Appendix:Dictionary of Mining, Mineral, and Related Terms/O/2
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- A process for separating the copper and nickel in the matte obtained by Bessemerizing. The matte, which consists of copper-nickel sulfides, is fused with sodium sulfide, and a separation into two layers, the top rich in nickel and the bottom rich in copper, is obtained. Also known as top-and-bottom process.
- A series of closely spaced props placed at the borders of the chamber at the coal face. Such an arrangement protects the future, adjoining chamber from caving.
- Being, containing, or relating to carbon compounds, esp. in which hydrogen is attached to carbon whether derived from living organisms or not. Usually distinguished from inorganic or mineral. CF: inorganic.
- Ash in coal derived from the incombustible material contained in plants.
- Any of the depressants used in the flotation process. They include glue, gelatin, albumen, dried blood, casein (proteins), tannin, licorice, quebracho extract, and saponin (complex polyhydroxy carboxylic acids and glucosides).
- A rock or other deposit formed by organisms or their remains.
- The ratio (normally expressed as a percentage) between the actual yield of a desired product and the theoretically possible yield (based on the reconstituted feed), both actual and theoretical products having the same percentage of ash.
- A general term applied to a soil that consists primarily of organic matter such as peat soil and muck soil.
- The difference between the total sulfur in coal and the sum of the pyritic sulfur and sulfate sulfur.
- A test in which organic matter in soil is destroyed by oxidizing agents and the loss measured. This test is used in preparation of soil for a sedimentation test, and gives an indication of the amount of organic matter present. See also: sedimentation test.
- Derived from or composed of organic materials; e.g., a crinoidal limestone.
- Rock formed from organic substances, esp. those of vegetable origin, such as coal, oil, resins, and bitumens.
- An ancient copper alloy resembling gold in color.
- a. To place a deflection wedge in a borehole in such an attitude that the concave surface is pointed in a predetermined direction.
b. To place a piece of core in the same relative plane as it occupied below the surface. See also: core orientation. c. To turn a map or planetable sheet in a horizontal plane until the meridian of the map is parallel to the meridian on the ground. d. In a transit, to turn the instrument so that the direction of the 0 degrees line of its horizontal circle is parallel to the direction it had in the preceding, or in the initial, setup. e. To place a diamond in a bit mold in such an attitude that when it is embedded in the crown matrix one of its hard vector planes will come in contact with the rock to be abraded or cut by the diamond. f. The characteristic sheen and irridescence displayed by pearl. g. To align an optical or crystallographic direction of a mineral with a rotation axis of a microscope stage.
- a. Frequently used in the same sense as precious when applied to minerals; from an old idea that gems came principally from the Orient; e.g., oriental amethyst, oriental chrysolite, oriental emerald, and oriental topaz, all of which are varieties of sapphire. Syn: precious.
b. Specially bright, clear, pure, and precious; said of gems.
- Calcium carbonate in the form of onyx marble. Gibraltar stone. Syn: Algerian onyx; onyx marble.
- See: cat's-eye; tiger's-eye.
- An explosive consisting of tan bark, sawdust, or other vegetable fiber, or resins, such as gamboge, impregnated with a nitrate or chlorate and mixed with gunpowder.
- a. Arrangement in space of the axes of a crystal with respect to a chosen reference or coordinate system. See also: preferred orientation.
b. In surveying, the rotation of a map (or instrument) until the line of direction between any two of its points is parallel to the corresponding direction in nature. c. In structural petrology, refers to the arrangement in space of particles (grains or atoms) of which a rock is composed. d. The act or process of setting a diamond in the crown of a bit in such an attitude that one of its hard vector planes will contact the rock and be the surface that cuts or abrades it. e. As used in borehole surveying and directional drilling practice, orientation refers to the method and procedure used in placing an instrument or tool, such as a deflection wedge, in a drilled hole so that its directional position, bearing, or azimuth is known. f. The position of important sets of planes in a crystal in relation to any fixed system of planes. g. The spatial relationship between crystallographic axes and principle optic directions in anisotropic minerals. h. The characteristic sheen or iridescence displayed by pearl.
- See: electrical twinning.
- In geochemical prospecting, a geochemical survey normally consisting of a series of preliminary experiments aimed at determining the existence and characteristics of anomalies associated with mineralization. This information is then used in selecting adequate prospecting techniques and in determining the factors and criteria that have a bearing on interpretation of the geochemical data.
- Said of a specimen or thin section that is so marked as to show its original position in space.
- A surface-set diamond bit with individual stones set so as to bring the hard vector direction or planes of the crystal into opposition with the rock surface to be abraded or cut. See also: orient.
- A core specimen that can be positioned on the surface as it was in the borehole prior to extraction. Such a core is useful where the general dip of the strata is required from one borehole. A magnetic method may be used to disclose the polarity the core specimen possessed while in situ. See also: true dip; borehole surveying; oriented sample. CF: core orientation.
- An instrument used in borehole surveying, which marks the core to show its position in space.
- A diamond inset in the crown of a bit in such an attitude that one of its hard vector planes will be the surface that cuts or abrades the rock. See also: orient.
- See: oriented core.
- a. In structural petrology, a hand specimen so marked that its exact arrangement in space is known.
b. In paleontology, a fossil whose position is known in regards to such features as anterior and dorsal sides, dorsal and ventral sides, the axis of coiling, the plane of coiling, etc.
- A borehole survey made by lining up a reference mark on the clinometer case with that on the drill rods, which in turn are oriented as they are lowered into the borehole.
- A rotatable coupling on a Thompson retrievable wedge-setting assembly that may be set and locked in a predetermined position in reference to the gravity-control member. This places the deflection wedge so as to direct the branch borehole in the desired course.
- An orthorhombic mineral, Ca (sub 2) Mn (super 2+) Mn (super 3+) (sub 2) Si (sub 3) O (sub 10) (OH) (sub 4) ; forms minute, brown to black, radiating, prismatic crystals.
- a. In ventilation, a hole in a very thin plate.
b. A hole or opening, usually in a plate, wall, or partition, through which water flows, generally for the purpose of control or measurement. c. The end of a small tube, such as the orifice of a Pitot tube, piezometer, etc. d. An opening through which glass flows. In a feeder, an opening in bottom of spout formed by orifice ring. e. Opening. Formerly applied to discs placed in pipelines or radiator valves to reduce the fluid flow to a desired amount.
