Final Feasibility Study Liuzhuang

7/30/2019 Final Feasibility Study Liuzhuang

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OUTREACH PROGRAM

Coalbed Methane

U.S. EPA

U.S. Environmental Protection Agency

February 2010

Feasibility Study for Coal Mine

Methane Drainage and Utilization

Liuzhuang Coal Mine, Huainan Coal Field Anhui Province, China


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LiuzhuangCoalMine,HuainanCoalFieldAnhuiProvince,China:

FeasibilityStudyforCoalMineMethaneDrainageandUtilization

Sponsoredby:USEnvironmentalProtectionAgency,Washington,DC USA

Preparedby:AdvancedResourcesInternational,Inc.,Arlington,Virginia USA

REIDrillingInc.,SaltLakeCity,Utah,USAValleyLongwallInternational,Sydney,AustraliaOrganicWasteTechnologies,HongKong,China

February2010


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_____________________________________________________________________________________________

FeasibilityofImprovedCoalMineMethaneDrainageandUtilizationattheLiuzhuangMine,AnhuiProvince,China.

TableofContents

AbbreviationsAcknowledgmentDisclaimerExecutive Summary

Section 1 - Pre-Feasibility and Mine Site Selection

Section 2 - Geologic Analysis and Resource Assessment

Section 3 - Coal Mine Methane Market Assessment

Section 4 - Evaluation of Degasification Technologies and Reservoir Simulation

Section 5 - Evaluation of CMM Utilization Technologies

Section 6 - Technical Analysis and Preliminary Engineering Design

Section 7 - Emissions Reductions from Project Implementation

Section 8 - Capital and Operating Costs

Section 9 - Economic and Financial Evaluation

Section 10 - Potential Impacts and Recommendations

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AcronymsandAbbreviationsUnitAbbreviations diameter partsperthousand% partsperhundredC degreesCelsiusF degreesFahrenheit$ UnitedStatesDollarBbl barrelBcf billion(109)standardcubicfeetBcfd billion(109)standardcubicfeetperdayBm3

billion(109)cubicmeters

Btu BritishthermalunitD(d) daydaf dry,ashfreebasis13C deltacarbon13isotoperelativetobelemnitestandardft feetin inchkm kilometerkm

2squarekilometer

m meterm

3cubicmeter

m3/min cubicmetersperminute

m3

/t cubicmeterspertonofcoalMcf thousand(103)standardcubicfeetMcfd thousand(103)standardcubicfeetperdayMcm thousand(103)cubicmetersMcmd thousand(103)cubicmetersperdaymD millidarcy(103D)mm millimeter(103m)MMcf million(106)standardcubicfeetMMcfdmillion(106)standardcubicfeetperdayMPa MegapascalMtoe milliontonnesofoilequivalentMW Megawattpsi poundspersquareinchRo VitrinitereflectanceSCE standardcoalequivalentscf standardcubicfeetTcf trillioncubicfeet

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AcronymsandOtherAbbreviationsAAGI AsianAmericanGasInc.ARI AdvancedResourcesInternational,Inc.CBM CoalbedMethaneCDM CleanDevelopmentMechanismCH4 MethaneCMM CoalMineMethaneCNG CompressedNaturalGasCO2 CarbonDioxideCO2eq CO2EquivalentFm FormationFOB FreightonboardGDG GreenDragonGasLtd.HCMG HuainanCoalMiningGroupHDPE HighDensityPolyethyleneIC InternalCombustionID InnerDiameterIPCC IntergovernmentalPanelonClimateChangeIRR InternalRateofReturnJCOAL JapanCoalEnergyCenterJWR JimWaltersResourcesLNG LiquifiedNaturalGasLPG LiquifiedPetroleumGasMLD MultilateralDrillingMTCO2e MilliontonnesCO2equivalentNDRC NationalDevelopmentandReformCommissionNPV NetPresentValueNiPt NickelPlatinumPSC ProductionSharingContractRMB RenminbiSDIC StateDevelopmentInvestmentCorporationSDICXinji StateDevelopmentInvestmentCorporation,XinjiEnergyCompanyLtd.Shengli ShengliPowerCompanyLtd.UK UnitedKingdomUS UnitedStatesUS$

United

States

Dollars

USBM UnitedStatesBureauofMinesUSDOE UnitedStatesDepartmentofEnergyUSEPA UnitedStatesEnvironmentalProtectionAgencyVAM VentilationAirMethaneVAT ValueAddedTaxYCG YangquanCoalGroup

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AcknowledgmentsTheARITeamgratefullyacknowledges the supportofSDICXinjiEnergyCorporationLtd. forproviding valued access to information, personnel, and the Liuzhuangmine site during thecourse

of

this

study.

We

also

acknowledge

the

project

sponsor,

the

Coalbed

Methane

Outreach

ProgramoftheUSEnvironmentalProtectionAgency.

DisclaimerThisreportwaspreparedfortheU.S.EnvironmentalProtectionAgency(USEPA). Thisanalysisusespubliclyavailable information in combinationwith informationobtained throughdirectcontactwithminepersonnel,equipmentvendors,andprojectdevelopers.USEPAdoesnot:

(a) makeanywarrantyor representation,expressedor implied,with respect to theaccuracy,completeness,orusefulnessofthe informationcontained inthisreport,orthattheuseofanyapparatus,method,orprocessdisclosed inthis reportmaynot infringeuponprivatelyownedrights;(b) assumeany liabilitywithrespectto theuseof,ordamagesresultingfromtheuseof,anyinformation,apparatus,method,orprocessdisclosedinthisreport;or(c) implyendorsementofanytechnologysupplier,product,orprocessmentionedinthisreport.

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ExecutiveSummary

ExecutiveSummary v


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ThisfeasibilitystudywassponsoredbytheU.S.EnvironmentalProtectionAgency (USEPA)undertheauspicesoftheMethanetoMarketsPartnership,ofwhichboththeU.S.andChinaarefoundingpartners. ItalsosupportsthegoalsoftheU.S.ChinaStrategicEconomicDialogue. Thestudyassesses the technical,economic,andgreenhousegas reductionpotential for improving theperformanceofcoalminemethane(CMM)drainageandutilizationattheLiuzhuangcoalmineinAnhuiProvince,locatedineastcentralChina.CurrentPracticesatLiuzhuangMine.SituatedinthewesternportionofthestrategicallyimportantHuainanCoalField,theLiuzhuangmineisoperatedbystateownedSDICXinjiEnergyCo.Ltd. Liuzhuangisamodernlongwallminethatwascommissionedin2006andhasa60yearplannedlife.Theminecurrentlyproducesabout3millionmetrictonnesperyear(t/year)ofbituminousgradecoal,whichismainlyusedforpowergeneration.Coalproductionisscheduledtoincreaseto7.85milliont/yearonceasecondplannedlongwalloperationisinstalled,tentativelybylate2010.Toenhancesafetyandproductivity,theLiuzhuangminecurrentlydrainsabout24.7cubicmetersperminute(m3/min)ofcoalminemethane(adjustedto100%CH4throughoutthisreportbasedonChineseconvention).TheCMMisdrainedprimarilyusingshort(100mlong),nonsteered,crosspanelboreholesthataredrivenhorizontallyintothecoalseams. Otherboreholesareslantedupwardsintothefracturedrock(gob)zonestodrainCMMthatisreleasedfromoverlyingcoalseamsandsandstonesastheminingfaceadvances. GascontentdataobtainedfromcoringatHuainanindicatesthatCMMoriginallystoredwithinthecoalseamreservoirsishighconcentrationmethane(~95%CH4byvolume).However,aircontaminationduringtheCMMdrainageprocessatLiuzhuangminereducestheactualconcentrationofmethaneinthedrainedgasstreamtoonlyabout7to10%,alowlevelwhichisdifficulttoutilize.InadditiontoCMMdrainedviatheboreholesandgascollectionsystem,verydilutemethaneisflushedfromLiuzhuangmineusinga2.8mdiameter,UKmanufacturedventilationfan.Theactualmethaneconcentrationintheventilationairisextremelylow(averagingabout0.02%),whichisfavorableforminesafetypurposesbutsignificantlybelowtheeconomiclimitforVAMmitigation.Altogether,CMMemissionsfromLiuzhuangminecurrentlytotalapproximately30.9m3/min(1.6MMcfdor0.41MtCO2eq/year), comprising24.7m3/minof 710%puritymethane from theboreholedrainagesystemplusanadditional6.2m3/minofverylowconcentrationVAM(0.02%).Atpresent,noneoftherelativelylowqualityCMMdrainedisbeingutilizedatLiuzhuangmine.SDICinitiallyevaluatedthepotentialinstallationofeightShenglimanufacturedlowconcentrationinternal combustion (IC) engines to generatepowerusing thedrainedCMM (4.0MW totalcomprising8unitsx0.5MW).However,SDIChasalsoexpressedinterestintheconceptpresentedinthisstudy,whichistoimproveboreholedrillingatthemine,increasemethaneconcentrationtoExecutiveSummary vi


