The Aggregates & Recycling Information Network

Glossary: A

  • AAV

    abbr. aggregate abrasion value

    A BS test retained after adoption of EN standards. A measure of the resistance of an aggregate to abrasion as determined by the abrasion test defined in BS 812. 

  • Absolute Pressure

    Pressure which is measured from the absolute zero of pressure, ie the sum of gauge pressure and atmospheric pressure.

  • Absolute Volume Method

    A means of calculating the yield of concrete on the basis that the volume of compacted concrete equals the sum of the absolute volumes of the aggregates, cement and water.

  • Ac

    abbr. alternating current

    A current varying with time in a cyclic manner, the current direction reversing periodically.

  • Acceleration

    The rate of change of the velocity of a point with respect to time. If no change of direction is involved linear acceleration units are m/s2.

    See also ‘angular acceleration’.

  • Acceleration Due To Gravity

    Acceleration with which a body would fall freely under the action of gravity in a vacuum. This varies according to the distance from the centre of the earth but the accepted value is 9.81 metres per second.

    Note: Variations from the accepted value may occur where, for instance, there are massive ore bodies close to the surface and these anomolies are employed in mineral exploration.

    Symbol: g.

  • Accelerator

    In concrete technology, an admixture which speeds up the hydration process to produce a high early compressive strength.

  • Acceptance Criteria

    Set of procedures for accepting waste materials on site, including: list of types of materials accepted; methods (e.g. tests or controls) of acceptance; requirements arising from the Waste Management Regulations and the Duty of Care.

  • Accumulator
    1. A voltaic cell which can be charged and discharged, a portable store of electric power usually called a battery.
    2. An accumulator consists of a chamber into which hydraulic fluid enters under pressure and in so doing compresses either a gas or a spring. A fall in the pressure at the inlet results in fluid being forced back into the system by the compressed gas or spring.
  • Acid Rock

    Igneous rock containing more than 66% silica.

  • ACOP

    abbr. approved code of practice

    A publication giving guidance on the implementation of requirements laid down in Regulations made under the Health and Safety at Work Act.

  • Action Level

    The Noise at Work Regulations 2005 define several action levels corresponding to particular exposure levels: notably 80 and 87dB(A) and a peak level of 135dB(C).

  • Activators
    1. Added active items that enable an otherwise inert material to demonstrate improved properties, eg cement with ground granulated blast-furnace slag. 
    2. A type of flotation reagent which may be divided into two groups.
  • Active Component

    The component of the phasor current or voltage which is in phase with the voltage or current respectively.

  • Active Power

    The product of the active component of the current and the voltage, or of the active component of the voltage and the current.

    Units: watts.

  • Active Tip

    A term no longer in use to describe a tip on quarry premises which is in use and covered by the now revoked Mines and Quarries (Tips) Regulations 1971.

  • Actual Power

    The product of the active component of the current and the voltage, or of the active component of the voltage and the current.

    Units: watts.

  • Actuator

    A machine using a form of energy (electrical, hydraulic, pneumatic) to move a load or apply a force.

  • ACV

    abbr. aggregate crushing value

    An obsolete measure of the resistance of an aggregate to crushing determined by the compression test as defined in BS 812. Largely replaced first by the Ten Percent Fines test and then by the Los Angeles test following harmonization of European standards.

  • Adiabatic

    A process during which no heat transfer takes place.

  • Adit

    Level, or nearly level, tunnel driven into hillside for exploration.

  • Admixture

    A material, usually a liquid, which is added to a batch of concrete during mixing in order to modify the properties of the fresh or hardened concrete. There are many types of admixtures for concrete including: accelerators, retarders, plasticizers, air-entrainers etc. see British Standard 5075, Parts 1,2 and 3.

  • Articulated dumptruck
    ADT

    abbr. articulated dumptruck

    An on-site tipping vehicle used for the transport of excavated mineral or overburden

     

     

     

  • Advance Reduction

    The process of overburden removal ahead of the coaling operation on an opencast coal site.

  • Aeolian

    Wind-borne materials.