- A form of gas or liquid flowmeter consisting of a diaphragm in which there is an orifice placed transversely across a pipe; the difference in pressure on the two sides of the diaphragm is a measure of flow velocity.
- Said of a fan with an orifice comparable to the equivalent orifice of a mine; i.e., the area in a thin plate that requires the same pressure to force a given volume of air through as is required to force the same volume through the fan. Orifice of passage O = 0.389 Q/w.g.f., where Q = volume of air passing in thousands cubic feet per minute; w.g.f.= loss of pressure in the fan in inches of water gage.
- The source or ground of the existence of anything, either as cause or as occasion; that from which a thing is derived or by which it is caused; esp., that which initiates or lays the foundation; e.g., the origin of ore deposits.
- The attitude of sedimentary beds immediately after deposition. Syn: initial dip; primary dip.
- See: main hole.
- The common lead in a uranium mineral.
- See: primary mineral.
- a. Gold ground for use in gilding; also metal gilded with ground gold.
b. A brass made to imitate gold and used in mounts for furniture and for other decorative purposes. Also called mosaic gold.
- See: gemstone.
- A stony meteorite composed of bronzite and olivine in a friable mass of chondri.
- An orogenic belt with an imposed curvature or sharp bend, interpreted by Carey (1958) as a result of horizontal bending of the crust, or deformation in plan.
- A belt of deformed rocks, in many places accompanied by metamorphic and plutonic rocks; e.g., the Appalachian orogen or the Alpine orogen.
- See: orogeny.
- Adj. of orogeny.
- The process by which structures within fold-belt mountainous areas were formed, including thrusting, folding, and faulting in the outer and higher layers, and plastic folding, metamorphism, and plutonism in the inner and deeper layers. Syn: orogenesis; mountain building; tectogenesis. Adj: orogenic; orogenetic.
- An aneroid barometer having a second scale that gives the approximate elevation above sea level of the place where the observation is made.
- An enamel paint for protecting metal surfaces from the action of hot vapors.
- A crossover switch that consists essentially of a single-acting cylinder hoist on a crossrail fastened to the roof at right angles to the track. While a car is being loaded, the switcher picks up the empty car next to the locomotive and holds it to one side. As soon as a car is loaded the locomotive pulls the train back past the switcher, and the empty car is placed at the front of the train and pushed under the slide.
- Abandoned and unreclaimed mines for which no owner or responsible party can be found. The reclamation and environmental conditions of such lands is then defaulted to the State or Federal Government.
- a. A yellow arsenic trisulfide, As (sub 2) S (sub 3) , containing 61% arsenic; monoclinic. Syn: yellow arsenic.
b. A monoclinic mineral, 4[As (sub 2) S (sub 3) ]; soft; pearly lemon yellow with one perfect cleavage; in powdery foliated masses and coatings, botryoidal or fibrous; a low-temperature alteration of other arsenides; associated with realgar and gold in hot springs. Syn: yellow ratsbane.
- An instrument for analyzing flue gases. Although outside its normal field of application, it may be used for analyzing mine air.
- A former name for allanite, esp. when found in slender prismatic or acicular crystals.
- a. A combining form meaning straight; at right angles; proper.
b. In petrology, a prefix that, when used with the name of a metamorphic rock, indicates that it was derived from an igneous rock, e.g., orthogneiss, orthoamphibolite; it may also indicate the primary origin of a crystalline, sedimentary rock, e.g., orthoquartzite as distinguished from metaquartzite. c. A prefix to the name of a mineral species or group to indicate orthorhombic symmetry as opposed to "clino" indicating monoclinic symmetry.
- The orthorhombic subgroup of amphiboles including anthophyllite, gedrite, and holmquistite. CF: clinoamphibole.
- a. A group name for distinctly crystalline forms of chlorite (such as clinochlore and penninite).
b. A group name for chlorites conforming to the general formula: (R (super 2+) ,R (super 3+) ) (sub 6) (Si,Al) (sub 4) O (sub 10) (OH) (sub 8) .
- A monoclinic mineral, KAlSi (sub 3) O (sub 8) ; feldspar group; prismatic cleavage; partly ordered, monoclinic potassium feldspar dimorphous with microcline, being stable at higher temperatures; also a general term applied to any potassium feldspar that is or appears to be monoclinic; e.g., sanidine, submicroscopically twinned microcline, adularia, and twinned analbite. It is a common rock-forming mineral and occurs esp. in granites, granite pegmatites, felsic igneous rocks, and crystalline schists, and is commonly perthitic. Syn: common feldspar; orthose; pegmatolite. CF: microcline; plagioclase; anorthoclase.
- A descriptive name for rocks now known as monzonite, in which the plagioclase is at least as calcic as labradorite.
- An orthoclase-bearing porphyritic intrusive rock, such as granite or syenite. The term is sometimes restricted to rocks containing more than 90% orthoclase. Not recommended usage.
- Cleaving in directions at right angles to each other.
- a. A primary dolomite, or one formed by sedimentation.
b. A term used by Tieje (1921) for a dolomite rock so well-cemented that the particles are interlocking.
- A monoclinic crystal form whose faces parallel the orthoaxis and cut the other axes. CF: dome; clinodome.
- An orthorhombic mineral, (Fe,Mg) (sub 2) Si (sub 2) O (sub ) 6 ; pyroxene group; now simply called ferrosilite. CF: ferrosilite; clinoferrosilite.
- Applied to gneissose rocks that have been derived from rocks of igneous origin. CF: paragneiss.
- At right angles.
- Cesaro's name for an orthorhombic form of guarinite, through superposition of hemitropic lamellae of the monoclinic mineral, clinoguarinite. See also: clinoguarinite.
- Maceral having a normal hydrogen content, such as vitrine.
- An artificial orthorhombic high-temperature polymorph of KAlSiO (sub 4) .
- A term proposed by Brooks (1954) for sedimentary limestone. CF: metalimestone; orthomarble.
- See: orthomagmatic stage.
- Applied to the main stage of crystallization of silicates from a typical magma; the stage during which perhaps 90% of the magma crystallizes. CF: pegmatitic stage. Syn: orthomagmatic; orthotectic stage.
- A crystalline limestone that will take a polish; e.g., the Holston orthomarble of Tennessee. CF: metamarble; metalimestone; ortholimestone.