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ashighas40%,andutilizetheCMMwithlarger,moreefficientICengines. Ifimplemented,thepowergeneratedbytheprojectmostlikelywouldbeusedinternallybythemine.HuainanCoalField.The

3,000

km

2Huainan

Coal

Field,

within

which

Liuzhuang

is

one

of

about

two

dozen

major

mines,

isoneofChinaslargestcoalandCMMproducingregions. Coaloutputfromthedistrictin2007totaledapproximately100milliont,equivalenttoabout5%ofChinastotaloutput.Huainancoalminesdrainedatotal190millionm3ofCMMduring2007(18.4MMcfd).WhereasCMMdrainagevolumeshave increased intheHuainanregionduringthepastdecade,theaveragemethaneconcentrationofdrainedgashasdeclinedsteadily. Notsurprisingly,theoverallutilizationrate(definedasutilizedCMM/drainedCMM)hasalsodeclinedoverthisperiodtoabout40%atpresent,reflectingthedifficultyofutilizinglowconcentrationCMM.Consequently,approximately60%ofdrainedmethaneintheHuainanregioniscurrentlyventedtotheatmosphere.Additionalmethaneisreleasedduringminingbutnotcapturedbyminedrainagesystems,mainlyfromthemineventilationsystems(ventilationairmethane). Together,thetotalemissionsrelatedtocoalmininginHuainanhaveincreasedtoanestimated1.9billionm3/year.Overall,includingnondrainedmethane,onlyabout5%ofthetotalCMMliberatedbymininginHuainaniscurrentlybeingutilized(95millionm3/year).CBM/CMMresourceestimatesconductedbyChineseresearchersindicatethereareapproximately425billioncubicmetersorBm3(15trillioncubicfeetorTcf)toadepthof1500minthiscoalfield.Muchofthismethaneresourceislikelytobeventedtotheatmosphereasminingexpandstodeeperlevelsincomingdecades.Clearly,theHuainanCoalFieldofferssignificantopportunitiesforimprovingtheeffectivenessofCMMdrainageandutilization.CMMdrainageatHuainanisparticularlychallengingbecauseofthemoderatelyhighgascontent(515m3/t),mechanicalfragility,andlowpermeabilityofthecoaldeposits. Longhorizontalinseamboreholes,appliedsuccessfullyduringthepastdecadeinShanxiProvincesQinshuiBasin,simplyarenotpracticalhereduetounstablecoalconditions.SurfaceCBMandgobwells,verticalandhorizontal,alsohavebeenineffective. Inminedrillinghasbeenlimitedtoshortinseamandcrossmeasuregobboreholes. Methaneconcentrationsoftenareverylow(


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GasUtilization&MarketAnalysis.Currently,theextremelylow(7to10%)methaneconcentrationofgasdrainedatLiuzhuangmineseverelylimitstherangeoffeasibleoptionsforeconomicallyviableCMMutilization. Inaddition,thegasconcentration iswithin theexplosive rangeofmethaneandnotconsidered safe forutilizationortransport.Inaddition,Liuzhuangminesrelativelyremotelocationwithinarural,principallyfarmingregion,approximately70kmfromsignificanturbanandindustrialgasmarkets,makestransportationviapipelineappeartobeimpractical.LocalenergyconsumptionreliesmainlyonlowqualitywastecoalthatisquiteinexpensiveandunlikelytobedisplacedbyhighercostCMM.Furthermore,giventhe relatively small CMM production volume, as well as its low methane concentration,constructingapipelinetotransportthegas70kmtoHuainancityorotherdemandcenterswouldbeimpractical.Huainanstowngassystemisundergoingconversiontohighconcentrationnaturalgas,thusCMMwouldbeincompatible.Thepotential forprocessingtheCMMto increasemethaneconcentrationusingcryogenicorcatalyticmethodswasevaluatedbutrejectedasimpracticalandcostlygiventhelargeenergyrequirementsforupgradingCMMwithsuchlowconcentration.Similarly,convertingtheCMMtoliquifiednaturalgas(LNG)orcompressednaturalgas(CNG)forsalewouldbefartooenergyintensiveandtheplantscalewouldbetoosmall.PowergenerationforlocalmineuseappearstobethemostviableapproachforCMMutilizationatLiuzhuangmine.Gasturbineshavehighefficiencyandreliabilitybutarenotpracticalforutilizinglow and characteristically timevariable CMM concentrations. However, in recent yearsreciprocatingengineshaveenjoyedwidesuccess inChinaforpowergenerationutilizing lowmoderate CMM concentration fuel. Assuming the recommended drilling and drainageimprovementsareabletoachieveupto40%qualitymethane,reciprocatingenginesinthe1 to2MWunitsizeappeartobethebestoptionforcosteffectiveCMMutilizationatLiuzhuangmine.Technologiesforventilationairmethane(VAM)oxidationdonotappeartobetechnicallyfeasibleforLiuzhuangminegiventheextremelylowmethaneconcentrationsintheventilationsystem,averagingonly0.02%CH4. MostcommerciallyavailablethermaloxidizersforVAMoxidationrequireconcentrationsofapproximately0.2%methaneorhigher.

