Designation: E877 − 13Standard Practice forSampling and Sample Preparation of Iron Ores and RelatedMaterials for Determination of Chemical Composition andPhysical Properties1This standard is issued under the fixed designation E877; 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 parentheses indicates the year of last reapproval. Asuperscript epsilon (´) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers procedures for mechanical sam-pling of iron ores and related materials in a falling stream orstopped-belt sampling and preparing the gross sample to thevarious test samples required for each characteristic to bemeasured. Included as Annexes are (1) design criteria toprevent bias, (2) statistical methods to determine qualityvariation and precisions of sampling and division, and (3)amethod for comparing two sampling procedures for possiblesystematic differences.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. Specific precau-tionary statements are given in Section 8.2. Referenced Documents2.1 ASTM Standards:2E135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE276 Test Method for Particle Size or ScreenAnalysis at No.4 (4.75-mm) Sieve and Finer for Metal-Bearing Ores andRelated MaterialsE279 Test Method for Determination ofAbrasion Resistanceof Iron Ore Pellets and Sinter by the Tumbler TestE389 Test Method for Particle Size or ScreenAnalysis at No.4 (4.75-mm) Sieve and Coarser for Metal-Bearing Oresand Related MaterialsE882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE1072 Test Method for Low Temperature Breakdown ofIron Ores (Withdrawn 1995)33. Terminology3.1 Definitions—For definitions of terms used in this testmethod, refer to Terminology E135.3.1.1 nominal topsize—in sampling, the opening of thescreen of the standard series that would pass 95 % of arepresentative sample.3.1.2 precision—a measure of reproducibility of test results,using the same equipment and method, statistically derivedfrom multiple data expressed at 95 % confidence level.4. Summary of Practice4.1 The precision required for the sampling and samplepreparation steps is calculated based on the objectives of thetesting, resulting in a sampling plan specifying the minimummasses and number of increments required for each step in theprocedure. Samples are then collected, dried, blended, divided,crushed, pulverized, and ground as required by the testmethods to be utilized.5. Significance and Use5.1 This practice is to be used for sampling and samplepreparation of iron ores and related materials, prior to use of areferee method for testing for compliance with compositionalspecifications for metal content or physical properties. It isassumed that all who use this procedure will be trained analystscapable of performing common laboratory practices skillfullyand safely. It is expected that work will be performed in aproperly equipped laboratory and that proper waste disposalprocedures will be followed. Appropriate quality control prac-tices must be followed, such as those described in Guide E882.5.2 Adequate methods for obtaining representative samplesfor testing the chemical and physical properties of a consign-ment of iron ore are essential. The sale and use are dependenton the chemical or physical properties, or both, of an ore.1This practice is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.02 on Ores, Concentrates, and Related Metallurgical Materials.Current edition approved Oct. 1, 2013. Published November 2013. Originallyapproved in 1982. Last previous edition approved in 2008 as E877 – 08. DOI:10.1520/E0877-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at

[email protected] For Annual Book of ASTMStandards volume information, refer to the standard’s Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 The criteria to prevent bias may be used for both designof a sampling system and in checking the design of an existingsystem.6. Apparatus6.1 Any mechanical sampler is acceptable that either bydesign or comparison, or both (as defined in Annex A1 andAnnex A4) can be shown to take nonbiased increments of atleast minimum mass and number required and can handle theseincrements in accordance with the practice.6.2 Templates and Related Equipment, to obtain incrementsfrom a stopped belt, with bias protection in accordance withAnnex A2, are acceptable.6.3 Riffle—Astationary sampler comprising an even numberof equally-sized, adjacent chutes discharging in opposite direc-tions. For use with this practice, there must be a minimum oftwelve chutes with an opening width of at least 3 times thenominal topsize.NOTE 1—For fine ores ( 12.5 mm) it is recommended not to exceed 31⁄2 timesnominal topsize as it is required that the full width of the riffle be usedsince