ASTM D5192/D5192M-22

Standard Practice for Collection of Coal Samples from Core

SIGNIFICANCE AND USE
5.1 A properly collected sample that includes the total coal bed interval provides a sample that is a representative cross section of the coal bed at the point of sampling. Core samples are taken for subsequent testing needed for evaluation of coal quality and characterization for commercial evaluations, for planning of mining operations to maintain coal quality, for the determination of coal rank in accordance with Classification D388, and for geologic coal resource studies.  
Note 1: Because of the potential for lateral variability, a sample may not represent the quality of the coal bed at another sample point. The reliability of the data generated from core samples is dependent on the number and spacing of the sample points and the variability of the coal characteristics in a given area.  
5.2 Moisture determined directly from a core sample shall be considered questionable in any core sample because of possible contamination from drilling fluids and groundwater. If a more representative estimate of the inherent moisture content of the core sample (with the exception of certain low-rank coals) is desired, the sample should be analyzed according to Test Method D1412.
SCOPE
1.1 This practice describes procedures for collecting and handling a coal sample from a core recovered from a borehole.  
1.2 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.3 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.  
1.4 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: 14-May-2022
• ICS: 73.040 - Coals
• Technical Committee: D05 - Coal and Coke
• Drafting Committee: D05.23 - Sampling

Relations

• Refers: ASTM D121-15(2024) - Standard Terminology of Coal and Coke
• Effective Date: 01-Mar-2024
• Refers: ASTM D388-19 - Standard Classification of Coals by Rank
• Effective Date: 01-Jun-2019
• Refers: ASTM D388-18a - Standard Classification of Coals by Rank
• Effective Date: 01-Nov-2018
• Refers: ASTM D388-18 - Standard Classification of Coals by Rank
• Effective Date: 01-Feb-2018
• Refers: ASTM D388-17a - Standard Classification of Coals by Rank
• Effective Date: 01-Nov-2017
• Refers: ASTM D388-17 - Standard Classification of Coals by Rank
• Effective Date: 01-Jul-2017
• Refers: ASTM D121-15 - Standard Terminology of Coal and Coke
• Effective Date: 01-Sep-2015
• Refers: ASTM D388-15 - Standard Classification of Coals by Rank
• Effective Date: 15-May-2015
• Refers: ASTM D4371-06(2012) - Standard Test Method for Determining the Washability Characteristics of Coal
• Effective Date: 01-Sep-2012
• Refers: ASTM D388-12 - Standard Classification of Coals by Rank
• Effective Date: 15-Mar-2012
• Refers: ASTM D121-09a - Standard Terminology of Coal and Coke
• Effective Date: 01-Oct-2009
• Refers: ASTM D4596-09 - Standard Practice for Collection of Channel Samples of Coal in a Mine
• Effective Date: 01-Jun-2009
• Refers: ASTM D121-09 - Standard Terminology of Coal and Coke
• Effective Date: 01-Feb-2009
• Refers: ASTM D4596-08 - Standard Practice for Collection of Channel Samples of Coal in a Mine
• Effective Date: 01-May-2008
• Refers: ASTM D121-08 - Standard Terminology of Coal and Coke
• Effective Date: 15-Feb-2008

Overview

ASTM D5192/D5192M-22 is a globally recognized standard practice for the collection of coal samples from core, issued by ASTM International. It outlines precise procedures for collecting and handling core samples recovered from boreholes drilled in coal-bearing formations. By following this standard, the resulting coal sample more accurately represents the full cross-section of the coal bed at the specific sampling location, which is essential for reliable coal quality assessment, resource characterization, and mining planning. Adhering to this practice is vital for coal exploration, commercial evaluations, geologic coal resource studies, and compliance with international reporting requirements.

Key Topics

• Sample Collection Procedures: Guidance on planning, drilling, extruding, measuring, splitting, and preparing core samples to minimize contamination and sample loss.
• Accurate Representation: Instructions for ensuring samples include the entire coal bed interval, while accounting for the exclusion of weathered zones, mineral partings, and other non-representative features.
• Moisture Considerations: Advice regarding the limitations of inherent moisture determination from core samples, highlighting the influence of drilling fluids and best practices for more representative measurements.
• Sample Handling and Packaging: Recommendations for maintaining sample integrity during transportation and storage, including the use of materials like polyethylene bags and proper labeling.
• Field Testing for Inherent Moisture: Procedures for assessing sample freshness and moisture retention using simple field methods.
• Geophysical Logging Integration: Use of geophysical logs (such as density, caliper, gamma-ray, and resistivity logs) to support core data and validate coal seam thickness and recovery.
• Sampling Plan Development: Emphasis on tailoring sampling strategies based on the intended use, coal seam characteristics, and site-specific conditions.
• Documentation and Recordkeeping: Essential practices for accurate field note-taking and sample identification.

