1、Designation: D 4596 08Standard Practice forCollection of Channel Samples of Coal in a Mine1This standard is issued under the fixed designation D 4596; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A num
2、ber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes procedures for collecting a coalsample from a channel extending from top to bottom in the faceof a coal seam in a
3、 mine.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For spec
4、ificprecautionary information, see Note 2.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.2. Referenced Documents2.1 ASTM Standards:2D 121 Terminology of Coal and CokeD 388 Classification of Coals by RankD 2234/D 2234M Prac
5、tice for Collection of a Gross Sampleof CoalD 2796 Terminology Relating to Megascopic Descriptionof Coal and Coal Seams and Microscopical Descriptionand Analysis of Coal3D 4371 Test Method for Determining the Washability Char-acteristics of Coal3. Summary of Practice3.1 At selected sites in the mine
6、 the face of the seam iscleaned of weathered coal and debris and the face is evened. Achannel of uniform horizontal cross section is cut from the coalseam and the coal therefrom is collected for analysis andtesting.4. Significance and Use4.1 A properly collected face channel sample that includesthe
7、total coal bed interval provides a sample that is a repre-sentative cross section of the coal bed at the point of sampling.Channel samples are taken for subsequent testing needed forevaluation of coal quality and characterization for commercialevaluations, for planning of mining operations to mainta
8、in coalquality, for the determination of coal rank in accordance withClassification D 388, and for geologic coal resource studies.NOTE 1Because of the potential for lateral variability, a sample maynot represent the quality of the coal bed at another sample point. Thereliability of the data generate
9、d from channel samples is dependent on thenumber and spacing of the sample points and the variability of the coalcharacteristics in a given area.NOTE 2Sampling of the mine product for these purposes is unsatis-factory because of contamination of the product with out-of-seam mate-rial, selective mini
10、ng of parts of a seam, inability to obtain samples fromone or more specific locations in the mine, or other incompatibility of thepurpose of sampling with the mining practice. Conversely, channelsamples should not be used for evaluation of the quality of commercialshipments of the mine product, whic
11、h should be sampled in accordancewith Methods D 2234.5. Apparatus5.1 Steel Measuring Tape, not less than3m(8ft)long.5.2 Miners Pick or Similar Tool, with file for sharpening.Other devices may be used such as a pneumatically operatedchain saw with tungsten carbide teeth.5.3 Brush or Broom, for removi
12、ng loose particles on thecoal face.5.4 Chalk.5.5 Sample Containers With ClosuresIf the sample is tobe used for determination of inherent moisture, the containershall be such that less than 0.05 % of the sample weight is lostbetween the time of sealing the container with sample and thetime of opening
13、 for preparation of the sample for analysis.Steel airtight containers with polyethylene bag liners have beenfound to be satisfactory for this purpose. For other purposes,bags made of a strong cloth and lined with a polyethylene bagmay be suitable.1This practice is under the jurisdiction of ASTM Comm
14、ittee D05 on Coal andCoke and is the direct responsibility of Subcommittee D05.18 on Classification ofCoals.Current edition approved May 1, 2008. Published May 2008. Originallypublished approved in 1986. Last previous edition approved in 2007 as D 4596 07.2For referenced ASTM standards, visit the AS
15、TM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428
16、-2959, United States.5.6 Ground ClothCanvas tarpaulin or heavy-duty plasticsheet about 3 by 3 m (10 by 10 ft). If the purpose of samplingincludes the determination of inherent moisture, the sheet shallbe of low water solubility and permeability, such as polyeth-ylene or oilcloth.5.7 Tags and Pen, fo
17、r sample identification and for marking.5.8 Shovel.5.9 Notebook and Pencil, or other means for record keeping.6. Planning of Sampling6.1 Considerations regarding weathered coal and inherentmoisture:Weathered coal is unsuitable for inclusion in channelsamples collected to secure fresh and unaltered m
18、aterial.Weathered coal typically contains anomalously low total mois-ture, yields low calorific value (dry and moisture-and-ash-freebasis), and also produces atypical results for other tests. It doesnot reflect unaltered in-situ coal properties, cannot be used forclassification according to rank, an
19、d does not give accurateestimates of typical as-mined moisture.6.1.1 Obvious indications of weathering include, but are notlimited to: (1) any discoloration of broken coal surfaces orcleats, (2) presence of sulfate minerals resulting from oxidationof pyrite, (3) presence of gypsum (calcium sulfate)
20、crystals,and (4) presence of dust, cracked and crazed coal surfaces, ora fragmented condition of the coal blocks resulting from loss ofinherent moisture.6.1.2 It is often useful to collect samples containing theirfull complement of inherent moisture, but that condition maynot always be readily disce
21、rnable. A simple field test can beused to qualitatively identify seemingly fresh coal that has lostsome inherent moisture but has not yet obviously weathered. Alight coating of water is sprayed or wiped onto the surface ofthe coal, and the rate at which it disappears is observed. Rapiddisappearance
22、(typically within a few seconds) indicates ab-sorption and demonstrates that the coal contains less than itsfull compliment of inherent moisture. Slower disappearance(taking perhaps a minute or more) is characteristic of evapo-ration and suggests that the pores are filled with moisture. Toaccount fo
