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(DOC) Chemical_3

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Chemical_3

    Chemical

CHINESEJ0URNALOFGEOCHEMISTRVo1.25(Supp1.)2006

    ;thesamplemass(orsamplevolume)islargeenoughtorepresenttheoriginalsite(thelocalsegmentbeingsampled);(3)whether

    ;assayportionispreparedwel1enoughtodepicttheinitia1sample.Samplenumbersaredictatedbytheconfidence1evel,thevariance

    ;ofpopulationandtheacceptableestimationerroraswel1asthehomogeneityandthespatialcontinuityofpopulation.Fora

    ;homogeneous/22S2/r2~population.samplenumberscanbecalculatedbytheformula:/1=Z/2thefunctionofNormal(wheren

    ;representsthesamplenumberrequired;Z.distributionforgivenconfidence1evel;S2,thevarianceofsamples;andtheestimation

    ;error).Samplemassdependsonthegrainsizeofthesample,theheterogeneityconstantofthemateria1oflnterestandthe

    ;fundamenta1variance.Itcanbecalculatedbytheformula:M=Cd3/s2(whereMrepresentsthesamplemassrequired;C,the

    ;heterogeneityconstantofthemateria1ofinterest;d.thegrainsizeofthecoarsesttop5%0fthesample;s,thefundamenta1errorof

    ;sampling).Inordertominimizethesamplepreparationerrors,designingandimplementingagoodsamplepreparationprocedureis

    ;veryimportant.whichincludesemployingsuitableequipmentandresponsiblepersonne1.Acasestudyhasbeenconductedusingthe

    ;geochemicaldata0fthegoldminetailingsrelatedtoacidrockdrainageintheWitwatersrandBasin,SouthAfrica,andtheresults

    ;indicatethatifsamplingmuchmorethannecessary,wewouldwastethecostlyresourcesandlfsamplingtewerthanreqmred,we

    ;wouldgetanincorrectconclusion.ThanksaregiventotheWaterResearchCommission(WRC)inSouthAfricaforfundingthis

    ;Droject(WRCProjectNumber1624)andgivingpermissiontopublishtheresults.

    ;Keywordsgeochemicalsampling;environmentalriskassessment;samplenumber;samplemass;samplepreparationerror

    ;ChemicaloriginofacidminedrainageanditscomputersimulationwithPhreeqcAcase

    ;studyofZibocoalminingdistrict

    ;YaoguoWU,ZhaoliSHEN2,ZuoshenZHONG2

    ;DepartmentofAppliedChemistry,NorthwesternPolytechenicalUniversity,Xi’an71O072,China

    ;CollegeofWaterandEnvironmentalSciences,ChinaUniversityofGeosciences,Beijing100083,China

    ;Researchontheoriginofacidminedrainage(AMD)ishelpfu1tofindawaytoavoidandremediateAMDanditspollution.AMDis

;mainlyfrompyrite(FeS2)

    containingminerals(suchascoalandore)duringminingprocessandreproduction,andiscommonand

    ;dangeroustowaterenvironmentintheworld.TheresultsofresearchshowedthationsofcalciumandmagnesiuminAMDcame

    ;mainlyfromcalciteanddolomite.Tomyknowledge.othersources(suchaschlorite)fortheionsandtheirchemica1originwerenot

    ;studied.InthisPa

    er,theAMDintheZibocoalminingdistrictasacase,itschemicalcharacteristicsanditsoriginweredetermined.

    ;Andbasedontheanalysisoftheregiona1geologicalconditions.PhreeqcwasusedtostimulatetheAMD’schemica1origin.The

    ;resultsshowedthatacidificationandneutralizationaretwoprocesses,andthecharacteristicsdependeduponchemicalreactionsthat

    ;occurredinthetwoprocesses.IntheAMD,sulfateioncamefromFeS,andisanindicatorofacidprocess,andionsofcalciumand

    ;magnesiumoriginatedfromcalciteandchloriteandwereindicatorsofneutra1process.Dissolvedsilica(SiO,1wasrichintheAMD.

    ;anditisaspecificcharacteristicfeatureoftheAMDintheZibocoa1miningdistrict.forchloritewasinvolvedinitsorigin.

    ;Keywordsacidminedrainage(AMD);chemicalthermodynamicssimulation;Zibocoalminingdistrict;chlorite;phreeqc

    ;Geochemicalcharacteristicsofacidminedrainageandsedimentsfromcoalmines,Shanxi

    ;Province,China

    ;HongfuSUN,FenghuaZHAO

    ;DepartmentofResourceandEarthSciences,ChinaUniversityofMiningandTechnology,Beijing100083,China

    ;Inthisstudy,geochemicalcharacteristicsofacidminedrainage(AMD1anditssedimentsfromtheMalanandSitaicoalmines.

    ;ShanxiProvince,China,wereinvestigated.Manyanalytica1approachessuchasIC,ICPMS,XRD,XRF9andmodelingcalculation

    ;ofhydrogeochemistryusingPHIEEOCIsoftwarewereemployed.TheAMDischaracterizedbyhigherconcentrationsofironand

    ;sulfate,a1owpH,andelevatedconcentrationsofawidevarietyofheavymetals.TheresultsofmodelingcalculationbyPHIEEOCI

    ;softwaredemonstratethemetalsinAMDarepresentmainlyasMeandMeS0dspecies.ThesedimentsofAMDarecomposed

    ;mainlyofironbearingmineralssuchasgoethiteandschwertmannite,whicharecontrolledbypH,FeandS04concentrations.The

    ;schwertmanniteminera1hasbeenfoundforthefirsttimeinChina. ;

    ;

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