USGS 2005 Minerals Yearbook - Silica.pdf

2005 Minerals YearbookSilica

U.S. Department of the Interior U.S. Geological Survey

October 2006

Silica—2005 66.1

Silica

ByThomasP.Dolley

Domestic survey data and tables were prepared by Nicholas A. Muniz, statistical assistant, and the world production table was prepared by Glenn J. Wallace, international data coordinator.

Foursilicacategoriesarecoveredinthisreport—industrialsandandgravel,quartzcrystal(aformofcrystallinesilica),specialsilicastoneproducts,andtripoli.Mostofthestonecoveredinthespecialsilicastoneproductssectionisnovaculite.Thesectionontripoliincludestripoliandotherfine-grained,poroussilicamaterials,suchasrottenstone,thathavesimilarpropertiesandenduses.certainsilicaandsilicatematerials,suchasdiatomiteandpumice,arecoveredinotherchaptersoftheU.S.GeologicalSurvey(USGS)MineralsYearbook,volumei,MetalsandMinerals.TradedatainthisreportarefromtheU.S.censusBureau.allpercentagesinthereportwerecomputedusingunroundeddata.

Industrial Sand and Gravel

Totalindustrialsandandgravelproductionincreasedto30.6millionmetrictons(Mt)in2005andwasthehighestproductiontotalinthehistoryoftheU.S.industry(table1).comparedwith2004,industrialsandproductionincreasedby3.5%,andgravelproductiondecreasedby11%.

industrialsandandgravel,oftencalled“silica,”“silicasand,”and“quartzsand,”includessandsandgravelswithhighsilicondioxide(SiO

2)content.Someexamplesofendusesof

thesesandsandgravelsareinglassmakingandforabrasivefiltration,foundry,hydraulicfracturing(frac),andsiliconmetalapplications.Thespecificationsforeachusevary,butsilicaresourcesformostusesareabundant.inalmostallcases,silicaminingusesopenpitordredgingmethodswithstandardminingequipment.Exceptfortemporarilydisturbingtheimmediateareawhileoperationsareactive,sandandgravelminingusuallyhaslimitedenvironmentalimpact.

Theproductionincreaseforsilicasandfollowedseveralyearsofincreasingdemandformanyuses,whichincludedceramics,chemicals,fillers(groundandwhole-grain),filtration,flatandspecialtyglass,hydraulicfracturing,recreational,androofinggranules.Thedemandforsilicagravel,whichwasmostlyusedforfiltrationandnonmetallurgicalflux,experiencedasignificantdecrease.increasesinthetotalproductionandvalueofsilicacanbeattributedinparttoanoverallincreaseindemandandtogrowthintheeconomy,particularlytheconstructionsectors,petroleumsector,andincreasedenergycoststothesilicaproducersin2005.

Legislation and Government Programs.—Oneofthemostimportantissuesaffectingtheindustrialmineralsindustryinrecenttimeshasbeenthepotentialeffectofcrystallinesilicaonhumanhealth.centraltotheongoingandoftenheateddebatehasbeentheunderstandingoftheregulationsandtheimplementationofthemeasurementsandactionstakentomitigateexposuretocrystallinesilicaand,mostsignificantly,appreciationofitsimpactonthefutureofmanyindustries

(industrialMinerals,1998a).TheU.S.Departmentoflabor,OccupationalSafetyandHealthadministration(OSHa)hascreatedapermissibleexposurelimitthatstipulatesthemaximumamountofcrystallinesilicatowhichworkersmaybesafelyexposedduringan8-hourworkshift(29cFR§§1926.55,1910.1000).TheOSHaalsopresentsguidelinesandtrainingfortheproperhandlingofcrystallinesilica(U.S.Departmentoflabor,OccupationalSafetyandHealthadministration,2002§1).

importantnewsduring2005centeredonasilicosislitigationdecisionthatcontinuestoaffecttheindustrialsandandgravelindustry.inadecisionagainsttheplaintiffsbyaFederaljudgeinreSilicaProductsliabilitylitigation,398F.Supp.2d563(S.D.TexasJune30,2005),defendantsrequestedthatthecourtexaminethereliabilityofthousandsofsilicosisdiagnosesunderFederalRuleofcivilProcedure702andtheanalyticalframeworkdevelopedbyDaubertv.MerrellDowPharmaceuticals,inc.,509U.S.579(1993).Thecourtfoundthattheplaintiffswereattemptingtogeneraterevenuethroughsilicosislitigationasopposedtocreatingaprocedureforcompensatingtrulyinjuredindividuals,andsanctionsrelatingtoconductwereimposedontheplaintiffs’counsel.TheOSHarecentlyfoundthatdeathsattributedtosilicosisintheUnitedStateshavedeclinedsteadilyeachyearsincethelate1960sto187in1999from1,157in1968.

Production.—DomesticproductiondataforindustrialsandandgravelweredevelopedbytheUSGSfromavoluntarysurveyofU.S.producers.TheUSGScanvassed73producerswith151operationsknowntoproduceindustrialsandandgravel.Ofthe151surveyedoperations,136(90%)wereactive,and15wereidle.TheUSGSreceivedresponsesfrom108operations,andtheircombinedproductionrepresented85%oftheU.S.total.Productionforthe43nonrespondentswasestimated,primarilyonthebasisofpreviouslyreportedinformationsupplementedwithworker-hoursreportsfromtheU.S.Departmentoflabor’sMineSafetyandHealthadministrationandinformationfromStateagencies.

TheMidwest(EastNorthcentralandWestNorthcentraldivisions)continuedtoleadtheNationwith42%ofthe30.6MtofindustrialsandandgravelproducedintheUnitedStates,followedbytheSouth(Southatlantic,EastSouthcentral,andWestSouthcentraldivisions)with37%,andtheWest(PacificandMountaindivisions)with12%(fig.1,table2).

TheleadingproducingStateswere,indecreasingorder,illinois,Texas,Wisconsin,california,NewJersey,Michigan,Oklahoma,andOhio(table3).Theircombinedproductionrepresented61%ofthenationaltotal.Statesforwhichdatahavebeenwithheldintable3arenotincludedamongtheleadingproducers.Ofthe34Statesthatproducedsilicain2005,22hadincreasedproduction,10haddecreasedproduction,and2had

1areferencethatincludesasectionmark(§)isfoundintheinternetReferencecitedsection.

66.2 U.S.GEOlOGicalSURvEYMiNERalSYEaRBOOk—2005

stableproductioncomparedwith2004.illinois,Minnesota,andPennsylvaniareportedthelargestincreases,andNorthcarolina,NewJersey,andMichiganreportedthelargestdecreases.

Ofthetotalindustrialsandandgravel,84%wasproducedby48operations,eachwithproductionof200,000metrictonsperyear(t/yr)ormore(tables4-5).The10leadingproducersofindustrialsandandgravelwere,indescendingorder,Unimincorp.,U.S.Silicaco.,FairmountMineralsltd.,OglebayNortonindustrialSandsco.,BadgerMiningcorp.,Simplotindustriesinc.,littleSixcorp.,NugentSandco.inc.,ManleyBrothers,inc.,andSandProductscorp.Theircombinedproductionfrom64operationsrepresented83%oftheU.S.total.

Consumption.—industrialsandandgravelproductionreportedbyproducerstotheUSGSwasmaterialsoldtotheircustomersorusedbytheproducingcompanies.Stockpiledmaterialisnotreporteduntilconsumedorsold.Ofthe30.6Mtofindustrialsandandgravelsoldorused,35%wasconsumedasglassmakingsand,and18%,asfoundrysand(table6).Fracsandandsandforwellpackingandcementingconsumed14%ofindustrialsandandgravelproduction.Otherimportantuseswerebuildingproducts(8%)andabrasivesand(3%).

MinabledepositsofindustrialsandandgraveloccurthroughouttheUnitedStates,andsuccessfulminingcompaniesarelocatednearmarketsthathavetraditionallybeenintheEasternUnitedStates.insomecases,consumingindustriesarespecificallylocatednearasilicaresource.TheautomotiveindustrywasoriginallylocatedintheMidwestnearclay,coal,iron,andsilicaresources.Therefore,foundrysandshavebeenwidelyproducedinillinois,indiana,Michigan,Ohio,andotherMidwesternStates.in2005,morethan80%offoundrysandwasproducedintheMidwest.

conversely,theglassindustrylocatedplantswhereitcouldminimizetheshippingdistanceoffinishedglassproducts(forexample,containerorflat).Hence,glassplantsweremoreevenlydistributed.in2005,42%ofglasssandwasproducedintheSouth;31%,intheMidwest;16%,intheWest;and11%,intheNortheast.Tovaryingdegrees,allsilicaproductionandsalesaresimilarlyinfluencedbythelocationoftheconsumingindustries.

