ASTM E877-21

Standard Practice for Sampling and Sample Preparation of Iron Ores and Related Materials for Determination of Chemical Composition and Physical Properties

SIGNIFICANCE AND USE
5.1 This practice is to be used for sampling and sample preparation of iron ores and related materials, prior to use of a referee method for testing for compliance with compositional specifications for metal content or physical properties. It is assumed that all who use this procedure will be trained analysts capable of performing common laboratory practices skillfully and safely. It is expected that work will be performed in a properly equipped laboratory and that proper waste disposal procedures will be followed. Appropriate quality control practices must be followed, such as those described in Guide E882.  
5.2 Adequate methods for obtaining representative samples for testing the chemical and physical properties of a consignment of iron ore are essential. The sale and use are dependent on the chemical or physical properties, or both, of an ore.  
5.3 The criteria to prevent bias may be used for both design of a sampling system and in checking the design of an existing system.
SCOPE
1.1 This practice covers procedures for mechanical sampling of iron ores and related materials in a falling stream or stopped-belt sampling and preparing the gross sample to the various test samples required for each characteristic to be measured. Included as Annexes are (1) design criteria to prevent bias, (2) statistical methods to determine quality variation and precisions of sampling and division, and (3) a method for comparing two sampling procedures for possible systematic differences.  
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.  
1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2021
• ICS: 73.060.10 - Iron ores
• Technical Committee: E01 - Analytical Chemistry for Metals, Ores, and Related Materials
• Drafting Committee: E01.02 - Ores, Concentrates, and Related Metallurgical Materials

Relations

• Refers: ASTM E135-20 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Jan-2020
• Refers: ASTM E135-19 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-May-2019
• Refers: ASTM E279-18 - Standard Test Method for Determination of Abrasion Resistance of Iron Ore Pellets, Lump, and Sinter by the Tumbler Test
• Effective Date: 01-Apr-2018
• Refers: ASTM E882-10(2016) - Standard Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
• Effective Date: 01-Dec-2016
• Refers: ASTM E882-10(2016)e1 - Standard Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
• Effective Date: 01-Dec-2016
• Refers: ASTM E135-16 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-May-2016
• Refers: ASTM E135-15a - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Jul-2015
• Refers: ASTM E135-15 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-May-2015
• Refers: ASTM E135-14b - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-Aug-2014
• Refers: ASTM E135-14a - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Apr-2014
• Refers: ASTM E135-14 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-Feb-2014
• Refers: ASTM E135-13a - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 01-Dec-2013
• Refers: ASTM E135-11b - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-Sep-2011
• Refers: ASTM E135-11a - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-Jun-2011
• Refers: ASTM E135-11 - Standard Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• Effective Date: 15-Jan-2011

Overview

ASTM E877-21 is a standard developed by ASTM International that provides recommended practices for sampling and sample preparation of iron ores and related materials. Its primary purpose is to ensure accurate and representative samples are obtained for determining the chemical composition and physical properties of these materials. This standard addresses procedures for both mechanical sampling in falling streams or stopped-belt conditions, as well as requirements for preparing the bulk sample for laboratory testing. Using ASTM E877-21 helps minimize bias, ensures reliable analysis, and supports compliance with compositional specifications for metal content and physical properties.

Key Topics

• Sampling Procedures

  • Guidelines for mechanical sampling of iron ores and related materials either from a falling stream or using stopped-belt methods.
  • Recommendations for the collection, drying, blending, division, crushing, pulverizing, and preparation of gross samples.

• Sample Preparation

  • Steps to ensure preparation aligns with the requirements of subsequent test methods.
  • Emphasis on avoiding contamination, loss of mass, and changes in sample properties during preparation.

• Bias Prevention

  • Criteria for the design of sampling systems to minimize bias.
  • Methods for verifying the absence of systematic errors, including comparison between different sampling techniques.

• Statistical Evaluation

  • Guidelines for estimating quality variation and determining the precision of sampling and division.
  • Use of statistical methods for measuring the reproducibility and accuracy of laboratory test results.

• Quality Control

  • Importance of adhering to good laboratory and safety practices.
  • Reference to ASTM E882 for quality control in the laboratory environment.

Applications

ASTM E877-21 is essential for laboratories, mining, and metallurgy sectors involved in the production, sale, or usage of iron ore and related materials. Its applications include:

• Production Quality Assurance

  • Ensuring that iron ore consignments comply with specified chemical and physical property requirements.
  • Validating material quality before shipping or further processing.

