ISO 1213-1:2020

INTERNATIONAL ISO
STANDARD 1213-1
Third edition
2020-09
Coal and coke — Vocabulary —
Part 1:
Terms relating to coal preparation
Charbon et coke — Vocabulaire —
Partie 1: Termes relatifs à la préparation du charbon
Reference number
©
ISO 2020
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative reference . 1
3 Terms and definitions . 1
3.1 General coal preparation terms . 1
3.2 Cleaning characteristics . 5
3.3 Capacity and throughput . 7
4 Terms related to sizing . 8
4.1 General . 8
4.2 Screening .10
4.3 Parts of screens .12
4.4 Screens according to purpose .13
4.5 Screens according to principle of construction .14
4.6 Sizing in a current of air or water .15
5 Terms related to cleaning .15
5.1 General .15
5.2 Dry cleaning .17
5.3 Jigging .18
5.4 Dense medium cleaning .21
5.5 Cleaning equipment (miscellaneous) .23
5.6 Froth flotation .25
6 Terms related to separation of solids from water or air .28
6.1 General .28
6.2 Dewatering .29
6.3 Clarification and thickening .30
6.4 Separation of solids from air .31
7 Terms related to size reduction .32
7.1 General .32
7.2 Size reduction machines .33
8 Terms related to the expression of results .34
8.1 General terms .34
8.2 Sizing operations .35
8.3 Cleaning operations .37
9 Terms related to miscellaneous .38
10 Terms related to blending and homogenization terms .39
11 Terms related to automatic control terms .41
11.1 General .41
11.2 Control equipment .42
11.3 Control terminology .45
Bibliography .49
Index .50
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 27, Coal and coke, Subcommittee SC 1,
Coal preparation: Terminology and performance.
This third edition cancels and replaces the second edition (ISO 1213-1:1993), which has been technically
revised.
A list of all parts in the ISO 1213 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

Introduction
This document takes into account the distinction between processes or operations and the methods or
machines for carrying them out.
Clause 3 is devoted primarily to coal properties and the principal operations involved in coal
preparation, and also includes general terms such as those relating to capacities and flowsheets.
Clauses 4 to 7 cover the detailed terminology relating to sizing, cleaning, separation of solids from
water or air, and size reduction.
Clause 8 deals with the terms involved in interpreting or expressing the results of coal preparation
operations.
Clause 9 includes some miscellaneous terms.
Clause 10 covers terms related to blending and homogenization.
Clause 11 covers terms related to automatic control. Of necessity, it covers only a limited selection of
terms. A list of other International Standards, which together provide a more comprehensive set of
terms, is given in Bibliography.
Most of the clauses are subdivided, and in each case the first subclause includes general terms and the
remaining subclauses cover groups of related terms. As far as possible, this logical principle has been
carried through into the arrangement of the terms themselves, which are also numbered for ease of
reference. An alphabetical index is also provided, with a numerical cross-reference.
INTERNATIONAL STANDARD ISO 1213-1:2020(E)
Coal and coke — Vocabulary —
Part 1:
Terms relating to coal preparation
1 Scope
This document defines terms commonly employed in coal preparation.
Note For terms relating to petrographic analysis, see ISO 7404-1.
2 Normative reference
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1 General coal preparation terms
3.1.1
coal preparation
collectively, physical and mechanical processes applied to coal to make it suitable for a particular use
3.1.2
run of mine
r.o.m.
r.o.m. coal
coal produced by mining operations, before screening, crushing (7.1.2) or preparation
3.1.3
raw coal
coal that has received no preparation other than possibly screening (4.2.1) or crushing (7.1.2)
3.1.4
raw coal feed
raw coal (3.1.3) supplied to a plant or machine, in which it undergoes some form of preparation
3.1.5
coal cleaning
treatment of raw coal (3.1.3) to lower the quantity of undesirable constituents, through the difference
in either density or surface properties
3.1.6
cleaned coal
clean coal
coal produced by a cleaning process (wet or dry)
3.1.7
middlings
product of coal preparation (3.1.1) that, because of its ash percentage, is intermediate between coal and
discard (3.1.11)
Note 1 to entry: It follows therefore that the relative density of middlings is intermediate between those of coal
and discard. Middlings may be reprocessed.
