SIST ISO 12742:2001

Copper, lead and zinc sulfide concentrates -- Determination of transportable moisture limits -- Flow table method

Concentrés sulfurés de cuivre, de plomb et de zinc -- Détermination des limites d'humidité transportable -- Méthode de la table d'écoulement

Koncentrati sulfidov bakra, svinca in cinka - Ugotavljanje meja prenosljive vlage - Metoda Flow table

General Information

• Status: Withdrawn
• Publication Date: 31-May-2001
• Withdrawal Date: 11-May-2010
• ICS: 73.060.99 - Other metalliferous minerals
• Technical Committee: I12 - Imaginarni 12 Imaginarni TC za ISO področje - vzdrževani privzeti ISO standardi
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 11-May-2010
• Due Date: 03-Jun-2010
• Completion Date: 12-May-2010
• Ref Project: ISO 12742:2000 - Copper, lead and zinc sulfide concentrates — Determination of transportable moisture limits — Flow table method

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 12742
First edition
2000-03-15
Copper, lead and zinc sulfide
concentrates — Determination of
transportable moisture limits —
Flow table method
Concentrés sulfurés de cuivre, de plomb et de zinc — Détermination des
limites d'humidité transportable — Méthode de la table d'écoulement
Reference number
ISO 12742:2000(E)
©
ISO 2000

---------------------- Page: 1 ----------------------
ISO 12742:2000(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2000
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body
in the country of the requester.
ISO copyright office
Case postale 56 � CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 734 10 79
E-mail [e-mail]
Web www.iso.ch
Printed in Switzerland
ii © ISO 2000 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 12742:2000(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 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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 12742 was prepared by Technical Committee ISO/TC 183, Copper, lead and zinc ores
and concentrates.
Annex A forms a normative part of this International Standard.
© ISO 2000 – All rights reserved iii

---------------------- Page: 3 ----------------------
INTERNATIONAL STANDARD ISO 12742:2000(E)
Copper, lead and zinc sulfide concentrates — Determination of
transportable moisture limits — Flow table method
WARNING — This International Standard may involve hazardous materials, operations and equipment. It is
the responsibility of the user of this International Standard to establish appropriate health and safety
practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This International Standard specifies a flow table method for the determination of the transportable moisture limit
(TML) of copper, lead and zinc concentrates which may liquefy during transport.
This International Standard is applicable to the determination of the TML of concentrates containing 10 % (m/m)to
80 % (m/m) of lead, or 10 % (m/m)to 65%(m/m)of zinc, or 10%(m/m)to 55%(m/m) of copper. It is applicable to
TMLs in the range 3 % (m/m)to 28%(m/m).
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 10251:1997, Copper, lead and zinc sulfide concentrates — Determination of mass loss in bulk material on
drying.
ISO 12743:1998, Copper, lead and zinc sulfide concentrates — Sampling procedures for determination of metal
and moisture content.
3Principle
Adjustment of the moisture content of the sample by mixing with water. Conversion of the mixture to a conical
shape using a mould and tamper. Placement of the sample on the flow table and removal of the mould.
Determination of the flow characteristic by repeated dropping of the flow table while observing the behaviour of the
sample. When sufficient water has been added to the sample so that plastic deformation occurs during the
dropping of the flow table, the sample is considered to be at its flow moisture point.
Calculation of the TML as 90 % of the flow moisture point.
© ISO 2000 – All rights reserved 1

