ASTM D7430-08
(Practice)Standard Practice for Mechanical Sampling of Coal
Standard Practice for Mechanical Sampling of Coal
SIGNIFICANCE AND USE
It is intended that this practice be used to provide a sample representative of the coal from which it is collected. Because of the variability of coal and the wide variety of mechanical sampling equipment available, caution should be used in all stages of the sample collection process, the design of sampling system specifications, the equipment procurement and the acceptance testing of installed equipment.
After removal from the sampling system and further preparation (Practice D 2013), the sample may be analyzed for a number of different parameters. These parameters may define the lot's value, its ability to meet specifications, its environmental impact, as well as other properties.
SCOPE
1.1 This practice is divided into 4 parts. These 4 parts represent the previous standards D 7256/D 7256M, D 4916, D 4702, and D 6518. These 4 standards are the 4 that govern the mechanical sampling of coal and have been combined into one document for the ease of reference of the users of these standards.
1.2 Part A—Mechanical Collection and Within-System Preparation of a Gross Sample of Coal from Moving Streams—Covers procedures for the mechanical collection of a sample under Classification I-B-1 and I-B-2 (Practice D 2234/D 2234M) and the within-system preparation (reduction and division) of gross samples utilizing various components of the mechanical sampling system.
1.2.1 Part A describes mechanical sampling procedures for coals (1) by size and condition of preparation (for example, mechanically cleaned coal or raw coal), and (2) by sampling characteristics.
1.3 Part B—Mechanical Auger Sampling——Describes procedures for the collection of an increment, partial sample, or gross sample of material using mechanical augers. Reduction and division of the material by mechanical equipment at the auger is also covered. Further manual or mechanical reduction or division of the material elsewhere shall be performed in accordance with Practice D 2013.
1.4 Part C—Quality Management of Mechanical Coal Sampling Systems—Is applicable to the quality management of cross-belt, falling stream, and auger sampling systems.
1.4.1 Spacing of increments pertains to the kind of interval between increments. Intervals can be defined in quantitative terms, such as units of time or mass, or in terms of position over the lot.
1.4.2 Spacing of Increments for Cross-Belt and Falling Stream Samplers—Cross-belt and falling stream type mechanical sampling systems take increments based on time, either at fixed time intervals or at random times during a fixed time strata. Some falling stream samplers can take increments based on equal mass of coal sampled as determined by scales. The sections of this practice that pertain to cross-belt and falling stream samplers describe procedures for only time-based sampling systems. This time-based inspection guideline will satisfy most criteria for mass-based or combination mass-based and time-based sampling systems. If there are items that are not covered, the inspector should refer to the manufacturer's literature.
1.4.3 Spacing of Increments for Auger Sampling—The spacing of increments collected by auger sampling systems is defined in terms of position over the lot.
1.4.4 It is essential that the inspector have the documentation listed in Section 2 of this practice when conducting an inspection.
1.5 Part D—Bias Testing of a Mechanical Coal Sampling System—Presents sample collection and statistical evaluation procedures for testing mechanical sampling systems, subsystems, and individual system components for bias. It is the responsibility of the user of this practice to select the appropriate procedure for a specific sampling situation.
1.5.1 Part D does not purport to define an absolute bias. Bias defined by this practice is the difference between the population mean of the mechanical sampler test results and the accepted reference value.
1.6 The values stated in either SI un...
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Designation: D 7430 – 08
Standard Practice for
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Mechanical Sampling of Coal
This standard is issued under the fixed designation D 7430; 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 (e) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Analysis data obtained from coal samples are used in establishing price, controlling mine and
cleaning plant operations, allocating production costs, and determining plant or component efficiency.
The task of obtaining a sample of reasonable weight to represent an entire lot presents a number of
problems and emphasizes the necessity for using standard sampling procedures.
Coal is one of the most difficult of materials to sample, varying in composition from noncombus-
tible particles to those which can be burned completely, with all gradations in between. The task is
further complicated by the use of the analytical results, the sampling equipment available, the quantity
to be represented by the sample, and the degree of precision required.
Thispracticegivestheoverallrequirementsforthecollectionandwithin-systempreparationofcoal
samples through the use of mechanical sampling systems utilizing falling stream, cross belt and auger
designs. This practice also gives the overall requirements for the bias testing and quality management
of mechanical coal sampling systems. The wide varieties of coal-handling facilities preclude the
publication of detailed procedures for every sampling situation. The proper collection of the sample
involves an understanding and consideration of the physical character of the coal, the number and
weight of increments, and the overall precision required.
1. Scope and division of the material by mechanical equipment at the
auger is also covered. Further manual or mechanical reduction
1.1 This practice is divided into 4 parts. These 4 parts
or division of the material elsewhere shall be performed in
represent the previous standards D 7256/D 7256M, D 4916,
accordance with Practice D 2013.
D 4702, and D 6518. These 4 standards are the 4 that govern
1.4 Part C—Quality Management of Mechanical Coal Sam-
the mechanical sampling of coal and have been combined into
pling Systems—Is applicable to the quality management of
one document for the ease of reference of the users of these
cross-belt, falling stream, and auger sampling systems.
standards.
1.4.1 Spacing of increments pertains to the kind of interval
1.2 Part A—Mechanical Collection and Within-System
between increments. Intervals can be defined in quantitative
Preparation of a Gross Sample of Coal from Moving
terms, such as units of time or mass, or in terms of position
Streams—Coversproceduresforthemechanicalcollectionofa
over the lot.
sample under Classification I-B-1 and I-B-2 (Practice D 2234/
1.4.2 Spacing of Increments for Cross-Belt and Falling
D 2234M) and the within-system preparation (reduction and
Stream Samplers—Cross-beltandfallingstreamtypemechani-
division) of gross samples utilizing various components of the
cal sampling systems take increments based on time, either at
mechanical sampling system.
fixed time intervals or at random times during a fixed time
1.2.1 Part A describes mechanical sampling procedures for
strata. Some falling stream samplers can take increments based
coals (1) by size and condition of preparation (for example,
on equal mass of coal sampled as determined by scales. The
mechanically cleaned coal or raw coal), and (2) by sampling
sections of this practice that pertain to cross-belt and falling
characteristics.
stream samplers describe procedures for only time-based
1.3 Part B—Mechanical Auger Sampling——Describes
sampling systems. This time-based inspection guideline will
proceduresforthecollectionofanincrement,partialsample,or
satisfymostcriteriaformass-basedorcombinationmass-based
gross sample of material using mechanical augers. Reduction
andtime-basedsamplingsystems.Ifthereareitemsthatarenot
covered, the inspector should refer to the manufacturer’s
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This practice is under the jurisdiction of ASTM Committee D05 on Coal and
literature.
Coke and is the direct responsibility of Subcommittee D05.23 on Sampling.
Current edition approved Feb. 1, 2008. Published February 2008.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D7430–08
1.4.3 Spacing of Increments for Auger Sampling—The 3. Terminology
spacing of increments collected by auger sampling systems is
3.1 Definitions—Definitions applicable to this practice are
defined in terms of position over the lot.
listed in Terminology D 121
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