the accuracy of the split increases with the number of chutes. Forfree-flowing ores such as pellets, the 3 times the nominal topsize may bereduced to 11⁄2 times provided it is ascertained that there is no chuteplugging for a particular ore type.6.4 Crushers—Crushers may be jaw, cone, rotary, or othertype that can reduce the particle size to the desired levelwithout significant loss of mass (less than 0.5 %) and notcontaminate the sample.6.5 Pulverizers and Grinders—Pulverizers and grindersmay be of plate, cylinder, or other type that can reduce theparticle size to the desired level. They should be made ofsufficiently hardened material to prevent contamination of thesample. Also, the loss of total mass during pulverizing shouldnot exceed 2.5 %.7. Design of Sampling Operations7.1 Basic Requirements:7.1.1 The characteristics to be determined and precisionsdesired must be known.7.1.2 The mass and special requirements for each testsample must be known.7.2 Overall Precision (βSDM):7.2.1 Overall precision for determining the mean values ofthe iron content, moisture content, and percentage passing thespecified size sieve (in accordance with Test Methods E276and E389), at 95 % confidence in absolute percentages are asin Table 1.7.2.2 Overall precisions for other characteristics shall beagreed upon between the parties concerned.NOTE 2—Nationally or internationally accepted measurement methodsshould be used to determine the characteristics desired.7.3 Equations:7.3.1 Calculate overall precision as follows:βSDM5 2 Œσw2nS111cD1σ2DMν(1)orβSDM5 2 Œσw2nS111σD1σD2ν1σM2νm(2)where:βSDM= overall precision for any characteristic,σw= estimated within-strata standard deviation of acharacteristic,σD= estimated standard deviation of division,σM= estimated standard deviation of measurement,σDM= estimated standard deviation of division and mea-surement combined,n = number of primary increments,ν = number of final samples taken for measurement,m = number of measurements taken on each finalsample, andc = average number of secondary increments taken perprimary increment.NOTE 3—Factor (1 + 1 ⁄c) is omitted from the equation if only primaryincrements are used.7.3.2 σwand σDMor σw, σD, and σMare estimated inaccordance with Annex A3.7.3.3 When designing a new sampling installation, refer toAnnex A1 for estimating σwand σDM.7.4 Selection of Sampling Parameters—Using the estimatedvalues of σwand σDMor σw, σD, and σMand Eq 1 or Eq 2,choose a combination of n, c, ν, and m to obtain the requiredprecision. It is recommended in routine sampling to use thesame value of c used in the determination of σw.7.5 Minimum Mass of Increment—The minimum mass of anincrement is calculated by the following formula to ensure thata particle the shape of a cube of the nominal topsize shall notrepresent more than 10 % of its mass, to avoid bias by largerparticles:W 5 ~S3/20! 3 ~sp gr/5! (3)where:W = minimum mass of increment, kg,S = nominal size of the ore, cm, andsp gr = specific gravity of the iron ore being sampled.NOTE 4—In practice, the mass of primary increments may be manytimes greater than that obtained in Eq 3.7.6 Treatment of Increments—Increments will be handledindividually or combined to form one or more gross samples orset(s) of subsamples from which test sample(s) for the requiredcharacteristics will be taken. Each gross sample must followthe requirements of sampling and preparation. Each grossTABLE 1 Overall PrecisionConsignment,tonsIron andMoistureContent,%Specification Size, Cumulative Percent Passing50%–90%A90%100000 ±0.3 ±0.75% ±0.075C ± 0.075 (100-C) ± 0.75 %20 000 to100 000± 0.4 ± 1.0 % ± 0.1C ± 0.1 (100-C)±1.0%20000 ±0.5 ±2.0% ±0.2C ± 0.2 (100-C)±2.0%AIn the formulae for calculating the precision estimates within this column,C = cumulative percent passing.E877 − 132sample must have, as a minimum number of increments, thelargest number (n) calculated from the individual characteris-tics taken from that gross sample.7.6.1 Example—Assume a gross sample is required for ironanalysis and moisture determination and a separate grosssample for size distribution and tumble test. Also assume from7.4 the number of increments required to obtain precisiondesired is as follows:Moisture 30 incrementsIron 20 incrementsSize 50 incrementsTumble 25 increments7.6.2 Example—Take 30 increments for iron analysis andmoisture determination and 50 increments for size distributionand tumble test, if the sampler has the capability (for example,computer controlled). If, however, alternative increments areused, take 50 increments for each gross sample. If one grosssample is to be used for all the determinations, use 50increments.7.7 Special Precautions:7.7.1 Samples for size determination or other tests requiringuncrushed