1、Designation: D5192 09 (Reapproved 2015)Standard Practice forCollection of Coal Samples from Core1This standard is issued under the fixed designation D5192; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice describes procedures for collecting andhandling a coal sample from a core recovered from a borehole.1.2 The values stat
3、ed in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 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
4、 health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D121 Terminology of Coal and CokeD388 Classification of Coals by RankD1412 Test Method for Equilibrium Moisture of Coal at 96to 97 Percent Relative Humidity and 30CD20
5、13 Practice for Preparing Coal Samples for AnalysisD2796 Terminology for Megascopic Description of Coaland Coal Seams and Microscopical Description andAnalysis of Coal (Withdrawn 1995)3D4371 Test Method for Determining the Washability Char-acteristics of CoalD4596 Practice for Collection of Channel
6、Samples of Coalin a Mine3. Terminology3.1 Definitions:3.1.1 For additional definitions of terms, refer to Terminol-ogy D121.3.1.2 borehole, nthe circular hole through soil and rockstrata made by boring.3.1.3 caves or washouts, nzones of increased hole diam-eter caused by rock fragments that fall fro
7、m the walls of aborehole and can block the hole or contaminate the cuttingsand which erode or abrade the sidewall of the borehole by theaction of the drilling. These zones can affect the accuracy ofcertain geophysical logs (especially density). Corrections toother geophysical logs can be made if a c
8、aliper log is available.The most common causes of caves or washouts include soft orfractured lithologies, the presence of water-producing zones,and the downhole pressure of the drilling medium (fluid or air)that often causes differential erosion of various strata within theborehole.3.1.4 concretion,
9、 nin a geological sense, a mass of min-eral matter found in rock of a composition different from itsown and produced by deposition from aqueous solution in therock.3.1.5 core, nin drilling, a cylindrical section of rock (coal)that is usually 5 to 10 cm in diameter, taken as part of theinterval penet
10、rated by a core bit and brought to the surface forgeologic examination, representative sampling, and laboratoryanalyses.3.1.6 core barrels, ntwo nested tubes above the bit of acore drill, the outer rotating with the bit, the inner receiving andpreserving a continuous section or core of the material
11、pen-etrated. The following two types of inner barrels are commonlyused.3.1.6.1 split-tube barrel, na type of inner barrel consistingof two longitudinal halves of pipe bound together by reinforcedtape at intervals along the barrel length that allows easy accessto a relatively intact core (by cutting
12、the tape). (This is thepreferred barrel type for coal exploration, when available.)3.1.6.2 solid-tube barrel, na type of inner barrel consist-ing of a single solid-walled length of pipe in which removal ofthe core is accomplished by mechanical or hydraulic pressureat one end of the pipe thus extrudi
13、ng the core onto a core tray.(The core is likely to be less intact than when a split-tube barrelis used.)3.1.7 core sample, nthat part of a core of rock or coalobtained so as to accurately represent a thickness of a unitpenetrating by drilling.1This practice is under the jurisdiction of ASTM Committ
14、ee D05 on Coal andCoke and is the direct responsibility of Subcommittee D05.18 on Classification ofCoals.Current edition approved Sept. 1, 2015. Published September 2015. Originallyapproved in 1991. Last previous edition approved in 2009 as D5192 09. DOI:10.1520/D5192-09R15.2For referenced ASTM stan
15、dards, visit the ASTM 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.3The last approved version of this historical standard is referenced onwww.astm.org.Co
16、pyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.1.8 geophysical log, na graphic record of the measuredor computed physical characteristics of the rock section en-countered in a borehole, plotted as a continuous function ofdepth. Measu
17、rements are made by a sonde, which contains thedetectors, as it is withdrawn from the borehole by a wire line.Several measurements are usually made simultaneously, andthe resulting curves are displayed side by side on the commondepth scale. A common suite of logs used in coal explorationinclude cali
18、per, density (gamma-gamma), natural gamma, andresistivity.3.1.8.1 caliper log, na continuous mechanical measure-ment of the diameter and thus the rugosity of the borehole. Thetool identifies zones where swelling or cavings (washouts)have occurred during drilling. The tools value is in allowingqualit
19、ative or quantitative corrections to be made to othergeophysical logs which are affected by borehole size (espe-cially density).3.1.8.2 density log (gamma-gamma log), n measures elec-tron density within lithologic units which is related to theirbulk density. The wireline tool records the intensity o
20、f gammaradiation (in counts per second) from a nuclear source withinthe tool after it has been attenuated and backscattered bylithologies within the borehole. Due to the distinctly lowdensity of coals, the density log is essential in coal explorationfor identifying coal seams and coal-seam partings.