• Trade and Compliance

  • Establishing standardized sampling and sample preparation protocols required for contract validation and dispute resolution.
  • Supporting regulatory compliance by providing defensible, unbiased data for traded iron ore commodities.

• R&D and Process Improvement

  • Assisting research laboratories in developing new analytical methods or refining existing processes.
  • Enabling reliable inter-laboratory comparisons.

• Environmental and Safety Considerations

  • Outlining waste disposal and safety protocols during sampling and preparation processes.

Related Standards

ASTM E877-21 is used in conjunction with several other important standards, including:

• ASTM E135 - Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
• ASTM E276 - Test Method for Particle Size or Screen Analysis at No. 4 Sieve and Finer for Metal-Bearing Ores
• ASTM E279 - Test Method for Determination of Abrasion Resistance of Iron Ore Pellets, Lump, and Sinter by the Tumbler Test
• ASTM E389 - Test Method for Particle Size or Screen Analysis at 4.75 mm (No.4) Sieve and Coarser
• ASTM E882 - Guide for Accountability and Quality Control in the Chemical Analysis Laboratory

Practical Value

Implementing ASTM E877-21 enhances the reliability of iron ore sampling and analysis by:

• Reducing the risk of sampling bias and variability.
• Promoting uniformity and comparability in quality testing results.
• Supporting efficient trade and ensuring customer confidence in raw material quality.
• Upholding internationally recognized best practices and improving laboratory safety and environmental stewardship.

