ASTM D8215-21

Standard Practice for Statistical Modeling of Uncertainty in Assessment of In-place Coal Resources

SIGNIFICANCE AND USE
5.1 Traditional methods for expressing geological uncertainty consist of preparing reliability categories based simply on the distance between drill hole data points, such as the one described by Wood et al. (5) that uses only the drill holes within the coal bed. A major drawback of distance methods is their weak to null association with estimation errors. This practice provides a methodology for effectively assessing the uncertainty in coal resource estimates utilizing stochastic simulation. In determining uncertainty for any coal assessment, stochastic simulation enables consideration of other important factors and information beyond the geometry of drill hole locations, both in and out of the coal bed, including: non-depositional channels, depth of weathering, complexity of seam boundaries, coal seam subcrop projections, and varying coal bed geology for different seams due to fluctuating peat depositional environments. Olea et al. (6) explains in detail the methodology behind this practice and illustrates it with an example.  
5.2 For multi-seam deposits, uncertainty can be expressed on an individual seam basis as well as an aggregated uncertainty for an entire coal deposit.  
5.3 The uncertainty is expressed directly in tons of coal. Additionally, this practice allows the statistical analysis to be presented according to widely-accepted conventions, such as percentiles and confidence intervals. For example, there is a 90 % probability that the actual tonnage in place is 314 million metric tons ± 28.8 million metric tons (346 million tons ± 31.7 million tons) of coal.  
5.4 The results of an uncertainty determination can provide important input into an overall risk analysis assessing the commercial feasibility of a coal deposit.  
5.5 A company may rank coal resources per block (cell) based on the degree of uncertainty.
SCOPE
1.1 This practice covers a procedure for quantitatively determining in-place tonnage uncertainty in a coal resource assessment. The practice uses a database on coal occurrence and applies geostatistical methods to model the uncertainty associated with a tonnage estimated for one or more coal seams. The practice includes instruction for the preparation of results in graphical form.  
1.2 This document does not include a detailed presentation of the basic theory behind the formulation of the standard, which can be found in numerous publications, with a selection being given in the references (1-3).2  
1.3 This practice should be used in conjunction with professional judgment of the many unique aspects of a coal deposit.  
1.4 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.
Note 1: All values given in parentheses after SI units are stated in inch-pound units.  
1.5 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.  
1.6 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: 35.240.70 - IT applications in science
• ICS: 73.020 - Mining and quarrying
• Technical Committee: D05 - Coal and Coke
• Drafting Committee: D05.07 - Physical Characteristics of Coal

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: D8215 − 21
Standard Practice for
Statistical Modeling of Uncertainty in Assessment of In-
1
place Coal Resources
This standard is issued under the fixed designation D8215; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Assessmentofcoaltonnagein-placeisafundamentalfactorinevaluatingthecommercialfeasibility
ofanydeposit.Equallyimportantisanappraisalofthereliabilitythatcanbeplacedinthedrillingdata
available for an estimation. Traditional methods for quantitatively expressing uncertainty use
reliability categories based simply on the distance between drill-hole data within the boundaries of a
coal bed. A significant limitation of the distance approach is the inability to express uncertainty in
terms of how close a resource estimate is to the true value.
This practice provides a geostatistical methodology to calculate the uncertainty of an in-place, coal
resourceestimate,bothatthedepositandblocklevel.Inadditiontoexaminingthedrillingpatternboth
within and outside the coal bed, other factors influencing the complexity in the geology are also
considered, resulting in realistic estimates of uncertainty. Most importantly, the uncertainty is
expressed directly in tons of coal. Like other coal properties, uncertainty can be used to rank the
resources in classes.
NOTE 1—All values given in parentheses after SI units are stated in
1. Scope*
inch-pound units.
1.1 This practice covers a procedure for quantitatively
1.5 This standard does not purport to address all of the
determining in-place tonnage uncertainty in a coal resource
safety concerns, if any, associated with its use. It is the
assessment. The practice uses a database on coal occurrence
responsibility of the user of this standard to establish appro-
and applies geostatistical methods to model the uncertainty
priate safety, health, and environmental practices and deter-
associated with a tonnage estimated for one or more coal
mine the applicability of regulatory limitations prior to use.
seams. The practice includes instruction for the preparation of
1.6 This international standard was developed in accor-
results in graphical form.
dance with internationally recognized principles on standard-
1.2 This document does not include a detailed presentation
ization established in the Decision on Principles for the
of the basic theory behind the formulation of the standard,
Development of International Standards, Guides and Recom-
which can be found in numerous publications, with a selection
mendations issued by the World Trade Organization Technical
2
being given in the references (1-3).
Barriers to Trade (TBT) Committee.
1.3 This practice should be used in conjunction with pro-
2. Referenced Documents
fessional judgment of the many unique aspects of a coal
3
2.1 ASTM Standards:
deposit.
D621Test Methods for Deformation of Plastics Under Load
1.4 Units—The values stated in SI units are to be regarded
4
(Withdrawn 1994)
as standard. The values given in parentheses after SI units are
D653Terminology Relating to Soil, Rock, and Contained
providedforinformationonlyandarenotconsideredstandard.
Fluids
D5549Guide for Contents of Geostatistical Site Investiga-
tion Report
1
This practice is under the jurisdiction of ASTM Committee D05 on Coal and
Coke and is the direct responsibility of Subcommittee D05.07 on Physical
3
Characteristics of Coal. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2021. Published October 2021. Originally contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
approved in 2018. Last previous edition approved in 2020 as D8215–20. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D8215-21. the ASTM website.
2 4
Theboldfacenumbersinparenthesesrefertothelistofreferencesattheendof The last approved version of this historical standard is referenced on
this standard. 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
1