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PreliminaryDesignofCMMDrainageandUtilizationSystem.Basedonareviewofthegeology,reservoirconditions,miningdesign,andmarketopportunitiesatLiuzhuangmineandtheHuainanCoalFieldingeneral,thefollowingpotentialimprovementstotheminesCMMdrainageandutilizationsystemarerecommended(TableA):

Component Technology Number of Units Anticipated Benefit

Borehole Drilling Directional Drills 2 Longer, precise borehole placement, higher methane concentration

Borehole Wellhead Improved Grouting - Reduced air leakage, higher methane concentration

CMM Pipeline Fused HDPE Pipeline 2 Reduced air leakage, higher methane concentration

Power Generation IC Engine Generators 10 x 1.255 MW CMM utilization, high efficiency & reliability

TableA: SummaryofCMMDrainageandUtilizationImprovementsRecommendedforLiuzhuangMine

1. SteerableBoreholeTechnology. Drillinglong(1000m)horizontalboreholesintothetopofthefuturegobzone situatedprecisely1520mabovethetargetcoalseamswithadvanceddownholesteerabledrillingtechnology coulddramaticallyincreaseboththequantityandCH4concentrationofCMMdrainedatLiuzhuangmine.ReservoirmodelingsuggeststhatCMMproductionandmethaneconcentrationbothcouldbeincreased severalfold, toapproximately100m3/minand40%CH4, increasing thepotentialmagnitudeandefficiencyofmethaneutilization(estimatedcosts$3.5million).

2. UpgradedCollectionSystem. ImprovedboreholestandpipecementingcouldreducecontaminationofthedrainedCMMbymineventilationair. ReplacingtheexistingflangedsteelpipelinesystemwithseamlessHDPE(plastic)pipewouldreducecorrosionandpotentialaircontamination. Improvedgasflowmonitoringand installationofautomaticshutoffvalvescouldimprovesafetyaswellasgasqualityincaseofpipelinedisruption(estimatedcosts$0.7million).

3. LargerReciprocatingEngines. DependingonthesuccessoftheanticipateddrainageimprovementsonCMMqualityandquantity,itmaybepossibletousereliableandefficient gas engines in the 1 to2MWunit size, currently aremanufacturedbyCaterpillar,GEJenbacher,andDeutz,thatarecapableofutilizingtheanticipated40%qualityCMM.Powergeneratedbytheprojectwouldusedbytheminetobackoutgridpurchases.Totalpowercapacityofapproximately12.55MWcouldbeachievable.Thecapitalcostsforthispowerstationareestimatedtobe$17.33million.

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KeyprojectparametersaresummarizedinTableB:Topic Key Project Parameters Value Unit

Timing Project Initiated

Project Fully Implemented

Project End

2010

2012

2034

mid-year

January

December

Coal

Production

Coal Production (2010)

Coal Production (2011 on)

3.00

7.85

million t/year

million t/year

CMM

Drainage

CMM Drainage Rate

CMM Utilized / CMM Drained

CMM Concentration Expected

37.50

100%

30-40

m3/minute

percent

percent

Power

Generation

Power Generation Capacity

Operating EfficiencyCumulative Project Power Production

12.55

90%2,448

MW

percentGWh

Power

Price

Power Price (base)

Power Price (escalation)

0.05

1%

USD/kWh

per year

Investment

Costs

Borehole Drainage Investment

CMM Pipeline Investment

Power Generation Investment

3.42

0.71

17.33

million USD

million USD

million USD

Total Capital Investment 21.46 million USD

Operating

Costs

CMM Drainage System Opex

Power Generation Opex

same

1.70

as current

million USD

Financial

Performance

Net Present Value (r = 10%; base case; pre-tax)

Internal Rate of Return (base case; pre-tax)

11.51

17.6%

million USD

percent

GHG

Reduction

Global Warming Potential of Methane

Total Emissions Avoided by Power Generation

Total Project Emissions

21

9.18

0.92

tCO2e/tCH4

million t CO2e

million t CO2e

Net Total Emissions Avoided 8.26 million t CO2e

TableB: SummaryofKeyProjectParameters

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GreenhouseGasEmissionReductions.By2011,underfullscalecoalproductionof7.85Mt/year,theannualemissionsreductionsfortheproposedprojectareestimatedtobeapproximately337,193tCO2eq,calculatedbysubtractingprojectemissionsofabout37,540tCO2eqfromthebaselineemissionsof374,733tCO2eq.Overthe25yearlifeoftheproject,totalnetemissionsreductionsareestimatedtobeapproximately8.26MtCO2eq(+/ about10%).If the recommendedupgrades to theCMMdrainage systematLiuzhuangmineprove tobeeffective,theymaybetransferabletoanumberofotherHuainancoalmineswithsimilargeologicandminingconditionsthatareoperatedbySDIC,HuainanCoalMiningGroup,orotherminingcompaniesintheregion.Assumingadrainageandutilizationpenetrationrateof50%throughouttheHuainanCoalField,aconservativeassumptionbasedonsimilaritiesinthegeologyandminingtechniquesacrossthisregion,comprehensiveapplicationofthesetechnologiescouldcutmethaneemissions from thisminingarea inhalf,perhapsavoiding1billionm3/year (25MtCO2eq)ofincrementalannualmethaneemissions.ProjectEconomics.TheLiuzhuangmineCMMdrainageandutilizationprojecthasthepotentialforfavorableeconomicperformance,includinganattractivepretaxinternalrateofreturn(IRR)of17.6%,withnetpresentvalue(NPV)estimatedat78.6millionRMB,andareasonablerealpaybackperiod(10years).Changesincapitalandoperatingcostswouldsignificantlyaffecttheprojectsperformance,whilechangesinthepowerpriceandpowerplantoperatingefficiencywouldtendtohaverelativelysmallerimpacts.Thebasecaseassumeda2yearconstructionperiod,initialpowersalespriceof$0.05/kWhrwitha1%/yearrealescalation,and90%plantoperatingefficiency.ThepretaxNPR(PV10)forthiscaseisestimatedtobeapproximately78.6millionRMB($11.5million),withanIRRof17.6%.Sensitivityanalysis(+/ 25%)indicatedthatchangesinthecapitalandoperatingcostsforboreholedrillingandpowergenerationwouldhavethelargestimpactonprojecteconomics.

Variable -25% Base Case 25%

IRR NPV IRR NPV IRR NPVPower Price Escalation

Drilling/Power Capex

Drilling/Power Opex

Operating Efficiency

17.1%

25.5%

21.3%

16.6%

71.60

118.47

113.47

68.78

17.6%

17.6%

17.6%

17.6%

78.60

78.60

78.60

78.60

18.1%

13.0%

14.1%

18.6%

85.82

38.74

43.74

88.43

TableC: FinancialSensitivitytoKeyProjectParameters

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OtherProjectBenefits.Inadditiontotheanticipatedeconomicgainsandemissionreductions,implementationofamoreeffectiveminedrainagesystemandrecoveryandutilizationoftheCMMforpowergenerationforuseonsiteatthemineisexpectedtoproduceanumberofadditionalbenefits. TheseincludeenhancedsafetyandminingproductivityattheLiuzhuangmine,asmallincreaseinemployment,reducedlocalairpollutionfromtheuseofacleanerfuel(CMM)forpowergeneration,andthewideradoptionofadvanceddrillingandpowergenerationtechnologyintheHuainanCoalField.