Keywords: ASTM E877-21, iron ore sampling standard, sample preparation, iron ore chemical analysis, physical properties, mechanical sampling, bias prevention, quality control, iron ore laboratory testing.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E877 − 21
Standard Practice for
Sampling and Sample Preparation of Iron Ores and Related
Materials for Determination of Chemical Composition and
Physical Properties
This standard is issued under the fixed designation E877; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope of Iron Ore Pellets, Lump, and Sinter by the Tumbler Test
E389 Test Method for Particle Size or Screen Analysis at
1.1 This practice covers procedures for mechanical sam-
4.75 mm (No.4) Sieve and Coarser for Metal-Bearing
pling of iron ores and related materials in a falling stream or
Ores and Related Materials
stopped-belt sampling and preparing the gross sample to the
E882 Guide for Accountability and Quality Control in the
various test samples required for each characteristic to be
Chemical Analysis Laboratory
measured. Included as Annexes are (1) design criteria to
E1072 Test Method for Low Temperature Breakdown of
prevent bias, (2) statistical methods to determine quality
Iron Ores (Withdrawn 1995)
variation and precisions of sampling and division, and (3)a
method for comparing two sampling procedures for possible
3. Terminology
systematic differences.
3.1 Definitions—For definitions of terms used in this test
1.2 This standard does not purport to address all of the
method, refer to Terminology E135.
safety concerns, if any, associated with its use. It is the
3.1.1 nominal topsize, n—in sampling, the opening of the
responsibility of the user of this standard to establish appro-
screen of the standard series that would pass 95 % of a
priate safety, health, and environmental practices and deter-
representative sample.
mine the applicability of regulatory limitations prior to use.
3.1.2 precision, n—a measure of reproducibility of test
Specific precautionary statements are given in Section 8.
results, using the same equipment and method, statistically
1.3 This international standard was developed in accor-
derived from multiple data expressed at 95 % confidence level.
dance with internationally recognized principles on standard-
ization established in the Decision on Principles for the
4. Summary of Practice
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
4.1 The precision required for the sampling and sample
Barriers to Trade (TBT) Committee.
preparation steps is calculated based on the objectives of the
testing, resulting in a sampling plan specifying the minimum
2. Referenced Documents
masses and number of increments required for each step in the
procedure. Samples are then collected, dried, blended, divided,
2.1 ASTM Standards:
crushed, pulverized, and ground as required by the test
E135 Terminology Relating to Analytical Chemistry for
methods to be utilized.
Metals, Ores, and Related Materials
E276 Test Method for Particle Size or Screen Analysis at
5. Significance and Use
4.75 mm (No. 4) Sieve and Finer for Metal-Bearing Ores
and Related Materials
5.1 This practice is to be used for sampling and sample
E279 Test Method for Determination ofAbrasion Resistance
preparation of iron ores and related materials, prior to use of a
referee method for testing for compliance with compositional
specifications for metal content or physical properties. It is
This practice is under the jurisdiction of ASTM Committee E01 on Analytical
assumedthatallwhousethisprocedurewillbetrainedanalysts
Chemistry for Metals, Ores, and Related Materials and is the direct responsibility of
capable of performing common laboratory practices skillfully
Subcommittee E01.02 on Ores, Concentrates, and Related Metallurgical Materials.
Current edition approved Oct. 1, 2021. Published October 2021. Originally
and safely. It is expected that work will be performed in a
approved in 1982. Last previous edition approved in 2013 as E877 – 13. DOI:
properly equipped laboratory and that proper waste disposal
10.1520/E0877-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on The last approved version of this historical standard is referenced on
the ASTM website. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E877 − 21
TABLE 1 Overall Precision
procedures will be followed. Appropriate quality control prac-
tices must be followed, such as those described in Guide E882. Iron and
Specification Size, Cumulative Percent Passing
Consignment, Moisture
5.2 Adequate methods for obtaining representative samples
tons Content,
A A
<10% 10%–50% >50%–90% >90%
%
for testing the chemical and physical properties of a consign-
>100000 ±0.3 ±0.75% ±0.075C ± 0.075 (100-C) ± 0.75 %
ment of iron ore are essential. The sale and use are dependent
20 000 to ± 0.4 ± 1.0 % ± 0.1C ± 0.1 (100-C)±1.0%
on the chemical or physical properties, or both, of an ore.
100 000
<20000 ±0.5 ±2.0% ±0.2C ± 0.2 (100-C)±2.0%
5.3 The criteria to prevent bias may be used for both design
A
In the formulae for calculating the precision estimates within this column,
of a sampling system and in checking the design of an existing
C = cumulative percent passing.
system.
6. Apparatus
NOTE 2—Nationally or internationally accepted measurement methods