- Triclinic feldspar, which by repeated twinning (orthomimicry) simulates a higher degree of symmetry with rectangular cleavages; e.g., orthoclase, anorthoclase, and cryptoclase.
- The product of a procedure that corrects the distortions in aerial photography due to the instability of the camera platform, the terrain relief, and the angle of the light rays entering the camera lens. The ortho instrumentation attached to a stereo plotting instrument rectifies the image in a transfer process so as to reposition it in its correct planar position.
- Said of the texture of the groundmass in certain holocrystalline, porphyritic, igneous rocks in which the feldspar crystals have quadratic or short, stumpy, rectangular cross sections, rather than the lath-shaped outline observed in trachytic texture. Also, said of a groundmass with this texture, or of a rock having an orthophyric groundmass.
- In the monoclinic system, the form consisting of two planes parallel to the vertical and orthodiagonal axes. See also: pinacoid.
- A monoclinic prism, the orthodiagonal intercept of which is greater than 1.
- The subgroup name for pyroxenes crystallizing in the orthorhombic system, commonly containing no calcium and little or no aluminum; e.g., enstatite, hypersthene, and ferrosilite. CF: clinopyroxene. Syn: labrador hornblende.
- A clastic sedimentary rock that is made up almost exclusively of quartz sand (with or without chert), and relatively free of or lacks a fine-grained matrix, derived by secondary silicification; a quartzite of sedimentary origin, or a pure quartz sandstone. The term generally signifies a sandstone with more than 90% to 95% quartz and detrital chert grains that are well-sorted, well-rounded, and cemented primarily with secondary silica (sometimes with carbonate) in optical and crystallographic continuity with the grains. The rock is characterized by stable but scarce heavy minerals (zircon, tourmaline, and magnetite), by lack of fossils, and by prominence of cross-beds and ripple marks. It commonly occurs as thin but extensive blanket deposits associated with widespread unconformities (e.g., an epicontinental deposit developed by an encroaching sea), and it represents intense chemical weathering of original minerals other than quartz, considerable transport and washing action before final accumulation (the sand may experience more than one cycle of sedimentation), and stable conditions of deposition (such as the peneplanation stage of diastrophism); e.g., St. Peter Sandstone (Middle Ordovician) of midwestern United States. See also: quartzite.
- a. Any mineral crystallizing with orthorhombic symmetry.
b. See: orthorhombic system.
- In crystallography, that system of crystals whose forms are referred to three unequal mutually perpendicular axes. Syn: prismatic system; rhombic system; orthorhombic.
- A schist derived from an igneous rock. CF: paraschist; schist.
- A polarizing microscope in which light is transmitted by the crystal parallel to the microscope axis, in contrast to the conoscope, in which a converging lens and Bertrand lens are used. CF: conoscope.
- A name for the whole feldspar family before it was divided into separate species. Syn: orthoclase.
- See: magmatic.
- See: orthomagmatic stage.
- The description applied to the elastic properties of material, such as timber, which has considerable variations of strength in two or more directions at right angles to one another. See also: isotropic.
- a. Pyrometric cone made in one of two sizes: 2-1/2 in (6.4 cm) high for industrial kiln control, and 1-1/8 in (3.2 cm) high for pyrometric cone equivalent testing. See also: pyrometric cone.
b. Used in the United States for heat recording, Orton cones are similar to Seger cones, but the same numbers do not indicate the same temperatures; e.g., Orton cone 14 corresponds to Seger cone 13.
- The description and systematic arrangement of minerals; mineralogy. See also: mineralogy.
- See: mineralogist.
- See: mineralogy.
- A purely chemical system of classification of igneous rocks.
- A trigonal mineral, PbCuAl (sub 2) (SO (sub 4) ) (sub 2) (OH) (sub 6) ; alunite group; the aluminum analog of beaverite; a yellow, powdery secondary crust; at the Osarizawa Mine, Akita prefecture, Japan.
- See: walking beam.
- A type of vibrating conveyor having a relatively low frequency and large amplitude of motion. See also: vibrating conveyor. Syn: grasshopper conveyor.
- See: conveyor-type feeder.
- An assembly of 4 to 8 metal trays, usually 30 in (76.2 cm) wide and 8 to 15 in (20.3 to 38.1 cm) long, arranged in series in the direction of flow. The trays are detachably mounted in the assembly by steps, so that the overflow from one tray overlaps the next tray by 1 in (2.54 cm) and is 2 to 4 in (5.1 to 10.2 cm) above it. The trays are inclined downward in the direction of the flow at an angle adjustable from 14 degrees to 18 degrees. The entire assembly is mechanically oscillated transversely to the direction of the flow at about 200 strokes/min with an adjustable stroke of about 1/2 in (1.27 cm). The storage bin and feed roller are independently mounted and discharge a layer 1 grain thick.
- Independent movement through a limited range, usually on a hinge.
- A thin slab of quartz which, by mechanical vibration, controls the frequency of a radio transmitter.
- Flawless quartz, which can be used in the manufacture of oscillator plates.
- Repeated twinning in which a crystal is made up of thin lamellae alternately in reversed position; polysynthetic twinning; found in some feldspars. Syn: polysynthetic twinning.
- Repetitious concentric compositional variation in minerals resulting from cyclical changes in the chemical environment during crystal growth; e.g., garnet and plagioclase.
- A record of phenomena observed on an oscillograph.
- An instrument that renders visible, or automatically traces, a curve representing the time variations of various phenomena. The recorded trace is an oscillogram.
- An instrument for showing visual representations of electrical outputs from measuring devices.
- See: iridosmine.
- The native element, Os; occurs in magmatic deposits in mafic and ultramafic rocks and placers derived from them.
- The passage of a solvent through a membrane from a dilute solution into a more concentrated one, the membrane being permeable to molecules of solvent but not to molecules of solute.
- A massive, earthy mineral (apatite) consisting of an impure, altered phosphate.
- A minute crustacean with a bean-shaped bivalve shell completely enclosing the body.
- A trigonal mineral, CdCO (sub 3) ; calcite group; associated with oxidized base-metal ores.
- As used in the Mining Law of 1872, means any rocky substance containing mineral matter.
- Includes nonmetalliferous as well as metalliferous deposits.