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SECTION1PreFeasibilityStudyandMineSiteSelection

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SECTION1CONTENTS1.1 Introduction.............................................................................................................. 111.2 MineSelectionProcess............................................................................................. 121.3 CMMDrainageinChina............................................................................................. 131.4 CoalMiningOperatorsintheHuainanCoalField...................................................... 15

1.4.1 StateDevelopmentInvestmentCorporation(SDIC)............................................................1 61.4.2 SDICXinjiEnergy..................................................................................................................1 61.4.3 HuainanCoalMiningGroupCo.,Ltd....................................................................................1 6

1.5 PreFeasibilityEvaluationofLiuzhuangMineandXinji1and2Mines....................... 171.6 XinjiNo.1and2Mines............................................................................................. 19

1.6.1 XinjiNo.1Mine....................................................................................................................1 91.6.2 XinjiNo.2Mine....................................................................................................................1 9

1.7 LiuzhuangMine....................................................................................................... 1101.7.1 Introduction.......................................................................................................................1 101.7.2 CoalDeposits......................................................................................................................1 111.7.3 HighTemperatureHazard..................................................................................................1 141.7.4 CoalDust............................................................................................................................1 141.7.5 GasContentandCMMResources.....................................................................................1 141.7.6 MiningPractices ................................................................................................................. 1161.7.7 MethaneDrainagePractices..............................................................................................1 171.7.8 Ventilation..........................................................................................................................1 181.7.9 CMMUtilization.................................................................................................................1 191.7.10 MethaneEmissions............................................................................................................1 19

1.8 ConclusionsandRecommendations ........................................................................120

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SECTION1FIGURESFigure11: LocationofLiuzhuangMine,AnhuiProvince......................................................11Figure12: LargeScaleLocationMapofLiuzhuangMine.....................................................12Figure13: CMMDrainageandUtilizationinChina...............................................................13Figure14: CMMDrainagebyCoalfield.................................................................................15Figure15: StructureMapoftheHuajiahuCoalDistrict.....................................................110Figure16: CoalStratigraphyandLithologyatLiuzhuangmine..........................................112Figure17: DetailedCoalStratigraphyatLiuzhuangmine..................................................113Figure18: Photomicrograph(300x)ofaCoalSampleintheHuainanCoalField...............114

SECTION1TABLESTable11: CMMPowerStationsOperatedbyHCMG...........................................................17Table12: CoalSeamThicknessandMiningCharacteristicData

HuajiahuCoalDistrict......................................................................................111Table13: CoalSeamGasContentandCompositionDatafromthe

Liuzhuangminearea.......................................................................................... 115

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1.1 IntroductionThisprefeasibilitystudywassponsoredbytheU.S.EnvironmentalProtectionAgency(USEPA)undertheauspicesoftheMethanetoMarketsPartnership,ofwhichboththeU.S.andChinaare

founding

partners.

It

also

supports

the

goals

of

the

U.S.

ChinaStrategic

Economic

Dialogue.

It was conducted by Advanced Resources International, Inc. (Arlington, Virginia, USA), withsupportfromREIDrilling,Inc.(Utah,USA),ValleyLongwallInternational(Australia)andOrganicWasteTechnologies(HongKong,China).TheprefeasibilityassessmentdiscussestheARITeamspreliminarydatagatheringandanalysisonLiuzhuangandtwoothernearbyminesintheHuainanCoalFieldthatareoperatedbySDICXinji Energy Company Limited. The remainder of the report (Sections 28) provides a moredetailedfeasibilitystudyontheapplicationofadvancedtechnologiesforimprovingcoalminemethanedrainageandutilizationattheLiuzhuangminespecifically.TheLiuzhuangmineislocatedinthewesternportionoftheHuainanCoalField,incentralAnhuiProvince, eastcentral China. Liuzhuang mine is about 70 km west of the regional city ofHuainan (population 1 million; Figure 11 and Figure 12). A large, modern, undergroundretreatinglongwallmine,Liuzhuangisscheduledforexpansionfromitsinitialdesigncapacityof3 million metric tonnes per year (t/year),witha currentupgraded production targetof 7.85milliont/yearbytheendof2010.

Figure11: LocationofLiuzhuangMine,AnhuiProvince(Source:ARI)

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Figure12: LargeScaleLocationMapofLiuzhuangMine(Source:ARI)

As of May 2009 the mine was draining about 21 million m3/year of coal mine methane (40m

3/minor2.0MMcfd,recalculatedaspuremethane). Currently,methaneconcentrationinthe

drainedCMMflowisverylow,typicallyonly7to10%CH4,whichisdifficulttoutilizeefficiently.BothCMMdrainagevolumesandmethaneconcentrationareexpectedtoincreasesignificantlywiththe installationofadditionalvacuumpumpsaswellasseparatehighmethaneand lowmethane collection systems. The installation is planned to be implemented along with mineexpansionduring2010.1.2 MineSelectionProcessInJuly2007ARIconductedaninitialtechnicalvisittoallthreeofSDICXinjiscoalminesintheHuainanCoalField,theXinjiNo.1andNo.2minesandtheLiuzhuangmine. Thisvisitincludedsurface and subsurface mine tours and examination of initial technical data on these threemines. ARIsinitialreviewidentifiedLiuzhuangmineasthebestcandidate,primarilybecauseitisthedeepest,gassiest,andmostmodernmineownedbySDICXinji. LiuzhuangclearlyhadthebestpotentialforaCMMdrainageandutilizationimprovementproject.PreFeasibilityStudyandMineSiteSelection 1-2


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AnotherfactorfavoringLiuzhuangmineintheselectionprocesswasthepotentialforextendingtechnologiesdevelopedandproveninthisminetoupgradetheCMMdrainageandutilizationatothercoalminesintheHuainanCoalField. AsdiscussedmorefullyinSection1.3,inadditiontothethreeminesoperatedbySDICXinji,severaldozenotherundergroundcoalminesareinoperationelsewhereintheHuainanregion. Manyofthese,particularlyineasternHuainan,areconsideredmoderate tohighmethanemines.1.3 CMMDrainageinChinaCMMdrainagehas increasedrapidly inChinafromabout0.88billionm3/year(85MMcfd) in2000to4.79billionm3/year(464MMcfd)in2007,themostrecentyearforwhichfiguresareavailable (Figure 13). However, over this period the national utilization rate for CMM hasslipped steadily to 30.6% in 2007 (vs. 57% in 2000) as more challenging lowconcentrationmethanestreamsarecaptured.

Figure13: CMMDrainageandUtilizationinChina(ModifiedfromZhao,2009)

Nationally, much of the increase in Chinas total volume of CMM drainage and the directlyrelatedreduction inmethaneconcentrations canbeexplained by increasinguseof powerfulvacuumpumpsatthesurface. ThesepumpscanbehighlyeffectiveatremovingmethanefromPreFeasibilityStudyandMineSiteSelection 1-3


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theworkingfaceandmaintainingmethaneconcentrationsinthemineatsafelevels. However,the pumps also tend to draw considerable volumes of mine ventilation air into the gob andworking areas of the mine. This tends to lower the CMM concentration of the capturedmethaneandmakesithardertoutilize.In contrast, underground coal mines in the U.S. and Australia capture CMM with mostlymediumtohighmethaneconcentrations(5095%CH4)and,notsurprisingly,thecapturedCMMisutilizedatahighrate. However,itshouldbenotedthatinseveralregardstheminingandgasmarket conditions in Australia and the U.S. differ significantly from those in China (andgenerallyaremorefavorableforCMMdrainageandutilization):

U.S.andAustraliancoalminestendtohavehigherpermeabilitythanthose inChina,allowingthemtodrainadditionalmethanefromlargercoalvolumes.

U.S. and Australian coal mines also tend to be less faulted than those in China,enablinglongerhorizontalboreholestobedrilledwithoutsuddendisruption.

The U.S./Australian coals also tend to have more stable mechanical properties. Incontrast, the coal seams in many parts of China (including Huainan) are fragile,collapseeasily,andmakelonghorizontalinseamdrillingnearlyimpossible.