6.1 Any mechanical sampler is acceptable that either by
should be used to determine the characteristics desired.
design or comparison, or both (as defined in Annex A1 and
Annex A4) can be shown to take nonbiased increments of at 7.3 Equations:
7.3.1 Calculate overall precision as follows:
leastminimummassandnumberrequiredandcanhandlethese
increments in accordance with the practice.
2 2
σ 1 σ
w DM
β 5 2Œ 11 1 (1)
6.2 Templates and Related Equipment, to obtain increments S D
SDM
n c ν
from a stopped belt, with bias protection in accordance with
or
Annex A2, are acceptable.
6.3 Riffle—Astationarysamplercomprisinganevennumber σ 2 σ 2
σ 1
D M
w
β 5 2Œ 11 1 1 (2)
S D
SDM
of equally-sized, adjacent chutes discharging in opposite direc-
n σ ν νm
tions. For use with this practice, there must be a minimum of
where:
twelve chutes with an opening width of at least 3 times the
β = overall precision for any characteristic,
SDM
nominal topsize.
σ = estimated within-strata standard deviation of a
w
NOTE 1—For fine ores (< 3 mm), the 3 times nominal topsize should
characteristic,
be increased to the point where the plugging of chutes is eliminated. For
σ = estimated standard deviation of division,
D
coarse ores (> 12.5 mm) it is recommended not to exceed 3 ⁄2 times
σ = estimated standard deviation of measurement,
M
nominal topsize as it is required that the full width of the riffle be used
σ = estimated standard deviation of division and mea-
since the accuracy of the split increases with the number of chutes. For DM
surement combined,
free-flowing ores such as pellets, the 3 times the nominal topsize may be
reduced to 1 ⁄2 times provided it is ascertained that there is no chute
n = number of primary increments,
plugging for a particular ore type.
ν = number of final samples taken for measurement,
m = number of measurements taken on each final
6.4 Crushers—Crushers may be jaw, cone, rotary, or other
sample, and
type that can reduce the particle size to the desired level
c = average number of secondary increments taken per
without significant loss of mass (less than 0.5 %) and not
primary increment.
contaminate the sample.
NOTE 3—Factor (1 + 1⁄c) is omitted from the equation if only primary
6.5 Pulverizers and Grinders—Pulverizers and grinders
increments are used.
may be of plate, cylinder, or other type that can reduce the
7.3.2 σ and σ or σ , σ , and σ are estimated in
w DM w D M
particle size to the desired level. They should be made of
accordance with Annex A3.
sufficiently hardened material to prevent contamination of the
7.3.3 When designing a new sampling installation, refer to
sample. Also, the loss of total mass during pulverizing should
Annex A1 for estimating σ and σ .
w DM
not exceed 2.5 %.
7.4 Selection of Sampling Parameters—Using the estimated
7. Design of Sampling Operations values of σ and σ or σ , σ , and σ and Eq 1 or Eq 2,
w DM w D M
choose a combination of n, c, ν, and m to obtain the required
7.1 Basic Requirements:
precision. It is recommended in routine sampling to use the
7.1.1 The characteristics to be determined and precisions
same value of c used in the determination of σ .
w
desired must be known.
7.1.2 The mass and special requirements for each test 7.5 Minimum Mass of Increment—Theminimummassofan
sample must be known. increment is calculated by the following formula to ensure that
a particle the shape of a cube of the nominal topsize shall not
7.2 Overall Precision (β ):
SDM
represent more than 10 % of its mass, to avoid bias by larger
7.2.1 Overall precision for determining the mean values of
particles:
the iron content, moisture content, and percentage passing the
specified size sieve (in accordance with Test Methods E276 W 5 ~S /20! 3 ~sp gr/5! (3)
andE389),at95 %confidenceinabsolutepercentagesareasin
where:
Table 1.
W = minimum mass of increment, kg,
7.2.2 Overall precisions for other characteristics shall be
S = nominal size of the ore, cm, and
agreed upon between the parties concerned.
E877 − 21
8.3 If secondary increments (c) are used, they shall be taken
sp gr = specific gravity of the iron ore being sampled.
at equal time intervals with a maximum time such that cis1or
NOTE 4—In practice, the mass of primary increments may be many
greater.
times greater than that obtained in Eq 3.
7.6 Treatment of Increments—Increments will be handled
8.4 Increments are treated individually or combined to form
individuallyorcombinedtoformoneormoregrosssamplesor a gross sample(s) or subsamples, or both, in accordance with
set(s) of subsamples from which test sample(s) for the required
final test sample requirements in conjunction with precision
characteristics will be taken. Each gross sample must follow requirements, as determined in 7.3.1.
the requirements of sampling and preparation. Each gross
8.5 At this stage, individual test samples are obtained by a
sample must have, as a minimum number of increments, the
combination of division (mass reduction) (8.6), crushing and
largest number (n) calculated from the individual characteris-
pulverizing (8.7), and drying (8.8), as directed in Section 8.
tics taken from that gross sample.
8.6 Division of gross sample, subsamples, or increment
7.6.1 Example—Assume a gross sample is required for iron
must conform with the following rule:
analysis and moisture determination and a separate gross