3.1.8
true middlings
bone
middlings (3.1.7) so nearly homogeneous that their quality cannot readily be improved by crushing
(7.1.2) and recleaning
3.1.9
false middlings
interbanded middlings
middlings (3.1.7) in which the particles consist of bands of coal and shale, and from which the coal may
be liberated by crushing (7.1.2)
3.1.10
reject
refuse
material extracted from the feed (3.3.6) during cleaning, for retreatment or discard (3.1.11)
3.1.11
discard
dirt
stone
material extracted from the raw coal (3.1.3) and finally discarded
3.1.12
recirculation
operation in which the whole or part of a product from a process is returned to the feed (3.3.6) to a process
Note 1 to entry: For example, return of the crushed overflow from a screen to the screen feed for rescreening.
3.1.13
foreign coal
coal received at a preparation plant from a source other than that to which the plant is attached
3.1.14
imported coal
coal coming from a foreign country, or other state within the country
3.1.15
low-grade coal
combustible material that has only limited uses owing to undesirable characteristics (e.g. ash
percentage or size)
3.1.16
part-cleaned coal
mixed product of cleaned and uncleaned fractions of coal
2 © ISO 2020 – All rights reserved

3.1.17
segregation
partial separation of a material into its constituents, occurring as a result of differences in particle
characteristics such as particle size or relative density
3.1.18
beneficiate
to increase the commercial value of a coal by appropriate treatment
3.1.19
coal preparation plant
plant in which a coal preparation (3.1.1) process is carried out
3.1.20
compressor air
compressor, either rotary or reciprocating, used to produce air at a pressure suitable for specific
operations in the coal preparation plant (3.1.19)
3.1.21
concentrate clean coal
cleaned product from a beneficiation process e.g. froth flotation (5.1.22)
3.1.22
demagnetise
to promote dispersion (6.1.12), by means of a suitable magnetic field, in a dense medium (5.4.2) of solids
that have been flocculated magnetically
3.1.23
Durham cone
laboratory apparatus used for evaluation of the flow or handling characteristics of coal
3.1.24
flowsheet
diagram indicating the method of treating the raw coal (3.1.3) in a preparation plant, by showing in correct
sequence the chief units of plant, the principal operations and (normally) the quantities of each stage
3.1.25
haematite
iron oxide mineral, typically forming the non-magnetic component of industrial magnetite (3.1.30)
3.1.26
idlers
rollers for supporting a conveyor belt
3.1.27
impact box
container interposed at impact points in the flow of material to resist wear
3.1.28
tramp iron
pieces of magnetic metal, metallic equipment of machine parts, used welding rods that have become
accidently mixed with the run-of-mine coal
3.1.29
magnetite
strongly magnetic iron oxide mineral, making up the magnetic component of industrial magnetite
(3.1.30)
3.1.30
industrial magnetite
commercially available magnetic material used for preparation of dense medium (5.4.2) for use in coal
preparation (3.1.1), commonly referred to as magnetite (3.1.29)
3.1.31
metering box
container, having single or multiple compartments, and a weir (3.1.44) or weirs to provide the controlled
addition of one or more reagents (3.1.36)
3.1.32
percentage recovery
amount of a certain constituent in the product, expressed as a percentage of that constituent in the
feed (3.3.6)
3.1.33
finger planimeter
flow rate indicator for determining the volumetric rate of flow of a solid particulate material, in which a
series of flexible steel fingers mounted on a common frame are situated above a conveyor belt with the
fingers resting on the belt surface
3.1.34
pilot plant
coal preparation plant (3.1.19) of limited capacity but duplicating the operations of a proposed plant or a
part of the proposed plant, so that the effectiveness of the designed process may be determined
3.1.35
metering pump
variable, positive-displacement pump to control the addition of reagents (3.1.36) to a coal preparation
plant (3.1.19) circuit
3.1.36
reagent
chemical substance added to the preparation plant circuit for some specific purpose
3.1.37
residence time
mean time for which a unit of material is within a vessel or process
3.1.38
solids concentration
a) mass of solids in a solids/liquid mixture or suspension (5.1.11), expressed as a percentage
of the total pulp (5.6.6) or slurry (5.1.21) mass
b) volume of solids in a solids/liquid mixture or suspension (5.1.11), expressed as a
percentage of the total pulp or slurry (5.1.21) volume
c) mass or volume of solids in a solids/liquid mixture or suspension (5.1.11),
expressed as a mass per unit volume, or volume per unit mass, of the total pulp (5.6.6) or slurry
(5.1.21) respectively
3.1.39
spigot
orifice of a device [e.g. the apex of a cyclone (5.5.8)] through which the underflow discharges
