agents.

chemical mineralogy

The investigation of the chemical composition of minerals and its variation, the processes of mineral formation, and the changes minerals undergo when acted upon chemically. CF: physical mineralogy; crystallogeny.

chemical rock

A sedimentary rock composed primarily of material formed directly by precipitation from solution or colloidal suspension (such as by evaporation) or by the deposition of insoluble precipitates (such as by mixing solutions of two soluble salts); e.g., gypsum, rock salt, chert, or tufa. It generally has a crystalline texture. CF: detrital rock.

chemical sediment

See: chemical rock.

chemical soil consolidation

A process for sinking through loose, heavily watered ground. A gel-forming chemical is injected into the loose material that is eventually consolidated. The time delay in the gel formation can be controlled by chemical means, and the rate of injection at waterlike viscosity is rapid. See also: bentonite; silicatization process.

chemical stoneware

A clay pottery product that is widely employed to resist acids and alkalies. It is used for utensils, pipes, stopcocks, pumps, etc.; sp gr, 2.2; hardness, scleroscope 100. Stoneware is made from special clays free from lime and iron, low in sand content, with low temperatures, and having sufficient plasticity to permit turning on a potter's wheel. Syn: chemical brick.

chemical water treatment

A method of treating hard water by adding selected chemical substances that break down the offending impurities, the residue being passed on in solution in harmless or less harmful form, driven off as a gas, or precipitated for subsequent retention in an incorporated filter. The general reagents are lime or soda or a combination of both with or without the addition of zeolites or colloids.

chemical weathering

The process of weathering by which chemical reactions (hydrolysis, hydration, oxidation, carbonation, ion exchange, and solution) transform rocks and minerals into new chemical combinations that are stable under conditions prevailing at or near the Earth's surface; e.g., the alteration of orthoclase to kaolinite. CF: mechanical weathering. Syn: decomposition.

chemihydrometry

Determination of flow rate and channels taken by water by the introduction of suitable chemicals upstream and measurement of dilution. (Radiotracers and fluorescin are also used for tracing flow direction.)

chemiluminescence

Luminosity caused by chemical changes in a substance.

chemisorption

Irreversible sorption, an adsorbate being held as a product of chemical reaction with an absorbent. Activation energy is relatively high.

chemist

A person versed in chemistry. One whose business is to make chemical examinations or investigations, or one who is engaged in the operations of applied chemistry.

chemolithotroph

Autotrophic microorganism that derives energy to do metabolic work from the oxidation of inorganic compounds and assimilate carbon as CO (sub 2) , HCO (sub 3) (super -) , or CO (sub 3) (super 2-) ; e.g., Thiobacillus ferrooxidans, a bacterium that oxidizes ferrous iron to ferric iron for energy. See also: autotroph.

chempure tin

Purest commercially available tin; 99.9% tin.

chenevixite

A monoclinic mineral, Cu (sub 2) Fe (sub 2) (AsO (sub 4) ) (sub 2) (OH) (sub 4) .H (sub 2) O ; earthy to opaline; associated with olivenite in copper deposits.

Chenot process

The process of making iron sponge from ore mixed with coal dust and heated in vertical cylindrical retorts.

cheralite

A monoclinic mineral, (Ca,Ce,Th)(P,Si)O (sub 4) ; monazite group; an intermediate member of a crystal-solution series between CePO (sub 4) (monazite) and CaTh(PO (sub 4) ) (sub 2) (a synthetic compound).

cheremchite

A variety of sapropelic coal composed of a mixture of structureless humic sapropel and algal remains. Also spelled tscheremchite.

cherry picker

a. A fishing tool in the modified form of a horn socket. The lower end or mouth is cut away on one side and resembles a scoop; because of its shape, the device, as it is turned, works around and behind an object that has become partly embedded in the wall of a borehole, thus engaging it where a regular horn socket would fail.

b. A small hoist to facilitate car changing near the loader in a tunnel. An empty car is either lifted above the track (to allow a loaded car to pass beneath) or swung to one side free of the track. See also: double-track portable switch. The equipment is fairly common, particularly for handling large cars. c. In tunneling, a small traveling crane spanning tracks that transfers an empty car to a parallel track so that a loaded one can be drawn from the advancing end. d. A small derrick made up of a sheave on an A-frame, a winch and winch line, and a hook. Usually mounted on a truck.

cherry-red heat

A common term used on the color scale, generally given as about 1,382 degrees F (750 degrees C).

chert

A hard, dense, dull to semivitreous, microcrystalline or cryptocrystalline sedimentary rock, consisting dominantly of interlocking crystals of quartz less than about 30 mu m in diameter; it may contain amorphous silica (opal). It sometimes contains impurities such as calcite, iron oxide, and the remains of siliceous and other organisms. It has a tough, splintery to conchoidal fracture, and may be white or variously colored. Chert occurs principally as nodular or concretionary nodules in limestone and dolomites, and less commonly as layered deposits (bedded chert); it may be an original organic or inorganic precipitate or a replacement product. The term "flint" is essentially synonymous, although it has been used for the dark variety of chert. See also: jasper; silexite.

chertification

A type of silicification in which fine-grained quartz or chalcedony is introduced into limestones, such as in the Tri-State mining district of the Mississippi Valley.

chervetite

A monoclinic mineral, Pb (sub 2) V (sub 2) O (sub 7) ; occurs in small crystals at the Mounana uranium mine, Gabon.

chessy copper

See: chessylite.

chessylite

A term commonly used for azurite. Syn: chessy copper. See also: azurite.

chesterite

Microcline feldspar found in Chester County, PA.

chestnut coal

a. In anthracite only, coal small enough to pass through a square mesh of 1 to 1-1/8 in (2.54 to 2.86 cm), but too large to pass through a mesh of 5/8 in or 1/2 in (1.59 cm or 1.27 cm). Known as No. 5 coal.

b. Arkansas. Coal that passes through a 2-in (5.1-cm) round hole and over a 1-in (2.5-cm) round hole. See also: anthracite coal sizes.

chevee

A flat gem having a polished concave depression. CF: cuvette.

chevron crossbedding

Crossbedding that dips in different directions in superimposed beds, forming a chevron pattern. Also called herringbone crossbedding; zigzag crossbedding.

chevron drain

A rubble-filled trench system in the slope of a railway cutting, laid out in herringbone fashion and leading surface water into buttress drains arranged along the line of steepest slope.

chews

A fold with a sharp angular hinge and planar limbs of equal length. Syn: zigzag fold. "� ��� j�� ��2�� � k DICTIONARY TERMS:chews Scot. Coal loaded with a screening shovel; mi Scot. Coal loaded with a screening shovel; middling-sized pieces of coal. Syn: chows.