---------------------- Page: 4 ----------------------
ISO 12742:2000(E)
4 Apparatus
NOTE Copper, lead and zinc concentrates may gain or lose moisture rapidly when exposed to air. The laboratory should
be designed so that excessive temperatures, air currents and humidity variations are avoided.
4.1 Flow table and frame, as specified in annex A.
The flow table mounting shall be as specified in Figure A.1.
4.2 Mould, as specified in Figure A.1.
4.3 Tamper.
The required tamping pressure may be achieved by using calibrated, spring-loaded tampers or some other suitable
design of tamper that allows a controlled pressure to be applied via a 30 mm diameter tamper head as specified in
Figure A.2.
4.4 Balance, top loading, having the sensitivity specified in Table 1.
Table 1 — Sensitivity of balance and precision of weighing
Mass of sample plus tray Precision of balance and
weighing
g
g
100 0,01
200 0,02
300 0,03
400 0,04
500 0,05
4.5 Measuring cylinder, 100 ml to 200 ml capacity.
4.6 Burette, 10 ml capacity.
4.7 Water applicator, for adding a fine spray of water to the sample, having a capacity greater than 200 ml and
5 ml calibration divisions.
4.8 Mixing bowl, hemispherical of 30 cm diameter.
4.9 Rubber gloves.
4.10 Drying trays or pans, having dimensions that permit the sample to be spread to a thickness of less than
30 mm.
The trays shall be made of corrosion-resistant and heat-resistant material such as stainless steel, glass or enamel
plate.
4.11 Drying oven, ventilated, with forced circulation of air or inert gas, regulated at a temperature of
105 �C � 5 �C.
2 © ISO 2000 – All rights reserved

---------------------- Page: 5 ----------------------
ISO 12742:2000(E)
5 Sampling
5.1 General
TML figures are required to be updated on a periodic basis, usually six monthly or when there is a known change to
the process used to produce the material. The reported figure should be the mean of samples taken during the
period.
To ensure that the TML result is representative, increments of the material shall be taken either
a) while a stockpile is being built up or broken down or
b) while loading or discharging a vessel.
These increments are combined to form the sample used to determine TML.
NOTE 1 The sample used to determine TML should not be used to determine moisture.
NOTE 2 Stationary sampling of stockpiles should never be used for the determination of TML. This method of sampling can
only be used to provide an indicative moisture value for use during the planning of shipping schedules.
5.2 Laboratory sample
Samples for the determination of TML shall be taken in accordance with ISO 12743. The laboratory sample shall
not weigh less than 5 kg. To minimize changes to the flow characteristics of the sample it shall not be oven dried or
ground during its preparation.
5.3 Separation of test sample into test portions
Place the laboratory sample in the mixing bowl (4.8) and gently mix it thoroughly. Remove four test portions (A, B,
C and D) from the mixing bowl as follows:
a) Test portion A
Take approximately 1,2 kg of sample which is to be used for determining the moisture content of the sample "as
received". This test is performed in accordance with ISO 10251. With routine samples, the result of this test
provides the operator with a guide as to how much water to add to the samples, thereby speeding up the TML test.
b) Test portion B
Take approximately 1,2 kg of sample. This sample is to be used for the preliminary TML test. Store this sample in
an appropriately labelled airtight container.
c) Test portion C
Take approximately 1,2 kg of sample. This sample is to be used for the first duplicate of the final TML test. Store
this sample in an appropriately labelled airtight container.
d) Test portion D
Take approximately 1,2 kg of sample. This sample is to be used for the second duplicate of the final TML test.
Store this sample in an appropriately labelled airtight container.
© ISO 2000 – All rights reserved 3