21、 The bias/resolution of density logs can be affected by source-detectorspacing (closer spacing increases resolution), borehole size andirregularities (see caves or washouts), and the presence ofcasing and logging speed.3.1.8.3 natural gamma-ray log, na record of the naturalradioactivity of the litho
22、logies encountered in the boreholeenvironment. During recording of geophysical logs, theamount of natural radiation is recorded and presented in eithercounts per second (CPS) or American Petroleum Institute(API) units. Unlike many other log types, a representativenatural gamma log can be obtained wh
23、ere borehole or fluidconditions, or both, are not optimal or where casing is present.The natural gamma log is most often used in the coalenvironment for identifying classic lithologies and differenti-ating coal seams and coal-seam partings.3.1.8.4 resistivity log, na measure of the voltage differen-
24、tial of strata along the walls of a borehole when electricalcurrent is passed through the strata. The resistivity log requiresa fluid-filled hole to constantly provide a conductive mediumbetween electrodes on the tool. The spacing between theelectrodes determines the precision of the bed boundaryrel
25、ationships in much the same manner as with the density log.The resistivity log is useful primarily in conjunction with otherlog types. The logs are affected by casing, logging speed,electrode spacing, formation porosity, and resistivity changesin the borehole fluid.3.1.9 floor, nthe rock material im
26、mediately underlying acoal bed.3.1.10 roof, nthe rock material immediately overlying acoal bed.3.1.11 sonde, nan elongate cylindrical tool assembly usedin a borehole to acquire a geophysical log.4. Summary of Practice4.1 At selected sites in a deposit of coal, a borehole is drilledand the core conta
27、ining the coal and surrounding strata of rockis recovered.4.2 The coal core is cleaned of drilling fluid, if necessary,properly described, and packaged so that loss of moisture isminimized. From this core, coal and roof and floor material ofinterest are collected for analysis and testing.5. Signific
28、ance and Use5.1 A properly collected sample that includes the total coalbed interval provides a sample that is a representative crosssection of the coal bed at the point of sampling. Core samplesare taken for subsequent testing needed for evaluation of coalquality and characterization for commercial
29、 evaluations, forplanning of mining operations to maintain coal quality, for thedetermination of coal rank in accordance with ClassificationD388, 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 an
30、other sample point. Thereliability of the data generated from core samples is dependent on thenumber and spacing of the sample points and the variability of the coalcharacteristics in a given area.5.2 Moisture determined directly from a core sample shallbe considered questionable in any core sample
31、because ofpossible contamination from drilling fluids and groundwater. Ifa more representative estimate of the inherent moisture contentof the core sample (with the exception of certain low-rankcoals) is desired, the sample should be analyzed according toTest Method D1412.6. Apparatus6.1 Steel Measu
32、ring Tape, not less than 10 m (30 ft) long.6.2 Rock Hammer, Chisel, or Pick, with file for sharpening.6.3 Water Source, to provide fresh, clean water for rinsingdrilling mud from cut surface of the core.6.4 Waterproof Marking Pencils that are visible on coal,such as a yellow lumber crayon.6.5 Polyet
33、hylene Bags, Tubing, or Sheets, 0.1 mm (4 mil) orthicker.6.6 Core Tray, constructed of wood, plastic, or metal, ontowhich to extrude the core from the core barrel.6.7 Boxes for Core Storage, constructed of wood, plastic, orcoated cardboard or if the core is to remain stratigraphicallyoriented, use c
34、ontainers such as polyvinyl chloride (PVC) pipe.6.8 Tags and Waterproof Marking Pens, for sample identi-fication and for marking depths, orientation, and so forth, onthe plastic sheeting.6.9 Notebook and Pencil, or other means for record keeping.6.10 Waterproof Container, to hold sample tag.6.11 Geo
35、physical Logging Unit (optional), consisting ofrecording equipment and sondes for high-resolution densityand caliper logs and possibly gamma and resistivity logs.D5192 09 (2015)27. Planning for Sampling7.1 Obtain information such as geologic, topographic, andland ownership for locating suitable site