Applications

Adoption of ASTM D5192/D5192M-22 provides practical benefits across several sectors of the coal industry:

• Coal Quality Evaluation: Establishes sampling protocols for laboratory analysis to determine coal rank, composition, and key properties relevant to classification systems (such as ASTM D388).
• Resource Assessment and Reporting: Facilitates accurate estimation of coal resources for regulatory compliance, investment decisions, and geologic studies.
• Mining Planning and Operations: Ensures reliable data for mine design, operational planning, and maintaining product quality.
• Environmental and Regulatory Compliance: Supports the collection of data required for environmental assessments and reporting.
• Commercial Transactions: Provides a reliable basis for coal quality claims in supply contracts and negotiations.
• Scientific Research: Supplies high-quality core samples suitable for advanced geochemical, petrographic, and paleoclimate investigations.

Related Standards

Professionals using ASTM D5192/D5192M-22 may also reference the following ASTM standards to support comprehensive coal sampling and analysis workflows:

• ASTM D121: Terminology of Coal and Coke
• ASTM D388: Classification of Coals by Rank
• ASTM D1412: Test Method for Equilibrium Moisture of Coal
• ASTM D2013/D2013M: Practice for Preparing Coal Samples for Analysis
• ASTM D4371: Test Method for Determining the Washability Characteristics of Coal
• ASTM D4596: Practice for Collection of Channel Samples of Coal in a Mine

Together, these standards help ensure consistent, internationally accepted coal sampling and evaluation, enhancing the credibility and utility of collected data in technical, regulatory, and commercial contexts.

Keywords: coal sampling, core samples, ASTM D5192/D5192M-22, borehole, coal resource assessment, coal quality, mining planning, sample integrity, moisture determination, geophysical logging.

