ISO 20905:2004

Coal preparation - Determination of dust/moisture relationship for coal

ISO 20905:2004 sets out a laboratory procedure for the dust testing of higher rank coals. The procedure defines a means of evaluating the dust/moisture relationship characteristic of a coal and a dust extinction moisture (DEM).

Préparation du charbon — Détermination de la relation particules/humidité du charbon

Priprava premoga – Določanje razmerja prah-vlaga v premogu

General Information

• Status: Published
• Publication Date: 07-Jul-2004
• ICS: 73.040 - Coals
• Technical Committee: ISO/TC 27/SC 1 - Coal preparation: Terminology and performance
• Drafting Committee: ISO/TC 27/SC 1 - Coal preparation: Terminology and performance
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 09-Oct-2024
• Completion Date: 13-Dec-2025
• Ref Project: SIST ISO 20905:2005 - Coal preparation -- Determination of dust/moisture relationship for coal

Relations

• Revised: ISO 20905:2024 - Coal preparation - Determination of dust/moisture relationship for coal
• Effective Date: 14-Oct-2023

Overview

ISO 20905:2004 - Coal preparation - Determination of dust/moisture relationship for coal - describes a laboratory procedure for measuring coal dustiness and the relationship between dust generation and total moisture for higher‑rank coals. The method uses the Rio Tinto Dust Tumbler Test to produce a dust/moisture curve and to determine the dust extinction moisture (DEM), a practical metric for comparing coals and assessing dust‑suppression measures.

Key topics and technical requirements

• Scope: Laboratory dust testing of higher‑rank coals to evaluate dust/moisture behavior and derive DEM.
• Dust definition: Particles ≤ 150 µm entrained in an airstream.
• Controlled environment: Laboratory humidity 63 ± 2% and temperature 20 ± 2 °C.
• Apparatus:
  • Rotating drum dust tester (30 cm diameter × 30 cm length), 29 r/min drum speed and ~175 L/min airflow.
  • Double filter bags (single use), thermohydrograph, tachometer, balance readable to 0.01 g, mixer, ovens.
• Sample requirements:
  • Remove >6.3 mm fraction (do not crush); prepare ~1.2 kg subsamples.
  • Typical program: eight subsamples across a moisture range (≈10 kg total) to build a dust/moisture curve.
• Moisture adjustment:
  • Measure initial moisture per ISO 589; add water or remove moisture by low‑temperature drying to target levels (≈1% intervals).
  • Reagent dosing (aqueous solutions) is applied using controlled mixing and syringe dosing (ISO 7886‑1 referenced).
• Test procedure:
  • 1 000 g sample tumbled for 10 minutes with fan on; fan runs an additional 13 s to collect airborne dust.
  • Dust collected on pre‑weighed filter bag; dust number = mass yield × 100 000.
• Outputs:
  • Dust/moisture curve, slope (sensitivity of dustiness to moisture), and DEM (moisture at which dust number = 10).

Applications and users

ISO 20905:2004 is practical for:

• Coal preparation laboratories and QA/QC teams validating product handling risks.
• Mine operators and material‑handling engineers determining minimum water addition for dust suppression.
• Occupational health & safety and environmental compliance groups assessing airborne particulate risk.
• Manufacturers and evaluators of dust‑suppression reagents (to validate reagent performance and optimal dosing).
• Researchers comparing coal types using the DEM and dust/moisture curves.

Benefits include improved dust control strategies, water‑use optimization in mines, and standardized, reproducible dustiness data for operational decision‑making.

Related standards

• ISO 589 - Hard coal: Determination of total moisture
• ISO 1953 - Hard coal: Size analysis by sieving
• ISO 7886‑1 - Sterile hypodermic syringes (used for dosing technique guidance)

Keywords: ISO 20905:2004, coal dust testing, dust/moisture relationship, dust extinction moisture (DEM), Rio Tinto Dust Tumbler Test, coal handling, dust suppression, laboratory procedure.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2005
3ULSUDYDSUHPRJD±'RORþDQMHUD]PHUMDSUDKYODJDYSUHPRJX
Coal preparation -- Determination of dust/moisture relationship for coal
Préparation du charbon -- Détermination de la relation particules/humidité du charbon
Ta slovenski standard je istoveten z: ISO 20905:2004
ICS:
73.040 Premogi Coals
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 20905
First edition
2004-07-15
Coal preparation — Determination of
dust/moisture relationship for coal
Préparation du charbon — Détermination de la relation
particules/humidité du charbon

Reference number
©
ISO 2004
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 2004
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 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2004 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 1
4 Safety. 1
5 Apparatus and equipment. 2
6 Reagent. 2
7 Sample — Initial . 2
8 Sample preparation — Initial. 3
8.1 Initial total moisture . 3
8.2 Moisture adjustment. 3
9 Sample preparation — Reagent. 4
10 Dust determination. 5
10.1 Environment and equipment checks . 5
10.2 Dust testing. 5
11 Calculation. 6
12 Report. 6
13 Precision. 6
Annex A (informative) Worked example. 7
Annex B (informative) Worksheet example. 11