- A process that uses an inert heavy liquid with a specific gravity between that of coal and free mineral matter to separate coarse or fine-size coal in a static bath or cyclone separator.
- A selective agglomeration process under development, in which ultra-fine grinding of the feed coal to 15 mu m releases almost all the associated impurities prior to agglomeration with a low-molecular-weight hydrocarbon. The agglomerant is then recovered and recycled.
- In a four-stroke internal combustion engine two complete revolutions of the crankshaft correspond with the working cycle-inlet stroke (suction downstroke of piston in cylinder); compression upstroke; explosion at peak of compression followed by expansion of hot exploded gases on driving downstroke; rising exhaust stroke to complete the cycle.
- See: novaculite.
- See: wadi.
- The name applied to the violent evolution of combustible gases (usually together with large quantities of coal dust) from a working face. The occurrence is violent and may overwhelm the workings and fill the entire district with gaseous mixtures. Roadways advancing into virgin and stressed areas of coal are particularly prone to outbursts in certain seams and faults often intersect in the area. See also: floor burst; blow; bump.
- Nearer to the shaft, and therefore away from the face, toward the pit bottom or surface; toward the mine entrance. The opposite of inby. Also called outbyeside. Syn: out-over.
- a. The part of a rock formation that appears at the surface of the ground.
b. A term used in connection with a vein or lode as an essential part of the definition of apex. It does not necessarily imply the visible presentation of the mineral on the surface of the earth, but includes those deposits that are so near to the surface as to be found easily by digging. c. The part of a geologic formation or structure that appears at the surface of the Earth; also, bedrock that is covered only by surficial deposits such as alluvium. CF: exposure. Syn: crop; cropping; outcropping. d. To appear exposed and visible at the Earth's surface; to crop out.
- A special type of geologic map that represents only actual outcrops. Areas without exposures are left blank.
- See: outcrop.
- Rain and surface water that seeps downward through outcropping porous and fissured rock, fault planes, old shafts, or surface drifts.
- That stroke of a Cornish pumping engine by which the water is forced upward by the weight of the descending pump rods, etc.
- All submerged lands lying seaward and outside of the area of lands beneath navigable waters as defined in Section 2 of the Submerged Lands Act (Public Law 31, 83rd Congress, 1st Session), and of which the subsoil and seabed appertain to the United States and are subject to its jurisdiction and control. Abbrev. OCS. See also: continental shelf.
- The outer or upper zone of the Earth's core, extending from a depth of 2,900 km to 5,100 km, and including the transition zone; it is equivalent to the E layer and the F layer. It is inferred to be liquid because it does not transmit shear waves. Its density ranges from 9 to 11 g/cm (super 3) . The outer core is the source of the principal geomagnetic field. CF: inner core.
- Syn. for outside diameter.
- A diamond set on the outside wall of a bit crown. Also called reamer; reamer stone. Syn: outside stone; kicker stone.
- a. Eng. A seam cropping out at a lower level.
b. The mouth of a stream or the outlet of a lake; esp. the narrow end of a watercourse or the lower part of any body of water where it drops away into a larger body. c. The vent or end of a drain, pipe, sewer, ditch, or other conduit that carries waste water, sewage, storm runoff, or other effluent into a stream, lake, or ocean.
- a. The act of laying out or expending.
b. Something that is laid out; expenditure. c. The cost of equipping a mine and placing it on a producing basis.
- An opening from a mine to the surface. Syn: upcast.
- a. An isolated mass or detached group of rocks surrounded by older rocks; e.g., an isolated hill or butte. CF: inlier.
b. Ore or favorable geologic indications distant from the main ore zone of a district.
- a. Bits and reaming shells having set inside or outside diameters greater or lesser than those specified as standard.
b. A borehole the inside diameter of which is undersize or oversize.
- See: outby.
- being so many tons per shift, per week, or per year.
b. The power or product from a plant or prime mover in the specific form and for the specific purpose required. See also: concentration of output; productivity. c. Amount delivered; e.g., volume of a liquid discharged by a pump; volume of air discharged by a compressor; horsepower delivered by a motor. d. Current or signal delivered by any circuit or device. e. The terminal or other point at which a current or a signal may be delivered.
- Machine that prints information computed from its memory or store.
- A shaft that transmits power from a transmission or clutch.
- An outward extension of a frame that is supported by a jack or block. Used to increase stability.
- See: angling.
- One-half the total difference between the outside diameter of any piece of downhole equipment and the inside diameter of the borehole.
- The peripheral portion or that part of a bit crown, roller bit cutter, or any cutting edge of a bit in contact with the walls of a borehole while drilling.
- In bituminous coal mining, a person who supervises all operations at the surface of a mine.
- See: outer stone.
- See: bell tap.
- The act or process of thickening a length of tubing at its ends by increasing its outside diameter without changing the inside diameter; a length of tubing or drill rod so processed. See also: upset.
- That part of a bit crown, bit shank, reaming shell, core barrel, drill rod, casing, or other piece of downhole equipment that when in use, comes in contact with the wall of a borehole.
- Drilling operations conducted on the surface, as opposed to drilling done in underground or enclosed workplaces.
- The face of the spoil or embankment sloping downward from the highest elevation to the toe.
- A location which provides local monitoring and control, and provides a communications interface between a sensor and the trunk connected to a central station computer. Also called field data station.
- The passage by which the ventilating current is taken out of the mine; the upcast. The return air course. An outlet.
- A fishing tool used to recover broken drill rods from a borehole.
- A chamber in which substances are artificially heated for the purposes of baking, roasting, annealing, etc.; specif.: (1) a kiln, such as a coke oven; and (2) a leer, which is used in glassmaking.
- Aging at a higher temperature, or for a longer time, or both, than required for critical dispersion, thus causing particle agglomeration of the precipitating phase and, as a result, loss of strength and hardness. See also: aging.
- The ratio of pithead output in tons (P) to length of main haulage roads in yards (L) or tons per yard of main haulage roads; i.e., P/L. See also: concentration of output.
- The sum of the times required for actual rock drilling, setting up and withdrawal, moving drills from hole to hole and machine delays. The overall drilling time is a better basis for estimating drilling efficiency than penetration speed alone.
- a. Of an air compressor, the product of the compression efficiency and the mechanical efficiency.
b. Ratio of power output of an engine to the power input; the measure of the difference between indicated and brake horsepower.