---------------------- Page: 6 ----------------------
ISO 12742:2000(E)
6 Procedure
6.1 General
Copper, lead and zinc concentrates may undergo rapid changes in moisture when exposed to air, so all stages of the
test should be accomplished in the shortest time period and shall definitely be completed within the day of
commencement. Where possible, sample containers should be covered with plastic film or any other suitable airtight
cover.
As more accurate results are obtained when the moisture of the test portion is close to the flow moisture point, a
preliminary test shall be carried out. The result of this test is used to adjust the moisture of the final test portion to
1 % to 2 % below the flow moisture point.
6.2 Preparation of test portions
6.2.1 General
Test portions B, C and D are prepared, with test portion B prepared first to determine the preliminary flow moisture
point in accordance with 6.2.2 to 6.3.5.
Once the preliminary flow moisture point has been determined, test portions C and D are then prepared and the main
flow moisture point determined in accordance with 6.4.2 to 6.4.6.
6.2.2 Filling the mould
Place the mould on the centre of the flow table and fill it in three stages with the test portion as follows:
a) the first charge, after tamping, shall aim to fill the mould to approximately one third of its depth;
b) the second charge, after tamping, shall fill the mould to about two thirds of its depth;
c) the third and final charge, after tamping, shall reach to just below the top of the mould (see Figure 1).
The quantity of test portion required to achieve each of these stages will vary from one material to another, but is
readily established after experience has been gained on the packing characteristics of the material being tested.
6.2.3 Tamping pressure
The aim of tamping is to simulate the amount of compaction prevailing at the bottom of a shipboard cargo for the
material being tested. The correct pressure to be applied via the tamper is calculated as follows:
p = � � d � g (1)
T D max
where
p is the tamping pressure, in pascals;
T
� is the bulk density, in kilograms per cubic metre;
D
d is the maximum depth of the cargo, in metres;
max
2
g is the acceleration due to gravity (= 981 cm/s ).
If, when calculating the tamping pressure, there is no information available concerning the cargo depth use the
maximum likely depth.
4 © ISO 2000 – All rights reserved

---------------------- Page: 7 ----------------------
ISO 12742:2000(E)
Alternatively, the pressure may be estimated from Table 2.
a
Table 2 — Tamping pressures for selected concentrates
Typical
Maximum cargo depth
Bulk density
concentrate
3
kg/m
type 2m 5m 10 m 20m
Copper 2000 39 [2,8] 98 [6,9] 196 [13,9] 392 [27,7]
Lead 2100 41 [2,9] 103 [7,3] 206 [14,6] 412 [29,1]
Zinc 1950 38 [2,7] 96 [6,8] 192 [13,5] 384 [27,1]
a
Values in brackets are equivalent kgf when applied via a 30 mm diameter tamper head.
6.2.4 Tamping procedure
The number of tamping actions (applying the correct, steady pressure each time) should be about 35 for the bottom
layer, 25 for the middle layer and 20 for the top layer. Tamping shall be performed successively over the complete
area including the edges of the sample, to form a uniform surface for each layer (see Figure 1).
6.2.5 Removal of the mould
Tap the mould on its side until it becomes loose, leaving the material in the shape of a truncated cone on the flow
table.
6.3 Determination of flow moisture point
6.3.1 General
The determination of the flow moisture point is carried out by controlled dropping of the flow table and observation
of the sample, followed by addition of water if necessary as outlined in the following steps.
6.3.2 Dropping the flow table
Immediately after removing the mould, raise and drop the flow table up to 50 times through a height of 12,5 mm at a
rate of 25 times/min. Whilst the flow table is going through these cycles, observe the behaviour of the material using
the information provided in 6.3.3 as a guide for determining the flow state.
6.3.3 Identification of the flow state
The impacting action of the flow table causes the grains of the material to re-arrange themselves to produce
compaction of the mass. As a result, the fixed volume of moisture contained in the material at any given level
increases as a percentage of the total volume. A flow state is considered to have been reached when the moisture
content and compaction of the material produce such a level of saturation that plastic deformation occurs. At this
stage, the moulded sides of the cone may deform, giving a convex or concave profile (see Figure 2). With repeated
action of the flow table, the cone continues to slump and to flow outwards. In certain materials, cracks may also
develop on the top surface.
© ISO 2000 – All rights reserved 5

---------------------- Page: 8 ----------------------
ISO 12742:2000(E)
Further criteria to use when determining if the flow state has been reached are as follows:
a) Cracking with the appearance of free moisture is not an indication of development of a flow state. In most
cases, measurement of the deformation is helpful in deciding whether or not plastic flow has occurred. A
template which, for example, will indicate an increase in diameter of up to 3 mm in any part of the cone, is a
useful guide for this purpose.
b) Measuring the diameter of the cone, at the base or at half height, will always be useful. By addition of water in
increments of 0,3 % to 0,5 % by mass and applying 25 drops of the flow table, the first diameter increase will
generally be between 1 mm and 5 mm and after a further increment in water content the base diameter would
have expanded to between 5 mm to 10 mm.
c) When the moi
...