  • Aerated Concrete

    Concrete made by adding constituents to the mix, usually powdered aluminium, which, by chemical reaction, cause gas bubbles to form within the concrete. This reduces the density and increases the insulation value of the concrete.

  • Aerial Surveying

    The making of maps by photography from the air using reference pointsof known level and position which can be identified on the photographs.

    Also: photogrammetry

  • Aggregate Abrasion Value

    A BS test retained after adoption of EN standards. A measure of the resistance of an aggregate to abrasion as determined by the abrasion test defined in BS 812.

    abbr. AAV.

  • Aggregate Crushing Value

    An obsolete measure of the resistance of an aggregate to crushing determined by the compression test as defined in BS 812. Largely replaced first by the Ten Percent Fines test and then by the Los Angeles test following harmonization of European standards.

    abbr. ACV

  • Aggregate Impact Value

    An obsolete relative measure of the of the resistance of an aggregate to sudden shock as determined by the impact test defined in BS 812.

    abbr. AIV

  • Agitator

    A rotatable truck-mounted container used for keeping plant-mixed concrete in a fresh state.

  • Air Classification

    The process of sizing of particles in a current of air.

  • Air compressor
    Air Compressor

    A machine, driven by a motor, for compressing air for power purposes, eg rock drilling.

    Also: compressor

  • Air Entrainment

    The deliberate incorporation of air into a concrete mix, usually by admixture.

    See also: aerated concrete

  • Air Overpressure

    The pressure in excess of ambient atmospheric pressure which occurs when an air blast wave passes a given position. The maximum excess pressure is known as the peak overpressure and it is when this is excessive (>180dB) that structural damage may occur.

  • Air-flush

    Term applied to drilling using compressed air to clear the chippings and to cool the bit.

  • Air-line Lubricator

    An oil reservoir connected into the compressed-air supply line 2m or 3m from the drill or air motor to which it feeds lubricating oil in the form of an atomized spray.

  • Airblast

    An airborne shock wave resulting from the detonation of explosives. May be caused by burden movement or the release of expanding gas into the air. Airblast may or may not be audible.

  • Airblaster

    Pervious ceramic pads introduced into the base cone of a hopper so that compressed air can be introduced to assist the flow of difficult powders.

  • Airleg

    A device incorporating a pneumatic cylinder, providing support and thrust for a jackhammer.

  • Airlift Pump

    A pump for the raising of water from a well or sump by the injection of compressed air into the bottom of a pipe which has been submerged to a considerable depth in the water. The compressed air expands and rises, and, as the overall density of water and air bubbles is lower than that of the water, it is forced to the surface by the higher pressure of the water outside the pipe.

  • AIV

    abbr. aggregate impact value

    An obsolete relative measure of the of the resistance of an aggregate to sudden shock as determined by the impact test defined in BS 812.

  • Alidade
    1. The rotatable part of a theodolite.
    2. An instrument used in plane-tabling.
  • Alkali-silica Reaction

    A process of deterioration in concrete resulting from the reaction between alkalis, principally from the cement, and certain types of aggregate.

    abbr. ASR

  • All-in Aggregate

    A mixture of coarse and fine aggregate.

  • Alligator Fastener

    A type of fastener used to join the ends of conveyor belts. It consists of a pair of steel strips, each incorporating a series of teeth along both edges which are hammered through the belt and their ends bent over; the ends of the belts are connected by a hinge pin.

  • Alloy Steels

    Steels to which have been added elements not present in plain carbon steels to impart to them certain special properties.

  • Alluvium

    A collective term for unconsolidated detritus such as clay, silt, sand and gravel deposited by streams and rivers as sorted or semi-sorted sediment in channels and over flood plains and deltas.

  • Alternating Current

    A current varying with time in a cyclic manner, the current direction reversing periodically.

    abbr. ac

  • Alternator

    A machine used to generate alternating current.

  • Aluminium

    A metal commonly used as a fuel or sensitizer in explosives and blasting agents, normally used in finely divided particle or flake form. It is also used, in a powdered form, as a foaming agent in the production of lightweight bricks and blocks.