- The ratio of the horsepower in the air to the horsepower absorbed by the driving motor of the fan.
- With reference to a crusher, mean size of feed/mean size of product. See also: reduction ratio.
overall ventilation efficiency
- The ratio between the air horsepower and the indicated horsepower of a driving unit. The percentage is expressed by air horsepower x 100/indicated hp of driving unit. Measurements are taken of the air pressure and volume in the fan drift, and the power absorbed by the driving unit. See also: volumetric efficiency; thermometric fan test.
- Two endless chains or other linkage between which carriers are mounted and controlled, so that the carriers remain in an upright and horizontal position throughout the complete cycle of the conveyor.
- The pressure of the rocks over active mine workings. It is the roof weight that acts on the packs and the solid coal in the working area. See also: abutment; nether roof; underweight.
- Excessive breakage of rock beyond the desired excavation limit. See also: neat lines. CF: underbreak.
- See: overhand stoping.
- a. Designates material of any nature, consolidated or unconsolidated, that overlies a deposit of useful materials, ores, or coal--esp. those deposits that are mined from the surface by open cuts.
b. Loose soil, sand, gravel, etc. that lies above the bedrock. Also called burden, capping, cover, drift, mantle, surface. See also: baring; burden; top.
- A special diamond-set bit, similar to a set casing shoe, used to drill casing through overburden composed of sand, gravel, boulders, etc.
- a. A technique developed in Sweden that involves the sinking, by percussive-rotary drilling, of a drill casing through the overburden to where it seats in the underlying rock. A rotary percussion drill hole is then continued to the desired depth in the rock. While the casing is being sunk through the overburden it is coupled to the drill rod and rotates and reciprocates with it. The rock bit on the end of the drill rod projects about an inch beyond the end of the ring bit with which the casing is fitted and acts as a pilot bit for the casing bit.
b. A drilling method whereby drilling is carried out through subsoil and boulders or underwater to and through bedrock.
- a. An enclosed airway that permits an air current to pass over another one without interruption. Syn: overcrossing; overgate. CF: undercast. See also: air crossing.
b. To place the overburden removed from coal in surface mines in an area from which the coal has been mined. c. Pushed forward, so as to overlie other rocks, such as in thrust faults. See also: jack pit.
- A procedure used in certain mining activities including strip mining and in some heavy construction work such as channel excavation. Overcasting may be performed in a simple operation consisting of digging out the material, lifting it from one position, moving it over, and dumping it in the spoil position where it remains, for practical purposes, indefinitely. The mechanics of the operation are called "simple overcasting."
- Adding material in excess of the capacity of the equipment used for processing.
- A soil deposit that has been subjected to an effective pressure greater than the present overburden pressure.
- See: air crossing; overcast.
- Relay used to trip circuit breakers when an abnormal current of two to three times the normal flow is detected in a circuit. Relays are adaptable to transmission lines, buses, feeder circuits, transformers, and motors.
- a. A machine cut made along the top or near the top of a coal seam; sometimes used in thick seams or a seam with sticky coal. By releasing the coal along the roof, its mining becomes easier. See also: overcut; turret coal cutter.
b. The process of producing a larger size hole than the outside diameter of a bit and/or reaming shell used, due to the eccentric rotational movements of the bit, core barrel, or drill stem.
- Coal-cutting machine that is an adaptation of a shortwall machine, designed to make the cut, or kerf, at desired place in the coal seam some distance above the floor. The main difference between an overcutting machine and an ordinary shortwall machine is that the cutter bar in the overcutting machine is mounted at the top of the machine instead of at the bottom. See also: turret coal cutter.
- Medium of specific gravity greater than that in the separating bath; usually produced in the medium recovery system and used to maintain the desired specific gravity in the bath.
- The act or process of drilling a run or length of borehole greater than the core-capacity length of the core barrel, resulting in loss of the core.
- The act of inducing a velocity higher than the steady state velocity in a column of explosive material upon detonation by the use of a powerful primer or booster; it is a temporary phenomenon and the explosive quickly assumes its steady state velocity.
- A term related to the condition of a ceramic product which has been heated to a temperature in excess of that required to produce proper vitrification.
- Heating ceramic materials or ware above the temperature required to produce the necessary degree of vitrification. Usually results in bloating, deformation, or blistering of the ware.
- A standpipe in which water rises and overflows at the hydraulic gradeline.
- See: air crossing; overcast.
- Comminution of ore to a smaller particle size than is required for effective liberation of values before concentrating treatment. Opposite of undergrinding.
- In this method, two level drives are first connected, the lower and upper one by a raise, from the bottom of which mining is begun. The work proceeds upwards, filling the mined-out room, but in the filling, chutes are left through which the broken ore falls. In inclined seams the chutes, also inclined, have to be timbered. The lower-level drive is protected either by timbering or vaulting, or by a fairly strong pillar of vein fillings. Stoping in the different cuts always proceeds upwards, but as a whole it proceeds between the two level drives in a horizontal direction. Overhand cut-and-fill, esp. in mining irregular orebodies of greater size, is also called back stoping.
- a. Stope in which the ore above the point of entry to the stope is attacked, so that severed ore tends to gravitate toward discharge chutes and the stope is self-draining.
b. An overhand stope is made by working upward from a level into the ore above.
- a. In this method, which is widely used in highly inclined deposits, the ore is blasted from a series of ascending stepped benches. Both horizontal and vertical holes may be employed. Horizontal breast holes are usually more efficient and safer than vertical upper holes, although the latter are still used in narrow stopes in steeply inclined orebodies.
b. The working of a block of ore from a lower level to a level above. In a restricted way overhand stoping can be applied to open or waste-filled stopes that are excavated in a series of horizontal slices either sequentially or simultaneously from the bottom of a block to its top. Stull timbering or the use of pillars characterize the method. Filling is used in many instances. Modifications are known as backfilling method; back stoping; block system; block system of stoping and filling; breast stoping; combined side and longwall stoping; crosscut method of working; cross stoping; Delprat method; drywall method; filling system; filling-up method; flatback stoping; longwall stoping; open cut system; open stope and filling; open-stope method; open-stope, timbering with pigsties, and filling; overhand stoping on waste; resuing; rock filling; room-and-pillar with waste filling; sawtooth back stoping; side stoping; slicing-and-filling system; stoping and filling; stoping in horizontal layers; transverse with filling. Syn: combined side and longwall stoping; Delprat method; overbreaking. CF: back-filling system; chimney work; underhand stoping.
overhand stoping and milling system
- See: combined overhand and underhand stoping.