---------------------- Page: 1 ----------------------
D8215 − 21
D5922Guide for Analysis, Interpretation, and Modeling of 3.1.9 histogram, n—agraphicalrepresentationofanempiri-
Spatial Variation in Geostatistical Site Investigations cal probability distribution.
D5923GuideforSelectionofKrigingMeth
...

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: D8215 − 20 D8215 − 21
Standard Practice for
Statistical Modeling of Uncertainty in Assessment of In-
1
place Coal Resources
This standard is issued under the fixed designation D8215; 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.
INTRODUCTION
Assessment of coal tonnage in-place is a fundamental factor in evaluating the commercial feasibility
of any deposit. Equally important is an appraisal of the reliability that can be placed in the drilling data
available for an estimation. Traditional methods for quantitatively expressing uncertainty use
reliability categories based simply on the distance between drill-hole data within the boundaries of a
coal bed. A significant limitation of the distance approach is the inability to express uncertainty in
terms of how close a resource estimate is to the true value.
This practice provides a geostatistical methodology to calculate the uncertainty of an in-place, coal
resource estimate, both at the deposit and block level. In addition to examining the drilling pattern both
within and outside the coal bed, other factors influencing the complexity in the geology are also
considered, resulting in realistic estimates of uncertainty. Most importantly, the uncertainty is
expressed directly in tons of coal. Like other coal properties, uncertainty can be used to rank the
resources in classes.
1. Scope*
1.1 This practice covers a procedure for quantitatively determining in-place tonnage uncertainty in a coal resource assessment. The
practice uses a database on coal occurrence and applies geostatistical methods to model the uncertainty associated with a tonnage
estimated for one or more coal seams. The practice includes instruction for the preparation of results in graphical form.
1.2 This document does not include a detailed presentation of the basic theory behind the formulation of the standard, which can
2
be found in numerous publications, with a selection being given in the references (1-3).
1.3 This practice should be used in conjunction with professional judgment of the many unique aspects of a coal deposit.
1.4 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided
for information only and are not considered standard.
NOTE 1—All values given in parentheses after SI units are stated in inch-pound units.
1
This practice is under the jurisdiction of ASTM Committee D05 on Coal and Coke and is the direct responsibility of Subcommittee D05.07 on Physical Characteristics
of Coal.
Current edition approved Oct. 1, 2020Oct. 1, 2021. Published October 2020October 2021. Originally approved in 2018. Last previous edition approved in 20192020 as
D8215 – 19a.D8215 – 20. DOI: 10.1520/D8215-20.10.1520/D8215-21.
2
The boldface numbers in parentheses refer to the list of references at the end of this standard.
*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
1

---------------------- Page: 1 ----------------------
D8215 − 21
1.5 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.
1.6 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
3
2.1 ASTM Standards:
4
D621 Test Methods for Deformation of Plastics Under Load (Withdrawn 1994)
D653 Terminology Relating to Soil, Rock, and Contained Fluids
D5549 Guide for Contents of Geostatistical Site Investigation Report
D5922 Guide for Analysis, Interpretation, and Modeling of Spatial Variation in Geostatistical Site Investigations
D5923 Guide for Selection of Kriging Methods in Geostatistical Site Investigations
D5924 Guide for Selection of Simulation Approaches in Geostatistical Site Investigations
5
2.2 ASTM Manuals, Monogra
...