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: D5192/D5192M − 22
Standard Practice for
Collection of Coal Samples from Core
This standard is issued under the fixed designation D5192/D5192M; 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* D4371 Test Method for Determining the Washability Char-
acteristics of Coal
1.1 This practice describes procedures for collecting and
D4596 Practice for Collection of Channel Samples of Coal
handling a coal sample from a core recovered from a borehole.
in a Mine
1.2 Units—The values stated in either SI units or inch-
pound units are to be regarded separately as standard. The
3. Terminology
values stated in each system are not necessarily exact equiva-
3.1 Definitions:
lents; therefore, to ensure conformance with the standard, each
3.1.1 For additional definitions of terms, refer to Terminol-
system shall be used independently of the other, and values
ogy D121.
from the two systems shall not be combined.
3.1.2 borehole, n—the circular hole through soil and rock
1.3 This standard does not purport to address all of the
strata made by boring.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 3.1.3 caves or washouts, n—zones of increased hole diam-
eter caused by rock fragments that fall from the walls of a
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use. borehole and can block the hole or contaminate the cuttings
and which erode or abrade the sidewall of the borehole by the
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard- action of the drilling. These zones can affect the accuracy of
certain geophysical logs (especially density). Corrections to
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom- other geophysical logs can be made if a caliper log is available.
The most common causes of caves or washouts include soft or
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee. fractured lithologies, the presence of water-producing zones,
and the downhole pressure of the drilling medium (fluid or air)
thatoftencausesdifferentialerosionofvariousstratawithinthe
2. Referenced Documents
2 borehole.
2.1 ASTM Standards:
3.1.4 concretion, n—in a geological sense, a mass of min-
D121 Terminology of Coal and Coke
D388 Classification of Coals by Rank eral matter found in rock of a composition different from its
own and produced by deposition from aqueous solution in the
D1412 Test Method for Equilibrium Moisture of Coal at 96
to 97 Percent Relative Humidity and 30 °C rock.
D2013/D2013M Practice for Preparing Coal Samples for
3.1.5 core, n—in drilling,acylindricalsectionofrock(coal)
Analysis
that is usually 5 to 10 cm in diameter, taken as part of the
D2796 Terminology for Megascopic Description of Coal
interval penetrated by a core bit and brought to the surface for
and Coal Seams and Microscopical Description and
geologic examination, representative sampling, and laboratory
Analysis of Coal (Withdrawn 1995)
analyses.
3.1.6 core barrels, n—two nested tubes above the bit of a
coredrill,theouterrotatingwiththebit,theinnerreceivingand
This practice is under the jurisdiction of ASTM Committee D05 on Coal and
preserving a continuous section or core of the material pen-
Coke and is the direct responsibility of Subcommittee D05.23 on Sampling.
etrated.Thefollowingtwotypesofinnerbarrelsarecommonly
Current edition approved May 15, 2022. Published June 2022. Originally
approved in 1991. Last previous edition approved in 2015 as D5192 – 09(2015).
used.
DOI: 10.1520/D5192_D5192M-22.
3.1.6.1 split-tube barrel, n—a type of inner barrel consisting
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
oftwolongitudinalhalvesofpipeboundtogetherbyreinforced
Standards volume information, refer to the standard’s Document Summary page on
tape at intervals along the barrel length that allows easy access
the ASTM website.
to a relatively intact core (by cutting the tape). (This is the
The last approved version of this historical standard is referenced on
www.astm.org. preferred barrel type for coal exploration, when available.)
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5192/D5192M − 22
3.1.6.2 solid-tube barrel, n—a type of inner barrel consist- log types. The logs are affected by casing, logging speed,
ing of a single solid-walled length of pipe in which removal of electrode spacing, formation porosity, and resistivity changes
the core is accomplished by mechanical or hydraulic pressure in the borehole fluid.
at one end of the pipe thus extruding the core onto a core tray.
3.1.9 floor, n—the rock material immediately underlying a
(Thecoreislikelytobelessintactthanwhenasplit-tubebarrel
coal bed.
is used.)
3.1.10 roof, n—the rock material immediately overlying a