3.1.40
splitter box
receiver fitted with an adjustable device to divert or apportion flow
4 © ISO 2020 – All rights reserved

3.1.41
spoil bank
stockpile of reject (3.1.10) material; may also refer to waste material (e.g. overburden) from mining
operations
3.1.42
trash
extraneous material associated with the run-of-mine coal, e.g. wood, metal, and plastic materials
3.1.43
belt weigher
apparatus used to quantify the mass flow of a material on a belt conveyor
3.1.44
weir
plate or dam (over which the liquid must flow) to control the level of the liquid
3.2 Cleaning characteristics
3.2.1
washability
amenability of a coal to improvement in quality by cleaning, generally through its relative density/ash
relationship
3.2.2
float-and-sink analysis
division of a sample into relative density fractions having defined limits, the amounts of the fractions
being expressed as weight percentages of the total sample, commonly with an indication of the ash
percentage (and other characteristics, if required) of each fraction
3.2.3
washability curve
curve obtained from the results of a float-and-sink analysis (3.2.2) permitting the theoretical yield (8.3.2)
of floats (8.3.11) or sinks (8.3.12) to be read off
Note 1 to entry: The following are examples of washability curves:
a) characteristic ash curve; see 3.2.4;
b) cumulative floats curve; see 3.2.6;
c) cumulative sinks curve; see 3.2.7;
d) densimetric (relative density) curve; see 3.2.8;
e) near-density curve; see 3.2.9;
f) instantaneous ash curve; see 3.2.15;
g) ash/relative density curve. See 3.2.14.
3.2.4
characteristic ash curve
curve obtained from the results of a float-and-sink analysis (3.2.2) showing, for any mass percentage of
floats (8.3.11) [or sinks (8.3.12)] the ash percentage of the highest density (or lowest density) fraction
passing into these floats (8.3.11) [or sinks (8.3.12)], the mass percentage being plotted on the ordinate
(vertical axis) and the ash percentage on the abscissa (horizontal axis)
3.2.5
cumulative curve
curve expressing the results of combining successive relative density fractions or size fractions
3.2.6
cumulative floats curve
curve obtained from the results of a float-and-sink analysis (3.2.2) by plotting the cumulative mass
percentage of floats (8.3.11) at each relative density against the cumulative ash of the total floats
(8.3.11) at that density
3.2.7
cumulative sinks curve
curve obtained from the results of a float-and-sink analysis (3.2.2) by plotting the cumulative mass
percentage of sinks (8.3.12) at each relative density against the cumulative ash of the total sinks (8.3.12)
at that density
3.2.8
densimetric curve
curve obtained from the results of a float-and-sink analysis (3.2.2) by plotting
the cumulative mass percentage of floats (8.3.11) or sinks (8.3.12) against the relative density
3.2.9
near-density curve
difficulty curve
curve obtained from the results of a float-and-sink analysis (3.2.2), or from the densimetric curve (3.2.8), by
plotting the mass percentage within the limits ± 0,1 of a given relative density against that relative density
3.2.10
performance curve
curve used to show the relationship between properties of coal and results of a specific treatment
3.2.11
actual performance curve
performance curve (3.2.10) showing the results actually obtained from a coal preparation (3.1.1)
treatment
3.2.12
expected performance curve
performance curve (3.2.10) showing the expected results of a coal preparation (3.1.1) treatment
3.2.13
M-curve
Mayer curve
vectorial curve, obtained by plotting the cumulative ash percentages against their cumulative yields
(8.1.3), used to express the washability (3.2.1) of a coal, plotted on a vectorial diagram in which the
projection of the vector on the ordinate (vertical axis) represents the percentage of the product (coal)
and the direction of the vector represents the percentage of a particular constituent of the product
3.2.14
ash/relative density curve
curve obtained from the float-and-sink analysis (3.2.2) by plotting the ash percentages of successive
fractions against the mean relative density of the fraction
3.2.15
ash/instantaneous
maximum ash percentage of any particle in any given relative density fraction mass
3.2.16
ash curve instantaneous
standard washability curve (3.2.3) that relates the maximum ash percentage of any particle (contained
in a cumulative-floats mass) to the cumulative-floats mass of a known ash percentage
6 © ISO 2020 – All rights reserved

3.2.17
ash adventitious
ash arising from mineral matter that was not associated with the original plant material from which
the coal was formed; this form of mineral can be removed readily by physical means
3.2.18
ash extraneous
ash arising from that part of the mineral matter associated with but not inherent in coal
3.2.19
ash inherent