sample for size distribution and tumble test.Also assume from 8.6.1 The minimum mass of the total divided sample must
be greater than:
7.4 the number of increments required to obtain precision
desired is as follows: 3
W 5 S 3 sp gr/5 (4)
~ !
Moisture 30 increments
where:
Iron 20 increments
Size 50 increments
W = mass of the divided sample, kg
Tumble 25 increments
S = nominal topsize at that division level, cm, and
7.6.2 Example—Take 30 increments for iron analysis and
sp gr = specific gravity of the ore being sampled.
moisture determination and 50 increments for size distribution
8.6.1.1 The equation is based on the concept that the mass
and tumble test, if the sampler has the capability (for example,
of the largest piece should be less than 0.5 % of the mass of the
computer controlled). If, however, alternative increments are
divided sample.
used, take 50 increments for each gross sample. If one gross
8.6.2 Divide the sample by one of the following procedures:
sample is to be used for all the determinations, use 50
8.6.2.1 A mechanical sampler operated in accordance with
increments.
the guidelines in Annex A1.
7.7 Special Precautions:
8.6.2.2 Riffling—Use a pan the same width as the riffle
7.7.1 Samples for size determination or other tests requiring
chutestofeedtheorefordivision.Addincrementsoforetothe
uncrushed particles must be taken prior to crushing.
pan and gently agitate the pan over the center of the chutes,
7.7.2 Samples for moisture determination must be protected
feedingtheoreataconstantrate,sothatanyoreparticlehasan
from ambient conditions.Asubsample should be taken at least
equal chance of falling to either side of the device. Select the
every 8 h and the total moisture of the consignment should be
half of the divided sample to be included in subsequent
the weighted average of these samples. The 8 h period may be
sampling steps, at random. Thoroughly clean the equipment
extended provided the sample is protected from moisture
between samples. Warning—Use proper dust collection to
change (for example, refrigerated). To avoid moisture change,
protect the operator from fine respirable dust particles.
samples must be prepared as quickly as possible, with mini-
8.6.2.3 Manual Increment Division (Note 5)—Mix the en-
mum handling, and must be kept in sealed containers while
tire sample and spread on a flat nonmoisture-absorbing surface
awaiting any stage of preparation prior to the initial weighing.
so that the sample forms a rectangle of uniform thickness.
Moisture samples should not be crushed below 6.3 mm ( ⁄4 in.)
Divide into at least 20 segments of equal area. With a flat
sieve and the minimum mass of samples used should conform
bottom, square-nose tool, take scoopfuls of approximate equal
with Eq 4 (8.6.1). Mix sample prior to moisture determination.
size from each segment from the full depth of the bed. These
scoopfulsmusthaveaminimummassinaccordancewithEq3.
8. Sampling and Preparation Procedure (See Fig. 3 for
Combine the scoopfuls to form the divided sample.
examples)
NOTE 5—Manual increment division, although very efficient for moist
8.1 Collectthroughoutthemovementoftheconsignment,in or cohesive ores, or both, is not recommended for dry ores, sinter, or
pellets.
accordance with Annex A1 or Annex A2, the number of
primary increments, as determined in 7.4 (with a minimum of
8.7 Drying, Crushing, Pulverizing, and Grinding:
20). Start at random within the first stratum, then sample at
8.7.1 Always dry samples before sample preparation, if
equalmassortimeintervals.Iftheoreishandledinsuchaway
possible, to limit contamination from moist ore sticking to
that there is a cycle to the variability of a characteristic, it must
surfaces of sample preparation equipment.
be ascertained that the sampling cycle is not in phase with the
8.7.2 Crush, pulverize, and grind samples to the required
handling cycle.
maximumsizeinstagesconvenienttotheequipmentavailable.
8.2 Iftherequirednumberofincrementsiscollectedpriorto At each stage, reduce the sample mass to the extent that the
completion of the movement of the consignment, additional mass of the divided sample exceeds that obtained by Eq 4.
increments shall be taken at the same interval until ore Warning—Use proper dust collection to protect the operator
handling is complete. from fine respirable dust particles.
E877 − 21
FIG. 1 Procedures for Calculating Standard Deviation
FIG. 2 Sampling Plan for Determination of Precision of Sampling and Quality Variation
E877 − 21
FIG. 3 Flowsheet Examples
provided it is ascertained this will have no effect on any of the
8.8 Drying—Drying of any portion of the sample is accom-
characteristics to be determined.
plished in any heating medium as long as the ore temperature
does not exceed 110 °C. Where specifications call for a dried
8.9 Crushing—Clean and preset the crusher(s) to the size
sample, it must be dried to constant mass in an oven capable of
required and slowly feed the sample to the crusher so as not to
maintaining a temperature of 105 °C 6 5 °C. Constant mass is
overload it. Ore adhering to the crushing surfaces must be
obtained when an additional hour drying at 105 °C 6 5°C
added to the sample by scraping, brushing, or other means.
does not cause a change greater than 0.05 % mass.
Most ores can be crushed to pass a 6.3 mm ( ⁄4 in.) sieve in