- See: overhand stoping.
overhand stoping with shrinkage and delayed filling
- See: shrinkage stoping.
- See: square-set stoping.
- a. Cliff overhang.
b. A part of the mass of a salt dome that projects out from the top of the dome much like the cap of a mushroom.
- a. Describes a condition when a journey travels towards a haulage engine at a faster rate than the rope, which then becomes slack and liable to foul the drum. Also called overrun.
b. The transportation of excavated material beyond certain specified limits. c. In many highway contracts, a movement of dirt far enough so that payment, in addition to excavation pay, is made for its haulage. d. Applied to inspection, cleaning, and repairing of machines or plant.
- A type of equipment for the removal of soil or rock. It consists of a strong overhead cable, usually attached to towers at either end, on which a car or traveler may run back and forth. From this car a pan or bucket may be lowered to the surface, subsequently raised and locked to the car, and transported to any position on the cable where it is desired to dump its contents.
- See: trolley conveyor.
- This system is popular for use in mines since it can be suspended from the roadway supports as the face advances and can carry supplies over equipment installed in the roadway; transport is by means of endless, main-and-tail, or main-rope winches. They are generally slow-moving and can carry light loads into and around many places inaccessible to other forms of transport. See also: monorail.
- In this system, the loads are carried by bogies running on a taut wire rope instead of steel joists or flat-bottomed rails. See also: monorail.
- See: aerial ropeway.
- A tractor loader that digs at one end, swings the bucket overhead, and dumps at the other end.
- A crane that traverses the whole width of a workshop along the rails on which it runs.
- See: trolley conveyor.
- a. A general term referring to the extension of marine, lacustrine, or terrestrial strata beyond underlying rocks whose edges are thereby concealed or overlapped, and to the unconformity that commonly accompanies such a relation; esp. the relationship among conformable strata such that each successively younger stratum extends beyond the boundaries of the stratum lying immediately beneath. CF: onlap.
b. The area common to two successive aerial or space photographs or images along the same flight strip, expressed as a percentage of the photo area. c. The portion of a borehole that must be redrilled after caving of the hole, cementing a section of the hole, or bypassing unrecoverable material. d. A reversed fault or thrust. e. The lineal portion of a branch hole that nearly parallels the parent hole.
- To combine the forcing and exhausting systems, it is not necessary to provide two ducts, one forcing and one exhausting, throughout the length of the heading. An arrangement that serves the same purpose is the overlap system. In this system a main exhausting duct is used within a convenient distance of the face, often about 100 ft (30.5 m). Some of the intake air in the heading, before reaching the end of this duct, enters a short length of tubing and is blown onto the face. The advantages of both systems are thus obtained. Precautions must be taken against recirculation of air by the forcing unit, to prevent concentration of dust, and in collieries, combustible gases, at the face. The two ducts must overlap by a minimum distance which, in practice, is usually taken as 30 ft (9.1 m). See also: auxiliary ventilation. Syn: two-fan auxiliary ventilation.
- a. See: thrust fault.
b. A fault structure in which the displaced strata are doubled back upon themselves.
- a. Scot. The material above the rock in a quarry. See also: overburden.
b. Graphic data on a transparent or translucent sheet to be superimpossed on another sheet (such as a map or photograph) to show details not appearing, or requiring special emphasis, on the original. Also, the medium or sheet containing an overlay.
- A tracing on which the workings in a seam are shown. A series of such tracings allows the workings in several seams to be seen in their correct horizontal relationship. Also called layover tracing (undesirable usage).
- a. In general, a load or weight in excess of the designed capacity. The term may be applied to mechanical and electrical engineering plants, to loads on buildings and structures, and to excess loads on haulage ropes and engines.
b. To apply an excessive pressure, by stretching beyond the yield point, to a drill string and bit. CF: crowd.
- A loading machine of the power-shovel type for quarry and opencast operations. It may be either pneumatic-tired or continuous-tracked. It need not turn from the face to the truck if the latter can be spotted parallel to the face. The bucket is filled, the machine retracted, and the bucket swung over to the discharge point; used chiefly in sand and gravel pits.
- S. Afr. Mining a grade of ore above the average grade of the ore reserves. This practice has the effect of leaving the lower grade ore in the reserves. The opposite is undermining.
- In refining blister copper by reducing its oxides through stirring a molten bath of metal with a green timber pole, continuation of this process until the desirable characteristic fracture of tough-pitch refined metal is lost. Some reoxidation then becomes necessary. See also: tough pitch.
- The superposition of a new set of structural features on an older set. Syn: superprint; metamorphic overprint.
- A royalty or percentage of the gross income from production deducted from the working interest.
- The term applied to a royalty reserved in a sublease or assignment over and above that reserved in the original lease.
- A winding or hoisting rope.
- Usually applied to endless rope haulage in which the rope is carried on top of the mine cars, which may be either clipped or lashed to the rope. See also: underrope haulage.
- See: overhaul.
- A special brake fitted to a towed vehicle that operates as soon as the towing vehicle slows down.
- A coupling that transmits rotation in only one direction, and disconnects when the torque is reversed.
- A rock that contains silica in excess of that necessary to form saturated minerals from the bases present. CF: saturated rock.
- A fishing tool for recovering lost drill pipe or casing.
- Discharging over the side; e.g., by a dredge.
- a. In reference to a mixture of material screened or classified into two products of definite size limits, the larger is the oversize and the smaller the undersize. See also: classifier.
b. In quarry or opencast blasting, that size of rock or ore which is too large to handle without secondary blasting.
- A screen used to prevent the entry into a machine of large particles that might interfere with its operation. Syn: guard screen; check screen.
- a. Core cut by a thin-wall bit, as opposed to a standard-diameter core.
b. A core the diameter of which is greater than a standard size.
- a. See: swelled coupling.
b. Sometimes used in Canada as a synonym for reaming shell.
- A borehole the diameter of which is excessive because of the whipping action or eccentric rotation of the drill string and bit.
- See: drill collar; guide rod.
- See: springing.