Producersofindustrialsandandgravelwereaskedtoprovidestatisticsonthedestinationofsilicaproducedattheiroperations.Theproducerswereaskedtolistonlythequantityofshipments(novaluedatawerecollectedinthissectionofthequestionnaire)andtowhichStateorotherlocationthematerialwasshippedforconsumption.TheStatesthatreceivedthemostindustrialsandandgravelwereTexas(9.2%),california(8.7%),illinois(7.5%),Ohio(5.2%),NewJersey(5%),andWisconsin(4%).Producersreportedsendingatleast821,000tofsilicatocanadaand439,000ttoMexico(table7).Becausesomeproducersdidnotprovidethisinformation,theirdatawereestimatedorassignedtothe“Destinationunknown”category.in2005,8.4%ofindustrialsandandgravelshippedbyproducerswasassignedtothatcategory.

Theshareofsilicasoldforalltypesofglassmakingasapercentageofallsilicasoldwas35%,thesamecomparedwiththatof2004.in2005,salestocontainerglassmanufacturersincreasedby9%comparedwiththoseof2004.Onaverage,inthecontainerglassmakingindustry,silicaaccountsfor60%of

rawmaterialsused(industrialMinerals,2004b).Theamountofsandconsumedforfiberglassproductiondecreasedby4%comparedwiththatof2004.

in2005,salesofsandforflatglassproductiondecreasedby8%comparedwiththoseof2004.intheMidwest,consumptionforflatglassdecreasedby22%,andintheSouth,consumptiondecreasedby4%.

Specialtyglassconsistsofmanysegments,butthelargestportioncompriseslaboratoryandlightingglass(forexample,incandescentandfluorescentlightbulbs).Specialtylaboratoryglassalsomakesuppartofthecomponentsusedinmanysegmentsoftheelectronicsindustry,includingtheproductionofopticalfiberandsemiconductors.

TheU.S.fiberglassindustrycomprisesfourmajorinsulationmanufacturersandsixmajortextileproducers.continuousglassfiberspecificationsareverystrict.Batchgrain-sizecontrolisveryimportant,sogroundsilica(ultrafinepowder)isused.iron,potassium,andsodiumoxidecontentistightlycontrolled.Therawmixisfusedat1,600°candthendrawnthroughplatinumbushingsat1,300°c.variousmineralwoolsarefabricatedusingbasaltanddiabase(rockwool),blastfurnaceslag(slagwool),orglass(glasswool)(industrialMinerals,1998c).

Silicaisusedinceramicsingroundandwhole-grainforms.Generally,22%to32%oftheceramicbodyofsanitaryware(forexample,sinks,toilets,urinals)consistsofwhole-grainsilica.Groundsilicaisusedtodecreaseviscosityandtheexpansioncoefficientofceramicglazesandceramicmaterialsinapplications.atypicalglazecompositionconsistsof25%quartzorsilica.in2005,208,000metrictons(t)ofgroundsilicawasusedinceramicproduction.

advancedceramics,suchassiliconnitrideandsiliconcarbide,representagrowingmarketforsilicaandsilica-basechemicals.Siliconcarbideismanufacturedbycookingsilicasandorcrushedquartzandoilcokeat2,400°cinanelectricfurnaceforseveraldays;sawdustorricehusksareaddedtoincreaseporosity.Becauseoftheanthropomorphicthermalconductivityandexpansioncoefficientofsiliconcarbide,itisespeciallyusefulintherefractoryindustry(industrialMinerals,1998b).applicationsforsiliconcarbideincludecompositebearingsusedinavarietyofpumpsorwearparts,suchasdynamicpressure,sealrings,shafts,andslidebearings.Theglobalmarketforsiliconnitride,basedonpowderuse,hasbeenestimatedtobe300,000t/yr.Primarymarketsforhybridbearings,whicharebasedonsiliconnitrideandsiliconcarbide,havebeenaerospacecomponents,dentaldrills,gyroscopes,machinetoolspindles,andvacuumsystems.Othermarketsforsiliconnitrideincludedcuttingtoolsandenginecomponents(ceramicindustry,1998).

Silicaalsoisusedinplasticsasanextender,filler,andreinforcer.Whole-grainandgroundsilicaareusedinfiller-typeapplications.Groundsilicaisusedtothickenliquidsystems,toavoidplateoutinpolyvinylchloride,asathixotropicandflattingagent,andinmanyotherfillerapplications.Silicaalsoisusedinpaintbecauseitoffersacid,scrubbing,andwearresistance.in2005,consumptionofwhole-grainfillerwas2.5Mt,andgroundsilicaforfillerwas465,000t.

Specialtysilicasareproducedprimarilybymeansofchemicalandthermalprocessingofnaturalsilicaorsiliconmetalorasa

Silica—2005 66.3

byproductofothermineralorchemicalprocessing.althoughtheUSGSdoesnotspecificallycollectinformationonspecialtysilicas,consumptiondoesaffectnaturalsilicasales.Specialtysilicasandsilanes(silicachemicals)includecolloidalsilicas,fusedsilica,organofunctionalsilanes,precipitatedsilica,pyrogenic(fumed)silica,quartz,silicagels,silicones,andultra-high-puritysilica.Thesesilicasareusedinavarietyofindustriesandproducts,whichincludeabrasives,adhesives,beverages,catalysts,coatings,electronics,encapsulants,food,healthcare,optics,paperandpackaging,plastics,refractories,rubber,sealants,specialtycoatings,textiles,thermoplastics,waferpolishing,andwatertreatment.additionally,surfacemodificationwithsilanescanimprovetheperformanceofseveraltypesofmineralfillersusedinplastics.Forexample,whentreatedwithsilanes,theperformanceofironoxidemineralfillerisgreatlyenhanced(industrialMinerals,2004a).

Fumedsilicaformstridimensionalpolymersusedasthixotropicagentsinsiliconsandsilanesandiswidelyusedasacoatingagentforfiller-gradecalciumcarbonate(industrialMinerals,1998c).intable6,industrialsandandgravelthatwouldfinditswayintothesespecialtysilicasismostlikelyreportedbytheproducersinthecategories“Sand,abrasives,chemicals,groundandunground,”“Gravel,silicon,ferrosilicon,”andpossibly“Glassmaking,specialty.”in2005,silicasalesforchemicalproductionwere830,000t,whichwasanincreaseof8%comparedwiththoseof2004.accordingtotheUSGSsurvey,reportedsalesofsilicagravelforsiliconandferrosiliconproductiondecreasedby11%in2005comparedwiththoseof2004.Themainusesforsiliconmetalareinthemanufactureofsilanesandsemiconductor-gradesiliconandintheproductionofaluminumalloys.consumptionmaybedownowingtonewtechniquesinthefieldofsemiconductorstoenablemanufacturerstodepositathin,defect-freelayerofsingle-crystalsilicononwafer-thinmicrochipsinagascontainingsilicon.Thisnewtechniquehassupersededthetraditionalmethodofcreatingamassivecylindricalingotofsiliconfromabatchofmoltensilicon,thesinglelargecrystalhavingtoomanydefectsforcurrentapplications(Hutcheson,2004).anothernewtechniqueinvolvesdeformingthecrystalstructureofsilicon,aprimarycomponentofallelectronicdevices.Thetechniquealtersthepropertiesofsiliconsothatthematerialwilltransmitanopticalorlight-basedsignal,possiblyresultinginreplacingelectroniccomponentswithfasteropticalcomponents.Moderncomputersmaybenefitfromsuchimprovements(Jacobsenandothers,2006).

Opticalfiberproductioninvolvesaseriesofhighlysophisticatedmanufacturingmethods.Fortheopticalfiber,aglasscorewithahighrefractiveindexsurroundedbyglasswithalowerrefractiveindexisrequired.Thisproblemhasbeensolvedbyusingseveralmanufacturingmethods,suchasproducingthefiberwithfusedsilicabutdopingitscorewithanelementthatincreasestherefractiveindex(industrialMinerals,1998b).

Thehigh-purityfusedsilicausedbytheelectronicsindustryistypicallyatleast99.95%SiO

2andhasahighelectromagnetic

radiationtransparency,averylowexpansioncoefficient,andgoodinsulationproperties.Silicagrainandpowderproductsaremainlyproducedfromfusedsilica,whichismadefromsilicasands.Fusedsilicahascharacteristicssimilartozircon

andisoftenmixedwithzircontoformcastingshells(industrialMinerals,2002b).

Syntheticprecipitatedsilicaandsilicagelareproducedbyreactingsodiumsilicatewithhydrochloricacid.Precipitatedsilicahasbeenusedincreasinglyintires,moresoinEuropethanintheUnitedStates.Throughreplacementofaportionofcarbonblackwithprecipitatedsilicainthetread,thereinforcingactionofthesilicaparticlesextendstirelife(industrialMinerals,2000b).Europeanconsumerspreferthe“green”tiresmadewithprecipitatedsilica,whichisusedin70%to80%oftiresforpassengercarsinEurope(industrialMinerals,2000a).

Transportation.—Ofallindustrialsandandgravelproduced,64%wastransportedbytruckfromtheplanttothesiteoffirstsaleoruse,upslightlyfrom2004;34%wastransportedbyrail,downslightlyfrom2004;andlessthan1%bywaterway.