  • Ammeter

    An instrument for measuring current. It is connected either in series with the circuit carrying the current or, where heavy currents have to be measured, to the secondary winding of a current transformer the primary of which carries the current to be measured.

  • Ammonium Nitrate

    The most commonly used oxidizer in explosives and blasting agents (NH4NO3).

  • Amortization

    Depreciation of assets over a fixed life.

  • Ampere

    The SI unit of electric current.

    Symbol: A.

  • Ampere-hour

    A unit of electric charge. It is the quantity of electric charge which passes in one hour at a current of one ampere.

    Symbol: Ah.

  • Amphibole

    Group of rock-forming silicate minerals characterized by a double chain silicate structure.

  • Amplitude

    The maximum displacement from the mean position in an oscillating motion, ie the height of the wave measured from the axis. Note: In the case of a screen with a straight-line motion or elliptical motion, it is half the total movement or half the major axis of the ellipse. In the case of a circular motion, it is the radius of the circle.

  • AN/FO

    A mixture of ammonium nitrate and fuel oil in such proportions that the mixture can be detonated with a suitable initiator.

    More commonly shown as: ANFO

  • Anchor Bolt

    A bolt with its threaded end projecting above the foundation and secured so as to hold down a steel structure against wind loads or machinery against its vibration.

    Also: foundation bolt and holding-down bolt

  • Anchor Dredger

    A marine aggregate recovery vessel which dredges from one point on the sea-bed.

    Also: trailer dredger

  • ANFO

    A mixture of ammonium nitrate and fuel oil in such proportions that the mixture can be detonated with a suitable initiator.

    Also: AN/FO

  • ANFO Mixer

    A trailer- or truck-mounted machine for on-site mixing of ammonium nitrate and fuel oil and charging the blasthole.

  • Angle Grinder

    Hand-held tool with a grinding disc at the side of the power unit.

  • Angle Of Friction

    The angle between the normal to two contacting surfaces and the direction of the resultant reaction between them, when a force is just tending to cause sliding.

  • Angle Of Nip

    Angle between the faces of a crusher.

  • Angle Of Repose

    The maximum angle between the surface of a heap of loosely piled material and the horizontal.

    Also: repose angle 

  • Angledozer

    A bulldozer with the blade set at an angle so that it pushes material forward and to the side.

  • Angular Acceleration

    The rate of change of angular velocity.

    Units: rad/s2.

  • Angular Velocity

    The rate of change of angular displacement.

    Units: rad/s.

  • Angularity Number

    An indication of aggregate shape which relates the voids content of a compacted sample to that of a rounded gravel sample.

  • Annealing

    A process which removes stresses set up during the manufacture of a structure of steel and restores it to its normal condition, at the same time softening it and refining the grain structure. It involves heating the metal to a selected temperature, holding at this temperature for some time and cooling at a slow, controlled rate. Annealing is also applied to copper and other metals, as well as glass.

  • Anode

    The electrode from which an electric current flows.

  • Anticline

    An arch-like fold in stratified rocks.

  • Aperture Size

    The dimension or dimensions defining the opening in the screen deck, usually with a qualification as to the shape of the aperture, eg round hole, square mesh, long slot.

  • Apparent Power

    In an ac circuit, the product of the rms values of the voltage and current.

    Units: voltamperes (VA).

  • Appoint

    Legally, to appoint a person to a position in writing.

  • Approved Code Of Practice

    A publication giving guidance on the implementation of requirements laid down in Regulations made under the Health and Safety at Work Act.

    abbr. ACOP

  • Apron Feeder

    A device, consisting of a series of steel flights (pans) bolted to heavy-duty chains which run on sprockets, used to draw material at a regulated rate from a stockpile, storage bin or feed hopper. The rate of flow is controlled by varying either the speed of the apron or the depth of material on it.

  • APS

    abbr. Assisted Private Study Course in Quarrying

    The distance learning and tutorial scheme to prepare candidates for the Institute of Quarrying’s Professional Examination.