particles must be taken prior to crushing.7.7.2 Samples for moisture determination must be protectedfrom ambient conditions. A subsample should be taken at leastevery 8 h and the total moisture of the consignment should bethe weighted average of these samples. The 8-h period may beextended provided the sample is protected from moisturechange (for example, refrigerated). To avoid moisture change,samples must be prepared as quickly as possible, with mini-mum handling, and must be kept in sealed containers whileawaiting any stage of preparation prior to the initial weighing.Moisture samples should not be crushed below1⁄4-in. sieve (6.3mm) and the minimum mass of samples used should conformwith Eq 4 (8.6.1). Mix sample prior to moisture determination.8. Sampling and Preparation Procedure (See Fig. 3 forexamples)8.1 Collect throughout the movement of the consignment, inaccordance with Annex A1 or Annex A2, the number ofprimary increments, as determined in 7.4 (with a minimum of20). Start at random within the first stratum, then sample atequal mass or time intervals. If the ore is handled in such a waythat there is a cycle to the variability of a characteristic, it mustbe ascertained that the sampling cycle is not in phase with thehandling cycle.8.2 If the required number of increments is collected prior tocompletion of the movement of the consignment, additionalincrements shall be taken at the same interval until orehandling is complete.8.3 If secondary increments (c) are used, they shall be takenat equal time intervals with a maximum time such that c is1orgreater.8.4 Increments are treated individually or combined to forma gross sample(s) or subsamples, or both, in accordance withfinal test sample requirements in conjunction with precisionrequirements, as determined in 7.3.1.8.5 At this stage, individual test samples are obtained by acombination of division (mass reduction) (8.6), crushing andpulverizing (8.7), and drying (8.8), as directed in Section 8.8.6 Division of gross sample, subsamples, or incrementmust conform with the following rule:8.6.1 The minimum mass of the total divided sample mustbe greater than:W25 S33 ~sp gr/5! (4)where:W2= mass of the divided sample, kgS = nominal topsize at that division level, cm, andsp gr = specific gravity of the ore being sampled.8.6.1.1 The equation is based on the concept that the massof the largest piece should be less than 0.5 % of the mass of thedivided sample.8.6.2 Divide the sample by one of the following procedures:8.6.2.1 A mechanical sampler operated in accordance withthe guidelines in Annex A1.8.6.2.2 Riffling—Use a pan the same width as the rifflechutes to feed the ore for division.Add increments of ore to thepan and gently agitate the pan over the center of the chutes,feeding the ore at a constant rate, so that any ore particle has anequal chance of falling to either side of the device. Select thehalf of the divided sample to be included in subsequentsampling steps, at random. Thoroughly clean the equipmentbetween samples. Warning—Use proper dust collection toprotect the operator from fine respirable dust particles.8.6.2.3 Manual Increment Division (Note 5)—Mix the en-tire sample and spread on a flat nonmoisture-absorbing surfaceso that the sample forms a rectangle of uniform thickness.Divide into at least 20 segments of equal area. With a flatbottom, square-nose tool, take scoopfuls of approximate equalsize from each segment from the full depth of the bed. Thesescoopfuls must have a minimum mass in accordance with Eq 3.Combine the scoopfuls to form the divided sample.NOTE 5—Manual increment division, although very efficient for moistor cohesive ores, or both, is not recommended for dry ores, sinter, orpellets.8.7 Drying, Crushing, Pulverizing, and Grinding:8.7.1 Always dry samples before sample preparation, ifpossible, to limit contamination from moist ore sticking tosurfaces of sample preparation equipment.8.7.2 Crush, pulverize, and grind samples to the requiredmaximum size in stages convenient to the equipment available.At each stage, reduce the sample mass to the extent that themass of the divided sample exceeds that obtained by Eq 4.Warning—Use proper dust collection to protect the operatorfrom fine respirable dust particles.8.8 Drying—Drying of any portion of the sample is accom-plished in any heating medium as long as the ore temperaturedoes not exceed 110 °C. Where specifications call for a driedsample, it must be dried to constant mass in an oven capable ofmaintaining a temperature of 105 °C 6 5 °C. Constant mass isobtained when an additional hour drying at 105 °C 6 5°Cdoes not cause a change greater than 0.05 % mass.NOTE 6—The maximum temperature of 110 °C may be exceeded,E877 − 133