NOTE 6—The maximum temperature of 110 °C may be exceeded,
E877 − 21
their natural state; however,
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E877 − 13 E877 − 21
Standard Practice for
Sampling and Sample Preparation of Iron Ores and Related
Materials for Determination of Chemical Composition and
Physical Properties
This standard is issued under the fixed designation E877; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice covers procedures for mechanical sampling of iron ores and related materials in a falling stream or stopped-belt
sampling and preparing the gross sample to the various test samples required for each characteristic to be measured. Included as
Annexes are (1) design criteria to prevent bias, (2) statistical methods to determine quality variation and precisions of sampling
and division, and (3) a method for comparing two sampling procedures for possible systematic differences.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. Specific precautionary statements are given in Section 8.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E135 Terminology Relating to Analytical Chemistry for Metals, Ores, and Related Materials
E276 Test Method for Particle Size or Screen Analysis at No. 4 (4.75-mm) Sieve and Finer for Metal-Bearing Ores and Related
Materials
E279 Test Method for Determination of Abrasion Resistance of Iron Ore Pellets, Lump, and Sinter by the Tumbler Test
E389 Test Method for Particle Size or Screen Analysis at 4.75 mm (No.4) Sieve and Coarser for Metal-Bearing Ores and Related
Materials
E882 Guide for Accountability and Quality Control in the Chemical Analysis Laboratory
E1072 Test Method for Low Temperature Breakdown of Iron Ores (Withdrawn 1995)
3. Terminology
3.1 Definitions—For definitions of terms used in this test method, refer to Terminology E135.
3.1.1 nominal topsize—topsize, n—in sampling, the opening of the screen of the standard series that would pass 95 % 95 % of a
representative sample.
This practice is under the jurisdiction of ASTM Committee E01 on Analytical Chemistry for Metals, Ores, and Related Materials and is the direct responsibility of
Subcommittee E01.02 on Ores, Concentrates, and Related Metallurgical Materials.
Current edition approved Oct. 1, 2013Oct. 1, 2021. Published November 2013October 2021. Originally approved in 1982. Last previous edition approved in 20082013
as E877 – 08.E877 – 13. DOI: 10.1520/E0877-13.10.1520/E0877-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E877 − 21
3.1.2 precision—precision, n—a measure of reproducibility of test results, using the same equipment and method, statistically
derived from multiple data expressed at 95 % 95 % confidence level.
4. Summary of Practice
4.1 The precision required for the sampling and sample preparation steps is calculated based on the objectives of the testing,
resulting in a sampling plan specifying the minimum masses and number of increments required for each step in the procedure.
Samples are then collected, dried, blended, divided, crushed, pulverized, and ground as required by the test methods to be utilized.
5. Significance and Use
5.1 This practice is to be used for sampling and sample preparation of iron ores and related materials, prior to use of a referee
method for testing for compliance with compositional specifications for metal content or physical properties. It is assumed that all
who use this procedure will be trained analysts capable of performing common laboratory practices skillfully and safely. It is
expected that work will be performed in a properly equipped laboratory and that proper waste disposal procedures will be followed.
Appropriate quality control practices must be followed, such as those described in Guide E882.
5.2 Adequate methods for obtaining representative samples for testing the chemical and physical properties of a consignment of
iron ore are essential. The sale and use are dependent on the chemical or physical properties, or both, of an ore.
5.3 The criteria to prevent bias may be used for both design of a sampling system and in checking the design of an existing system.
6. Apparatus
6.1 Any mechanical sampler is acceptable that either by design or comparison, or both (as defined in Annex A1 and Annex A4)
can be shown to take nonbiased increments of at least minimum mass and number required and can handle these increments in
accordance with the practice.
6.2 Templates and Related Equipment, to obtain increments from a stopped belt, with bias protection in accordance with Annex
A2, are acceptable.
6.3 Riffle—A stationary sampler comprising an even number of equally-sized, adjacent chutes discharging in opposite directions.
For use with this practice, there must be a minimum of twelve chutes with an opening width of at least 3 times the nominal topsize.
NOTE 1—For fine ores (< 3 mm)mm), the 3 times nominal topsize should be increased to the point where the plugging of chutes is eliminated. For coarse
ores (> 12.5 mm) it is recommended not to exceed 3 ⁄2 times nominal topsize as it is required that the full width of the riffle be used since the accuracy
of the split increases with the number of chutes. For free-flowing ores such as pellets, the 3 times the nominal topsize may be reduced to 1 ⁄2 times