    In 2007 this was superseded by the Diploma in Quarry Technology at the University of Derby.

  • Aquifer

    A permeable water-bearing stratum which is capable of storing and yielding water when tapped by a well.

  • Arc Welding

    Welding in which the heat necessary to melt both the plate and filler material is supplied by an electric arc.

  • Are

    The metric unit of area equal to 100m2. A hectare is 100 ares.

  • Arenaceous

    Sandy.

  • Argillaceous

    Clayey or silty.

  • Arkose

    Type of sandstone or gritstone containing over 25% feldspar.

  • Armature
    1. The part of a machine in which electromotive forces are induced.
    2. The movable part of an electromagnetic circuit which, by attraction, can do useful mechanical work, as in a relay.
    3. A piece of ferromagnetic material placed across the ends of a permanent magnet to complete the magnetic circuit.
  • Armour stone
    Armour-stone

    Large irregular lumps of hard rock used for sea defences etc.

  • Armouring

    The steel wires or tapes incorporated in an electric cable to provide mechanical protection for the conductors and insulation and to provide a low-resistance earth path between the two ends of the cable.

  • Artesian Well

    A well sunk into a permeable stratum which has impervious strata above and below it and from which water flows without pumping.

  • Articulation

    The articulated dumptruck connection of two parts in such a way as to permit the same relative movement, eg the two sections of the frame joined by two or more pins to form an articulated dumptruck.

  • Asbestos

    A toxic material that was once used to make insulation and fireproofing material in construction. Because some forms of asbestos have been linked to certain lung diseases, it is no longer used in new homes. However, some older buildings may still contain asbestos, which is a hazardous (special in Scotland) waste.

  • Asphaltic Cement

    Bitumen, a mixture of lake asphalt and bitumen, or lake asphalt and flux oil, or pitch used as a binder.

  • Asphaltic Concrete

    A term applied, particularly in the USA, to a rolled asphalt incorporating a continuously graded aggregate.

  • ASR

    abbr. alkali-silica reaction

    A process of deterioration in concrete resulting from the reaction between alkalis, principally from the cement, and certain types of aggregate.

  • Assets

    Resources owned by a company which have been acquired at a measureable money cost.

  • Assisted Private Study Course In Quarrying

    The distance learning and tutorial scheme to prepare candidates for the Institute of Quarrying’s Professional Examination.

    abbr. APS

    In 2007 this was superseded by the Diploma in Quarry Technology at the University of Derby. 

  • Atomizer

    A nozzle through which fuel oil is sprayed into the combustion chamber of an oil engine or burner. Its function is to break up the oil into a fine mist in order to ensure good combustion.

  • Auger

    A tool developed from the Archimedean screw, used for soil sampling or drilling of shallow holes.

  • Augite

    Common pyroxene containing calcium, magnesium and iron.

  • Authorized Capital

    The total amount of capital which the company is allowed to issue as shares of different types, as stated in its Articles of Association and its Memorandum lodged with the Registrar of Companies.

  • Auto-transformer

    A transformer having only one winding per phase; part of the winding is common to both primary and secondary sides. The uses of auto-transformers include the supplying of reduced voltages when starting large induction and synchronous motors.

  • Auto-transformer Starter

    A tapped auto-transformer reduces the voltage supplied to a motor during the starting period in order to limit the current taken during that time.

  • Autoclaving

    The curing, in a steam chamber, of freshly cast concrete or sand-lime bricks for up to 24 hours at a steam pressure of about 10 atmospheres, which results in the material acquiring the same strength as would be achieved after a month if air-curing was used.

  • Autogenous

    A term applied to grinding mills which use tumbling action to effect comminution which is achieved by the action of rock or ore particles on one another; no steel balls or rods are used.

  • Average Value

    The arithmetic mean of the instantaneous values of a periodic quantity taken over half a cycle.

    Also: mean value

  • Axial Priming

    A system of priming for blasting agents in which a core of priming material extends through most or all of the length of the charge.