3.1.7 core sample, n—that part of a core of rock or coal
coal bed.
obtained so as to accurately represent a thickness of a unit
3.1.11 sonde, n—an elongate cylindrical tool assembly used
penetrating by drilling.
in a borehole to acquire a geophysical log.
3.1.8 geophysical log, n—a graphic record of the measured
or computed physical characteristics of the rock section en- 4. Summary of Practice
countered in a borehole, plotted as a continuous function of
4.1 Atselectedsitesinadepositofcoal,aboreholeisdrilled
depth. Measurements are made by a sonde, which contains the
and the core containing the coal and surrounding strata of rock
detectors, as it is withdrawn from the borehole by a wire line.
is recovered.
Several measurements are usually made simultaneously, and
4.2 The coal core is cleaned of drilling fluid, if necessary,
the resulting curves are displayed side by side on the common
properly described, and packaged so that loss of moisture is
depth scale. A common suite of logs used in coal exploration
minimized. From this core, coal and roof and floor material of
include caliper, density (gamma-gamma), natural gamma, and
interest are collected for analysis and testing.
resistivity.
3.1.8.1 caliper log, n—a continuous mechanical measure-
5. Significance and Use
ment of the diameter and thus the rugosity of the borehole.The
5.1 A properly collected sample that includes the total coal
tool identifies zones where swelling or cavings (washouts)
bed interval provides a sample that is a representative cross
have occurred during drilling. The tool’s value is in allowing
section of the coal bed at the point of sampling. Core samples
qualitative or quantitative corrections to be made to other
are taken for subsequent testing needed for evaluation of coal
geophysical logs which are affected by borehole size (espe-
quality and characterization for commercial evaluations, for
cially density).
planning of mining operations to maintain coal quality, for the
3.1.8.2 density log (gamma-gamma log), n—measures elec-
determination of coal rank in accordance with Classification
tron density within lithologic units which is related to their
D388, and for geologic coal resource studies.
bulk density. The wireline tool records the intensity of gamma
NOTE 1—Because of the potential for lateral variability, a sample may
radiation (in counts per second) from a nuclear source within
not represent the quality of the coal bed at another sample point. The
the tool after it has been attenuated and backscattered by
reliability of the data generated from core samples is dependent on the
lithologies within the borehole. Due to the distinctly low
number and spacing of the sample points and the variability of the coal
density of coals, the density log is essential in coal exploration
characteristics in a given area.
for identifying coal seams and coal-seam partings. The bias/
5.2 Moisture determined directly from a core sample shall
resolution of density logs can be affected by source-detector
be considered questionable in any core sample because of
spacing(closerspacingincreasesresolution),boreholesizeand
possible contamination from drilling fluids and groundwater. If
irregularities (see caves or washouts), and the presence of
a more representative estimate of the inherent moisture content
casing and logging speed.
of the core sample (with the exception of certain low-rank
3.1.8.3 natural gamma-ray log, n—a record of the natural coals) is desired, the sample should be analyzed according to
radioactivity of the lithologies encountered in the borehole
Test Method D1412.
environment. During recording of geophysical logs, the
6. Apparatus
amount of natural radiation is recorded and presented in either
counts per second (CPS) or American Petroleum Institute
6.1 Steel Measuring Tape, not less than 10 m [30 ft] long.
(API) units. Unlike many other log types, a representative
6.2 Rock Hammer, Chisel, or Pick, with file for sharpening.
natural gamma log can be obtained where borehole or fluid
6.3 Water Source, to provide fresh, clean water for rinsing
conditions, or both, are not optimal or where casing is present.
drilling mud from cut surface of the core.
The natural gamma log is most often used in the coal
environment for identifying classic lithologies and differenti-
6.4 Waterproof Marking Pencils that are visible on coal,
ating coal seams and coal-seam partings.
such as a yellow lumber crayon.
3.1.8.4 resistivity log, n—a measure of the voltage differen-
6.5 Polyethylene Bags, Tubing, or Sheets, 0.1 mm [4 mil] or
tial of strata along the walls of a borehole when electrical
thicker.
current is passed through the strata. The resistivity log requires
6.6 Core Tray, constructed of wood, plastic, or metal, onto
