ASTM D7430-2018 red 3125 Standard Practice for Mechanical Sampling of Coal.pdf

1、Designation: D7430 17D7430 18Standard Practice forMechanical Sampling of Coal1This standard is issued under the fixed designation D7430; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parenth

2、eses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONAnalysis data obtained from coal samples are used in establishing price, controlling mine andcleaning plant operations, allocating production costs, and

3、 determining plant or component efficiency.The task of obtaining a sample of reasonable mass to represent an entire lot presents a number ofproblems and emphasizes the necessity for using standard sampling procedures.Coal is one of the most difficult of materials to sample, varying in composition fr

4、om 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 required.This practice

5、 gives the overall requirements for the collection and within-system preparation of coalsamples through the use of mechanical sampling systems utilizing falling stream, cross beltfalling-stream, cross-belt, and auger designs. This practice also gives the overall requirements for thebias testing and

6、quality management of mechanical coal sampling systems. The wide varieties ofcoal-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 physicalcharacter of the coal, the

7、 number and mass of increments, and the overall precision required.1. Scope1.1 This practice is divided into 4 partsfour parts: A, B, C, and D. These 4four parts represent the previous standardsD7256/D7256M, D4916, D4702, and D6518. These 4four standards are the 4four that govern the mechanical samp

8、ling of coal andhave been combined into one document for the ease of reference of the users of these standards.1.2 The scope of Part A can be found in Section 4.1.3 The scope of Part B can be found in Section 13.1.4 The scope of Part C can be found in Section 19.1.5 The scope of Part D can be found

9、in Section 32.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability ofregulatory limitations

10、prior to use. For specific hazard statements, see Sections 7, 39.1.611.2.2, 21, 1.4, and 38.1.1.1.7 This international standard was developed in accordance with internationally recognized principles on standardizationestablished in the Decision on Principles for the Development of International Stan

11、dards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D121 Terminology of Coal and CokeD2013/D2013M Practice for Preparing Coal Samples for Analysis1 This practice is under the jurisdiction of AS

12、TM Committee D05 on Coal and Coke and is the direct responsibility of Subcommittee D05.23 on Sampling.Current edition approved Nov. 1, 2017March 1, 2018. Published January 2018May 2018. Originally approved in 2008. Last previous edition approved in 20162017 asD7430D7430 17.16b1. DOI: 10.1520/D7430-1

13、7.10.1520/D7430-18.2 For referencedASTM 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

14、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 changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only th

15、e 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. United States1D2234/D2234M Practice for Collection of a Gross Sample of CoalD3302 Test Method for Total

16、Moisture in CoalD4621 Guide for Quality Management in an Organization That Samples or Tests Coal and Coke (Withdrawn 2010)3D4702 Practice for Quality Management of Mechanical Coal Sampling Systems (Withdrawn 2008)3D4749 Test Method for Performing the Sieve Analysis of Coal and Designating Coal SizeD

17、4916 Practice for Mechanical Auger Sampling (Withdrawn 2008)3D6518 Practice for Bias Testing a Mechanical Coal Sampling System (Withdrawn 2008)3D7256/D7256M Practice for Mechanical Collection and Within-System Preparation of a Gross Sample of Coal from MovingStreams (Withdrawn 2008)3E105 Practice fo

18、r Probability Sampling of MaterialsE122 Practice for Calculating Sample Size to Estimate, With Specified Precision, the Average for a Characteristic of a Lot orProcessE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Pra

19、ctice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Terminology3.1 DefinitionsDefinitions applicable to this practice are listed in Terminology D121.3.2 Definitions of Terms Specific to This Standard:3.2.1 accuracy, n(1) generally, a term used to indicate the

20、reliability of a sample, a measurement, or an observation;(2) specifically, a measure of closeness of agreement between an experimental result and the true value. An example is theobserved and true sulfur content of a coal consignment. This measurement is affected by chance errors as well as by bias