ash arising from finely dispersed mineral matter present in the original plant material or from
which the coal was formed, or from mineral matter incorporated intimately in the coal during the
coalification process
3.2.20
Rosin-Rammler curve
particular form of particle size distribution curve graphed on specific ordinate and abscissa scales that
results in any individual material’s size distribution, due to natural breakage (7.1.6), being represented
by a straight line
3.3 Capacity and throughput
3.3.1
nominal capacity
notional figure, expressed in mass per hour, used in the title of a flowsheet (3.1.24) and in the general
description of a plant, applying to the plant and to the specific product under consideration
3.3.2
operational capacities
figures given on a flowsheet (3.1.24) to indicate quantities per unit time passing various points in the
plant, taking account of fluctuations in the rate of supply and composition (as to size and impurity
content)
3.3.3
design capacity
rate of feed (3.3.6) at which specific items of plant must operate continuously and give the guaranteed
results on a particular quality of feed (3.3.6)
3.3.4
peak design capacity
rate of feed (3.3.6) in excess of the design capacity (3.3.3) that specific items of plant equipment will accept
for short periods without necessarily fulfilling the performance guarantees given in respect of them
3.3.5
mechanical maximum capacity
highest rate of feed (3.3.6) at which specific items of equipment, not subject to performance guarantees,
will function on the type and quality of feed (3.3.6) for which they are supplied
3.3.6
feed
material for treatment supplied to an appliance or plant
3.3.7
basic flowsheet
schematic diagram representing the various preparation process stages in the treatment of the raw
coal (3.1.3)
3.3.8
process flowsheet
basic flowsheet (3.3.7) indicating the main operational steps within the plant, the movement of the
various materials between the steps and the final products obtained, and often also the average mass
flow at various points in the plant
3.3.9
equipment flowsheet
diagram indicating, by standard symbols, the units of equipment used in the various operational steps
carried out within a coal preparation plant (3.1.19)
3.3.10
materials flowsheet
flowsheet (3.1.24) principally concerned with solid materials
3.3.11
liquids flowsheet
flowsheet (3.1.24) to indicate the flow of liquids throughout a series of operations
3.3.12
weighted flowsheet
capacity flowsheet
materials flowsheet (3.3.10) used in the design of a plant, including statements of the mass flow per hour
at principal points in the plant
3.3.13
capacity design
rate of feed (3.3.6), defined by limits expressing the extent and duration of load variations, at which
specific items of plant equipment, subject to a performance guarantee, operate continuously and give
the guaranteed results on a quality of feed (3.3.6)
3.3.14
capacity peak design
rate of feed (3.3.6), in excess of the design capacity (3.3.3) that specific items of plant equipment will
accept for short periods without fulfilling the performance guarantees given in respect of them
3.3.15
capacity mechanical maximum
highest rate of feed (3.3.6) at which specific items of equipment, not subject to performance guarantees,
will function on the type and quality of feed (3.3.6) for which they are supplied
4 Terms related to sizing
4.1 General
4.1.1
sizing
division of a material into products between nominal size (4.1.6) limits
4.1.2
classification
separation of particles according to their size, density and shape by control of their settling rate through
a fluid medium
4.1.3
size analysis
process or the result of the division of a sample into size fractions, each within defined limits, the mass
or number of particles in each fraction being expressed as percentages of the total sample
8 © ISO 2020 – All rights reserved

4.1.4
sieve analysis
size analysis (4.1.3) in which the division is carried out using test sieves
4.1.5
mean size
weighted average particle size of any sample, batch or consignment of particulate material
Note 1 to entry: Several bases for calculating mean size have been proposed which give results that vary widely
for the same size distribution. The method of calculation should, therefore, always be stated whenever results
are reported.
4.1.6
nominal size
limiting size
limit or limits of particle size used to describe a product of a sizing (4.1.1) operation
4.1.7
oversize
product of coal preparation (3.1.1) that, because of its ash percentage, is intermediate between coal and
discard (3.1.11)
4.1.8
undersize
material in a product of size smaller than the lower nominal size (4.1.6) limit; may be expressed as a
percentage of the product
4.1.9
dust
particles of solid material sufficiently fine to allow suspension (5.1.11) in air
Note 1 to entry: See also 6.4.