a fluid-filled hole to constantly provide a conductive medium
which to extrude the core from the core barrel.
between electrodes on the tool. The spacing between the
electrodes determines the precision of the bed boundary 6.7 Boxes for Core Storage, constructed of wood, plastic, or
relationships in much the same manner as with the density log. coated cardboard or if the core is to remain stratigraphically
The resistivity log is useful primarily in conjunction with other oriented, use containers such as polyvinyl chloride (PVC) pipe.
D5192/D5192M − 22
6.8 Tags and Waterproof Marking Pens, for sample identi- ance (typically within a few seconds) indicates absorption and
fication and for marking depths, orientation, and so forth, on demonstrates that the coal contains less than its full comple-
the plastic sheeting. ment of inherent moisture. Slower disappearance (taking per-
haps a minute or more) is characteristic of evaporation and
6.9 Notebook and Pencil,orothermeansforrecordkeeping.
suggests that the pores are filled with moisture. To account for
6.10 Waterproof Container, to hold sample tag.
variations in field conditions such as temperature, humidity,
different absorption rates by different coals, and so forth, the
6.11 Geophysical Logging Unit (optional), consisting of
recording equipment and sondes for high-resolution density test is applied to a number of coal pieces both before and
during the sample collection process.
and caliper logs and possibly gamma and resistivity logs.
7.3 A core approximately 47 mm [1.87 in.] in diameter
7. Planning for Sampling
yields a sufficient sample for most purposes. Minimum sample
7.1 The objective of core sampling is to collect representa-
mass requirements for analytical tests, such as washability
tive samples of the fresh, unweathered coal seam at each
testing, may dictate a sample mass that can only be obtained
drilling location for subsequent testing needed for the evalua-
from larger diameter cores or multiple separate cores.
tion the coal quantity and quality or commercial assessments.
NOTE 3—The diameter and length of the core (or number of separate
Obtain information such as geologic, topographic, and land
cores) required to obtain a desired mass of sample may be estimated from
ownership for locating suitable sites for drilling. Choose sites 3 3
the density of coal, approximately 1.3 g ⁄cm to 1.35 g ⁄cm . The selected
that will best satisfy the purpose of sampling. ASTM Manual
diameter of the core can have an effect on the representativeness of
11 provides comprehensive technical information to help in subsamples obtained from the core sample for various types of testing.As
an example in washability testing, the diameter of the core should be at
planningsuccessfulcoalcoringandtestingprograms.Topicsin
least three times the largest dimension of the topsize of any subsamples to
Manual 11 include sampling coal cores; geophysical logging;
be obtained from the core sample. For information on determining the
compositing core data; analysis and evaluation of core data;
washability characteristics of coal, see Test Method D4371 and the report
and the prediction of as-mined coal quality.
by Wizzard.
A larger diameter core can also be necessary to obtain a more
NOTE 2—Practice D5192 and ASTM Manual 11 were developed and
representative sample if the quality of the coal varies greatly from layer to
published simultaneously. In preparing the standard, a number of concepts
layer in the seam.
and terms were encountered that required explanations and technical
7.4 Increment Sampling—Where differences of coal quality
background in greater detail than was practicable within the scope of the
proposed standard. Because no individual publication could be used to
parameters exist among different layers or benches in the same
reference all the necessary topics, it became apparent that a reference
coal seam or where the seam is thick, it is best to sample and
manual needed to be compiled to facilitate the drafting of the core-
analyze the seam in vertical increments.
sampling standard.
7.4.1 Compositing—Data obtained from the separate analy-
7.2 Considerations Regarding Weathered Coal and Inherent
ses of the vertical core increments can be composited by
Moisture—Weathered coal is unsuitable for inclusion in core
calculation, preferably by sample mass if sufficient information
samples collected to secure fresh and unaltered material.
such as core length and density has been measured for each
Weathered coal typically contains anomalously low total
increment.Alternatively,acompositesampleoftheentireseam
moisture, yields low calorific value (as-received, dry and
can be produc
...