21、.3.2.2 activation interval, nfor a falling-stream or cross-belt cutter, the time from the beginning of movement for taking anincrement, to the beginning of movement for taking of the next increment.3.2.3 auger increment, nthe retained portion of one extraction operation of the auger.3.2.4 auger samp

22、ler, na mechanical device that extracts a columnar sample of coal from a railcar, truck, barge, or stockpileand any associated sub-system or within-system components.3.2.5 bias, nthe difference between the population mean of the mechanical sampler test results and the accepted referencevalue.3.2.6 c

23、onfidence interval, na numeric interval with a lower limit and a higher limit within which the true parameter value isestimated to fall. The confidence interval percentage indicates the percentage of time the true value will fall within the interval ifthe procedure is continuously repeated.3.2.7 con

24、signment, na discrete amount of coal, such as a shipment, a car load, a unit train, or a days production. Aconsignment may include more than one lot of coal and may correspond to a specific period of time, such as a sampling periodor a billing period.3.2.8 correlation, na measure of the linear depen

25、dence between paired system and reference measurements. Correlationfrequently is expressed by the correlation coefficient, which can take a value from minus one (perfect negative linear relationship)to plus one (perfect positive linear relationship).3.2.9 cross-belt sampler, na single sampling machi

26、ne or component of a mechanical sampling system designed to extract anincrement directly from a conveyor belt surface by sweeping a sampling device (cutter) through the material on the conveyor.3.2.10 delimitation error, na material error that occurs when all the elements in a cross section of a coa

27、l stream do not havean equal probability of being intercepted (captured) by the sampler cutter during increment collection.3.2.11 ellipsoidal region, nan area that is formed by plane sections of ellipses that are defined by the values selected for thelargest tolerable bias of each coal characteristi

28、c used in the bias test. The region will be used to determine if the system is biased.3.2.12 falling-stream sampler, na single sampling machine or component of a mechanical sampling system designed to extractan increment from a falling stream of coal at the discharge end of a conveyor or chute by mo

29、ving a sampling device (cutter) throughthe falling stream of material.3.2.13 Hotellings T 2 test, na statistical test that is used to evaluate multivariate data. It is the multivariate equivalent of theStudents t-test.3.2.14 largest tolerable bias (LTB), nan interval whose upper and lower bounds rep

30、resent the limits of an acceptable bias.3.2.15 mechanical sampling system, na single machine or series of interconnected machines whose purpose is to extractmechanically, or process (divide and reduce), or a combination thereof, a sample of coal.3 The last approved version of this historical standar

31、d is referenced on www.astm.org.D7430 1823.2.16 paired data set, nsystem and reference values observed on samples collected and compared from the same batch ofmaterial.3.2.17 precision, na term used to indicate the capability of a person, an instrument, or a method to obtain reproducible results;spe

32、cifically, a measure of the chance error as expressed by the variance, standard error, or a multiple of the standard error (seePractice E177).3.2.18 reference sample, na sample used in testing of a mechanical sampling system which is comprised of one or moreincrements collected from the test batch o

33、r lot of coal by the stopped belt method as described in Practice D2234/D2234M.3.2.19 reject stream, nthe coal flow within a mechanical sampling system, which occurs at each stage of division, before andafter reduction, and is not included in the system sample.3.2.20 sampling ratio, nthe mass of the

34、 system sample divided by the mass of the corresponding coal sampled.3.2.21 save stream, nthe coal flow within a mechanical sampling system which occurs at each stage of division, before andafter reduction, and after the final stage of division becomes the system sample.3.2.22 statistical independen

35、ce, ntwo sample values are statistically independent if the occurrence of either one in no wayaffects the probability assigned to the occurrence of the other.3.2.23 surrogate sample, na sample, used in the evaluation of a mechanical sampling system, which is comprised of one ormore increments collec