SLOVENSKI STANDARD
SIST ISO 12742:2001
01-junij-2001
Koncentrati sulfidov bakra, svinca in cinka - Ugotavljanje meja prenosljive vlage -
Metoda Flow table
Copper, lead and zinc sulfide concentrates -- Determination of transportable moisture
limits -- Flow table method
Concentrés sulfurés de cuivre, de plomb et de zinc -- Détermination des limites
d'humidité transportable -- Méthode de la table d'écoulement
Ta slovenski standard je istoveten z: ISO 12742:2000
ICS:
73.060.99 Druge rude Other metalliferous minerals
SIST ISO 12742:2001 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST ISO 12742:2001

---------------------- Page: 2 ----------------------

SIST ISO 12742:2001
INTERNATIONAL ISO
STANDARD 12742
First edition
2000-03-15
Copper, lead and zinc sulfide
concentrates — Determination of
transportable moisture limits —
Flow table method
Concentrés sulfurés de cuivre, de plomb et de zinc — Détermination des
limites d'humidité transportable — Méthode de la table d'écoulement
Reference number
ISO 12742:2000(E)
©
ISO 2000

---------------------- Page: 3 ----------------------

SIST ISO 12742:2001
ISO 12742:2000(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not
be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this
file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this
area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters
were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event
that a problem relating to it is found, please inform the Central Secretariat at the address given below.
© ISO 2000
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body
in the country of the requester.
ISO copyright office
Case postale 56 � CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 734 10 79
E-mail [e-mail]
Web www.iso.ch
Printed in Switzerland
ii © ISO 2000 – All rights reserved

---------------------- Page: 4 ----------------------

SIST ISO 12742:2001
ISO 12742:2000(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 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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 12742 was prepared by Technical Committee ISO/TC 183, Copper, lead and zinc ores
and concentrates.
Annex A forms a normative part of this International Standard.
© ISO 2000 – All rights reserved iii

---------------------- Page: 5 ----------------------

SIST ISO 12742:2001

---------------------- Page: 6 ----------------------

SIST ISO 12742:2001
INTERNATIONAL STANDARD ISO 12742:2000(E)
Copper, lead and zinc sulfide concentrates — Determination of
transportable moisture limits — Flow table method
WARNING — This International Standard may involve hazardous materials, operations and equipment. It is
the responsibility of the user of this International Standard to establish appropriate health and safety
practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This International Standard specifies a flow table method for the determination of the transportable moisture limit
(TML) of copper, lead and zinc concentrates which may liquefy during transport.
This International Standard is applicable to the determination of the TML of concentrates containing 10 % (m/m)to
80 % (m/m) of lead, or 10 % (m/m)to 65%(m/m)of zinc, or 10%(m/m)to 55%(m/m) of copper. It is applicable to
TMLs in the range 3 % (m/m)to 28%(m/m).
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 10251:1997, Copper, lead and zinc sulfide concentrates — Determination of mass loss in bulk material on
drying.
ISO 12743:1998, Copper, lead and zinc sulfide concentrates — Sampling procedures for determination of metal
and moisture content.
3Principle
Adjustment of the moisture content of the sample by mixing with water. Conversion of the mixture to a conical
shape using a mould and tamper. Placement of the sample on the flow table and removal of the mould.
Determination of the flow characteristic by repeated dropping of the flow table while observing the behaviour of the
sample. When sufficient water has been added to the sample so that plastic deformation occurs during the
dropping of the flow table, the sample is considered to be at its flow moisture point.
Calculation of the TML as 90 % of the flow moisture point.
© ISO 2000 – All rights reserved 1

