1、Designation: D2234/D2234M 16D2234/D2234M 17Standard Practice forCollection of a Gross Sample of Coal1This standard is issued under the fixed designation D2234/D2234M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last
2、 revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONData obtained from coal samples are used in establishing price, controlling mine and cleaning plantoperations, allocating
3、production costs, and determining plant or component efficiency. The task ofobtaining a sample of reasonable mass to represent an entire lot presents a number of problems andemphasizes the necessity for using standard sampling procedures.Coal is one of the most difficult of materials to sample, vary
4、ing in composition from noncombus-tible particles to those which can be burned completely, with all gradations in between. The task isfurther complicated by the use of the analytical results, the sampling equipment available, the quantityto be represented by the sample, and the degree of precision r
5、equired.This practice gives the overall requirements for the collection of coal samples. The wide varietiesof 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 p
6、hysicalcharacter of the coal, the number and mass of increments, and the overall precision required.1. Scope1.1 This practice covers procedures for the collection of a sample under various conditions of sampling. The sample is to becrushed and further prepared for analysis in accordance with Practic
7、e D2013/D2013M. However, the procedures for dividing largesamples before any crushing are given in this practice. For the sampling of coal using mechanical sampling systems see D7430Practice for the Mechanical Sampling of Coal.1.2 This practice describes general and special purpose sampling procedur
8、es for coals (1) by size and condition of preparation(for example, mechanically cleaned coal or raw coal) and (2) by sampling characteristics.1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equiv
9、alents; therefore, each system shall be used independently of the other. Combining values from thetwo systems may result in non-conformance with the standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user
10、 of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine theapplicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardizationestablish
11、ed in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D2013/D2013M Practice for Preparing Coal Samples for AnalysisD7430
12、Practice for Mechanical Sampling of Coal1 This practice is under the jurisdiction of ASTM Committee D05 on Coal and Coke and are the direct responsibility of Subcommittee D05.23 on Sampling.Current edition approved March 1, 2016Oct. 15, 2017. Published April 2016October 2017. Originally approved in
13、1963. Last previous edition approved in 20102016 asD2234_D2234 10. 16. DOI: 10.1520/D2234_D2234M-16.10.1520/D2234_D2234M-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, re
14、fer to the standards Document Summary page on the ASTM website.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. Becauseit may not be technically possible to adequately depict all c
15、hanges accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.
16、 United States13. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 accuracy:3.1.1.1 generallya term used to indicate the reliability of a sample, a measurement, or an observation.3.1.1.2 specificallya measure of closeness of agreement between an experimental result and the true va
17、lue. Example: theobserved and true sulfur content of a coal consignment. This measure is affected by chance errors as well as by bias.3.1.2 gross samplea sample representing one lot of coal and composed of a number of increments on which neither reductionnor division has been performed.3.1.3 increme
18、nta small portion of the lot collected by one operation of a sampling device and normally combined with otherincrements from the lot to make a gross sample.3.1.4 probability samplea sample collected using a sampling process such that at each stage of the process, a specifiednon-zero probability of b
19、eing selected for the sample can be attached to every sampling unit in the lot to be sampled. Givenadequate information about the sample results obtained using probability sampling, the probability distribution of sampling errorscan be estimated.3.1.5 samplea quantity of material taken from a larger
20、 quantity for the purpose of estimating properties or composition of thelarger quantity.3.1.6 size consistthe particle size distribution of a coal.4. Summary of Practice4.1 The general-purpose sampling procedures are intended to provide, in 19 of 20 cases, dry ash results that are within aninterval
21、of 6110 of the average dry ash results that would be obtained in hypothetical repeated sampling.4.2 Special-purpose sampling procedures apply to the sampling of coal when other precision limits are required, or when otherconstituents are used to specify precision, or for performance tests.4.3 For co
22、als of known size and condition of preparation, tables are given for the determination of the number and mass ofincrements required for a gross sample for both general and special-purpose sampling.4.4 The procedures appear in the following order:Test Method SectionSampling of Coals Based on Size and
23、 Condition of Preparation 8.1General-Purpose Sampling Procedure 8.1.1Number and Mass of Increments 8.1.1.2Number of Gross Samples 8.1.1.4Special-Purpose Sampling 8.1.2Number and Mass of Increments 8.1.2.2Number of Gross Samples 8.1.2.3Division of the Gross Sample Before Crushing 8.2Sampling of Coal
24、for Total Moisture Determinations 8.3Types of Moisture Samples 8.3.1Entire Gross Sample 8.3.1.1Special Moisture Subsample 8.3.1.2Other Subsamples for Moisture Testing 8.3.1.3Special Precautions 8.3.2Mass of Increments 8.3.3Number of Increments 8.3.4Moisture Sampling Based Only on Size 8.3.4.15. Sign
25、ificance and Use5.1 It is intended that this practice be used to provide a sample representative of the coal from which it is collected. Becauseof the variability of coal and the wide variety of sampling equipment, caution should be used in all stages of sampling from systemspecifications and equipm
26、ent procurement to equipment acceptance testing and actually taking the final sample.5.2 After further processing (Practice D2013/D2013M), the sample may be analyzed for a number of different parameters.These parameters may affect the lots value, its ability to meet specifications, its environmental
27、 impact, as well as other properties.6. Increment Collection Classification6.1 The type of selection, the conditions under which individual increments are collected, and the method of spacing ofincrements from the coal consignment or lot are classified according to the following descriptions and Tab