36、s for drilling. Choosesites that will best satisfy the purpose of sampling.7.2 A core approximately 47 mm (1.87 in.) in diameteryields a sufficient sample for most purposes. Minimum samplemass requirements for analytical tests, such as washabilitytesting, may dictate a sample mass that can only be o
37、btainedfrom larger diameter cores or multiple separate cores.NOTE 2The diameter and length of the core (or number of separatecores) required to obtain a desired mass of sample may be estimated fromthe density of coal, approximately 1.3 to 1.35 g/cm3. The selecteddiameter of the core can have an effe
38、ct on the representativeness ofsubsamples obtained from the core sample for various types of testing. Asan example in washability testing, the diameter of the core should be atleast three times the largest dimension of the topsize of any subsamples tobe obtained from the core sample. For information
39、 on determining thewashability characteristics of coal, see Test Method D4371 and the reportby Wizzard.4A larger diameter core can also be necessary to obtain a morerepresentative sample if the quality of the coal varies greatly from layer tolayer in the seam.7.3 Increment SamplingWhere differences
40、of coal qualityparameters exist among different layers or benches in the samecoal seam or where the seam is thick, it is best to sample andanalyze the seam in vertical increments.7.3.1 Compositing5Data obtained from the separateanalyses of the vertical core increments can be composited bycalculation
41、, preferably by sample mass if sufficient informationsuch as core length and density has been measured for eachincrement.Alternatively, a composite sample of the entire seamcan be produced by combining representative splits of theincrements by increment thickness for the determination ofwhole core c
42、haracteristics. The use of an ash/density relation-ship for the specific geographic area and seam being studiedcan be helpful in validating direct density measurements.Extreme care and cross-checking should be exercised whencombining a sample composite for analysis or when calculatinga composite ana
43、lysis from the analysis of increments. Somecoal quality parameters are not additive in a linear fashion andcannot be accurately determined by calculated compositing.Fusion temperatures of ash and Hardgrove grindability andGieseler fluidity indices are examples of physical propertiesthat are nonaddit
44、ive and best determined on whole samples.7.4 Sampling Plans for Different Purposes:7.4.1 Variations in the purpose of sampling and in condi-tions encountered in the field may preclude the establishmentof rigid procedures covering every sampling situation.Therefore, formulate a plan taking into accou
45、nt the conditionsof drilling, the purpose of the sampling, and the knowncharacteristics of the coal seam. Characteristics include lateralor vertical variations in coal quality and occurrences ofpersistent mineral parting or concretions within a seam.7.4.2 Sampling Plan for Classification According t
46、o Rank:7.4.2.1 A minimum of three, but preferably five or more,whole-seam samples are required to characterize the rank ofthe coal in a given area in accordance with Classification D388.7.4.2.2 All roof and floor rock, all mineral partings morethan 10 mm (38 in.) thick, and mineralized lenses or con
47、cre-tions (such as sulfur balls) more than 13 mm (12 in.) thick and50 mm (2 in.) wide shall be excluded from the sample.Angularor wedge-shaped mineral lenses or concretions that are notcontinuous shall be excluded from the samples if the volumeexceeds that of a parting 10 mm thick. (Refer to Practic
48、eD4596.)8. Core Recovery8.1 Recovery for Classification According to Rank andSome Other PurposesThe recovery of 100 % of the entireseam is not possible on every core under even the best of fieldconditions. However, useful information such as apparent rankcan many times be obtained from cores where l
49、ess than 100 %of the seam has been recovered. When portions of the intervalhave been lost, the following information should be recorded:(1) the percent recovery and (2) the estimated location andthickness of the lost intervals. Use of data from cores thatrepresent less than 100 % of the total seam thickness shall beidentified as such and used with caution.8.2 Determining Recovery From Comparison of Geophysi-cal Logs and Core5The most reliable measurement of coalseam thickness can be obtained from deflections on thehigh-resolution density log and the caliper