provided it is ascertained that there is no chute plugging for a particular ore type.
6.4 Crushers—Crushers may be jaw, cone, rotary, or other type that can reduce the particle size to the desired level without
significant loss of mass (less than 0.5 %) 0.5 %) and not contaminate the sample.
6.5 Pulverizers and Grinders—Pulverizers and grinders may be of plate, cylinder, or other type that can reduce the particle size
to the desired level. They should be made of sufficiently hardened material to prevent contamination of the sample. Also, the loss
of total mass during pulverizing should not exceed 2.5 %.2.5 %.
7. Design of Sampling Operations
7.1 Basic Requirements:
7.1.1 The characteristics to be determined and precisions desired must be known.
7.1.2 The mass and special requirements for each test sample must be known.
7.2 Overall Precision (β ):
SDM
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7.2.1 Overall precision for determining the mean values of the iron content, moisture content, and percentage passing the specified
size sieve (in accordance with Test Methods E276 and E389), at 95 % 95 % confidence in absolute percentages are as in Table
1.
7.2.2 Overall precisions for other characteristics shall be agreed upon between the parties concerned.
NOTE 2—Nationally or internationally accepted measurement methods should be used to determine the characteristics desired.
7.3 Equations:
7.3.1 Calculate overall precision as follows:
2 2
σ 1 σ
w DM
β 5 2 11 1 (1)
ΠS D
SDM
n c ν
or
σ 2 σ 2
σ 1
D M
w
β 5 2 11 1 1 (2)
Œ
S D
SDM
n σ ν νm
where:
β = overall precision for any characteristic,
SDM
σ = estimated within-strata standard deviation of a characteristic,
w
σ = estimated standard deviation of division,
D
σ = estimated standard deviation of measurement,
M
σ = estimated standard deviation of division and measurement combined,
DM
n = number of primary increments,
ν = number of final samples taken for measurement,
m = number of measurements taken on each final sample, and
c = average number of secondary increments taken per primary increment.
NOTE 3—Factor (1 + 1 ⁄c) is omitted from the equation if only primary increments are used.
7.3.2 σ and σ or σ , σ , and σ are estimated in accordance with Annex A3.
w DM w D M
7.3.3 When designing a new sampling installation, refer to Annex A1 for estimating σ and σ .
w DM
7.4 Selection of Sampling Parameters—Using the estimated values of σ and σ or σ , σ , and σ and Eq 1 or Eq 2, choose
w DM w D M
a combination of n, c, ν, and m to obtain the required precision. It is recommended in routine sampling to use the same value of
c used in the determination of σ .
w
7.5 Minimum Mass of Increment—The minimum mass of an increment is calculated by the following formula to ensure that a
particle the shape of a cube of the nominal topsize shall not represent more than 10 % of its mass, to avoid bias by larger particles:
W 5 S /20 3 sp gr/5 (3)
~ ! ~ !
TABLE 1 Overall Precision
Iron and
Specification Size, Cumulative Percent Passing
Consignment, Moisture
tons Content,
A A
< 10 % 10 % – 50 % > 50 % – 90 % > 90 %
%
> 100 000 ± 0.3 ± 0.75 % ± 0.075C ± 0.075 (100-C) ± 0.75 %
20 000 to ± 0.4 ± 1.0 % ± 0.1C ± 0.1 (100-C) ± 1.0 %
100 000
< 20 000 ± 0.5 ± 2.0 % ± 0.2C ± 0.2 (100-C) ± 2.0 %
A
In the formulae for calculating the precision estimates within this column,
C = cumulative percent passing.
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where:
W = minimum mass of increment, kg,
S = nominal size of the ore, cm, and
sp gr = specific gravity of the iron ore being sampled.
NOTE 4—In practice, the mass of primary increments may be many times greater than that obtained in Eq 3.
7.6 Treatment of Increments—Increments will be handled individually or combined to form one or more gross samples or set(s)
of subsamples from which test sample(s) for the required characteristics will be taken. Each gross sample must follow the
requirements of sampling and preparation. Each gross sample must have, as a minimum number of increments, the largest number
(n) calculated from the individual characteristics taken from that gross sample.
7.6.1 Example—Assume a gross sample is required for iron analysis and moisture determination and a separate gross sample for
size distribution and tumble test. Also assume from 7.4 the number of increments required to obtain precision desired is as follows:
Moisture 30 increments
Iron 20 increments
Size 50 increments
Tumble 25 increments
7.6.2 Example—Take 30 increments for iron analysis and moisture determination and 50 increments for size distribution and
tumble test, if the sampler has the capability (for example, computer controlled). If, however, alternative increments are used, take
50 increments for each gross sample. If one gross sample is to be used for all the determinations, use 50 increments.
7.7 Special Precautions:
7.7.1 Samples for size determination or other tests requiring uncrushed particles must be taken prior to crushing.
7.7.2 Samples for moisture determination must be protected from ambient conditions. A subsample should be taken at least every
8 h and the total moisture of the consignment should be the weighted average of these samples. The 8-h8 h period may be extended
provided the sample is protected from moisture change (for example, refrigerated). To avoid moisture change, samples must be