Prices.—comparedwiththeaveragevalueof2004,theaveragevalue,freeonboardplant,ofU.S.industrialsandandgravelincreasedby7%to$24.56permetrictonin2005(table6).Theaverageunitvaluesforindustrialsandandindustrialgravelwere$24.69pertonand$20.42perton,respectively.Theaveragepriceforsandrangedfrom$6.75pertonformetallurgicalfluxto$103.85pertonforgroundfoundrysand.Forgravel,pricesrangedfrom$9.29pertonfornonmetallurgicalfluxto$49.79pertonforfiltration.ProducerpricesreportedtotheUSGSforsilicacommonlyrangedfromseveraldollarspertontohundredsofdollarsperton,andoccasionallypricesexceededthe$1,000-per-tonlevel.Nationally,groundsandforfoundrymoldingandcorehadthehighestvalue($103.85perton),followedbysilicaforswimmingpoolfilters($81.81perton),groundsandusedasfillersforpaint,putty,andrubber($59.32perton),groundsandforceramics($50.30perton),groundsandforscouringcleansers($47.96perton),silicaformunicipalwaterfiltration($46.02perton),sandforhydraulicfracturing($43.45perton),andgroundsandforfiberglass($40.81perton).

Bygeographicregion,theaveragevalueofindustrialsandandgravelwashighestintheSouth($26.72perton),followedbytheWest($26.05perton),theMidwest($23.16perton),andtheNortheast($20.13perton)(table6).PricescanvarygreatlyforsimilargradesofsilicaatdifferentlocationsintheUnitedStates.Forexample,theaveragevalueofcontainerglasssandvariedfrom$22.37pertonintheWestto$12.02pertonintheMidwest.TightersuppliesandhigherproductioncostsintheWestandmuchgreatercompetitionintheMidwestcausedthedifferenceinthecosttotheconsumerofsandandgravelinthesetworegions.

Foreign Trade.—Exportsofindustrialsandandgravelin2005increasedby63%comparedwiththeamountexportedin2004,andtheassociatedvaluedecreasedby12%(table8).ThelargeincreaseinexportscanbeattributedmainlytoincreaseddemandfromasianandNorthamericanmarkets.canadawastheleadingrecipientofU.S.exports.Thedistributionofexportswasasfollows:73%tocanada,10%toJapan,9.6%toMexico,1.4%toGermany,andtheremaindertoafricaandtheMiddleEast,Europe,Southamerica,andOceania.Theaveragepriceofexportsdecreasedto$53pertonin2005from$97pertonin2004.in2005,exportpricesvariedwidelybyregion;exportsofhighergradesilicatoEuropeaveraged$557perton,andexportstotherestoftheworldaveraged$40perton.


importsforconsumptionofindustrialsandandgravelroseto711,000t,whichwasanincreaseof45%comparedwiththoseof2004(table9).Mexicosupplied54%ofthesilicaimports,whichaveraged$10.66perton;thispriceincludedinsuranceandfreightcoststotheU.S.port.Thetotalvalueofimportswas$18.2million,withanaverageof$24perton.Higherpricedimportscamefromaustralia,china,Germany,andJapan.

World Industry Structure.—Basedoninformationprovidedmainlybyforeigngovernments,worldproductionofindustrialsandandgravelwasestimatedtobe118Mt(table11).TheUnitedStateswastheleadingproducerfollowed,indescendingorder,bySlovenia,Germany,austria,France,Spain,Japan,andtheUnitedkingdom.Mostcountriesintheworldhadsomeproductionandconsumptionofindustrialsandandgravel,whichareessentialtotheglassandfoundryindustries.Becauseofthegreatvariationinreportingstandards,however,obtainingreliableinformationwasdifficult.inadditiontothecountrieslisted,manyothercountrieswerethoughttohavehadsometypeofsilicaproductionandconsumption.

Outlook.—U.S.consumptionofindustrialsandandgravelin2006wasexpectedtobe26to28Mt.consumptionisexpectedtobe27Mt.allforecastsarebasedonpreviousperformancesforthiscommoditywithinvariousenduses,contingencyfactorsconsideredrelevanttothefutureofthecommodity,andforecastsmadebyanalystsandproducersinthevariousmarkets.

Salesofglasssandcanbeexpectedtovaryfrommarkettomarket.Growthhasbeennotedinsomesegments,suchasflatandspecialtyglasses,containerglass,fiberglass,andfracsand.Totaldemandforallglasssandendusesisexpectedremainstaticorpossiblyexhibitslowgrowth,probablytotherangeof10to11Mtthrough2006.Demandforindustrialsandandgravelwillalsobeconstrainedbytheproducer’srisingenergycostsforbothproductionandtransportationofproduct.

Thedemandforfoundrysandisdependentmainlyonautomobileandlighttruckproduction.anotherimportantfactorforthefutureconsumptionofvirginfoundrysandistherecyclingofusedfoundrysand.Thelevelofrecyclingisbelievedtobeincreasing.Othermaterialsormineralscompetewithsilicaasfoundrysand,buttheseother“sands”usuallysufferfromaseverepricedisadvantage.Basedonthesefactors,consumptionofsilicafoundrysandin2006isexpectedtobe5Mt,andconsumptionisexpectedtorangefrom5to5.3Mt.

Fracsandsalesincreasedin2005comparedwiththoseof2004.Basedonthistrend,demandforfracsandisexpectedtoincreasemodestlyduring2006to4Mt,witharangeof4to4.2Mt.

TheUnitedStatesistheleadingproducerandamajorconsumerofsilicasandandisself-sufficientinthisminedcommodity.MostofitisproducedatpremierdepositsintheMidwestandnearmajormarketsintheEasternUnitedStates.asignificantamountofsilicasandisalsoproducedintheWestandSouthwest,mostlyincaliforniaandTexas,respectively.Domesticproductionisexpectedtocontinuetomeet97%or98%ofdemandwellbeyond2006.importsmostlyfromcanadaandMexicoandhighervaluedmaterialfromchinaareexpectedtoremainminor.

Becausetheunitpriceofsilicasandisrelativelylow,exceptforafewendusesthatrequireahighdegreeofprocessing,thelocationofasilicasanddepositinrelationtothemarketisan

importantfactorthatmayworkfororagainstasandproducer.consequently,asignificantnumberofrelativelysmalloperationssupplylocalmarketswithalimitednumberofproducts.

Severalfactorscouldaffectsupplyanddemandrelationsforsilicasand.Furtherincreasesinthedevelopmentofsubstitutematerialsforglassandcastmetalscouldreducedemandforfoundryandglasssand.Thesesubstitutes,whicharemainlyceramicsandpolymers,wouldlikelyincreasethedemandforgroundsilica,whichisusedasafillerinplastics;glassfibers,whichareusedinreinforcedplastics;andsilica(chemical,ground,orwhole-grain),whichisusedtomanufactureceramics.increasedeffortstoreducewasteandtoincreaserecyclingalsocouldlowerthedemandforminedglasssand.Recyclingofglassculletisincreasinginmostindustrializednationsandrecyclingaccountsforapproximately25%to70%oftherawmaterialneededfortheglasscontainerindustryinmanycountries.ithasbeenestimatedthatforevery10%ofrecycledglassculletusedinthemeltingprocessforglasscontainermanufacture,energyusewillfallapproximately2.5%.Duringthepast20years,a25%to40%reductioninglasscontainerweighthastakenplaceinmanynations,includingtheUnitedStates(industrialMinerals,2004b).althoughdevelopmentscouldcausethedemandforsilicasandtodecrease,thetotalvalueofproductioncouldincreasebecauseoftheincreasedunitvalueofthemorespecializedsands.

Healthconcernsabouttheuseofsilicaasanabrasiveandstricterlegislativeandregulatorymeasuresconcerningcrystallinesilicaexposurecouldreducethedemandinmanysilicamarkets.Theuseofsilicasandintheabrasiveblastindustrywasbeingevaluatedasahealthhazardasmarketersofcompetingmaterials,whichincludegarnet,olivine,andslags,encouragedtheuseoftheir“safer”abrasivemedia.additionally,abrasive-gradebauxite,whichisthefeedstockforbrownfusedalumina,isfindingincreasinguseinabrasivesandproppants;inthelatterapplication,bauxiteisusedtoholdfracturesopeninoilwells,asissilicasand(industrialMinerals,2002a).

Quartz Crystal

Electronic-gradequartzcrystalissingle-crystalsilicawithpropertiesthatmakeituniquelyusefulinaccuratefilters,frequencycontrols,andtimersusedinelectroniccircuits.Thesedevicesareusedforavarietyofelectronicapplicationsinaerospacehardware,commercialandmilitarynavigationalinstruments,communicationsequipment,computers,andconsumergoods(forexample,clocks,games,televisionreceivers,andtoys).Suchusesgeneratepracticallyallthedemandforelectronic-gradequartzcrystal.alesseramountofoptical-gradequartzcrystalisusedforlensesandwindowsinspecializeddevices,whichincludesomelasers.