Although China is rapidly developing its national natural gas pipeline system, thepipeline networks in the coal mining regions of Australia and the U.S. are relativelybetterestablished,facilitatingCMMsalesandutilization.

Nevertheless,therearetechnicalimprovementsemployedinU.S.andAustralianminesthatarepotentially applicable to China. Generally, U.S. and Australian mines tend to employ muchlonger horizontal boreholes (500 to 1500 m in length), improved borehole wellhead sealingtechniques,leakproofseamlessHDPEpipelines,andadvancedmonitoringandcontrolsystems.They also avoid application of high vacuum levels to the CMM system. Together, thesetechnicalmeasuresminimizecontaminationofCMMwithventilationairandhelpensurehighmethaneconcentrationinthedrainedgasstream.Following a longterm trend in nearly all of Chinas coal mining areas, CMM drainage at theHuainan Coal Field has grown rapidly since 2000 (Figure 14). By 2007 CMM drainage hadreachedanestimated190million m3 (18.4MMcfd),placingHuainanthird inthecountry forCMM drainage. Yet, the CMM utilization rate has not kept up with the growth in CMMdrainage, creating multiple opportunities for a CMM drainage and utilization project in theHuainanCoalField.



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Figure14: CMMDrainagebyCoalfield(ModifiedfromZhao,2009)

1.4 CoalMiningOperatorsintheHuainanCoalFieldTwo large companies controlled by the centralgovernment dominate coal production in theHuainan Coal Field. In addition, numerous smaller provincially and locally controlled miningfirmsoperatecoalminesthereaswell. ThelargerofthetwocentralcompaniesistheHuainanCoalMiningGroup (HCMG),whichoperates15mines intheregion, includingonewhichhasregisteredaCMMutilizationprojectforCleanDevelopmentMechanism(CDM)credits. ManyofHCMGsotherminesaredeepandgasprone. Somecouldbecandidatesfor futureCMMdrainageandutilizationprojects.ARIs evaluation at Liuzhuang mine was with the second most active centrally owned coalmining firm in theHuainan Coal Field, the State Development InvestmentCorporations coalmining unit, Xinji Energy CompanyLimited (SDICXinji). SDICXinji currently operatesthreerelativelymodernminesintheHuainanCoalField. SDICXinjislargestandnewestcoalmineiscalled Liuzhuang, the focus of ARIs current evaluation. The company plans to open threeadditionalminesintheHuainanCoalFieldinthecomingfiveyears.



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1.4.1 StateDevelopmentInvestmentCorporation(SDIC)The owner and host organization for the Liuzhuang mine evaluation is SDIC Xinji EnergyCompany Limited (SDICXinji). SDICXinji in turn is controlled by the State DevelopmentInvestmentCorporation(SDIC),alargeChinesecentralgovernmentorganizationwhichengagesin investment and operation of stateowned industrial assets. SDICs activities range fromhydro andthermalpowergenerationtomining,construction,andshipping. SDIC isactive inmanyofChina'sprovincesincludingAnhui,Shandong,Henan,Hebei,andShanxi.1.4.2 SDICXinjiEnergySDICXinjiEnergyfocusesmainlyoncoalminingandprocessingwithadditionalcoalandsmallscaleCMMfueledpowergeneration. Thecompany is listedontheShanghaistockmarket(Ashare) and has recently attained market capitalization of over US$1 billion. SDICXinji holds10.16billiontofcertifiedcoalreservesextendingoveratotalareaof1,092km2. Thecompanycurrently operates three production mines in the Huainan region with the total annualproduction capacity of about 8 million t/year. It also operates a trial operation mine, has afourthmineunderconstruction,andtwoadditionalminesunderdevelopment. Otherprojectsincludetwocoalsortingplantsandtwocoalganguefueledpowerplants. Thecompanyplanstoincreaseoutputtoapproximately36milliont/yearduringthenextfiveyears.PriortodevelopingtheLiuzhuangmine,SDICXinjihaddevelopedChinasfirstcoalmine(theXinjiminein1989;referredtolaterastheXinji1mineaftertheXinji2minewasconstructed)that was established under the new marketoriented mechanism, as opposed to centralplanning. TheXinji1minebecameamodelforChinasmoderncoalindustryundertheLegalPersonResponsibilitySystem. Xinji1hasbeeninspectedandpraisedbymanyofChinasstateleadersincludingPrimeMinisterLiPengandChairmanHuJintao.1.4.3 HuainanCoalMiningGroupCo.,Ltd.WhollyseparatefromSDICXinji,thelargestcoalminingoperator intheHuainanCoalField istheHuainanCoalMiningGroupCo.,Ltd.(HCMG). Asof2004HCMGoperated10undergroundcoal mines, all characterized by coal and gas outbursts, with total production capacity of 34milliont/year. By2007HCMGwasscheduledtobringanotherfivecoalminesintoproduction,adding a further 46 million t/yr for a total production capacity of approximately 80 milliont/year. By 2010 the companys production capacity is planned to reach 100 million t/year(accountingforabout5%ofChinastotaloutput).OverthisperiodHCMGscoalminemethanedrainageandutilizationalsohasgrown. Annualgasdrainageisexpectedtoreach416millionm3 by2010(40MMcfd),ofwhich354millionm3(34MMcfd)couldbeavailableforutilization. (Forperspective,thisisabouttwicethesizeofthelargestU.S.coalminemethaneutilizationproject,theBrookwoodfieldintheWarriorbasin,PreFeasibilityStudyandMineSiteSelection 1-6


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which drains highconcentration (>80% CH4) CMM using gob wells and inmine horizontalboreholes,thenmarketsthegasviapipeline.)HCMGoperatessevensmallCMMpowerstationsinvariousminelocations,withtotalinstalledgenerationcapacityofabout19MW(Table11).

Mine Units Capacity(MW)

TotalCapacity(MW)

ManufacturerXieyi

PansanPanyi

ZhangjiZhangbei

XinzhuangziXieqiao

2222222

0.501.801.361.361.801.361.42

1.003.602.722.723.602.722.84

Chinese(mobile)Caterpillar

DeutzDeutz

CaterpillarDeutz

Jenbacher

Total 19.2Table11: CMMPowerStationsOperatedbyHCMG

Oneofthesepowerstations,atPansan,isregisteredforCDM. InitiatedinFebruary2003,andhaving registered since March 2007, HCMG is operating the Pansan Coal Mine MethaneUtilization and Destruction Project (UNFCCC reference number 0840). The project has twocomponents:first,toconnect4,000 localhouseholdstoCMM,replacingcoal;andsecond,toinstall 8.4 MW of CMMfueled power generation. The power project utilizes reciprocatingengines,comprising4x1.2MWChinesemanufacturedunitsand2x1.8MWCaterpillarunits,withallenginesonlineasofJanuary2007. ElectricitygeneratedfromCMMsuppliesaportionoftheminesenergydemand,offsettingpurchasesfromtheEastChinaPowerGrid.1.5 PreFeasibilityEvaluationofLiuzhuangMineandXinji1and2MinesThe initialstepoftheevaluationwastoassessthefeasibilityofconductinga largerstudyforoptimizingCMMdrainageandutilizationatthethreeSDICXinjimines inHuainan(Liuzhuang,Xinji1and 2). ARIpersonnel firstvisitedthese mines inJuly2008 togather initialdataandconductfirstleveldiscussionswithminemanagementandtechnicalpersonnel. Thenewerandmore modern Liuzhuang mine appeared to have the most potential for CMM drainage andutilization optimization, although the two Xinji mines also have good potential. Given thepotential fordrainage andutilization improvementatLiuzhuang,this initialevaluation ledtothedecisionthatalargerfeasibilitystudyoftheminewaswarranted.DatagatheredduringtheJuly2008visitrevealedthatnoneofthethreeSDICXinjiminesareconsidered particularly highgas mines by the Chinese government. In fact, they arePreFeasibilityStudyandMineSiteSelection 1-7