28、le 1. These designationsare to be used for sampling specifications and for descriptions of sampling programs and sampling equipment.6.2 Types of IncrementsThe types of selection of increments are based on whether or not there is human discretion in theselection of the pieces of coal or portions of t
29、he coal stream.D2234/D2234M 1726.2.1 Type I, in which specific pieces or portions are not subject to selection on a discretionary basis. This includes that in whichthe increment is collected in precise accord with previously assigned rules on timing or location that are free of any bias. Type Iselec
30、tion increments generally yield more accurate results.6.2.2 Type II, in which some measure of human discretion is exercised in the selection of specific pieces of coal or of specificportions of the stream, pile, or shipment.6.3 Conditions of Increment CollectionThe conditions under which individual
31、increments are collected are the conditions ofthe main body of coal relative to the portion withdrawn. Four conditions are recognized:6.3.1 Condition A (Stopped-Belt Cut), in which a loaded conveyor belt is stopped and a full cross-section cut with parallel sidesis removed from the coal stream. The
32、distance between the parallel faces shall not be less than three times the normal top size ofthe coal.6.3.2 Condition B (Full-Stream Cut), in which a full cross-section cut is removed from a moving stream of coal.6.3.3 Condition C (Part-Stream Cut), in which a portion, not a full cross section, is r
33、emoved from a moving stream of coal.6.3.4 Condition D (Stationary Coal Sampling), in which a portion of coal is collected from a pile, a rail car, a barge, or ashiphold.6.4 Spacing of IncrementsThe spacing of increments pertains to the kind of intervals between increments. Two spacingmethods are rec
34、ognized: systematic and random. Systematic spacing is usually preferable.6.4.1 Systematic Spacing 1, in which the movements of individual increment collection are spaced evenly in time or in positionover the lot.6.4.2 Random Spacing 2, in which the increments are spaced at random in time or in posit
35、ion over the lot.7. Organization and Planning of Sampling Operations7.1 This practice provides definitive procedures for the collection of a gross sample. Parties claiming to use this practice mustadhere to the procedures as set out in this standard. If the sampling is not done in accordance with th
36、e procedures set out in thispractice then that sample may not be suitable for comparison with a sample collected by the procedures described in this practice.Since it may be impracticable or impossible to take another sample of a given lot of coal it is essential that parties agree onsampling proced
37、ures prior to undertaking sampling.7.2 Selection of Appropriate Sampling ProcedureVariations in coal-handling facilities make it impossible to publish rigidrules covering every sampling situation in complete and exact details. Proper sampling involves an understanding and properconsideration of the
38、minimum number and mass of increments, the size consist of the coal, the condition of preparation of the coal,the variability of the constituent sought, and the degree of precision required.7.2.1 Number and Mass of IncrementsThe number and mass of increments required for a given degree of precision
39、dependsupon the variability of the coal. This variability increases with an increase in free impurity. A coal high in inherent impurity andwith comparatively little free impurity may exhibit much less variability than a coal with a low inherent impurity and a relativelyhigh proportion of free impuri
40、ty. For most practical purposes, an increase in the ash content of a given coal usually indicates anincrease in variability. It is imperative that not less than the minimum specified number of increments of not less than the minimumspecified mass be collected from the lot. For Condition D, the incre
41、ments shall be of equal mass.7.2.2 Condition of PreparationIf there is any doubt as to the condition of preparation of the coal (for example, mechanicallycleaned coal or raw coal), the number of increments for raw coal shall apply. For the purpose of application of the minimumnumber of increments in
42、 Table 1, mechanically cleaned coal is defined as coal, which has been mechanically cleaned by a specificgravity process in all sieve sizes above No. 100 USA Standard. Similarly, although a coal has been mechanically cleaned it maystill show significant variation. For example, the coal may be a blen
43、d of two different portions of one seam or a blend of twodifferent seams. In such cases where significant variation is possible, the number of increments should be as specified for raw(uncleaned) coal.7.2.3 Increment Collection Method to Be UsedTo obtain complete representation of all sizes, it is m
44、ost desirable that thesample increments be withdrawn from the full cross section of the stream. The best possible increment is a full cross-section cutremoved from a stopped belt, Classification I-A-1 in Table 1. The best possible increment from a flowing stream of coal is oneobtained by moving a cu
45、tter device entirely across the stream at a uniform speed, the same for each increment, into one side ofTABLE 1 Increment Types, Conditions, and SpacingCondition of Increment Collectionfrom the Main Body of CoalTypes of IncrementType INo Human Discretion Is UsedType IIHuman Discretion Is UsedSpacing
46、 of Increments Spacing of Increments1. Systematic 2. Random 1. Systematic 2. RandomCondition A, stopped belt cut I-A-1 I-A-2 II-A-1 II-A-2Condition B, full-stream cut I-B-1 I-B-2 II-B-1 II-B-2Condition C, part-stream cut I-C-1 I-C-2 II-C-1 II-C-2Condition D, stationary sampling I-D-1 I-D-2 II-D-1 II
47、-D-2D2234/D2234M 173the stream and out of the other, without allowing the receptacle to overflow (Classification I-B-1 in Table 1). For the sampling ofcoal under Classification I-B-I see D7430 Practice for the Mechanical Sampling of Coal. Classification methods given in Table 1are listed in order of
48、 decreasing reliability. The highest possible classification method, wherever feasible, should be used. Detailsof sampling procedures should be agreed upon in advance by all parties concerned. Whenever circumstances dictate utilization ofincrement collection classifications “Condition C” or “Conditi
49、on D” or “Type II,” details of sampling procedure shall be agreedupon in advance by all parties concerned.7.3 Distribution of IncrementsIt is essential that the increments be distributed throughout the lot to be sampled. Thisdistribution is related to the entire volume of the lot, not merely its surface or any linear direction through it or over it. Ifcircumstances prevent the sampler from applying this principle, the lot is sampled only in part, and the gross sample isrepresentative only of this part. The spacing of the increments shall be varied if the possi
