1、Designation: D2234/D2234M 10D2234/D2234M 16Standard 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 weightmass to represent an entire lot presents a number of problemsand emphasizes the necessity for using standard sampling procedures.Coal is one of the most difficult of materials to sample
4、, varying 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 preci
5、sion required.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
6、 the physicalcharacter of the coal, the number and weightmass 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
7、with Practice D2013D2013/D2013M. However, the procedures fordividing large samples before any crushing are given in this practice. For the sampling of coal using mechanical sampling systemssee D7430 Practice for the Mechanical Sampling of Coal.1.2 This practice describes general and special purpose
8、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 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may n
9、ot be exact equivalents; 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 responsi
10、bilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D2013D2013/D2013M Practice for Preparing Coal Samples for AnalysisD7430 Practice for Mechanical Sam
11、pling of Coal3. 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.1 This practice is under the jurisdiction of ASTM Committee D05 on Coal and Coke and are the direct resp
12、onsibility of Subcommittee D05.23 on Sampling.Current edition approved Jan. 1, 2010March 1, 2016. Published February 2010April 2016. Originally approved in 1963. Last previous edition approved in 20092010 asD2234_D2234 09a. 10. DOI: 10.1520/D2234_D2234M-10. 10.1520/D2234_D2234M-16.2 For referencedAS
13、TM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer 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
14、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 changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as p
15、ublished by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.1.2 specificallya measure of closeness of agreement between an experimental result and the true value. Example: theobserved
16、 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 incrementa small portion of the
17、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 being selected for the sam
18、ple 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 quantity for the purpose
19、 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 of 6110 of the average dr
20、y 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 coals of known size and con
21、dition of preparation, tables are given for the determination of the number and weightmassof increments required for a gross sample for both general and special-purpose sampling.4.4 The procedures appear in the following order:Test Method SectionTest Method SectionSampling of Coals Based on Size and
22、 Condition of Preparation 8.1General-Purpose Sampling Procedure 8.1.1Number and Weight of Increments 8.1.1.2Number and Mass of Increments 8.1.1.2Number of Gross Samples 8.1.1.4Special-Purpose Sampling 8.1.2Number and Weight of Increments 8.1.2.2Number and Mass of Increments 8.1.2.2Number of Gross Sa
23、mples 8.1.2.3Division of the Gross Samples Before Crushing 8.2Division of the Gross Sample Before Crushing 8.2Sampling of Coal for Total Moisture Determination 8.3Sampling of Coal for Total Moisture Determinations 8.3Types of Moisture Samples 8.3.1Entire Gross Samples 8.3.1.1Entire Gross Sample 8.3.
24、1.1Special Moisture Subsamples 8.3.1.2Special Moisture Subsample 8.3.1.2Other Subsamples for Moisture Testing 8.3.1.3Special Precautions 8.3.2Weight of Increments 8.3.3Mass of Increments 8.3.3Number of Increments 8.3.4Moisture Sampling Based Only on Size 8.3.4.15. Significance and Use5.1 It is inten
25、ded 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 equipment procurement to equipment ac
26、ceptance testing and actually taking the final sample.5.2 After further processing (Practice D2013D2013/D2013M), the sample may be analyzed for a number of differentparameters. These parameters may affect the lots value, its ability to meet specifications, its environmental impact, as well as otherp
27、roperties.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 Table 1. These designationsare
28、 to be used for sampling specifications and for descriptions of sampling programs and sampling equipment.D2234/D2234M 1626.2 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 the coal str
29、eam.6.2.1 Type I, Type I,in which specific pieces or portions are not subject to selection on a discretionary basis. This includes thatin which the increment is collected in precise accord with previously assigned rules on timing or location that are free of any bias.Type I selection increments gene
30、rally yield more accurate results.6.2.2 Type II, Type II,in which some measure of human discretion is exercised in the selection of specific pieces of coal or ofspecific portions of the stream, pile, or shipment.6.3 Conditions of Increment CollectionThe conditions under which individual increments a
31、re 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), Condition A (Stopped-Belt Cut),in which a loaded conveyor belt is stopped and a fullcross-section cut with parallel sides is removed from th
32、e coal stream. The distance between the parallel faces shall not be less thanthree times the normal top size of the coal.6.3.2 Condition B (Full-Stream Cut), Condition B (Full-Stream Cut),in which a full cross-section cut is removed from a movingstream of coal.6.3.3 Condition C (Part-Stream Cut), Co
33、ndition C (Part-Stream Cut),in which a portion, not a full cross section, is removedfrom a moving stream of coal.6.3.4 Condition D (Stationary Coal Sampling), Condition D (Stationary Coal Sampling),in which a portion of coal is collectedfrom a pile, a rail car, a barge, or a shiphold.6.4 Spacing of
34、IncrementsThe spacing of increments pertains to the kind of intervals between increments. Two spacingmethods are recognized: systematic and random. Systematic spacing is usually preferable.6.4.1 Systematic Spacing 1, Systematic Spacing 1,in which the movements of individual increment collection are
35、spaced evenlyin time or in position over the lot.6.4.2 Random Spacing 2, Random Spacing 2,in which the increments are spaced at random in time or in position over the lot.7. Organization and Planning of Sampling Operations7.1 This practice provides definitive procedures for the collection of a gross
36、 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 the procedures set out in thispractice then that sample may not be suitable for comparison with a sample collected by the procedures described in th
37、is 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 procedures prior to undertaking sampling.7.2 Selection of Appropriate Sampling ProcedureVariations in coal-handling facilities make it impossible to pub
38、lish rigidrules covering every sampling situation in complete and exact details. Proper sampling involves an understanding and properconsideration of the minimum number and weightmass of increments, the size consist of the coal, the condition of preparation ofthe coal, the variability of the constit
39、uent sought, and the degree of precision required.7.2.1 Number and WeightMass of IncrementsThe number and weightmass of increments required for a given degree ofprecision depends upon the variability of the coal. This variability increases with an increase in free impurity. A coal high ininherent im
40、purity and with comparatively little free impurity may exhibit much less variability than a coal with a low inherentimpurity and a relatively high proportion of free impurity. For most practical purposes, an increase in the ash content of a givencoal usually indicates an increase in variability. It
41、is imperative that not less than the minimum specified number of incrementsof not less than the minimum specified weightmass be collected from the lot. For Condition D, the increments shall be of equalweight. mass.7.2.2 Condition of PreparationIf there is any doubt as to the condition of preparation
42、 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 Table 1, mechanically cleaned coal is defined as coal, which has been mechanically cleaned by a specificgravity pr
43、ocess 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 blend of two different portions of one seam or a blend of twodifferent seams. In such cases where significant variation
44、 is possible, the number of increments should be as specified for raw(uncleaned) coal.TABLE 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 of Increments Spa
45、cing 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-D-2D2234/D2234M 1
46、637.2.3 Increment Collection Method to Be UsedTo obtain complete representation of all sizes, it is most 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-
47、1 in Table 1. The best possible increment from a flowing stream of coal is oneobtained by moving a cutter device entirely across the stream at a uniform speed, the same for each increment, into one side ofthe stream and out of the other, without allowing the receptacle to overflow (Classification I-
48、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 decreasing reliability. The highest possible classification method, wherever feasible, should be used. Detailsof s
49、ampling procedures should be agreed upon in advance by all parties concerned. Whenever circumstances dictate utilization ofincrement collection classifications “Condition C” or “Condition 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 s
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