4.1.10
fines
coal having a maximum particle size usually less than 4 mm, and having no lower limit
Note 1 to entry: upper limit may vary widely. To avoid confusion, the term should always be qualified by stating
the nominal size (4.1.6).
4.1.11
smalls
coal having a maximum particle size usually less than 25 mm, and having no lower limit
4.1.12
oversize in undersize stream
, particles that are larger than the nominal dimension of the size of the separation
4.1.13
undersize in oversize stream
particles in a screen oversize (4.1.7) stream that are smaller than the nominal dimensions of the screen
apertures
4.1.14
nominal top size
size of aperture of the finest sieve (4.2.21) through which a minimum of 95 % of the mass of the material
passes (11.3.29)
4.2 Screening
4.2.1
screening
separation of solid materials of different sizes, by causing part to remain on a surface provided with
apertures through which the remainder passes (11.3.29)
4.2.2
screen
device for carrying out the operation of screening (4.2.1)
Note 1 to entry: Commonly used abbreviation for screen deck (4.3.1) or screening surface (4.3.1), e.g. woven-
wire screen.
Examples are as follows:
a)  bar screen, see 4.5.9;
b)  multi-slope or banana screen, see 4.5.2;
c)  desliming screen, see 4.4.4;
d)  dewatering screen, see 4.4.3;
e)  fixed screen, see 6.2.2;
f)  jigging screen, see 4.5.3;
g)  loose rod; loose-rod deck, see 4.3.5;
h)  medium draining screen; drain and rinse screen, see 5.4.18;
i)  medium recovery screen, see 5.4.20;
j)  multi deck screen, see 4.5.2;
k)  oversize control screen (guard screen), see 4.4.8;
l)  primary screen (raw coal screen), see 4.4.2;
m)  resonance screen, see 4.5.4;
n)  rinsing screen, see 4.4.6;
o)  roll screen, see 4.5.8;
p)  rotating probability screen, see 4.5.6;
q)  run of mine screen, see 4.4.1;
r)  single deck screen, see 4.5.1;
s)  sizing screen (grading screen), see 4.4.7;
t)  slurry screen, see 4.4.5;
u)  trommel screen, see 4.5.7;
v)  vibrating screen, see 4.5.5.
10 © ISO 2020 – All rights reserved

4.2.3
amplitude
maximum displacement from the mean position in an oscillating motion
Note 1 to entry: In the case of a screen (4.2.2) having a straight-line motion or elliptical motion, it is half of the
total movement or half of the major axis of the ellipse. In the case of a circular motion, it is the radius of the circle.
Note 2 to entry: See also stroke (4.2.4).
4.2.4
stroke
throw
distance between the extreme positions of an oscillating or vibrating motion, i.e. the stroke is equal to
twice the amplitude (4.2.3)
4.2.5
aperture size
dimension or dimensions defining the opening in the screening surface (4.3.1), qualified as to the shape
of aperture, e.g. "round-hole", "square-mesh", "long-slot"
4.2.6
dry screening
screening (4.2.1) of solid materials of different sizes without the aid of water
4.2.7
wet screening
screening (4.2.1) of solid materials of different sizes with the aid of water
4.2.8
probability screening
method of screening (4.2.1) that, by making extended use of the probability of a particle passing through
an aperture, allows sizing (4.1.1) at fine sizes to be performed with relatively large apertures
4.2.9
desliming
removal of slimes (5.1.20) from coal or a mixture of coal and water, however accomplished
4.2.10
fines removal
removal of fine particles from a feed (3.3.6) material, by either wet or dry methods, to facilitate
treatment or utilization of the remainder
4.2.11
dedusting
fines removal (4.2.10) by dry methods
4.2.12
screen overflow
that portion of the feed (3.3.6) material discharged from the screen (4.2.2) deck without having passed
through the apertures
4.2.13
misplaced undersize
particles in a screen (4.2.2) overflow that are smaller than a reference size (8.2.6)
4.2.14
screen underflow
that portion of the feed (3.3.6) material that has passed through the apertures in a screen (4.2.2) deck
4.2.15
misplaced oversize
particles in a screen (4.2.2) that are larger than a reference size (8.2.6)
4.2.16
misplaced material
undersize (4.1.8) contained in the overflow, or oversize (4.1.7) contained in the underflow
4.2.17
near-mesh material
near-size material
material approximating in size to a reference size (8.2.6), usually within ± 25 % of that reference
4.2.18
nominal area
total area of the screen (4.2.2) deck exposed to the flow of the material feed (3.3.6)