---------------------- Page: 7 ----------------------

SIST ISO 12742:2001
ISO 12742:2000(E)
4 Apparatus
NOTE Copper, lead and zinc concentrates may gain or lose moisture rapidly when exposed to air. The laboratory should
be designed so that excessive temperatures, air currents and humidity variations are avoided.
4.1 Flow table and frame, as specified in annex A.
The flow table mounting shall be as specified in Figure A.1.
4.2 Mould, as specified in Figure A.1.
4.3 Tamper.
The required tamping pressure may be achieved by using calibrated, spring-loaded tampers or some other suitable
design of tamper that allows a controlled pressure to be applied via a 30 mm diameter tamper head as specified in
Figure A.2.
4.4 Balance, top loading, having the sensitivity specified in Table 1.
Table 1 — Sensitivity of balance and precision of weighing
Mass of sample plus tray Precision of balance and
weighing
g
g
100 0,01
200 0,02
300 0,03
400 0,04
500 0,05
4.5 Measuring cylinder, 100 ml to 200 ml capacity.
4.6 Burette, 10 ml capacity.
4.7 Water applicator, for adding a fine spray of water to the sample, having a capacity greater than 200 ml and
5 ml calibration divisions.
4.8 Mixing bowl, hemispherical of 30 cm diameter.
4.9 Rubber gloves.
4.10 Drying trays or pans, having dimensions that permit the sample to be spread to a thickness of less than
30 mm.
The trays shall be made of corrosion-resistant and heat-resistant material such as stainless steel, glass or enamel
plate.
4.11 Drying oven, ventilated, with forced circulation of air or inert gas, regulated at a temperature of
105 �C � 5 �C.
2 © ISO 2000 – All rights reserved

---------------------- Page: 8 ----------------------

SIST ISO 12742:2001
ISO 12742:2000(E)
5 Sampling
5.1 General
TML figures are required to be updated on a periodic basis, usually six monthly or when there is a known change to
the process used to produce the material. The reported figure should be the mean of samples taken during the
period.
To ensure that the TML result is representative, increments of the material shall be taken either
a) while a stockpile is being built up or broken down or
b) while loading or discharging a vessel.
These increments are combined to form the sample used to determine TML.
NOTE 1 The sample used to determine TML should not be used to determine moisture.
NOTE 2 Stationary sampling of stockpiles should never be used for the determination of TML. This method of sampling can
only be used to provide an indicative moisture value for use during the planning of shipping schedules.
5.2 Laboratory sample
Samples for the determination of TML shall be taken in accordance with ISO 12743. The laboratory sample shall
not weigh less than 5 kg. To minimize changes to the flow characteristics of the sample it shall not be oven dried or
ground during its preparation.
5.3 Separation of test sample into test portions
Place the laboratory sample in the mixing bowl (4.8) and gently mix it thoroughly. Remove four test portions (A, B,
C and D) from the mixing bowl as follows:
a) Test portion A
Take approximately 1,2 kg of sample which is to be used for determining the moisture content of the sample "as
received". This test is performed in accordance with ISO 10251. With routine samples, the result of this test
provides the operator with a guide as to how much water to add to the samples, thereby speeding up the TML test.
b) Test portion B
Take approximately 1,2 kg of sample. This sample is to be used for the preliminary TML test. Store this sample in
an appropriately labelled airtight container.
c) Test portion C
Take approximately 1,2 kg of sample. This sample is to be used for the first duplicate of the final TML test. Store
this sample in an appropriately labelled airtight container.
d) Test portion D
Take approximately 1,2 kg of sample. This sample is to be used for the second duplicate of the final TML test.
Store this sample in an appropriately labelled airtight container.
© ISO 2000 – All rights reserved 3