- In strata control, describes an area where the force is concentrated on pillars. This type of area is said to be overstressed or superstressed. This superstressing is limited by the strength of the seam or pillar. CF: destressed area.
- Similar to a Wilfley table but of diamond shape (rhomboid), thus eliminating the waste corners.
- Hauling over public highways, usually by a dump truck. Various restrictions, such as weight, width of vehicle, safety features, guard against spillage, etc. must be considered in the type equipment used. CF: off-the-road hauling.
- A low-angle thrust fault of large scale, with displacement generally measured in kilometers. CF: underthrust. Syn: overthrust fault.
- See: overthrust nappe.
- See: overthrust.
- The body of rock that forms the hanging wall of a large-scale overthrust; a thrust nappe. Syn: overthrust block; overthrust sheet; overthrust slice.
- See: thrust plane.
- See: overthrust nappe.
- See: overthrust nappe.
- The period beyond the normal shift time when a worker, on request by the management, performs emergency tasks that are necessary for safety or efficient operation of the oncoming shift.
- Flow of water over the top of a dam or embankment.
- See: overwind.
- An endless-rope system in which the rope runs over the tubs or cars in the center of the rails. This system is generally adopted on undulating roads, where the tension in a heavily loaded rope would cause the rope to lift in swilleys and derail tubs. It is also generally adopted in highly inclined roads, as the lashing chain, often adopted with this method of haulage, obtains a good positive grip on the rope and is easier to detach than a clip. The rope is kept from rubbing on roof supports by holding-down pulleys: six or eight small pulleys are mounted in circular cheeks, allowing chains or clips to be accommodated in the spaces between the pulleys; or large diameter pulleys may be used, of the hat or mushroom shape, often starred to provide recesses for chains and clips. Similar large pulleys direct the rope around curves. CF: undertub system.
- Said of a fold, or the limb of a fold, that has tilted beyond the perpendicular. The sequence of strata thus appears reversed. Syn: inverted; inverted fold; reversed.
- A type of skip commonly used at metal mines, but not as often at coal mines, because of increased breakage. This skip consists of a rectangular receptacle for the material and a suspending frame of bail to an upper crosspiece of which is attached a suspension gear connecting the rope to the skip. Three guide shoes are generally provided at each side of the bail to keep it vertical. The skip body turns about a horizontal shaft at the lower end of the bail. Two rollers on the upper part are mounted on a shaft and cause the skip to tilt at an angle of 35 degrees at the tipping point in the headgear, where rollers run onto the curved guides. To prevent shocks in the case of an overwind the skips are fitted with overwind guides which glide along rollers fitted to the headgear above the tipping point.
- Too much air in the mine workings.
- The difference between the actual electrode potential, when appreciable electrolysis begins, and the reversible electrode potential.
- Relay that serves primarily the same purpose as an overcurrent relay except that it is connected in the line by a potential transformer which measures the voltage across the line. When an overvoltage exists the relay operates and opens the circuit breaker.
- a. To hoist a cage into or over the top of a headframe. Syn: overtravel.
b. In hoisting through a mine shaft, failure to bring a cage or skip smoothly to rest at the proper unloading point at the surface. If severe, it can lead to a serious accident unless the special preventive devices function effectively. Overwind can also cause a cage to be lowered into the sump at the bottom of the shaft, also with serious consequences.
- One of the best known overwinder prevention devices consists of two vertical-screwed spindles, each carrying two traveling nuts and chain driven from the drum shaft so as to rotate in opposite directions. The nuts are prevented from rotating by projections engaging with a fixed plate and therefore travel up and down according to the movement of the cages. The upper nut takes care of overwinding and the lower nut of overspeeding.
- a. A term applied to a continued pull on the hoisting rope of a cage, after the cage has reached the top of the shaft. The result of this carelessness, or accident, is a broken hoisting rope and all the danger that implies.
b. A rope or cable wound and attached so that it stretches from the top of a drum to the load.
- A switch that may be used on winders, or haulages, to cause the power to cut off from the driving motor, or engine, and the brakes to be applied. Such a switch may be: (1) situated in the headgear and operated by the conveyance, (2) mounted on the automatic contrivance, or (3) operated by the depth or distance indicator.
- See: oolith.
- A flotation process involving the violent agitation of the pulp in cold water to which a small percentage of eucalyptus oil, about 62.5 g, is added.
Owen's borehole surveying instrument
- A clockwork photographic apparatus that records clinometer and compass readings on sensitized paper. It is used during borehole surveying.
- An instrument similar to the konimeter but differing in that the air to be sampled undergoes humidification prior to being blown through the jet. The velocity of impingement is about 200 to 300 m/s and the jet is rectangular instead of circular. The prior humidification of the air causes condensation of moisture upon the dust particles by super saturation due to the pressure drop at the jet, and so assists in the deposition and retention of the particles on the slide. The Bausch and Lomb dust counter is the American counterpart of this instrument.
- See: whewellite.
- See: humboldtine.
- An orthorhombic mineral, (NH (sub 4) ) (sub 2) C (sub 2) O (sub 4) .H (sub 2) O ; transparent; yellowish-white; forms lamellar and pulverent masses in guano.
- A variety of aliphite hydrocarbon containing oxygen; light-yellow; soft.
- Sediment composed of the oxides and hydroxides of iron and manganese, crystallized from aqueous solution. It is one of Goldschmidt's groupings of sediments or analogues of differentiation stages in rock analysis.
- a. The firing of a kiln in such a manner that combustion is complete and in consequence the burning gases are amply supplied with oxygen, which causes metals in clay and glazes to give their oxide colors.
b. Combination with oxygen; increase in content of a molecular compound; increase in valency of the electropositive part of compound, or decrease in valency of the electronegative part. c. A reaction in which there is an increase in valence resulting from a loss of electrons. CF: reduction. d. In fuel practice, the combination of oxygen with a substance, with or without the production of food.
- The absorption of oxygen from the air by coal, particularly in the crushed state; this engenders heat which can result in fire. Ventilation, while dispersing the heat generated, supports oxidation that increases rapidly with a rise in temperature. Fresh air should not gain access to the coal. See also: gob fire.
- A compound of oxygen with another element.
- Discoloration of a metal surface caused by oxidation during thermal treatment.
- A mineral formed by the union of an element with oxygen; e.g., corundum, hematite, magnetite, and cassiterite.