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 2.
The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 20905 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 1, Coal
preparation: Terminology and performance.
iv © ISO 2004 – All rights reserved

Introduction
The development of the dust/moisture curve provides an indication of the likely response of different coal
types to drying or water addition during mining and handling processes. The dust/moisture curve provides a
good basis for comparing the response of different coal types. Understanding the dust/moisture characteristics
of a coal will allow minimized water addition to the product for dust suppression. This will in turn assist in water
conservation at mines and other handling facilities, as well as minimizing the total moisture of the product.
This International Standard describes a reliable measurement of dustiness of coal and extends to cover the
relationship between dust and total moisture utilizing the Rio Tinto Dust Tumbler Test. This test provides a
quantitative measure of the dustiness of a coal that can be used to predict operational dust problems, and is
also suitable for the assessment of dust suppression chemicals.
The Rio Tinto Dust Tumbler Test was developed using rotating equipment in a controlled temperature and
humidity environment, and uses a stream of air to remove particles which become airborne during the
tumbling process. It is a batch test in which dust particles (−150 µm particles) are collected in a pre-weighed
filter bag and weighed. From this mass, a dust number, calculated as the mass yield of dust multiplied by
100 000, is determined for the test total moisture. Only 1 kg of sample is required for each dust test, but eight
sample lots are required to develop the dust/moisture curve for a particular coal, i.e. approximately 10 kg is
required for each coal type.
This dust test can be repeated with subsamples at different coal total moisture levels to develop a
dust/moisture curve. The slope of the curve provides information on how sensitive the dustiness is to changes
in total moisture and a dust number of 10 has been used to provide a comparison between coals.
The test has been successfully used for several years on many coals and other bulk materials. The results
have been correlated with the operating practice. The method has been applied to the evaluation of dust-
control products, and the determination of dust-elimination total moisture requirements for coal-handling
systems.
INTERNATIONAL STANDARD ISO 20905:2004(E)

Coal preparation — Determination of dust/moisture relationship
for coal
1 Scope
This International Standard sets out a laboratory procedure for the dust testing of higher rank coals. The
procedure defines a means of evaluating the dust/moisture relationship characteristic of a coal and a dust
extinction moisture (DEM).
NOTE In this standard, an experimental dust number of 10 has been used in the example given in Annex A.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 589, Hard coal — Determination of total moisture
ISO 1953, Hard coal — Size analysis by sieving
ISO 7886-1, Sterile hypodermic syringes for single use — Part 1: Syringes for manual use
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
dust
particles of 150 µm or less diameter entrained in an air stream
3.2
dust extinction moisture
DEM
total moisture at which a dust number of 10 is attained on the dust/moisture curve
NOTE DEM is a useful point for comparing different coals and the effectiveness of reagents.
4 Safety
The following safety precautions shall be observed.
a) To prevent nitrogen build-up within the laboratory, the exhaust tube of the minimum-free-space oven shall
remain clear of obstruction.
b) Safety glasses shall be worn at all times.
c) The exhaust tube of the minimum-head-space oven shall remain free of obstruction to prevent nitrogen
build-up within the laboratory.
d) A dust mask shall be worn when handling coal.
e) Cloth or leather gloves shall be worn when using ovens.
f) The hazards associated with a reagent shall be determined prior to use. Instructions on all relevant
Material Safety Data Sheets (MSDS) shall be followed.
5 Apparatus and equipment
The following apparatus and equipment is required.
5.1 Humidity- and temperature-controlled laboratory, with relative humidity of 63 ± 2 % and temperature
of 20 ± 2 °C.
5.2 Dust-test apparatus, having a rotating drum of 30 cm diameter and 30 cm effective length, as shown
in Figure 1. The required drum speed is 29 r/min, and the desired airflow through the drum is 175 L/min.
5.3 Double filter bags, single use only.
5.4 Electronic thermohydrograph.
5.5 Tachometer.
5.6 Laminar flow differential-pressure manometer.
5.7 Stopwatch.
5.8 Capped bottles, of capacity 250 mL, wide mouth, polypropylene.
5.9 Top loading balance, having a minimum capacity of 1 g and readable to the nearest 0,01 g.
5.10 Laboratory trays.
5.11 Minimum-free-space drying oven.
6 Reagent
Tap water is used in solution and sample preparation.
7 Sample — Initial
Before testing, remove the particles greater than 6,3 mm. Do not
...