Naturalquartzcrystalwasusedinmostelectronicandopticalapplicationsuntil1971whenitwassurpassedbyculturedquartzcrystal.ithasbeenestimatedthatapproximately10billionquartzcrystalsandoscillatorswillbemanufacturedandinstalledworldwideinalltypesofelectronicdevices,fromautomobilestocellphonesin2006.Despitethisstaggeringnumber,quartztechnologycouldfacecompetitioninthenearfuturewiththeadventofmorecosteffectivemicroelectromechanicalsystems(MEMS).MEMStechnologywasfirstdevelopedin1965and

Silica—2005 66.5

consistsofsilicononinsulatedwafers.MEMStechnologyisphysicallycompatiblewithexistingquartzoscillatorproductsandhavebetterlong-termstabilityperformancecharacteristicsforuseinconsumerandcomputationalproducts,automotive,andwirelessapplications(Partridge,2006).

Theuseofnaturalquartzcrystalforcarvingsandothergemstoneapplicationshascontinued;moreinformationcanbefoundinthe“Gemstones”chapteroftheUSGSMineralsYearbook,volumei,MetalsandMinerals.

Legislation and Government Programs.—ThestrategicvalueofquartzcrystalwasdemonstratedduringWorldWariiwhenitgainedwidespreaduseasanessentialcomponentofmilitarycommunicationsystems.afterthewar,naturalelectronic-gradequartzcrystalwasofficiallydesignatedasastrategicandcriticalmaterialforstockpilingbytheFederalGovernment.culturedquartzcrystal,whicheventuallysupplantednaturalcrystalinnearlyallapplications,wasnotcommerciallyavailablewhenacquisitionofnaturalquartzcrystalforanationalstockpilebegan.

asofDecember31,theNationalDefenseStockpile(NDS)contained7,236kilograms(kg)ofnaturalquartzcrystal.Thestockpilehas11weightclassesfornaturalquartzcrystalthatrangefrom0.2kgtomorethan10kg.Thestockpiledcrystals,however,areprimarilyinthelargerweightclasses.Thelargerpiecesaresuitableasseedcrystals,whichareverythincrystalscuttoexactdimensions,toproduceculturedquartzcrystal.inaddition,manyofthestockpiledcrystalscouldbeofinteresttothespecimenandgemstoneindustry.little,ifany,ofthestockpiledmaterialislikelytobeusedinthesameapplicationsasculturedquartzcrystal.

NonaturalquartzcrystalwassoldfromtheNDSin2005.TheFederalGovernmentcontinuestoassessitsstockpilegoalsfortheremainingmaterial.Previously,onlyindividualcrystalsintheNDSinventorythatweighed10kgormoreandcouldbeusedasseedmaterialweresold.Braziltraditionallyhasbeenthesourceofsuchlargenaturalcrystals,butchangesinminingoperationshavereducedoutput.

Quartzcrystalisalsoaffectedbytheregulationofcrystallinesilicaasdiscussedinthe“legislationandGovernmentPrograms”portionofthe“industrialSandandGravel”sectionofthischapter.

Production.—TheUSGScollectsproductiondataforquartzcrystalthroughasurveyofthedomesticindustry.in2005,nodomesticcompaniesreportedtheproductionofculturedquartzcrystal.inthepastseveralyears,culturedquartzcrystalwasbeingpredominantlyproducedoverseas,primarilyinasia.

companiesproduceculturedquartzcrystalbyusingahydrothermalprocessinlargepressurevesselscalledautoclaves.Seedcrystalsaremountedonracksandsuspendedintheuppergrowthregionofthevessel.lascas,whichisahigh-puritynaturalquartzfeedstock,isloadedinanopen-meshwirebasketthatisplacedinthebottomoftheautoclave.asolutionofsodiumhydroxideorsodiumcarbonate(themineralizer)withsuchadditivesaslithiumsaltsanddeionizedordistilledwaterisusedtofillthevesselto75%to85%ofitsvolume.Thebottomhalfofthegrowingvesselisheatedtotemperaturesaveragingbetween350°and400°c;thetemperatureofthetopportionismaintainedat5°to50°clowerthanthatinthebottomhalfofthevessel,dependinguponthemineralizerused.atthese

temperatures,thesolutionexpandsandcreatesinternalpressurebetween700and2,100kilogramspersquarecentimeter.Undertheseconditions,thelascasdissolvestocreateasolutionsaturatedwithsilica.Throughconvection,thesaturatedsolutiontransportsdissolvedsilicatothecoolerupperhalfofthevesselwhereitbecomessupersaturated,andtheexcessdissolvedquartzdepositsontheseedcrystalsinthetophalfoftheautoclave.Theprocesscontinuesuntilthegrowingcrystalsreachtheirdesiredsize.Theprocessnormallytakesfrom30to60daysfora1-inch-thickbarandlongerforlargercrystals;atleastoneproducerhasmaderunsof180days.Theculturedcrystalscanbecustomgrownwithspecificproperties.

Processingquartzcrystalforvariousendusesisthesamewhethernaturalorculturedseedcrystalisused.Producers,however,mustavoidseedcrystalswithdefectsthatcouldbepassedontonewgenerationsofculturedcrystal.Naturalquartzcrystalispreferredasseedmaterialtoensurethatgeneticdefectswillnotberepeatedinthesucceedinggenerations.

Onceproduced,culturedcrystalsareexaminedforphysicaldefectsbeforecutting.Theyarethencut,usuallywithdiamondorslurrysaws,alongapredeterminedcrystallographicplanetoathicknessslightlylargerthanthatdesired.Eachwaferisinspectedanddicedintoblanksofthedesireddimensions.Theblanksthenprogressthroughaseriesoflappingstagesuntiltheyreachthefinalthickness,electrodesareattached,andthecrystalsaremountedinsuitableholders.Thefinalassembly,whichiscalledaquartzcrystalunit,isreadyforinsertionintoanelectroniccircuit.

Consumption.—in2005,theUSGScollecteddomesticconsumptiondataforquartzcrystalthroughasurveyof23U.S.operationsthatfabricatequartzcrystaldevicesin9States.Ofthe23operations,9respondedtothesurvey.consumptionfornonrespondentswasestimatedbasedonreportsfrompreviousyears.

Quartzcrystalisusedinpiezoelectricandopticalapplications.Thepiezoelectriceffectisachievedwhenasuitableelectricalsignalappliedtoaquartzwafermakesthewafervibratemechanicallythroughoutthebulkofthematerialatacharacteristicnaturalresonancefrequency.Quartzresonatorsareuniquelysuitableforaerospace,commercial,andmilitarybandpassfilterapplicationsthatrequireveryhighselectivityorforoscillatorapplicationsthatrequireveryhighstability.inaddition,formanyapplicationsthatrequireonlymoderatestability,aquartzresonatoroffersauniquecombinationofhighperformance,smallsize,andlowcost.Quartzresonatorsalsoareusedformanylessdemandingapplications,suchasprovidingtimingsignalsforelectroniccircuitsinautomotive,consumer,andindustrialproducts.

culturedquartzisusedalmostexclusivelybythecrystaldeviceindustrybecauseofthecostadvantages.Forresonatorapplications,rawculturedquartzmustbecutintothinwafersorientedpreciselyinlinewithrawmaterialcrystalaxes.Theuniformityandconvenienceofculturedquartzhavemadeitsusealmostuniversal.Unlikeculturedquartz,naturalelectronic-gradequartzrequiresspecialorientation,cutting,grading,andsizingtoproduceaquartzwafer.asaresult,mostdevicemanufacturersthatcutnaturalquartzinthepasthavediscontinueditsuse.Oneoftheremainingapplicationsofthenaturalelectronic-gradematerialisinpressuretransducersusedindeepwells.


Quartzwafersmustbecutthinforpracticaluseatveryhighfrequencies(above100megahertz).Quartzcrystalstructuresthatusesurfacevibrations,inwhichthefrequencyisdeterminedbyelectrodedimensionsratherthanbywaferthickness,havebecomemoreprevalentatthesehigherfrequencies.Thesestructuresarecalledsurfaceacousticwavedevices.

Mostopticalapplicationsusequartzinthefusedformassilicaglass.Smallquantitiesofculturedquartzcrystalareuseddirectlyinopticalapplications.Quartzcrystalalsohasusesthatinvolvebirefringentfilters,Brewsterwindowsandprisms,normallypolarizedlaserbeams,quartzretardationplates(especiallyquartzwaveplates),andtuningelementsinlaseroptics.

Prices.—Theaveragevalueofas-grownculturedquartzandlumberedquartz,whichisas-grownquartzthathasbeenprocessedbysawingandgrinding,wasestimatedtobe$156perkilogramin2005.

Foreign Trade.—TheU.S.Departmentofcommerce(DOc),whichisthemajorGovernmentsourceofU.S.tradedata,doesnotprovidespecificimportorexportstatisticsonlascas.TheDOcalsocollectsexportandimportstatisticsonelectronicandoptical-gradequartzcrystal;however,thequartzcrystalexportandimportquantitiesandvaluesreportedinpreviousyearsincludedzirconiaandwereinadvertentlyreportedtobequartzcrystalnotincludingmountedpiezoelectriccrystals.