---------------------- Page: 9 ----------------------

SIST ISO 12742:2001
ISO 12742:2000(E)
6 Procedure
6.1 General
Copper, lead and zinc concentrates may undergo rapid changes in moisture when exposed to air, so all stages of the
test should be accomplished in the shortest time period and shall definitely be completed within the day of
commencement. Where possible, sample containers should be covered with plastic film or any other suitable airtight
cover.
As more accurate results are obtained when the moisture of the test portion is close to the flow moisture point, a
preliminary test shall be carried out. The result of this test is used to adjust the moisture of the final test portion to
1 % to 2 % below the flow moisture point.
6.2 Preparation of test portions
6.2.1 General
Test portions B, C and D are prepared, with test portion B prepared first to determine the preliminary flow moisture
point in accordance with 6.2.2 to 6.3.5.
Once the preliminary flow moisture point has been determined, test portions C and D are then prepared and the main
flow moisture point determined in accordance with 6.4.2 to 6.4.6.
6.2.2 Filling the mould
Place the mould on the centre of the flow table and fill it in three stages with the test portion as follows:
a) the first charge, after tamping, shall aim to fill the mould to approximately one third of its depth;
b) the second charge, after tamping, shall fill the mould to about two thirds of its depth;
c) the third and final charge, after tamping, shall reach to just below the top of the mould (see Figure 1).
The quantity of test portion required to achieve each of these stages will vary from one material to another, but is
readily established after experience has been gained on the packing characteristics of the material being tested.
6.2.3 Tamping pressure
The aim of tamping is to simulate the amount of compaction prevailing at the bottom of a shipboard cargo for the
material being tested. The correct pressure to be applied via the tamper is calculated as follows:
p = � � d � g (1)
T D max
where
p is the tamping pressure, in pascals;
T
� is the bulk density, in kilograms per cubic metre;
D
d is the maximum depth of the cargo, in metres;
max
2
g is the acceleration due to gravity (= 981 cm/s ).
If, when calculating the tamping pressure, there is no information available concerning the cargo depth use the
maximum likely depth.
4 © ISO 2000 – All rights reserved

---------------------- Page: 10 ----------------------

SIST ISO 12742:2001
ISO 12742:2000(E)
Alternatively, the pressure may be estimated from Table 2.
a
Table 2 — Tamping pressures for selected concentrates
Typical
Maximum cargo depth
Bulk density
concentrate
3
kg/m
type 2m 5m 10 m 20m
Copper 2000 39 [2,8] 98 [6,9] 196 [13,9] 392 [27,7]
Lead 2100 41 [2,9] 103 [7,3] 206 [14,6] 412 [29,1]
Zinc 1950 38 [2,7] 96 [6,8] 192 [13,5] 384 [27,1]
a
Values in brackets are equivalent kgf when applied via a 30 mm diameter tamper head.
6.2.4 Tamping procedure
The number of tamping actions (applying the correct, steady pressure each time) should be about 35 for the bottom
layer, 25 for the middle layer and 20 for the top layer. Tamping shall be performed successively over the complete
area including the edges of the sample, to form a uniform surface for each layer (see Figure 1).
6.2.5 Removal of the mould
Tap the mould on its side until it becomes loose, leaving the material in the shape of a truncated cone on the flow
table.
6.3 Determination of flow moisture point
6.3.1 General
The determination of the flow moisture point is carried out by controlled dropping of the flow table and observation
of the sample, followed by addition of water if necessary as outlined in the following steps.
6.3.2 Dropping the flow table
Immediately after removing the mould, raise and drop the flow table up to 50 times through a height of 12,5 mm at a
rate of 25 times/min. Whilst the flow table is going through these cycles, observe the behaviour of the material using
the information provided in 6.3.3 as a guide for determining the flow state.
6.3.3 Identification of the flow state
The impacting action of the flow table causes the grains of the material to re-arrange themselves to produce
compaction of the mass. As a result, the fixed volume of moisture contained in the material at any given level
increases as a percentage of the total volume. A flow state is considered to have been reached when the moisture
content and compaction of the material produce such a level of saturation that plastic deformation occurs. At this
stage, the moulded sides of the cone may deform, giving a convex or concave profile (see Figure 2). With repeated
action of the flow table, the cone continues to slump and to flow outwards. In certain materials, cracks may also
develop on the top surface.
© ISO 2000 – All rights reserved 5

---------------------- Page: 11 ----------------------

SIST ISO 12742:2001
ISO 12742:2000(E)
Further criteria to use when determining if the flow state has been reached are as follows:
a) Cracking with the appearance of free moisture is not an indication of development of a flow state. In most
cases, measurement of the deformation is helpful in deciding whether or not plastic flow has occurred. A
template which, for example, will
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