prepared as quickly as possible, with minimum handling, and must be kept in sealed containers while awaiting any stage of
preparation prior to the initial weighing. Moisture samples should not be crushed below 6.3 mm ( ⁄4-in. in.) sieve (6.3 mm) and
the minimum mass of samples used should conform with Eq 4 (8.6.1). Mix sample prior to moisture determination.
8. Sampling and Preparation Procedure (See Fig. 3 for examples)
8.1 Collect throughout the movement of the consignment, in accordance with Annex A1 or Annex A2, the number of primary
increments, as determined in 7.4 (with a minimum of 20). Start at random within the first stratum, then sample at equal mass or
time intervals. If the ore is handled in such a way that there is a cycle to the variability of a characteristic, it must be ascertained
that the sampling cycle is not in phase with the handling cycle.
8.2 If the required number of increments is collected prior to completion of the movement of the consignment, additional
increments shall be taken at the same interval until ore handling is complete.
8.3 If secondary increments (c) are used, they shall be taken at equal time intervals with a maximum time such that c is 1 or greater.
8.4 Increments are treated individually or combined to form a gross sample(s) or subsamples, or both, in accordance with final
test sample requirements in conjunction with precision requirements, as determined in 7.3.1.
8.5 At this stage, individual test samples are obtained by a combination of division (mass reduction) (8.6), crushing and
pulverizing (8.7), and drying (8.8), as directed in Section 8.
8.6 Division of gross sample, subsamples, or increment must conform with the following rule:
8.6.1 The minimum mass of the total divided sample must be greater than:
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FIG. 1 Procedures for Calculating Standard Deviation
FIG. 2 Sampling Plan for Determination of Precision of Sampling and Quality Variation
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FIG. 3 Flowsheet Examples
W 5 S 3 sp gr/5 (4)
~ !
where:
W = mass of the divided sample, kg
S = nominal topsize at that division level, cm, and
sp gr = specific gravity of the ore being sampled.
8.6.1.1 The equation is based on the concept that the mass of the largest piece should be less than 0.5 % of the mass of the divided
sample.
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8.6.2 Divide the sample by one of the following procedures:
8.6.2.1 A mechanical sampler operated in accordance with the guidelines in Annex A1.
8.6.2.2 Riffling—Use a pan the same width as the riffle chutes to feed the ore for division. Add increments of ore to the pan and
gently agitate the pan over the center of the chutes, feeding the ore at a constant rate, so that any ore particle has an equal chance
of falling to either side of the device. Select the half of the divided sample to be included in subsequent sampling steps, at random.
Thoroughly clean the equipment between samples. Warning—Use proper dust collection to protect the operator from fine
respirable dust particles.
8.6.2.3 Manual Increment Division (Note 5)—Mix the entire sample and spread on a flat nonmoisture-absorbing surface so that
the sample forms a rectangle of uniform thickness. Divide into at least 20 segments of equal area. With a flat bottom, square-nose
tool, take scoopfuls of approximate equal size from each segment from the full depth of the bed. These scoopfuls must have a
minimum mass in accordance with Eq 3. Combine the scoopfuls to form the divided sample.
NOTE 5—Manual increment division, although very efficient for moist or cohesive ores, or both, is not recommended for dry ores, sinter, or pellets.
8.7 Drying, Crushing, Pulverizing, and Grinding:
8.7.1 Always dry samples before sample preparation, if possible, to limit contamination from moist ore sticking to surfaces of
sample preparation equipment.
8.7.2 Crush, pulverize, and grind samples to the required maximum size in stages convenient to the equipment available. At each
stage, reduce the sample mass to the extent that the mass of the divided sample exceeds that obtained by Eq 4. Warning—Use
proper dust collection to protect the operator from fine respirable dust particles.
8.8 Drying—Drying of any portion of the sample is accomplished in any heating medium as long as the ore temperature does not
exceed 110 °C. Where specifications call for a dried sample, it must be dried to constant mass in an oven capable of maintaining
a temperature of 105 °C 6 5 °C. Constant mass is obtained when an additional hour drying at 105 °C 6 5 °C does not cause a
change greater than 0.05 % mass.
NOTE 6—The maximum temperature of 110 °C may be exceeded, provided it is ascertained this will have no effect on any of the characteristics to be
determined.
8.9 Crushing—Clean and preset the crusher(s) to the size required and slowly feed the sample to the crusher so as not to overload
it. Ore adhering to the crushing surfaces must be added to the sample by scraping, brushing, or other means. Most ores can be
1 1
crushed to pass a ⁄4-in. (6.3-mm)6.3 mm ( ⁄4 in.) sieve in their natural state; however, pulverizing beyond this size normally
requires a dried sample.
8.10 Pulverizing and Grinding—Clean and preset disk type pulverizer
...