4.2.19
effective area
working area (deprecated)
nominal area (4.2.18) less any area occupied by fixings or supports that obstruct the passage
of material over or through the screen (4.2.2) deck
4.2.20
open area
ratio of the total area of the apertures to the total area of the wire cloth, perforated plate or wedge-wire
panel, expressed as a percentage
4.2.21
sieve
generally, a screen (4.2.2) of relatively small area. Particularly, a screen (4.2.2) used for size analysis (4.1.3)
4.3 Parts of screens
4.3.1
screen deck
screening surface
surface provided with apertures of specified size for carrying out the operation of screening (4.2.1)
4.3.2
screen plate
plate provided with apertures of specified size and range for use as a screen deck (4.3.1)
4.3.3
screen cloth
screen mesh
mesh of wires woven in a consistent manner to form the apertures
4.3.4
wedge-wire deck
wedge-wire sieve
screen deck (4.3.1), comprising wires of wedge-shaped cross-section spaced from each other at a fixed
dimension, in which the underflow passes (11.3.29) through an aperture of increasing cross-section
4.3.5
loose-rod deck
screening surface (4.3.1) consisting of loosely held parallel rods positioned at right angles to the flow of
material over the screen (4.2.2)
Note 1 to entry: Normally, a loose-rod deck is used only on high-speed vibrating screens (4.5.5).
12 © ISO 2020 – All rights reserved

4.3.6
relieving deck
screen (4.2.2) plate having large apertures mounted over the screening (4.2.1) deck to reduce the load
and wear thereon
4.3.7
rod deck
screening (4.2.1) surface consisting of loosely held parallel rods positioned at right angles to the flow of
material over the screen (4.2.2)
Note 1 to entry: Normally only used on high-speed screens.
4.4 Screens according to purpose
4.4.1
run-of-mine screen
screen (4.2.2) used for dividing run-of-mine coal into two or more sizes for further treatment or disposal
Note 1 to entry: A run-of-mine screen is usually employed to remove the largest pieces for crushing (7.1.2) and
re-addition to the run-of-mine coal.
4.4.2
primary screen
raw coal screen
screen (4.2.2) used to divide coal [usually raw coal (3.1.3)] into sizes more suitable for the subsequent
cleaning of some or all of them
4.4.3
dewatering screen
screen (4.2.2) used for the separation of water from solids
4.4.4
desliming screen
screen (4.2.2) used for the removal of slimes (5.1.20) from larger particles, usually with the aid of
water sprays
4.4.5
slurry screen
screen (4.2.2) used to recover and dewater granular products from circulating water (5.1.15) in a coal
preparation plant (3.1.19)
4.4.6
rinsing screen
spray screen
screen (4.2.2) used for the removal of fine solids by spraying, especially dense medium (5.4.2) solids
present among or adhering to larger particles
4.4.7
sizing screen(s)
grading screen(s)
classifying screen(s) (deprecated)
screen (4.2.2) or set of screens normally used for dividing a product (e.g. clean coal) into a range of sizes
4.4.8
guard screen
oversize control screen
screen (4.2.2) used to prevent the entry into a machine of coarse particles which can interfere with its
operation
4.4.9
undersize control screen
breakage screen (deprecated)
screen (4.2.2) used for the removal of undersize (4.1.8) from a product
4.5 Screens according to principle of construction
4.5.1
single-deck screen
screen (4.2.2) having one screening surface (4.3.1), not necessarily limited to one size or shape of
aperture
4.5.2
multi-deck screen
screen (4.2.2) having two or more superimposed screening surfaces (4.3.1) mounted rigidly within a
common frame
4.5.3
jigging screen
reciprocating screen
shaking screen (deprecated)
screen (4.2.2) to which a combined horizontal and vertical motion is imparted, normally by a crankshaft
and connecting rod, the screen deck (4.3.1) being horizontal or inclined at a small angle
4.5.4
resonance screen
screen (4.2.2) having a period of oscillation at or very close to the natural period of oscillation of the
resilient mounting
4.5.5
vibrating screen
screen (4.2.2) oscillated at high speed by either mechanical or electrical means
Note 1 to entry: The amplitude (4.2.3) of movement of the vibrating screen is smaller than that of the jigging
screen (4.5.3), and its frequency of oscillation is higher.