23、r variations in field conditions such as temperature,humidity, different absorption rates by different coals, and soforth, the test is applied to a number of coal pieces both beforeand during the sample collection process.6.2 Sampling Plan for Classification According to Rank:6.2.1 Refer to Section
24、7 of Classification D 388 for infor-mation on the required number and location of samples.6.2.2 The channel size shall be at least 8 cm (3 in.) deep and10 cm (4 in.) wide, and shall yield at least 3 kg (6 lb) of coalfor each foot of thickness of coal seam.6.2.3 All roof and floor rock, mineral parti
25、ngs more than 1cm (38 in.) thick, and mineralized lenses or concretions (suchas sulfur balls) more than 114 cm (12 in.) thick and 5 cm (2 in.)wide shall be excluded from the sample.NOTE 3In most cases a single whole-seam sample is used to identifythe one rank of coal present in the seam. However, wh
26、en more than onerank is thought to be present, it is acceptable to collect incrementalsamples to identify and define the coals of differing ranks.6.3 Sampling for Other PurposesVariations in the pur-pose of sampling and in conditions encountered in the fieldpreclude the establishment of rigid proced
27、ures covering everysampling situation. In each case, formulate a plan taking intoaccount the mining operation, the purpose of the sampling, andthe known characteristics of the coal seam. Characteristicsinclude lateral or vertical variations in coal quality, occurrencesof persistent mineral partings
28、or concretions within the seam,and the extent of oxidation or weathering of coal. Take theseconsiderations into account in planning sample site selectionand whether lithotypes, partings, and layers above and belowthe seam should be described.4,5Also establish a method ofpreparing the coal face, and
29、determining the size of sample.6.3.1 Obtain information for identification of suitable loca-tions for sampling. Choose sites that will best satisfy thepurpose of sampling.6.3.2 A channel at least 8 cm (3 in.) deep (into the face ofthe seam) and 10 cm (4 in.) wide yields a sufficient sample formost p
30、urposes. The channel may be enlarged to minimize theeffect of channel size variability when a coal characteristic ofinterest, such as ash content, varies greatly from layer to layerin the seam, or when the coal breaks unevenly. Also, thechannel cross-section may be enlarged to obtain sufficientsampl
31、e for tests requiring large amounts. The size of channelfor the required amount of coal may be estimated from thedensity of coalapproximately 1.3 g/cm3(0.05 lb/in.3). Forinformation on determining washability, see Test MethodD 4371 and the report by Wizzard.66.3.3 Practice with respect to weathering
32、 of the coal de-pends on a number of factors. Some characteristics of coal,such as total sulfur content, do not change appreciably withweathering if the coal is not leached. The forms of sulfur, themoisture-holding capacity, and oxygen content of high volatileC bituminous and lower rank coals, and t
33、he rheologicalproperties of coking coals do change with weathering. Sam-pling to different depths and testing of such properties may berequired to establish the depth at which unweathered coal canbe obtained.7. Sampling Procedures7.1 At each sampling site, survey the condition of the coalface and th
34、e rock above the coal (if exposed).NOTE 4Warning: Beware of danger from rock falling from the roofof underground mines or from the highwall of surface mines. Take downany loose blocks as a safety precaution and to prevent extraneous materialfrom subsequently contaminating the sample.7.2 With a miner
35、s pick, remove weathered coal from theface area to be sampled, to the depth (but at least 3 cm (1 in.)required in the plan of sampling. True up to the face to leave astraight surface normal to the bedding and free of extraneousmatter.4Schopf, J. M., “Field Description and Sampling of Coal Beds,” U.S
36、. GeologicalSurvey Bulletin No. 1111-B, 1960.5Field Description of Coal, ASTM STP 661, ASTM, 1978, pp. 333, 5868.6Wizzard, J. T., “The Reliability of Using Channel Samples to RepresentRun-of-Mine Coal Washability,” DOE/PETC/TR-82/3.D 4596 0827.3 Describe and record observations on the character ofla
37、yers in the coal seam (see Terminology D 121 or DefinitionsD 2796) to the extent required by the sampling plan.7.4 Mark the sides of the channel with chalk and mark anymineral partings or other parts of the seam that are to bediscarded.7.5 Clear and smooth the floor adjacent to the sample areaand sp
38、read a ground cloth on the floor with one edge at the coalface.7.6 Cut away with a miners pick (or other tool) a channelfrom top to bottom (or bottom to top) of the coal seam. If a sawis used at the sides of the channel, exercise care that finesgenerated by the saw do not become part of the sample.
39、Ensurethat all material from the channel that is to be sampledaccording to the plan of sampling falls on the ground cloth andthat any mineral matter to be discarded does not contaminatethe coal sample. Cut the channel to a uniform width and depthin a rectangular cross section, to ensure that represe
40、ntativevolumes of material are obtained from every part of the coalseam.7.7 As quickly as possible, if inherent moisture will bedetermined, transfer the material on the ground cloth to asample container and seal and then label the container. Ifsurface moisture is visible on the coal, or if there is
41、any reasonto question the accuracy of inherent moisture content deter-mined from the sample, the description of the sample shallinclude the warning: “Moisture content questionable.”8. Keywords8.1 channel; coal; mine; rank; sample collection; samplingASTM International takes no position respecting th
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45、tandard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 4596 083