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characterizedaslowmoderatelygassymines.1 Ontheotherhand,theminesarealsoclassifiedasHardlyDrainable,duetocoalseampermeabilityoflessthan0.025mD,2 andCMMcontrolisan integralstep for coal production at the three mines. Methane entry does interfere withmining operations at the SDICXinji mines and thus these mines have active drilling anddrainageefforts. Fortunately,todatetherehavebeennomajormethanerelatedaccidentsattheLiuzhuangmine,whichonlystartedoperationin2006.TheSDICXinjimineswarrantevaluationbecause:

CMMemissionsintotheminesaresignificantandrequireactiveinseampredrainageaswellascrossmeasuregobboreholedrillingduringminingtocontrol.

Lowmoderately gassy mines also have the potential to experience methanerelatedaccidents.

Lowmoderatelygassyminesfrequentlyrecoverlowqualitymethanethatisdifficulttoutilizeeffectively.

Gasemissionsanddrainageareexpectedtoincreasesignificantlyintheseminesasthelongwallsadvancedownintodeeperminingareas(>800m).

The three SDICXinji mines are representative of other lowmoderately gassy mineswith similar geologic and mining conditions in the Huianan Coal Field and perhapselsewhereineasternChina. ImprovedCMMdrainageandutilizationtechnologiesthatcanbedemonstratedattheseminesmaybeapplicableelsewhereintheregion. (NotethatduringrecentyearstheSiheminehasplayedasimilarlyimportantdemonstrationroleforhighgasminesinShanxiProvince.)

DrainedCMMvolumefromSDICXinjismineshasbeenincreasing,from20millionm3 in2006uptoaprojected35millionm3 in2008(totalofthethreemines;notethatCMMvolumescitedinthisreportareexpressedas100%CH4 concentrationequivalentunlessotherwisespecified).Theincreaseindrainedgasisduetoanumberoffactors,includingincreasingminedepthsaswellasregulationswhichrequirethatgasemissionsintothemineworkingsbereducedthroughpredrainage. Theconcentrationofdrainedmethanefromthethreemineswasreportedtobegenerallylow,rangingfrom530%andaveragingabout15%.Severaldifferentmethodsareemployedtocontrolthegasinthemineworkingsincludingcrossmeasureboreholes,thedrivingoftunnelsabovetheminedseamtocollectgas,andcrosspanel1

He,Xueqiu;Chen,Wenxue;Nie,Baisheng;andZhang,Ming,2009. ClassificationTechniqueforDangerClassesofCoalandGasOutburstinDeepCoalMines. SafetyScience,vol.48,p.173178.2

Wang,KaiandXue,Sheng,2008. GasDrainagePracticesandChallengesinCoalMinesofChina. 2008CoalOperatorsConference,February1415,UniversityofWollongong&theAustralasianInstituteofMiningandMetallurgy,Australia,p.178185.



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boreholes. Duringtheprefeasibilitystudyitquicklybecameapparentthatoneoftheprimaryfocuses of a feasibility study would be to increase the concentration of drained methaneproducedfromthedegasificationsystems.1.6 XinjiNo.1andNo.2Mines1.6.1 XinjiNo.1MineLocatedonthewesternsideoftheHuainancoalfield,theSDICXinjiXinjiNo.1minecoversanareaof25.2km2. Theoldestandoneofthe largerminescontrolledbySDIC,XinjiNo.1 isalongwall operation currently producing about 4 million t/year from five seams. The minecurrentlydrainsabout160millionm3 ofCMMatrelativelylowconcentration(10%methane).Drainage techniques include tunnels driven above and below the mined seam as well as anarray of closely spacedcrossmeasure boreholes into the roof and floor. The mine plans toinstall

six

500

kW(3

MW

total)

engines

to

utilize

drained

gas.

The

power

will

be

consumed

bothinternallyaswellassoldbacktothegrid.1.6.2 XinjiNo.2MineLocated10kmfromXinjiNo.1,theXinjiNo.2minehasadesignedcapacityof3milliont/year,withcurrentoutputapproximately2.6milliont/year. The30km2minehas491milliontoftotalcoalresources,about160milliontofwhichisconsideredrecoverable. TheXinjiNo.2minehassimilargeologytotheNo.1mine,andminingtargetsthesamefivemineableseams(No.1,6,8,11,and13). Totalcoalthicknessis33m. Alargefaulttransectstheminearea,alongwithonesmall

local

fault.

Currently

the

mine

is

650

m

deep.

CMM drainage at the Xinji No. 2 mine averages about 33.16 m3/min, extracted using twosurfacevacuumpumps. Thespecificgascontentrangesfrom1012m3/tofcoalmined. Themethane concentration at the surface is low (1015%), similar to Xinji No. 1 mine. CMMdilution is exacerbated by the high surface vacuum applied to the inmine degasificationboreholes, and the resulting contamination of ventilation air into the gob zone. Methanedrainage has increased in recent years and is forecasted to reach 14 million m3 in 2008,representinganestimated51%drainageefficiency.CMMdrainedattheXinjiNo.2minecurrently isbeingusedasfuelfortwo500kWShenglimanufacturedreciprocatingengines. Fourmoreengineswerescheduledtobeinstalledasofmid2008. Powerconsumptionatthemineisabout80millionKWh,withpeakdemandof12.2MW. SDICXinji Energys plan is to supply the mines power requirement through onsitegenerationandthensell2030%ofthegasoutputtolocalindustries.



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1.7 LiuzhuangMine1.7.1 IntroductionExtendingoveranareaof82.2km2,LiuzhuangmineisnearlythreetimesthesizeoftheXinjiNo.1orNo.2mines. It isoneofChinasnewestandmostmoderncoalmines,employingaretreating longwall design. Liuzhuang was constructed over a 44month period, with mineconstructioncommencingonFebruary20,2003andtrialoperationverifiedbytheProvincialEconomicCommitteeonOctober13,2006. Itscoalresourcestotalanestimated1.56billiont,ofwhich679milliontisconsideredprovenmineablereserves,givingthemineaprojected61yearservicelife.Liuzhuang mine is located in the Huajiahu district, which in terms of structural geology is a

relatively simple portion ofthe

Huainan

Coal

Field.

The

mine is situated on thesouthern flank of theXieqiao Syncline. Severalmajor regional faults notably the ShouxianLaorenandFufengFaults cut the district, but theLiuzhuang and Xinji minesare situated in betweenthese major structures andare relatively undisturbedbyfaulting(Figure15).

Liuzhuang mine comprisestwovertical shafts, asystem ofmain gateroads, separateminingdevelopment zones, separate ventilation zones, and centralized coal haulage. Advancedmonitoringequipmenthasbeeninstalledtoproviderealtimedataonmethaneflowrates,coalproduction, equipment location, and other coal production related information. Theseperformancemeasuresaremonitored,recordedandmanagedfromamoderncontrolroomatthesurface.CurrentlyonlySeams131and112arebeingminedatLiuzhuang. Eventually,SDICXinjiplanstotargetSeams1,5,and8aswellfromvariouslevelsusinglongwallmining. Asinglelongwallcurrentlyisinoperationwithasecondplannedtocommencein2010.