36、ted from a coal stream within the mechanical sampling system in accordance with Practice D2234/D2234M,Conditions “A” or “B.” Such a sample may be considered acceptable for evaluation of a mechanical sampling systemscomponents, excluding the primary cutter, when demonstrated to be equivalent to the r

37、eference sample.3.2.24 system sample, na sample collected from a test batch or lot of coal by the final stage of a mechanical sampling system.3.2.25 unbiased sample (representative sample), na sample free of bias.3.2.26 Walsh averages, ngiven a series of observations (differences) x1, x2, . xn, the

38、n (n + 1)/2 pair-wise averages givenby:xi1xj!/2,1#i#j#n (1)3.2.26.1 DiscussionAs an example of Walsh averages, assume one has three observations (differences) designated as x1, x2, and x3. There are thena total of 3(4)/2 = 6 Walsh averages. They are as follows: x1, x2, x3, (x1 + x2)/2, (x1 + x3)/2,

39、and (x2 + x3)/2.3.2.27 Wilcoxon Signed Rank Test, na non-parametric statistical procedure for calculating the point estimate and confidenceinterval for a sample drawn from a population with symmetric distribution.3.2.28 within-system preparation, nthe process of gross sample preparation carried out

40、mechanically by sequential crushing(reduction) equipment and/or division equipment. It may be carried out by processing increments individually or by batchingincrements together and processing them together as a group. In any case, within-system preparation is conducted in a manner tominimize moistu

41、re changes and without removing the gross sample or its increments from the sampling system.D7430 183PART A MECHANICAL COLLECTION AND WITHIN-SYSTEM PREPARATION OF A GROSS SAMPLE OFCOAL FROM MOVING STREAMSOld Practice D7256/D7256M4. Scope4.1 Part AMechanical Collection and Within-System Preparation o

42、f a Gross Sample of Coal from Moving StreamsCoversprocedures for the mechanical collection of a sample under Classification I-B-1 and I-B-2 (Practice D2234/D2234M) and thewithin-system preparation (reduction and division) of gross samples utilizing various components of the mechanical samplingsystem

43、.4.1.1 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.4.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard.

44、 The values stated in eachsystem may not 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.5. Summary of Practices5.1 The general-purpose sampling procedures are intended to prov

45、ide, in 19 of 20 cases, dry ash results that are within aninterval of 6110 of the average dry ash results that would be obtained in hypothetical repeated sampling.5.2 Special-purpose sampling procedures apply to the sampling of coal when other precision limits are required, or when otherconstituents

46、 are used to specify precision, or for performance tests.5.3 For coals of known size and condition of preparation, a table (Table 1) is given for the determination of the number andmass of increments required for a gross sample for both general- and special-purpose sampling.5.4 The only processes of

47、 sample division and reduction covered in this document are the use of mechanical sample dividersfor the division of the sample, and mechanical crushing equipment for the reduction of the sample, both of which are within-systemcomponents of the mechanical sampling system.5.5 The procedures appear in

48、 the following order:Test Method SectionSampling of Coals Based on Size and Conditionof Preparation10.1General-Purpose Sampling Procedure 10.1.1Number and Mass of Increments 10.1.1.2Number of Gross Samples 10.1.1.4Special-Purpose Sampling 10.1.2Number and Mass of Increments 10.1.2.2Number of Gross S

49、amples 10.1.2.3Division of the Gross Sample Before Crushing 10.2Reduction and Division 10.3TABLE 1 Number and Mass of Increments for General-PurposeSampling ProcedureATop Size 16 mm58 in.50 mm2 in.150 mm6 in.BMechanically Cleaned CoalCMinimum number ofincrements15 15 15Minimum mass ofincrements, kg lb1 2 3 6 7 15Raw (Uncleaned Coal)CMinimum number ofincrements35 35 35Minimum mass ofincrements, kg lb1 2 3 6 7 15A Conditions C and D are not addressed in this standard.B For coals above 150-mm 6-in. top size, the s