World Review.—culturedquartzcrystalproductionisconcentratedinchina,Japan,Russia,andtheUnitedStates;severalcompaniesproducecrystalineachcountry.OtherproducingcountriesareBelgium,Brazil,Bulgaria,France,Germany,Southafrica,andtheUnitedkingdom.Detailsconcerningquartzoperationsinchina,theEasternEuropeancountries,andmostnationsofthecommonwealthofindependentStatesareunavailable.OperationsinRussia,however,havesignificantcapacitytoproducesyntheticquartz.

Outlook.—Thetrendtowardimportingquartzcouldhaveanegativeeffectondomesticquartzgrowers.Growthoftheconsumerelectronicsmarket(forexample,automobiles,cellulartelephones,electronicgames,andpersonalcomputers),particularlyintheUnitedStates,willcontinuetoprovideconsumeroutletsfordomesticproduction.Thegrowingglobalelectronicsmarketmayrequireadditionalproductioncapacityworldwide.

Special Silica Stone Products

Silicastone(anothertypeofcrystallinesilica)productsarematerialsforabrasivetools,suchasdeburringmedia,grindingpebbles,grindstones,hones,oilstones,stonefiles,tube-millliners,andwhetstones.Theseproductsaremanufacturedfromnovaculite,quartzite,andothermicrocrystallinequartzrock.Thischapter,however,excludesproductsthatarefabricatedfromsuchmaterialsbyartificialbondingoftheabrasivegrains(informationonothermanufacturedandnaturalabrasivesmaybefoundinotherUSGSMineralsYearbook,volumei,MetalsandMineralschapters).

Specialsilicastoneisalsoaffectedbytheregulationofcrystallinesilicaasdiscussedinthe“legislationandGovernmentPrograms”partofthe“industrialSandandGravel”sectionofthischapter.

Production.—inresponsetoaUSGSproductionsurvey,fourofsevendomesticfirms,representing88%ofcrudeproduction,respondedduring2005.Datafortheremainingproducerswereestimated.arkansasaccountedformostofthevalueandquantityofproductionreported.Plantsinarkansasmanufacturedfiles,deburring-tumblingmedia,oilstones,andwhetstones(table10).

Theindustryhasproducedandmarketedfourmaingradesofarkansaswhetstoneinrecentyears.Thegradesrangefromthehigh-qualityblackhardarkansasstonedowntoWashitastone.ingeneral,theblackhardarkansasstonehasaporosityof0.07%andawaxyluster,andWashitastonehasaporosityof16%andresemblesunglazedporcelain.

Consumption.—Thedomesticconsumptionofspecialsilicastoneproductsisbyacombinationofcraft,household,industrial,andleisureuses.Theleadinghouseholduseisforsharpeningofknivesandothercutlery,lawnandgardentools,scissors,andshears.Majorindustrialusesincludedeburringofmetalandplasticcastings,polishingofmetalsurfaces,andsharpeningandhoningofcuttingsurfaces.Themajorrecreationaluseisinsharpeningofarrowheads,fishhooks,spearpoints,andsportsknives.Theleadingcraftapplicationissharpeningtoolsforengraving,jewelrymaking,andwoodcarving.Silicastonefilesarealsousedinthemanufacture,modification,andrepairoffirearms.

Prices.—Theaveragevalueofcrudematerialsuitableforcuttingintofinishedproductswas$989perton.Theaveragevalueofstoneproductsmadefromcrudematerialwas$3.97perkilogram(table1).

Foreign Trade.—in2005,silicastoneproductexportshadavalueof$10million,upfromthatof2004.Theseexportswerecategorizedas“handsharpeningorpolishingstones”bytheDOc.Thiscategoryaccountedformost,ifnotall,ofthesilicastoneproductsexportedin2005.

in2005,thevalueofimportedsilicastoneproductswas$7.7million;thiswasanincreaseof12.9%comparedwiththatof2004.Theseimportswerehandsharpeningorpolishingstones,whichaccountedformostoforalltheimportedsilicastoneproductsin2005.aportionofthefinishedproductsthatwereimportedmayhavebeenmadefromcrudenovaculiteproducedintheUnitedStatesandexportedforprocessing.

Outlook.—consumptionpatternsforspecialsilicastonearenotexpectedtochangesignificantlyduringthenextseveralyears.Mostoftheexistingmarketsarewelldefined,andtheprobabilityofnewusesislow.

Tripoli

Tripoli,broadlydefined,includesextremelyfinegrainedcrystallinesilicainvariousstagesofaggregation.Grainsizesusuallyrangefrom1to10micrometers(µm),butparticlesassmallas0.1to0.2µmarecommon.commercialtripolicontains98%to99%silicaandminoramountsofalumina(asclay)andironoxide.Tripolimaybewhiteorsomeshadeofbrown,red,oryellowdependinguponthepercentageofironoxide.

Tripolialsoisaffectedbytheregulationofcrystallinesilicaasdiscussedinthe“legislationandGovernmentPrograms”partofthe“industrialSandandGravel”sectionofthischapter.

Silica—2005 66.7

Production.—in2005,fiveU.S.firmswereknowntoproduceandprocesstripoli.americanTripolico.producedcrudematerialinOttawacounty,Ok,andfinishedmaterialinNewtoncounty,MO.keystoneFillerandManufacturingco.inNorthumberlandcounty,Pa,processedrottenstone,whichisdecomposedfine-grainedsiliceousshalepurchasedfromlocalsuppliers.MalvernMineralsco.inGarlandcounty,aR,producedcrudeandfinishedmaterialfromnovaculite.Harbison-WalkerRefractoriesco.inc.inHotSpringscounty,aR,producedcrudeandfinishedtripolithatisconsumedintheproductionofrefractorybricksandshapes.UniminSpecialtyMineralsinc.inalexandercounty,il,producedcrudeandfinishedmaterial.allthesefirmsexceptonerespondedtotheUSGSsurvey.

Consumption.—The2005USGSannualsurveyofproducersindicatedthatsalesofprocessedtripolidecreasedby3%inquantityto91,000twithavalueof$18.7million(table1).

Tripolihasuniqueapplicationsasanabrasivebecauseofitshardnessanditsgrainstructure,whichlacksdistinctedgesandcorners.itisamildabrasive,whichmakesitsuitableforuseintoothpasteandtooth-polishingcompounds,industrialsoaps,andmetal-andjewelry-polishingcompounds.Theautomobileindustryusesitinbuffingandpolishingcompoundsforlacquerfinishing.

Theend-usepatternfortripolihaschangedsignificantlyinthepast30years.in1970,nearly70%oftheprocessedtripoliwasusedasanabrasive.in2005,12%oftripolioutputwasusedasanabrasive.Theremainderwasusedinbrakefrictionproducts,asafillerandextenderinenamel,caulkingcompounds,linings,paint,plastic,refractories,rubber,andotherproducts.

Theprimaryuseoftripoli(84%)isasafillerandextenderinpaints.inexteriorlatexpaints,tripolialsoaidsindurability,flowability,leveling,andtintretention.inenamels,itmakesapplicationeasierandimprovessheen.Thecontrolledgrainandparticlesizeoftripoliinpaintsimprovesdispersalandpromotesamoreuniformcoating.additionally,paintswithtripoliresistchemicalagentsandwearbetterthanthoseinwhichwater-groundwhitingsandothersofterormorereactivefillersareused.

Plastics,resins,andrubberseachaccountfor5%ofthetripoliusedasafillerandextender.Tripoliisusedinplasticsforelectricalusesbecauseofitsdielectriccharacteristicsanditseffectsoncompressionandflexibilityproperties.itschemicalresistance,resistancetosaltspray,andweatherabilityalsoareimportanttoitsuseinplastics.Thephysicalpropertiesoftripoliallowhighfrictionalloadinginmostcompounds,butitsabrasivenessresultsinhighwearinextrudingnozzlesandmolds.Thesamepropertiesthatmaketripoliusefulasafillerandextenderinplasticmakeitvaluabletotherubberandresinindustries.

Price.—TheaveragereportedunitvalueofalltripolisoldorusedintheUnitedStateswas$206pertonin2005.TheaveragereportedunitvalueofabrasivetripolisoldorusedintheUnitedStatesduring2005was$197perton,andtheaveragereportedunitvalueoffillertripolisoldoruseddomesticallywas$209perton.

Outlook.—consumptionpatternsfortripoliarenotexpectedtochangesignificantlyduringthenextseveralyears.Mostoftheexistingmarketsarewelldefined,andtheprobabilityofnewusesislow.

References Cited

ceramicindustry,1998,Silicon-basedceramics:ceramicindustry,v.148,no.6,June,p.48.