- An iron ore with oxygen as its main impurity; also iron rust.
- A deposit that has resulted from surficial oxidation.
- Metalliferous minerals altered by weathering and the action of surface waters, and converted, partly or wholly, into oxides, carbonates, or sulfates. These compounds are characteristic of metalliferous deposits at the surface and often to a considerable depth. See also: mixed ore.
- The portion of an orebody near the surface that: (1) has been leached by percolating water carrying oxygen, carbon dioxide, or other gases; or (2) in which sulfide minerals have been partially dissolved and redeposited at depth, the residual portion changing to oxides, carbonates, and sulfates. CF: gossan; sulfide zone. Syn: zone of oxidation. See also: supergene enrichment.
- A material that readily yields oxygen or other oxidizing substances needed for an explosive reaction to take place; solid oxidizers common in industrial explosives are ammonium nitrate and sodium nitrate.
- In blowpiping, the outer, least visible, and less intense part of the flame, from which oxygen may be added to the compound being tested. See also: blowpiping. CF: reducing flame.
- An oxidation process used for fire refining bismuth, gold, and silver; the crude metals are melted down with oxidizing fluxes, so that the impurities are oxidized during the melting period and become part of the slag.
- See: pyritic smelting.
- An explosive prepared by dissolving picric acid in nitric acid.
- A mixture of oxygen, O (sub 2) , and acetylene gas, C (sub 2) H (sub 2) , in such proportions as to produce the hottest flame known for practical use. Oxyacetylene welding and cutting is used in almost every metalworking industry.
- An appliance for cutting metals by means of a flame obtained from acetylene and compressed oxygen, which are stored in separate steel cylinders. Oxyhydrogen and oxycoal gas flames are also used.
- A plastic cement formed by mixing finely ground caustic magnesite with a solution of magnesium chloride.
- A nonmetallic element, normally colorless, odorless, tasteless, nonflammable diatomic gas. Symbol, O. Occurs uncombined in the air to the extent of about 21% by volume and is combined in water, in most rocks and minerals, and in a great variety of organic compounds. Oxygen is very reactive and capable of combining with most elements. Essential for respiration in all plants and animals and for practically all combustion. Oxygen enrichment of steel blast furnaces accounts for the greatest use of the gas. Used in manufacturing ammonia, methanol, and ethylene oxide.
- The amount of oxygen in an explosive mixture, expressed in weight percent, liberated as a result of complete conversion of explosive material to CO (sub 2) , H (sub 2) O, SO (sub 2) , Al (sub 2) O (sub 3) , and other non-toxic gases; referred to as positive oxygen balance; negative oxygen balance is a deficient amount of oxygen leading to incomplete oxidation of explosive materials resulting in the possible formation of toxic gases, such as CO and NO.
- A steelmaking process in which the air blown through the bottom tuyeres is enriched with oxygen. If oxygen alone is used, tuyere wear is excessive. Oxygen plus steam or oxygen plus carbon dioxide can be used. Also called oxy-Thomas. See also: O.L.P. steel process.
- A person working hard requires about 10 ft (super 3) /min (283 L/min) of air to supply adequate oxygen.
- See: anoxia.
- A concentration of oxygen in the atmosphere equal to or less than 19.5% by volume.
- An atmosphere containing more than 23.5% oxygen by volume.
- Employed as an autogeneous matte smelting process for smelting copper-nickel concentrate.
- Electrolytic copper free from cuprous oxide; produced without the use of residual metallic or metalloidal deoxidizers.
- A process used in steel making in which pure oxygen is blown down onto the bath in a converterlike vessel.
- Volumetric ratio of oxygen to the total gases in a mixture.
- A device made up of a welding oxygen bottle and a length of rubber hose attached to a valve which is fitted to a steel pipe, so that when the tip of the lance is ignited it can be used to melt the solidified metal out of the iron tap hole in a blast furnace.
- A process for making steel in which oxygen is blown upon or through molten pig iron, whereby most of the carbon and impurities are removed by oxidation.
- The use of oxygen instead of air to convert molten pig iron into steel. The oxygen is used in different ways in different furnaces, but the fastest ones utilize the direct oxidation effects of a relatively pure (99.5%) oxygen. See also: L.D. steel process.
- A hornblende with (OH+F+Cl) less than 1.0. Also called basaltic hornblende. Syn: lamprobolite.
- Of, relating to, or utilizing a mixture of oxygen and hydrogen.
- A blowpipe in which hydrogen is burned in oxygen. Streams of the two gases in the proportion to form water are forced under pressure from separate reservoirs, and issue together from a jet, igniting just as they issue. The temperature produced which has been estimated at 5,000 degrees F (2,760 degrees C), is sufficient to fuse very refractory substances. Also called compound blowpipe.
- A former name for maghemite, isometric Fe (sub 2) O (sub 3) ; also called ferromagnetic ferric oxide.
- See: lithophile.
- A white, massive variety of thomsonite, from Arkansas.
- A mineral paraffin wax, of dark yellow, brown, or black color with a melting point of 55 to 110 degrees C and sp gr, 0.85 to 0.95. Is soluble in gasoline, benzene, and turpentine and is found near the Caspian Sea region and in Utah as narrow seams in sandstone. Also called mineral wax; fossil wax; native paraffin; earth wax. Also spelled ozokerite. Syn: ader wax; earth wax; mineral fat. See also: fibrous wax. CF: hatchettine; hatchettite.
- An allotropic, triatomic form of oxygen, O (sub 3) ; a faintly blue, irritating gas with a characteristic pungent odor, but at -112 degrees C it condenses to a blue magnetic liquid. It occurs in minute quantities in the air near the Earth's surface and in larger quantities in the stratosphere as a product of the action of ultraviolet light of short wavelengths on ordinary oxygen. Ozone is generated usually in dilute form by a silent electric discharge in oxygen or air. It decomposes to oxygen (as when heated) and it is a stronger oxidizing agent than oxygen. Used chiefly in disinfection and in deodorization (such as in water purification and in air conditioning), in oxidation and bleaching (such as in the treatment of industrial wastes), and in ozonolysis (such as in the manufacture of azelaic acid from oleic acid).
- Electrical apparatus that converts atmospheric oxygen to ozone; used in sterilizing water for drinking purposes and for purifying air.