Figure15: StructureMapoftheHuajiahuCoalDistrict(Source:SDIC)



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DuringtheperiodJanuarytoMay2009,coalproductionatLiuzhuangtotaledapproximately3million t, with an average monthly production of 600,000 t. Production is scheduled to beincreased to 7.85 million t/year during 2010 and then 10 million t/year by 2015. The hoistsystem is capable of lifting 10 million t/year. SDICXinji estimates CMM production atLiuzhuangtobeapproximately13millionm3/year(24.7m3/min)overthenextfiveyears. Thisseems conservative given rising coal production as well as the potential improvements todrainagesystemtechnologyrecommendedinthisstudy.1.7.2 CoalDepositsThetwomainminingtargetsatLiuzhuangareSeams131and112(Table12). Seam131isofstablethickness(2.4to4.3m,average3.85m),simplestructure,anddipstothesouthata10to30angle(average15.1). Hardnessoftheseamisclassifiedasloosetosoft,whichsuggeststhat long inseam drilling would be hard to achieve. The density of the layer is 1.37 g/cm3,porosity2to3%,andtheapparentelectricalresistivityisapproximately100ohm.

Coal

seam

Thickness

(m)

extreme

value/averagevalue

/

Spacing of

seam

(m)extreme

value/average

value

/

Stability

Number

of gangue

layers

Coal seam

structure

Lithology of roof and floor

Roof

Floor

1 1.135.80/3.39

94138/108

Stable

1 Simple MudstoneMudstone, sandy

mudstone

6-1 1.028.19/3.36

1561/33

Relatively

stable

1

Simple

Mudstone,

carbonaceousmudstone

Sandstone

8 1.594.73/3.4151138/83

Stable

0 SingleMudstone, sandy

mudstone

Mudstone, sandy

mudstone

11-2 2.294.84/3.64

6692/76

Stable

13 SimpleFine and medium

sandstone

Mudstone, sandy

mudstone

13-1 1.512.79/6.06

Relativelystable

12Simple

Mudstone, sandy

mudstone

Mudstone, sandy

mudstone

Table12: CoalSeamThicknessandMiningCharacteristicDataHuajiahuCoalDistrict

(Source:SDIC)The floor and roof rocks of Seams 131 and 112 comprise an interbedded sequence ofsandstone, siltstone, and mudstone rocks (Figure 16). Although the coal seams themselveshaveundergoneshearing,naturalfracturing intheclasticsectionappearstobe limited. Thissequencemaybeexpectedtoprovideastabledrillingenvironmentfordrillinglonghorizontaldegasificationboreholesinthegobzone.



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Feasibility of Improved Coal Mine Methane Drainage and Utilization

at the Liuzhuang Mine, Anhui Province, China.

oal-bearing section

Section

Thickness

87.0

Coal seam

No.

Thickness

m

Spacing

m

Comprehensive

column

15* coal seam

15* coal seam

0-3.240.63

0-1.460.57

45.5-36.466.65

6.891.60-17.40

13-1# coal seam

1.51-8.474.61

4.50-24.30

18.55

Lower 13-1 #coal

seam#1.95-1.37

0.98

12# coal seam

79.267.46-88.55

11-2# coal seam

2.29-5.76

3.85

11-1# coal seam

Upper 9 # coal

seam

0-2.720.97

0.950-1.73

28.1819.35-37.36

44.8939.93-52.71

Lithology

Purple brown-light yellow granitophyre, its bottom is the deep gray medium and

fine size quartzose sandstone and the

Quaternary coal-bearing section boundary

-

Consists of gray-deep gray sandstone,

sandy mudstone, mudstone and grayish white fine and medium size sandstone.

The middle coal-bearing seams are 5-7,

wherein, 13-1# coal seam has the

relatively stable growth, -300m and above

were displaced by the decken structure. About 18m below 13-1# coal seam grows

with one stable purple brown-grayish green granitophyre with oolite, commonly

called the large granitophyre, its bottom

consists of grayish white medium

sandstone and the Tertiary coal-bearing

section. - 5-713-1#-300m13-1#18m-

Consists of gray silty sandstone,

mudstone and grayish white fine and

medium sandstone, and quartzose

sandstone. Its medium and lower parts has

3-4 coal-bearing seams, wherein, 11-2 seam is totally grown stably, with the

complicated structure, with 1-3 gangue

layers, from its east to west, the coal seam

is thinner, the average thickness of 1-02 line is 4.31m, and that of 03-05 line

3.96m, the east part of 06 line is 2.97m,most of the 11-1 coal seam is recoverable,

the mudstone or sandy mudstone at the

top of 11-2# coal seam is abundant with

phytolites, its bottom is divided with the

second coal-bearing section with the

grayish white quartzose sandstone or

medium and fine

sandstone

3-411-

2 1-3 1-024.31m03-

053.96m062.97m11-111-2#

I 114.0

Figure 16: Coal Stratigraphy and Lithology at Liuzhuang mine

(Source: SDIC)

PreFeasibility Study and Mine Site Selection 1-12


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InadditiontotheminingtargetsSeams131and112,therelativelythincoalseams5through9underliethetargetcoalsandarenotyetbeingmined. Figure17showsthedetailedcoalstratigraphyofthesecoals,aswellascharacteristicsofthefloorandroofrocks. Theseseamsare not mined but contribute methane due to gob fracturing that occurs during longwallmining.

Figure17: DetailedCoalStratigraphyatLiuzhuangmine(Source:SDIC)

PhotomicrographyofcoalsamplesintheHuainanCoalFieldclearlyshowtheextensivenaturalmicrofracturingandshearingthattheyhaveundergoneduetothecomplexstructuralhistoryof the region (Figure 18). This deformation has weakened the coal and reduced itspermeability,makingitdifficulttodrillinseam.PreFeasibilityStudyandMineSiteSelection 1-13


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Figure18: Photomicrograph(300x)ofaCoalSampleintheHuainanCoalField(Liuetal.,2009)

1.7.3 HighTemperatureHazardA local geothermal anomaly has generated an abnormally high temperature gradient at theLiuzhuangmine(3Cper100mdepth). Attypicalminingdepthstheinitialrocktemperatureisquitehot,approximately38.9C. Ventilationappliedduring longwallretreatminingreducesthe maximum temperature at the mining face to about 26 to 30C. However, the elevatedtemperatureisconsideredtobehazardousforminepersonnel,whooftenworkshortenedandstaggeredshifts. Despitethis,theelevatedtemperatureisnotconsideredtohaveasignificantimpactonCMMdrainageatthismine.1.7.4 CoalDustUnrelatedto itsCMMdrainagepotential,butstill importantforminingproductivity,thecoalminedatLiuzhuang isconsideredtohaveahighriskofcoaldustexplosion. Coalvolatility is35.95and ischaracterizedbya long flame(>400m). Theminetakesstandardmeasurestosuppress the risk of coal dust explosion, mainly by maintaining the minimum rock contentabove65%.1.7.5 GasContentandCMMResourcesGascontentattheLiuzhuangminehasnotyetbeenpreciselymeasured usingCBMindustrystandardtechniques,but isbelievedtorangefromabout3to7m3/t, increasingwithdepth.Themostaccuratemethodfordetermininggascontent directgasdesorptionofcoresampled