Hutcheson,G.D.,2004,Thefirstnanochips:Scientificamerican,v.290,no.4,april,p.78.

industrialMinerals,1998a,crystallinesilica:industrialMinerals,no.367,april,p.109-117.

industrialMinerals,1998b,Syntheticminerals—Part1:industrialMinerals,no.371,august,p.45-55.

industrialMinerals,1998c,Syntheticminerals—Part2:industrialMinerals,no.372,September,p.57-67.

industrialMinerals,2000a,NipponSilicasuppliesfuel-efficienttires:industrialMinerals,no.395,august,p.11-12.

industrialMinerals,2000b,Writteninsand—Theworldofspecialtysilicas:industrialMinerals,no.390,March,p.49-59.

industrialMinerals,2002a,abrasivebauxite—Givingproppantsthenod:industrialMinerals,no.418,July,p.36-41.

industrialMinerals,2002b,Breakingthemould—Mineralopportunitiesininvestmentcasting:industrialMinerals,no.419,august,p.38-43.

industrialMinerals,2004a,Boundforsuccess—Silane-treatedfillersforplastics:industrialMinerals,no.445,October,p.54-59.

industrialMinerals,2004b,Theglasspack—Mineralsincontainerglass:industrialMinerals,no.439,april,p.75-81.

Jacobsen,R.S.,andersen,k.N.,Borel,P.i.,Fage-Pedersen,J.,Frandsen,l.H.,Hansen,O.,kristensen,M.,lavrinenko,a.v.,Moulin,G.,Ou,H.,Peucheret,c.,Zsigri,B.,andBjarklev,a.,2006,Strainedsiliconasanewelectro-opticmaterial:Nature,v.441,May,p.199-202.

Partridge,a.,2006,anewparadigmintime—SiliconMEMSresonatorsvs.quartzcrystals:R&DMagazine,v.48,no.4,april,p.18-21.

Internet Reference Cited

U.S.Departmentoflabor,OccupationalSafetyandHealthadministration,2002,crystallinesilicahealthhazardinformation,FactSheet,accessedJuly26,2004,atURlhttp://www.osha.gov/OshDoc/data_General_Facts/crystalline-factsheet.pdf.

GENERAL SOURCES OF INFORMATION

U.S. Geological Survey Publications

abrasives,Manufactured.ch.inMineralsYearbook,annual.abrasives,Manufactured.MineralindustrySurveys,quarterly.Garnet,industrial.ch.inMineralsYearbook,annual.PumiceandPumicite.ch.inMineralsYearbook,annual.Quartzcrystal.ch.inMineralcommoditySummaries,annual.SilicaSand.ch.inUnitedStatesMineralResources,

ProfessionalPaper820,1973.

Other

aStockpilePrimer.U.S.DepartmentofDefense,DirectorateofStrategicMaterialsManagement,august1995.

aggregatesManager,monthly.ceramicsindustry,monthly.ElectroniccomponentNews,monthly.ElectronicNews,weekly.Electronics,biweekly.EngineeringandMiningJournal,monthly.Glassinternational,monthly.industrialMinerals,monthly.Pit&Quarry,monthly.RockProducts,monthly.SandandGravel.ch.inMineralFactsandProblems,U.S.

BureauofMinesBulletin675,1985.


TABLE 1

SALIENT U.S. SILICA STATISTICS1

(Thousand metric tons and thousand dollars unless otherwise specified)

2001 2002 2003 2004 2005

Industrial sand and gravel:2

Sold or used:

Quantity:

Sand 26,900 25,900 26,300 28,700 29,700

Gravel 1,060 1,420 1,140 1,070 955

Total 27,900 27,300 27,500 29,700 30,600

Value:

Sand 559,000 554,000 594,000 668,000 733,000

Gravel 17,600 19,400 15,300 16,600 19,500

Total 576,000 573,000 609,000 685,000 752,000

Exports:

Quantity 1,540 1,410 2,620 1,790 2,910

Value 163,000 145,000 155,000 174,000 154,000

Imports for consumption:

Quantity 172 250 440 490 711

Value 11,000 8,650 9,210 12,400 18,200

Processed tripoli:3

Quantity metric tons 60,500 66,600 68,800 94,000 91,100

Value 15,000 16,600 17,700 19,400 18,700

Special silica stone:

Crude production:

Quantity metric tons 705 748 1,070 227 193

Value 234 240 313 132 191

Sold or used:

Quantity metric tons 393 386 513 655 576

Value 4,040 3,740 3,630 3,660 2,2901Data are rounded to no more than three significant digits; may not add to totals shown.2Excludes Puerto Rico.3Includes amorphous silica and Pennsylvania rottenstone.

TABLE 2

INDUSTRIAL SAND AND GRAVEL SOLD OR USED IN THE UNITED STATES, BY GEOGRAPHIC DIVISION1

2004 2005

Quantity Quantity

(thousand Percentage Value Percentage (thousand Percentage Value Percentage

Geographic region metric tons) of total (thousands) of total metric tons) of total (thousands) of total

Northeast:

New England W W W W W W W W

Middle Atlantic 2,760 9 $53,300 8 2,720 9 $54,800 7

Midwest:

East North Central 9,990 34 193,000 28 10,600 35 223,000 30

West North Central 2,030 7 57,300 8 2,240 7 74,300 10

South:

South Atlantic 4,460 15 92,700 14 4,080 13 96,800 13

East South Central 1,680 6 36,200 5 1,760 6 38,000 5

West South Central 5,290 18 165,000 24 5,550 18 170,000 23

West:

Mountain 1,210 4 22,700 3 1,280 4 26,000 3

Pacific 2,310 8 63,800 9 2,390 8 69,600 9

Total 29,700 100 685,000 100 30,600 100 752,000 100W Withheld to avoid disclosing company proprietary data; included in "Middle Atlantic."1Data are rounded to no more than three significant digits; may not add to totals shown.

Silica—2005 66.9

TABLE 3

INDUSTRIAL SAND AND GRAVEL SOLD OR USED IN

THE UNITED STATES, BY STATE1

(Thousand metric tons and thousand dollars)

2004 2005

State Quantity Value Quantity Value

Alabama 643 9,800 710 11,200

Arizona W 792 W W

Arkansas W W W W

California 1,990 55,700 2,030 60,400

Colorado W 3,300 W W

Florida 679 8,520 715 9,410

Georgia 665 13,400 689 15,000

Idaho W W W W

Illinois 4,950 86,200 5,510 104,000

Indiana W W W W

Iowa W W W W

Kansas W W W W

Louisiana 476 14,800 509 11,600

Maryland W W W W

Michigan 1,690 25,200 1,610 24,500

Minnesota W W W W

Mississippi W W W W

Missouri 589 14,200 559 14,500

Nebraska W W -- --

Nevada W W W W

New Jersey 2,020 35,800 1,820 34,100

New Mexico -- -- W W

New York W W -- --

North Carolina 1,630 29,000 1,150 29,200

North Dakota W W W W

Ohio 1,180 34,200 1,230 37,900

Oklahoma 1,390 31,600 1,480 33,500

Pennsylvania 570 11,800 711 15,400

Rhode Island W W 195 5,250

South Carolina 719 17,600 794 19,400

Tennessee 975 26,100 985 26,500

Texas 2,790 109,000 2,840 114,000

Virginia W W W W

Washington W W W W

West Virginia 343 17,300 369 17,800

Wisconsin 2,140 47,000 2,250 55,700

Other 4,300 93,300 4,380 112,000

Total 29,700 685,000 30,600 752,000W Withheld to avoid disclosing company proprietary data;

included in "Other." -- Zero.1Data are rounded to no more than three significant digits; maynot add to totals shown.


TABLE 4

INDUSTRIAL SAND AND GRAVEL PRODUCTION IN THE UNITED

STATES IN 2005, BY SIZE OF OPERATION1

Quantity

Number of Percentage (thousand Percentage

Size range operations of total metric tons) of total

Less than 25,000 20 16 259 1

25,000 to 49,999 9 7 303 1

50,000 to 99,999 21 17 1,390 5

100,000 to 199,999 25 20 3,140 10

200,000 to 299,999 10 8 2,210 7

300,000 to 399,999 9 7 2,860 9

400,000 to 499,999 3 2 1,200 4

500,000 to 599,999 6 4 2,970 10

600,000 to 699,999 4 3 2,330 8

700,000 and more 16 13 14,000 46

Total 123 100 30,600 1001Data are rounded to no more than three significant digits; may not add to totals

shown.

TABLE 5

NUMBER OF INDUSTRIAL SAND AND GRAVEL OPERATIONS AND PROCESSING PLANTS

IN THE UNITED STATES IN 2005, BY GEOGRAPHIC DIVISION

Mining operations on land

Stationary No plants Total

and or Dredging active

Geographic region Stationary Portable portable unspecified operations operations

Northeast:

New England 1 -- -- -- -- 1

Middle Atlantic 5 -- -- -- 3 8

Midwest:

East North Central 25 -- -- -- 3 28

West North Central 6 -- -- -- 3 9

South:

South Atlantic 18 1 -- -- 6 25

East South Central 9 -- -- -- 2 11

West South Central 17 -- -- -- 5 22

West:

Mountain 5 1 1 -- -- 7

Pacific 12 -- -- -- -- 12

Total 98 2 1 -- 22 123-- Zero.

