ISO 12743:2021

INTERNATIONAL ISO
STANDARD 12743
Fourth edition
2021-05
Copper, lead, zinc and nickel
concentrates — Sampling procedures
for determination of metal and
moisture content
Concentrés de cuivre, de plomb, de zinc et de nickel — Procédures
d'échantillonnage pour la détermination de la teneur en métal et de
l'humidité
Reference number
ISO 12743:2021(E)
©
ISO 2021

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ISO 12743:2021(E)

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ISO 12743:2021(E)

Contents Page
Foreword .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Sampling theory . 4
4.1 General . 4
4.2 Total variance . 4
4.3 Sampling-stage method of estimating sampling and total variance . 6
4.4 Simplified method of estimating sampling and total variance . 8
4.5 Interleaved sample method of measuring total variance .10
5 Establishing a sampling scheme .12
6 Mass of increment .17
6.1 General .17
6.2 Mass of increment for falling-stream samplers .17
6.3 Mass of increment for cross-belt samplers .17
6.4 Mass of increment for manual sampling from stationary lots .17
6.4.1 Primary increments .17
6.4.2 Mass of secondary and subsequent increments .18
6.5 Mass of increment for stopped-belt reference sampling .18
7 Methods of sampling from concentrate streams .18
7.1 General .18
7.2 Mass-basis systematic sampling .18
7.2.1 General.18
7.2.2 Sampling interval .19
7.2.3 Sample cutter .19
7.2.4 Taking of primary increments .19
7.2.5 Constitution of subsamples and lot samples .19
7.2.6 Types of division .20
7.2.7 Division of increments .20
7.2.8 Division of subsamples .20
7.2.9 Division of lot samples .20
7.3 Time-basis systematic sampling .21
7.3.1 General.21
7.3.2 Sampling interval .21
7.3.3 Sample cutter .21
7.3.4 Taking of primary increments .22
7.3.5 Constitution of subsamples and lot samples .22
7.3.6 Types of division .22
7.3.7 Division of increments and subsamples .22
7.3.8 Division of lot samples .22
7.4 Stratified random sampling .22
7.4.1 Fixed mass intervals .22
7.4.2 Fixed time intervals .23
8 Mechanical sampling of concentrate streams .23
8.1 General .23
8.2 Design of the sampling system .23
8.2.1 Safety of operators .23
8.2.2 Location of sample cutters .23
8.2.3 Provision for interleaved sampling .24
8.2.4 Provision for stratified random sampling .24
8.2.5 Checking precision and bias.24
8.2.6 Avoiding bias .24
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ISO 12743:2021(E)

8.2.7 Minimizing bias .24
8.2.8 Configuration of the sampling system .24
8.3 Sample cutters .25
8.3.1 General.25
8.3.2 Design criteria .25
8.3.3 Cutter speed .26
8.4 Mass of increments.27
8.5 Number of increments .27
8.6 Sampling interval .27
8.7 Routine checking .27
9 Manual sampling of concentrate streams .28
9.1 General .28
9.2 Choosing the sampling location .28
9.3 Sampling implements .28
9.4 Mass of increments.29
9.5 Number of increments .29
9.6 Sampling interval .29
9.7 Sampling procedures .29
9.7.1 General.29
9.7.2 Full stream cut from a falling stream .29
9.7.3 Partial stream cuts from a falling stream .29
9.7.4 Sampling from moving conveyor belts .30
10 Stopped-belt reference sampling .30
11 Sampling from grabs .31
11.1 General .31
11.2 Mass of primary increments .31
11.3 Number of primary increments .31
11.4 Method of sampling .32
11.5 Constitution of subsamples and lot samples.32
12 Sampling from trucks, railway wagons and sampling hoppers .32
12.1 General .32
12.2 Mass of primary increments .32
12.3 Number of primary increments .32
12.4 Method of sampling .32
12.5 Constitution of subsamples and lot samples.33
13 Sampling of concentrate in bags or drums .36
13.1 General .36
13.2 Mass of primary increments .36
13.3 Number of primary increments .36
13.4 Method of sampling .37
13.4.1 General.37
13.4.2 Sampling during filling or emptying .37
13.4.3 Spear sampling .37
13.5 Constitution of subsamples and lot samples.37
14 Sampling of stockpiles .38
15 Methods of comminution, mixing and division .38
15.1 General .38
15.2 Comminution .38
15.2.1 General.38
15.2.2 Mills .38
15.3 Mixing .39
15.3.1 General.39
15.3.2 Methods of mixing .39
15.4 Division .40
15.4.1 Chemical analysis samples .40
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ISO 12743:2021(E)