4.5.6
rotating probability screen
device for probability screening (4.2.8), consisting of a rotating horizontal deck having radial spokes, the
separation point being obtained by varying the rotational speed
4.5.7
trommel screen
revolving screen
screen (4.2.2) in which the screening surface (4.3.1) is formed into a cylinder or frustum of a cone,
mounted upon a horizontal or near horizontal rotating shaft, or on revolving rollers
4.5.8
roll screen
screen (4.2.2) consisting of several horizontal rotating shafts, fitted with elements arranged to provide
screening (4.2.1) apertures
4.5.9
bar screen
stationary inclined screen (4.2.2), comprising longitudinal bars, spaced at intervals, onto which the
material is fed at the upper end
14 © ISO 2020 – All rights reserved

4.5.10
grizzly
rugged screen (4.2.2) for rough sizing (4.1.1) at comparatively large size (e.g. 150 mm)
Note 1 to entry: A grizzly can comprise fixed or moving bars, discs, or shaped tumblers or ratters.
4.5.11
sieve bend
device for the sizing (4.1.1) of fine particles suspended in water by means of a stationary curved panel,
usually of wedge-wire, the aperture of which is at right angles to the flow of feed (3.3.6), whereby the
finer particles are removed with the bulk of the water in the underflow
Note 1 to entry: Note 1to entry: See also fixed screen (6.2.2).
4.5.12
banana screen
multi-slope screen
multi-slope screen that processes larger volumes of material using a smaller footprint
4.6 Sizing in a current of air or water
4.6.1
air classification
process of sizing (4.1.1) in a current of air
4.6.2
classifier
device that separates particles, according to their size, shape and density, by physical means other than
screening (4.2.1)
4.6.3
cyclone classifier
device for classification (4.1.2) by centrifugal means of fine particles suspended in a fluid, whereby the
coarser particles are discharged from the apex of the vessel, and the finer particles are removed with
the bulk of the fluid at the overflow orifice
5 Terms related to cleaning
5.1 General
5.1.1
dry cleaning
separation of impurities from coal by manual or mechanical methods that avoid the use of a liquid
5.1.2
wet cleaning
mechanical separation of impurities from coal by methods involving the use of a liquid
5.1.3
washery
coal preparation plant (3.1.19) in which a wet cleaning (5.1.2) process is carried out
5.1.4
reclean
rewash
to re-treat a product in the same or in another plant
5.1.5
washery products
final products from a washery (5.1.3)
5.1.6
reject elevator
refuse elevator (deprecated)
elevator for removing and draining (6.1.3) the reject (3.1.10) from a washing appliance
5.1.7
middlings elevator
elevator that removes middlings (3.1.7) for further treatment or for disposal as an inferior product
5.1.8
head tank
tank or vessel in the water circuit (5.1.13) that is used to maintain the delivery pressure of the water by
constant level to the washing units
5.1.9
launder
trough or channel along which liquids, or a mixture of liquids and solids, flow
5.1.10
pump sump
tank into which the process water gravitates and from which it is recirculated by means of a pump
5.1.11
suspension
mixture of solid particles and water or air in which the solid particles are completely and individually
supported
5.1.12
teeter (in)
fluidized suspension (in)
condition of a suspension of solids in an upward-moving current of water or air, whereby the support
given to the particles reduces the internal friction between them to such an extent that the suspension
acquires fluid or partially fluid properties
5.1.13
water circuit
complete system of pipelines, pumps, sumps, tanks, launders (5.1.9) and accessories used for the
circulation of water in a washery (5.1.3)
5.1.14
closed water circuit
water circuit (5.1.13) designed so that the only water added is that necessary to replace the loss on the
washery products (5.1.5) and that due to atmospheric evaporation
5.1.15
circulating water
water in the water circuit (5.1.13)
5.1.16
make-up water
water supplied to a plant to replace that lost from the circuit
5.1.17
rinsing water
spray water
water used to remove fine particles from larger sizes
16 © ISO 2020 – All rights reserved

5.1.18
waste water
surplus water
bleed water (deprecated)
excess water allowed to run to waste from the water circuit (5.1.13)
Note 1 to entry: See also effluent (6.1.9) and (6.1.10).
5.1.19
pit water
mine water
water from underground workings or an open-cut mine
5.1.20
slimes
extremely fine particles in suspension or adhering to larger particles
5.1.21
slurry
fine particles concentrated in a portion of the circulating water (5.1.15) and water-
borne for treatment or dis
...