Silica—2005 66.11

TABLE 6

INDUSTRIAL SAND AND GRAVEL SOLD OR USED BY U.S. PRODUCERS IN 2005, BY MAJOR END USE1

Northeast Midwest South

Unit Unit Unit

Quantity value2 Quantity value2 Quantity value2

(thousand Value (dollars (thousand Value (dollars (thousand Value (dollars

Major use metric tons) (thousands) per ton) metric tons) (thousands) per ton) metric tons) (thousands) per ton)

Sand:

Glassmaking:

Containers W W 20.39 1,640 $19,700 12.02 1,680 $28,600 17.08

Flat, plate and window W W 19.07 844 12,500 14.85 1,510 27,100 18.01

Specialty W W 26.24 284 7,630 26.87 331 8,270 24.98

Fiberglass, unground W W 19.88 332 4,710 14.20 520 8,870 17.07

Fiberglass, ground -- -- -- 155 4,540 29.26 453 20,500 45.16

Foundry:

Molding and core, unground 149 $4,620 30.98 4,400 70,200 15.93 737 13,200 17.92

Molding and core, ground -- -- -- 9 872 96.89 4 478 119.50

Refractory (3) 9 30.95 8 711 88.88 96 2,210 23.03

Metallurgical:

Silicon carbide -- -- -- -- -- -- -- -- --

Flux for metal smelting -- -- -- -- -- -- W W 19.05

Abrasives:

Blasting 55 1,910 34.73 78 3,210 41.18 655 17,200 26.25

Scouring cleansers, ground (3) 1 70.82 W W 97.50 W W 44.62

Sawing and sanding W W 21.00 -- -- -- W W 41.33

Chemicals, ground and unground W W 26.86 391 7,130 18.22 404 11,500 28.35

Fillers, ground, rubber, paints, putty, etc. W W 40.40 339 11,700 34.65 119 15,500 130.46

Whole grain fillers/building products 255 9,630 37.75 522 17,000 32.63 991 26,300 26.53

Ceramic, ground, pottery, brick, tile, etc. W W 82.80 33 2,120 64.30 120 6,800 56.68

Filtration:

Water, municipal, county, local 53 1,790 33.81 57 2,690 47.23 154 6,300 40.91

Swimming pool, other 8 752 94.00 W W 89.69 26 2,470 94.85

Petroleum industry:

Hydraulic fracturing (3) 2 41.45 2,740 110,000 40.19 1,250 63,100 50.53

Well packing and cementing 11 646 58.73 2 162 81.00 228 7,820 34.30

Recreational:

Golf course, greens and traps 134 3,200 23.87 337 7,650 22.71 344 4,240 12.31

Baseball, volleyball, play sand, beaches 10 611 61.10 101 3,310 32.72 122 1,530 12.51

Traction, engine 20 469 23.45 60 1,160 19.35 69 1,270 18.42

Roofing granules and fillers W W 26.75 33 867 26.27 145 2,660 18.31

Other, ground silica 5 213 42.80 37 1,540 41.19 46 2,060 44.74

Other, whole grain 2,020 30,600 15.15 344 6,590 19.14 934 12,700 13.64

Total or average 2,720 54,400 20.02 12,800 296,000 23.23 10,900 291,000 26.60

Gravel:

Silicon, ferrosilicon -- -- -- W W 7.08 W W 15.31

Filtration W W W 11 645 58.64 W W 57.00

Nonmetallurgical flux -- -- -- W W 18.74 -- -- --

Other uses, specified W W W W W 7.82 466 13,800 29.56

Total or average 4 374 93.50 99 1,330 13.45 466 13,800 29.56

Grand total or average 2,720 54,800 20.13 12,900 298,000 23.16 11,400 304,000 26.72

See footnotes at end of table.


TABLE 6—Continued

INDUSTRIAL SAND AND GRAVEL SOLD OR USED BY U.S. PRODUCERS IN 2005, BY MAJOR END USE1

West U.S. total

Unit Unit

Quantity value2 Quantity value2

(thousand Value (dollars (thousand Value (dollars

Major use metric tons) (thousands) per ton) metric tons) (thousands) per ton)

Sand:

Glassmaking:

Containers W W 22.37 4,950 $83,700 16.90

Flat, plate and window W W 22.19 3,130 56,200 17.97

Specialty W W 39.38 826 21,500 26.08

Fiberglass, unground W W 22.72 1,020 17,100 16.79

Fiberglass, ground W W 36.44 641 26,200 40.81

Foundry:

Molding and core, unground 68 $1,760 25.91 5,360 89,700 16.75

Molding and core, ground -- -- -- 13 1,350 103.85

Refractory -- -- -- 104 2,930 28.18

Metallurgical:

Silicon carbide -- -- -- -- -- --

Flux for metal smelting W W 6.63 W W 6.75

Abrasives:

Blasting 119 6,180 51.96 908 28,500 31.38

Scouring cleansers, ground -- -- -- W W 47.96

Sawing and sanding W W 42.10 18 711 39.50

Chemicals, ground and unground W W 28.71 830 19,500 23.53

Fillers, ground, rubber, paints, putty, etc. W W 36.67 465 27,600 59.32

Whole grain fillers/building products 749 25,800 34.38 2,520 78,700 31.28

Ceramic, ground, pottery, brick, tile, etc. W W 27.76 208 10,500 50.30

Filtration:

Water, municipal, county, local 112 6,470 57.79 375 17,300 46.02

Swimming pool, other W W 44.20 59 4,830 81.81

Petroleum industry:

Hydraulic fracturing W W 47.47 4,010 174,000 43.45

Well packing and cementing 32 913 28.53 273 9,540 34.96

Recreational:

Golf course, greens and traps 260 6,420 24.68 1,070 21,500 20.02

Baseball, volleyball, play sand, beaches 14 266 19.00 247 5,710 23.11

Traction, engine 12 361 30.08 161 3,260 20.26

Roofing granules and fillers W W 16.80 255 5,530 21.69

Other, ground silica 107 3,170 29.44 XX XX XX

Other, whole grain 1,810 40,200 22.23 XX XX XX

Total or average 3,280 91,500 27.90 29,700 733,000 24.69

Gravel:

Silicon, ferrosilicon -- -- -- 343 5,150 15.02

Filtration 22 715 32.50 52 2,590 49.79

Nonmetallurgical flux 263 2,400 9.12 W W 9.29

Other uses, specified 101 905 8.97 XX XX 31.65

Total or average 386 4,020 10.41 955 19,500 20.42

Grand total or average 3,670 95,500 26.05 30,600 752,000 24.56W Withheld to avoid disclosing company proprietary data; for sand, included in "Other, ground silica" or "Other, whole

grain;" for gravel, included in "Other uses, specified." XX Not applicable. -- Zero.1Data are rounded to no more than three significant digits except for unit values; may not add to totals shown.2Calculated using unrounded data.3Less then ½ unit.

Silica—2005 66.13

TABLE 7

INDUSTRIAL SAND AND GRAVEL SOLD OR USED, BY DESTINATION1

(Thousand metric tons)

Destination 2004 2005 Destination 2004 2005

States: States—Continued:

Alabama 657 623 New Jersey 1,460 1,490

Alaska (2) 1 New Mexico 179 169

Arizona 68 55 New York 397 381

Arkansas 75 83 North Carolina 956 947

California 2,720 2,680 North Dakota 35 52

Colorado 651 848 Ohio 1,510 1,610

Connecticut 94 107 Oklahoma 815 952

Delaware 14 25 Oregon 63 82

District of Columbia (2) 1 Pennsylvania 1,160 1,010

Florida 581 789 Rhode Island 50 60

Georgia 905 992 South Carolina 480 420

Hawaii -- -- South Dakota 10 8

Idaho 399 320 Tennessee 881 819

Illinois 1,990 2,290 Texas 2,810 2,830

Indiana 940 1,190 Utah 46 42

Iowa 333 325 Vermont 3 3

Kansas 438 412 Virginia 330 342

Kentucky 295 300 Washington 206 212

Louisiana 540 557 West Virginia 137 156

Maine 2 (2) Wisconsin 1,220 1,250

Maryland 93 101 Wyoming 154 170

Massachusetts 141 161 Countries:

Michigan 980 997 Canada 848 821

Minnesota 296 338 Mexico 413 439

Mississippi 125 129 Other 44 51

Missouri 284 286 Other:

Montana 48 23 Puerto Rico (2) (2)

Nebraska 38 21 U.S. possessions and territories -- 1

Nevada 42 109 Destination unknown 2,760 2,560

New Hampshire 3 2 Total 29,700 30,600-- Zero.1Data are rounded to no more than three significant digits; may not add to totals shown.2Less than ½ unit.