15.4.2 Moisture samples .41
15.4.3 Number of increments for division .41
15.4.4 Minimum mass of divided sample .41
15.4.5 Rotary sample division .42
15.4.6 Cutter-type division.43
15.4.7 Manual increment division .43
15.4.8 Spear division .43
15.4.9 Fractional shovelling .44
15.4.10 Ribbon division .45
15.4.11 Riffle division .47
16 Sample requirements .49
16.1 Moisture samples .49
16.1.1 Mass of test portion .49
16.1.2 Processing of samples .49
16.2 Chemical analysis samples . .49
16.3 Physical test samples .50
17 Packing and marking of samples .50
Annex A (normative) Sampling stage method of estimating sampling and total variance .51
Annex B (informative) Estimation of total variance — Barge unloading using a grab .58
Annex C (informative) Mechanical sample cutters .62
Annex D (informative) Checklist for mechanical sampling systems .67
Annex E (normative) Manual sampling devices .71
Annex F (informative) Apparatus for manual sampling of concentrates from stopped belts .73
Annex G (informative) Sampling of stockpiles .74
Annex H (normative) Increment division scoops for conducting manual increment division .76
Bibliography .77
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ISO 12743:2021(E)

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
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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
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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 183, Copper, lead, zinc and nickel ores and
concentrates.
This fourth edition cancels and replaces the third edition (ISO 12743:2018), which has been technically
revised. The main changes to the previous edition are as follows:
— The minimum cutting aperture for cross-belt cutters in 8.3.2.3 i) has been reduced to 30 mm.
— A NOTE has been added to 15.4.10 indicating that ribbons with smaller dimensions can be formed
depending on the mass of sample to be divided, and that the ribbon division method is particularly
suitable for dividing chemical analysis samples.
— The requirements for preparation of chemical analysis samples in 16.2 have been expanded.
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.
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INTERNATIONAL STANDARD ISO 12743:2021(E)
Copper, lead, zinc and nickel concentrates — Sampling
procedures for determination of metal and moisture
content
WARNING — This document can involve hazardous materials, operations and equipment. It
is the responsibility of the user of this document to establish appropriate health and safety
practices and to ensure compliance with any other restrictions.
1 Scope
This document sets out the basic methods for sampling copper, lead, zinc and nickel concentrates
from moving streams and stationary lots, including stopped-belt sampling, to provide samples for
chemical analysis, physical testing and determination of moisture content, in accordance with the
relevant International Standards. Where the concentrates are susceptible to significant oxidation
or decomposition, a common sample that is sufficiently representative, i.e. unbiased and sufficiently
precise, is used for moisture determination and chemical analysis to eliminate bias (see ISO 10251).
Any large agglomerates (>10 mm) present in the primary sample are crushed prior to further sample
processing. Sampling of concentrates in slurry form is specifically excluded from this document.
Stopped-belt sampling is the reference method for collecting concentrate samples against which
mechanical and manual-sampling procedures can be compared. Sampling from moving streams is the
preferred method. Both falling-stream and cross-belt samplers are described.
Sampling from stationary lots is used only where sampling from moving streams is not possible. The
procedures described in this document for sampling from stationary l
...