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: D5192 − 09 (Reapproved 2015) D5192/D5192M − 22
Standard Practice for
Collection of Coal Samples from Core
This standard is issued under the fixed designation D5192;D5192/D5192M; 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 Scope*
1.1 This practice describes procedures for collecting and handling a coal sample from a core recovered from a borehole.
1.2 Units—The values stated in either SI units or inch-pound units are to be regarded as standard. No other units of measurement
are included in this standard.separately as standard. The values stated in each system are not necessarily exact equivalents;
therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two
systems shall not be combined.
1.3 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.
1.4 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:
D121 Terminology of Coal and Coke
D388 Classification of Coals by Rank
D1412 Test Method for Equilibrium Moisture of Coal at 96 to 97 Percent Relative Humidity and 30 °C
D2013D2013/D2013M Practice for Preparing Coal Samples for Analysis
D2796 Terminology for Megascopic Description of Coal and Coal Seams and Microscopical Description and Analysis of Coal
(Withdrawn 1995)
D4371 Test Method for Determining the Washability Characteristics of Coal
D4596 Practice for Collection of Channel Samples of Coal in a Mine
3. Terminology
3.1 Definitions:
3.1.1 For additional definitions of terms, refer to Terminology D121.
3.1.2 borehole, n—the circular hole through soil and rock strata made by boring.
This practice is under the jurisdiction of ASTM Committee D05 on Coal and Coke and is the direct responsibility of Subcommittee D05.23 on Sampling.
Current edition approved Sept. 1, 2015May 15, 2022. Published September 2015June 2022. Originally approved in 1991. Last previous edition approved in 20092015 as
D5192 – 09.D5192 – 09(2015). DOI: 10.1520/D5192-09R15.10.1520/D5192_D5192M-22.
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.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D5192/D5192M − 22
3.1.3 caves or washouts, n—zones of increased hole diameter caused by rock fragments that fall from the walls of a borehole and
can block the hole or contaminate the cuttings and which erode or abrade the sidewall of the borehole by the action of the drilling.
These zones can affect the accuracy of certain geophysical logs (especially density). Corrections to other geophysical logs can be
made if a caliper log is available. The most common causes of caves or washouts include soft or fractured lithologies, the presence
of water-producing zones, and the downhole pressure of the drilling medium (fluid or air) that often causes differential erosion of
various strata within the borehole.
3.1.4 concretion, n—in a geological sense, a mass of mineral matter found in rock of a composition different from its own and
produced by deposition from aqueous solution in the rock.
3.1.5 core, n—in drilling, a cylindrical section of rock (coal) that is usually 5 to 10 cm in diameter, taken as part of the interval
penetrated by a core bit and brought to the surface for geologic examination, representative sampling, and laboratory analyses.
3.1.6 core barrels, n—two nested tubes above the bit of a core drill, the outer rotating with the bit, the inner receiving and
preserving a continuous section or core of the material penetrated. The following two types of inner barrels are commonly used.
3.1.6.1 split-tube barrel, n—a type of inner barrel consisting of two longitudinal halves of pipe bound together by reinforced
tape at intervals along the barrel length that allows easy access to a relatively intact core (by cutting the tape). (This is the preferred
barrel type for coal exploration, when available.)
3.1.6.2 solid-tube barrel, n—a type of inner barrel consisting of a single solid-walled length of pipe in which removal of the
core is accomplished by mechanical or hydraulic pressure at one end of the pipe thus extruding the core onto a core tray. (The core
is likely to be less intact than when a split-tube barrel is used.)
3.1.7 core sample, n—that part of a core of rock or coal obtained so as to accurately represent a thickness of a unit penetrating
by drilling.
3.1.8 geophysical log, n—a graphic record of the measured or computed physical characteristics of the rock section encountered
in a borehole, plotted as a continuous function of depth. Measurements are made by a sonde, which contains the detectors, as it
is withdrawn from the borehole by a wire line. Several measurements are usually made simultaneously, and the resulting curves
are displayed side by side on the common depth scale. A common suite of logs used in coal exploration include caliper, density
(gamma-gamma), natural gamma, and resistivity.
3.1.8.1 caliper log, n—a continuous mechanical measurement of the diameter and thus the rugosity of the borehole. The tool
identifies zones where swelling or cavings (washouts) have occurred during drilling. The tool’s value is in allowing qualitative or
quantitative corrections to be made to other geophysical logs which are affected by borehole size (especially density).
3.1.8.2 density log (gamma-gamma log), n—measures electron density within lithologic units which is related to their bulk
density. The wireline tool records the intensity of gamma radiation (in counts per second) from a nuclear source within the tool
after it has been attenuated and backscattered by lithologies within the borehole. Due to the distinctly low density of coals, the
density log is essential in coal exploration for identifying coal seams and coal-seam partings. The bias/resolution of density logs
can be affected by source-detector spacing (closer spacing increases resolution), borehole size and irregularities (see caves or
washouts), and the presence of casing and logging speed.
3.1.8.3 natural gamma-ray log, n—a record of the natural radioactivity of the lithologies encountered in the borehole
environment. During recording of geophysical logs, the amount of natural radiation is recorded and presented in either counts per
second (CPS) or American Petroleum Institute (API) units. Unlike many other log types, a representative natural gamma log can
be obtained where borehole or fluid conditions, or both, are not optimal or where casing is present. The natural gamma log is most
often used in the coal environment for identifying classic lithologies and differentiating coal seams and coal-seam partings.
3.1.8.4 resistivity log, n—a measure of the voltage differential of strata along the walls of a borehole when electrical current is
passed through the strata. The resistivity log requires a fluid-filled hole to constantly provide a conductive medium between
electrodes on the tool. The spacing between the electrodes determines the precision of the bed boundary relationships in much the