TABLE 8

U.S. EXPORTS OF INDUSTRIAL SAND AND GRAVEL, BY COUNTRY1


2004 2005

Country Quantity Value2 Quantity Value2

Africa and the Middle East:

Oman 5 3,180 3 2,130

United Arab Emirates 1 995 2 548

Other 3 2,330 3 967

Total 9 6,500 r 8 3,640

Asia:

China 18 8,730 17 14,600

Hong Kong 57 1,510 29 988

Japan 22 29,700 303 34,600

Korea, Republic of 3 1,820 4 2,450

Singapore 5 3,620 5 3,150

Taiwan 11 5,560 3 1,930

Other 4 1,540 2 1,120

Total 119 r 52,400 r 365 58,800

Europe:

Belgium 4 4,000 4 1,950

Germany 10 15,000 40 19,200

Italy (3) 81 5 335

Netherlands 14 11,600 11 9,340

Russia 19 11,700 5 4,390

United Kingdom 4 2,230 5 1,930

Other 17 r 17,500 r 2 2,380

Total 67 62,100 71 39,600

North America:

Bahamas, The 7 249 (3) 34

Canada 1,240 33,900 2,130 32,000

Mexico 287 9,210 279 7,980

Trinidad and Tobago 1 191 2 337

Other 9 r 2,000 r 3 712

Total 1,540 45,600 2,410 41,000

Oceania:

Australia 5 1,100 3 1,190

New Zealand (3) 193 (3) 34

Total 5 1,290 3 1,220

South America:

Argentina 30 4,490 35 5,970

Brazil 6 580 1 935

Colombia 2 286 2 344

Peru 2 227 6 897

Venezuela 2 464 3 1,050

Other 1 r 503 r 1 277

Total 43 r 6,550 r 49 9,480

Grand total 1,790 174,000 2,910 154,000rRevised.1Data are rounded to no more than three significant digits; may not add to totalsshown.2Free alongside ship value of material at U.S. port of export. Based on transaction price, includes all charges incurred in placing material alongside

ship.3Less than ½ unit.

Source: U.S. Census Bureau.

Silica—2005 66.15

TABLE 9

U.S. IMPORTS FOR CONSUMPTION OF INDUSTRIAL

SAND, BY COUNTRY1


2004 2005

Country Quantity Value2 Quantity Value2

Antigua and Barbuda -- -- 5 75

Australia 3 1,240 4 1,790

Canada 152 4,610 295 9,140

Chile 9 1,680 8 1,730

China (3) 281 (3) 361

Germany (3) 475 (3) 202

Japan 1 525 (3) 211

Mexico 300 2,830 382 4,080

New Zealand 2 232 -- --

Norway 21 84 15 63

Other 1 r 431 r 1 497

Total 490 12,400 711 18,200rRevised. -- Zero.1Data are rounded to no more than three significant digits; may notadd to totals shown.2Cost, insurance, and freight value of material at U.S. port of entry.Based on purchase price; includes all charges (except U.S. import

duties) in bringing material from foreign country to alongside carrier.3Less than ½ unit.

Source: U.S. Census Bureau.

TABLE 10

U.S. PRODUCERS OF SPECIAL SILICA STONE PRODUCTS IN 2005

Company and location Type of operation Product

B&C Abrasives, Inc., Hot Springs, AR Stone cutting and finishing Whetstones and oilstones.

Blue Mountain Whetstone Co., Hot Springs, AR do. Do.

Dan's Whetstone Co., Inc., Hot Springs, AR do. Do.

Do. Quarry Crude novaculite.

Hall's Arkansas Oilstones, Inc., Pearcy, AR Stone cutting and finishing Whetstones and oilstones.

Kraemer Co., The, Baraboo, WI Crushing and sizing Deburring media.

Do. Quarry Crude silica stone.

Norton Company Oilstones:

Hot Springs, AR do. Do.

Littleton, NH Stone cutting and finishing Whetstones and oilstones.

Smith Abrasives, Inc., Hot Springs, AR do. Do.

Do. Quarry Crude novaculite.

Taylor Made Crafts Inc.:

Hot Springs, AR Stone cutting and finishing Whetstones and oilstones.

Pearcy, AR Quarry Crude novaculite.


TABLE 11

INDUSTRIAL SAND AND GRAVEL (SILICA): WORLD PRODUCTION, BY COUNTRY1, 2


Country3 2001 2002 2003 2004 2005e

Argentina 891 280 301 r 848 r 850

Australiae 4,500 4 4,500 4,500 4,500 4,000

Austriae 6,800 6,800 6,800 6,800 6,800

Belgiume 1,800 1,800 1,800 1,800 1,800

Belize 28 46 37 33 34

Bosnia and Herzegovinae 50 50 50 50 50

Brazil, silexe 1,600 1,600 1,600 1,600 1,600

Bulgariae 900 900 900 900 900

Canada, quartz 1,613 1,540 1,581 r 1,690 r 1,600

Chilee 300 300 300 300 300

Croatiae 95 95 95 95 95

Cubae 50 50 50 50 50

Czech Republice 950 900 900 900 900

Denmark, salese 50 55 60 60 60

Ecuador 35 41 39 r 43 r 43

Egypte, 5 600 600 640 640 650

Eritrea -- (6) (6) e (6) e (6)

Estoniae 25 24 34 35 37

Ethiopiae 6 e 6 e 5 r 5 r 5

Finlande 148 148 112 r 100 r 100

Francee 6,500 6,500 6,500 6,500 6,500

Gambia 170 e 1,508 1,534 1,530 e 1,530

Germany 7,835 r 7,839 r 7,953 r 8,162 r 8,160

Greecee 90 90 100 100 100

Guatemala 161 38 30 -- r --

Hungarye 500 500 500 520 520

Icelande 4 4 4 4 4

Indiae 1,400 1,400 1,500 1,500 1,600

Indonesiae, 7 128 r 128 r 132 r 132 r 132

Iran8 1,782 r 1,879 r 1,965 r 1,880 r 1,900

Irelande 5 5 5 5 5

Israel 250 r, e 209 r 211 r 196 r 200

Italye 3,000 3,000 3,000 3,000 3,000

Jamaica 8 9 13 11 r 11

Japan 5,768 4,893 4,700 4,705 r 4,750

Jordane 90 r 60 r 33 r, 4 46 r, 4 46

Kenyae 12 r 12 r 13 r 13 r 13

Korea, Republic of 900 891 480 554 r 554

Latviae 50 50 50 50 50

Lithuaniae 30 30 30 30 30

Malaysia 575 447 534 631 r 620

Mexico 1,720 1,779 1,689 2,056 r 2,078 4

Netherlandse 5 5 5 5 5

New Caledoniae 40 40 40 40 40

New Zealande 48 45 45 45 45

Norwaye 1,500 1,400 1,500 1,500 1,600

Pakistane 165 165 165 165 165

Paraguaye 28 25 26 25 25

Peru 120 300 196 871 r 900

Philippinese 70 70 70 70 70

Poland 1,564 1,486 1,500 1,500 e 1,500

Portugale 5 5 5 5 5

Romania 733 1,569 3,061 r 1,458 r 1,500

Serbia and Montenegroe 75 75 75 75 r 100See footnotes at end of table.

Silica—2005 66.17

TABLE 11—Continued

INDUSTRIAL SAND AND GRAVEL (SILICA): WORLD PRODUCTION, BY COUNTRY1, 2


Country3 2001 2002 2003 2004 2005e

Slovakia 2,000 2,200 2,200 2,200 e 2,000

Slovenia 11,510 11,000 11,000 e 11,000 e 11,000

South Africa 2,127 2,239 r 2,448 r 2,388 2,754 4

Spaine 6,500 6,500 6,500 6,500 6,500

Swedene 600 600 600 700 r 700

Thailand 514 781 1,294 588 r 590

Turkey 1,207 1,274 1,283 1,188 r 1,200

United Kingdome 4,500 4,500 4,500 4,500 4,500

United States, sold or used by producers 27,900 27,300 27,500 29,700 30,600 4

Venezuela 627 690 700 e 700 e 750

Zimbabwe9 43 25 23 (6) (6) 4

Total 113,000 r 113,000 115,000 r 117,000 r 118,000eEstimated. rRevised. -- Zero.1World totals, U.S. data, and estimated data are rounded to no more than three significant digits; may not add to totals shown.2Table includes data available through June 20, 2006.3In addition to the countries listed, Angola, Antigua and Barbuda, The Bahamas, China, countries of the Commonwealth of Independent States, Iraq,and Saudi Arabia produce industrial sand, but current available information is inadequate to formulate reliable estimates of output levels.4Reported figure.5Fiscal years beginning July 1 of that stated.6Less than ½ unit.7The quantities for quartz sand and silica stone, in cubic meters, were as follows: 2001-02—145,000 (estimated) and 2003-05—150,000 (estimated).8Fiscal years beginning March 21 of that stated.9Includes rough and ground quartz as well as silica sand.


EXPLANATION

Includes Alaska and Hawaii

Includes New England

Production in thousand metric tons(graduated symbol area isproportional to the productiontonnage)

*

**

•

FIGURE 1PRODUCTION OF INDUSTRIAL SAND AND GRAVEL IN THE UNITED STATES IN 2005, BY GEOGRAPHIC DIVISION

Pacific*

Mountain

West NorthCentral

West SouthCentral

EastNorth

Central

EastSouth

Central

MiddleAtlantic

SouthAtlantic

NewEngland

2,390

1,2802,240

5,550

10,600

1,760

2,720**

4,080

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Documents

USGS 2005 Minerals Yearbook - Silica.pdf