INTERNATIONAL ISO
STANDARD 20905
First edition
2004-07-15
Coal preparation — Determination of
dust/moisture relationship for coal
Préparation du charbon — Détermination de la relation
particules/humidité du charbon

Reference number
©
ISO 2004
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 2004
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 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2004 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope. 1
2 Normative references. 1
3 Terms and definitions. 1
4 Safety. 1
5 Apparatus and equipment. 2
6 Reagent. 2
7 Sample — Initial . 2
8 Sample preparation — Initial. 3
8.1 Initial total moisture . 3
8.2 Moisture adjustment. 3
9 Sample preparation — Reagent. 4
10 Dust determination. 5
10.1 Environment and equipment checks . 5
10.2 Dust testing. 5
11 Calculation. 6
12 Report. 6
13 Precision. 6
Annex A (informative) Worked example. 7
Annex B (informative) Worksheet example. 11

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 2.
The main task of technical committees is to prepare International Standards. 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 document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 20905 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 1, Coal
preparation: Terminology and performance.
iv © ISO 2004 – All rights reserved

Introduction
The development of the dust/moisture curve provides an indication of the likely response of different coal
types to drying or water addition during mining and handling processes. The dust/moisture curve provides a
good basis for comparing the response of different coal types. Understanding the dust/moisture characteristics
of a coal will allow minimized water addition to the product for dust suppression. This will in turn assist in water
conservation at mines and other handling facilities, as well as minimizing the total moisture of the product.
This International Standard describes a reliable measurement of dustiness of coal and extends to cover the
relationship between dust and total moisture utilizing the Rio Tinto Dust Tumbler Test. This test provides a
quantitative measure of the dustiness of a coal that can be used to predict operational dust problems, and is
also suitable for the assessment of dust suppression chemicals.
The Rio Tinto Dust Tumbler Test was developed using rotating equipment in a controlled temperature and
humidity environment, and uses a stream of air to remove particles which become airborne during the
tumbling process. It is a batch test in which dust particles (−150 µm particles) are collected in a pre-weighed
filter bag and weighed. From this mass, a dust number, calculated as the mass yield of dust multiplied by
100 000, is determined for the test total moisture. Only 1 kg of sample is required for each dust test, but eight
sample lots are required to develop the dust/moisture curve for a particular coal, i.e. approximately 10 kg is
required for each coal type.
This dust test can be repeated with subsamples at different coal total moisture levels to develop a
dust/moisture curve. The slope of the curve provides information on how sensitive the dustiness is to changes
in total moisture and a dust number of 10 has been used to provide a comparison between coals.
The test has been successfully used for several years on many coals and other bulk materials. The results
have been correlated with the operating practice. The method has been applied to the evaluation of dust-
control products, and the determination of dust-elimination total moisture requirements for coal-handling
systems.
INTERNATIONAL STANDARD ISO 20905:2004(E)

Coal preparation — Determination of dust/moisture relationship
for coal
1 Scope
This International Standard sets out a laboratory procedure for the dust testing of higher rank coals. The
procedure defines a means of evaluating the dust/moisture relationship characteristic of a coal and a dust
extinction moisture (DEM).
NOTE In this standard, an experimental dust number of 10 has been used in the example given in Annex A.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 589, Hard coal — Determination of total moisture
ISO 1953, Hard coal — Size analysis by sieving
ISO 7886-1, Sterile hypodermic syringes for single use — Part 1: Syringes for manual use
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
dust
particles of 150 µm or less diameter entrained in an air stream
3.2
dust extinction moisture
DEM
total moisture at which a dust number of 10 is attained on the dust/moisture curve
NOTE DEM is a useful point for comparing different coals and the effectiveness of reagents.
4 Safety
The following safety precautions shall be observed.
a) To prevent nitrogen build-up within the laboratory, the exhaust tube of the minimum-free-space oven shall
remain clear of obstruction.
b) Safety glasses shall be worn at all times.
c) The exhaust tube of the minimum-head-space oven shall remain free of obstruction to prevent nitrogen
build-up within the laboratory.
d) A dust mask shall be worn when handling coal.
e) Cloth or leather gloves shall be worn when using ovens.
f) The hazards associated with a reagent shall be determined prior to use. Instructions on all relevant
Material Safety Data Sheets (MSDS) shall be followed.
5 Apparatus and equipment
The following apparatus and equipment is required.
5.1 Humidity- and temperature-controlled laboratory, with relative humidity of 63 ± 2 % and temperature
of 20 ± 2 °C.
5.2 Dust-test apparatus, having a rotating drum of 30 cm diameter and 30 cm effective length, as shown
in Figure 1. The required drum speed is 29 r/min, and the desired airflow through the drum is 175 L/min.
5.3 Double filter bags, single use only.
5.4 Electronic thermohydrograph.
5.5 Tachometer.
5.6 Laminar flow differential-pressure manometer.
5.7 Stopwatch.
5.8 Capped bottles, of capacity 250 mL, wide mouth, polypropylene.
5.9 Top loading balance, having a minimum capacity of 1 g and readable to the nearest 0,01 g.
5.10 Laboratory trays.
5.11 Minimum-free-space drying oven.
6 Reagent
Tap water is used in solution and sample preparation.
7 Sample — Initial
Before testing, remove the particles greater than 6,3 mm. Do not crush and replace this removed fraction as
the sample's particle size distribution will be altered.
Prepare sufficient sample to provide 1,2 kg for each dust determination over the desired range of total
moisture or reagent concentrations as well as 1,2 kg for sample characterization. Approximately 8 subsamples,
at a range of total moisture, are required to develop a dust/moisture relatio
...