same manner as with the density log. The resistivity log is useful primarily in conjunction with other log types. The logs are
affected by casing, logging speed, electrode spacing, formation porosity, and resistivity changes in the borehole fluid.
3.1.9 floor, n—the rock material immediately underlying a coal bed.
3.1.10 roof, n—the rock material immediately overlying a coal bed.
D5192/D5192M − 22
3.1.11 sonde, n—an elongate cylindrical tool assembly used in a borehole to acquire a geophysical log.
4. Summary of Practice
4.1 At selected sites in a deposit of coal, a borehole is drilled and the core containing the coal and surrounding strata of rock is
recovered.
4.2 The coal core is cleaned of drilling fluid, if necessary, properly described, and packaged so that loss of moisture is minimized.
From this core, coal and roof and floor material of interest are collected for analysis and testing.
5. Significance and Use
5.1 A properly collected sample that includes the total coal bed interval provides a sample that is a representative cross section
of the coal bed at the point of sampling. Core samples are taken for subsequent testing needed for evaluation of coal quality and
characterization for commercial evaluations, for planning of mining operations to maintain coal quality, for the determination of
coal rank in accordance with Classification D388, and for geologic coal resource studies.
NOTE 1—Because of the potential for lateral variability, a sample may not represent the quality of the coal bed at another sample point. The reliability
of the data generated from core samples is dependent on the number and spacing of the sample points and the variability of the coal characteristics in
a given area.
5.2 Moisture determined directly from a core sample shall be considered questionable in any core sample because of possible
contamination from drilling fluids and groundwater. If a more representative estimate of the inherent moisture content of the core
sample (with the exception of certain low-rank coals) is desired, the sample should be analyzed according to Test Method D1412.
6. Apparatus
6.1 Steel Measuring Tape, not less than 10 m (30 ft) 10 m [30 ft] long.
6.2 Rock Hammer, Chisel, or Pick, with file for sharpening.
6.3 Water Source, to provide fresh, clean water for rinsing drilling mud from cut surface of the core.
6.4 Waterproof Marking Pencils that are visible on coal, such as a yellow lumber crayon.
6.5 Polyethylene Bags, Tubing, or Sheets, 0.1 mm (4 mil) 0.1 mm [4 mil] or thicker.
6.6 Core Tray, constructed of wood, plastic, or metal, onto which to extrude the core from the core barrel.
6.7 Boxes for Core Storage, constructed of wood, plastic, or coated cardboard or if the core is to remain stratigraphically oriented,
use containers such as polyvinyl chloride (PVC) pipe.
6.8 Tags and Waterproof Marking Pens, for sample identification and for marking depths, orientation, and so forth, on the plastic
sheeting.
6.9 Notebook and Pencil, or other means for record keeping.
6.10 Waterproof Container, to hold sample tag.
6.11 Geophysical Logging Unit (optional), consisting of recording equipment and sondes for high-resolution density and caliper
logs and possibly gamma and resistivity logs.
D5192/D5192M − 22
7. Planning for Sampling
7.1 The objective of core sampling is to collect representative samples of the fresh, unweathered coal seam at each drilling location
for subsequent testing needed for the evaluation the coal quantity and quality or commercial assessments. Obtain information such
as geologic, topographic, and land ownership for locating suitable sites for drilling. Choose sites that will best satisfy the purpose
of sampling. ASTM Manual 11 provides comprehensive technical information to help in planning successful coal coring and
testing programs. Topics in Manual 11 include sampling coal cores; geophysical logging; compositing core data; analysis and
evaluation of core data; and the prediction of as-mined coal quality.
NOTE 2—Practice D5192 and ASTM Manual 11 were developed and published simultaneously. In preparing the standard, a number of concepts and terms
were encountered that required explanations and technical background in greater detail than was practicable within the scope of the proposed standard.
Because no individual publication could be used to reference all the necessary topics, it became apparent that a reference manual needed to be compiled
to facilitate the drafting of the core-sampling standard.
7.2 Considerations Regarding Weathered Coal and Inherent Moisture—Weathered coal is unsuitable for inclusion in core samples
collected to secure fresh and unaltered material. Weathered coal typically contains anomalously low total moisture, yields low
calorific value (as-received, dry and moisture-and-ash-free basis), and also produces atypical results for other tests. Additionally,
weathered coal cannot be used for classification according to rank. Sampling to different depths and testing of the properties may
be required to establish the depth at which unweathered coal can be obtained.
7.2.1 Obvious indications of weathering include, but are not limited to: (1) any discoloration or staining on broken coal surfaces
or cleats, (2) presence of sulfate minerals resulting from oxidation of pyrite, (3) presence of gypsum (calcium sulfate) crystals, and
(4) presence of dust, fine cracked and crazed coal surfaces, or (5) blocky, fragmented condition (slaking) of the coal resulting from
loss of inherent moisture.
7.2.2 For coal resource assessments, the collection of samples containing their full complement of inherent moisture is essential.
However, that condition may not always be readily discernable. A simple field test can be used to qualitatively identify seemingly
fresh coal that has lost some inherent moisture but has not yet obviously weathered. A light coating of water is sprayed or wiped
onto the surface of the coal, and the rate at which it disappears is observed. Rapid disappearance (typically within a few seconds)
indicates absorption and demonstrates that the coal contains less than its full complement of inherent moisture. Slower
disappearance (taking perhaps a minute or more) is characteristic of evaporation and suggests that the pores are filled with
moisture. To account for variations in field conditions such as temperature, humidity, different absorption rates by different coals,
and so forth, the test is applied to a number of coal pieces both before and during the sample collection process.
7.3 A core approximately 47 mm (1.87 in.) 47 mm [1.87 in.] in diameter yields a sufficient sample for most purposes. Minimum
sample mass requirements for analytical tests, such as washability testing, may dictate a sample mass that can only be obtained
from larger diameter cores or multiple separate cores.
NOTE 3—The diameter and length of the core (or number of separate cores) required to obtain a d
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