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from the virgin (nonmined) coal seams has not yet been conducted at Liuzhuang, mainlybecausenomodernCBMexplorationwellshavebeendrillednearby.Instead,theFushunCoalMineResearchInstituteusedinmineboreholecoredatatoestimategascontentatapproximately5.29m3/t. However,itshouldbenotedthattheFushuninminemethodismuchlessaccuratethantheCBMindustrystandarddirectdesorption(USBureauofMines)methodusingsurfacecores. Thus,thereremainssomeuncertaintyabouttheactualgascontentandCMMresourcesatLiuzhuangmine.GascontentmeasurementsobtainedbyFushunshowlargevariationandprobablyarenotveryreliable (Table 13). Methane contents measured range widely, from 0.42 to 12.47 m3/t.Methaneconcentrationmeasurementsalsoshowextremevariation,from32.76%to92.66%.This considerable data variability probably reflects contamination with mine ventilation airduringthesamplingprocedure.

Table13: CoalSeamGasContentandCompositionDatafromtheLiuzhuangminearea(Source:SDIC)

Desorptiondata measured fromsurfacecore taken fromotherportions ofthe Huainan CoalFieldindicatethatgascontentatLiuzhuang isprobablycloserto7m3/tatadepthof700m.Usingthelowergascontentestimate,FushunestimatedCMMresourcestobeapproximately69 billion m3, ofwhichsome 22.8 billion m3 are consideredtechnically recoverable methanereserves;thesefiguresmaybeunderestimatedby20%.PreFeasibilityStudyandMineSiteSelection 1-15


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1.7.6 MiningPracticesMineLayout. TheLiuzhuangmineusesatypicalretreatlongwallminingdesignwithcollapsingroof. Thelongwallpanelsarerelativelylarge,measuring250by1800m. Thecurrentminingdepth is 580 to 700 m below the surface. Seams 112 and 131 at Liuzhuang are notexceptionallythick(lessthan4.5m)andthusthecoalcanbereadilyexploitedusingasinglepass,fullheightminingtechnique.Asarelativelyrecentlydevelopedmine,initiallongwallminingfacedevelopmentatLiuzhuangtookplace inEastZone2,whichislocatedintheEastWingofthemineandboundedontheeastbyfaultF30,withfaultF31providingaprotectivecolumncontour. ThewesternboundaryofthemineisfaultF19,whilethenorthernboundaryisthe 500mstructurallevelofSeam131. Theinitialdipslopewas1317south,butthedipsteepenstoabout30atgreaterdepth.Thefirstminingfacemeasuredapproximately350macrossfromeasttowest. Aventilationairway was constructed above this face. Situated below is the gateway for coal haulage. Theupperzoneisclassifiedasthe1302workingzone,thelowerarea1304workingzone,easternside the East Mining Zone 3, and the western side the East Mining Zone 1. The longwallmeasuredsome1,623m long,withaverageslope length244m. Coalreservesforthispanelwere estimated at 2.079 million t, of which 1.933 million t is considered to be mineable(equivalentto93%miningefficiency).Roadway Development. Development of roadways at Liuzhuang mine utilizes road headermachines

as

well

as

drill

and

blast

methods.

Development

production

at

Liuzhuang

mine

is

approximately150,000t/year. Themainroadwayshavethefollowingcharacteristics: 7separateareas(zones). Advancerateisapproximately600mpermonthperroadheader. Roadwaydimensionsareapproximately4.65m(width)x3.8m(height). Longwall gateroads (from mine plan) are singleheading entry development, double

headingentrydevelopment,ordevelopedofffrommainroadways. Goaf drainage roadways (from the mine plan) appear to be offset to one side of the

longwallblock,18to25mabovethecoalseam.Longwall Development. As of November 2009, one longwall was in operation at Liuzhuangmine. Asecondlongwallisplannedtobeinstalledduring2010. Aftercompletionofthemineexpansion, coal production related to mining of longwalls at Liuzhuang (as opposed to theroadways)willbeexpandedtoabout7.85milliont/year.



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LongwallblocksatLiuzhuangminehavethefollowingcharacteristics: Lengthrangesfrom1500to1700m. Widthrangesfrom220to280m(plantogoupto340m).

Miningheight

depends

on

the

coal

seam

that

is

being

mined,

ranges

from

1.95

to

4.55

m.

Mineadvancerateisapproximately8to10mperday. Miningplanistoworkfromtheuppercoalseamdowntothelowerones. Thus,the

miningsequencestartswithSeam131,miningsequentiallytheseamsbelow(Seam112 currently. In the future Seams 8, 51 and finally Seam 1 are scheduled to bemined).

1.7.7 MethaneDrainagePracticesTo enhance safety and mining productivity, the Liuzhuang mine currently uses boreholesconnectedtoavacuumsystemtodrainapproximately24.7m3/minofcoalminemethane. Twotypes of CMM boreholes are drilled at the Liuzhuang mine. First, short (100m long), nonsteered,boreholesaredrivenhorizontally intothecoalseams inacrosspanelconfiguration.Second,crossmeasureboreholesslantedupwardsintothefracturedrock(gob)zonesarealsoinstalledtodrainCMMthatisreleasedfromoverlyingcoalseamsandsandstonesthatbecomefracturedastheminingfaceadvances.SignificantvolumesofaircontaminationleakintothedrainedCMMstreamatLiuzhuangmine,reducing the methane concentration from about 95% CH4 as originally stored in the coalreservoirtoonlyabout7to 10%bythetimetheCMM isvented. Mostof thisairprobablyenters the gob area and/or is sucked into the boreholes as the mining face advances.Additionalair likely leaksaroundthepoorlycementedboreholes. Airalsomay leak intothesteelpipelinesystemvialooseflangeconnections.ThecoalseamsminedatLiuzhuanghavelowtomoderatemethanelevels,arelooseandsoft,andhave lowpermeability(probably0.1mDor less). Thismakespredrainageverydifficult.Despite the modest gas contents, gas and rock outbursts are fairly common during miningbecauseoflowpermeability.ForSeam131,disruptionoftheoverlyingseamsby longwallminingcontributesasignificantfraction(1736%)ofthemethaneencounteredattheworkingface. Gasalsodesorbsfromthincoalseamsthatarenotminedordisrupted,duetodesorptioncausedbytheminespressuresink. Muchofthisgasaccumulatesinthegobzoneabovethetargetseamand isdifficulttodealwith.



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Severaldegasificationmethodsareemployedtocontrolthemethaneemissionsintothemineworkings. The first isto excavatea35 degreesloping tunnelto getabove theminedseam.Then 10 boreholes are drilled from a small gallery tojust above the working face. Thissequenceisrepeatedevery80morsoabovetheworkingseam. Thesecondmethodistodrillcross

measureboreholesfromtheroadwaysoverthe longwallpanel. Bothofthesesystems

producelowqualityCMM,intherangeof15%methane.The main method for methane drainage at Liuzhuang mine is gob gas removal using shortboreholes drilled along strike, angled up into the roof of the coal seam. Gas productionincreasesoncetheworkingfaceandgobzonereachestheendoftheboreholes,butmethaneconcentrationisdilutedseverelybymineventilationair. AtLiuzhuangminetheconcentrationofdrainedgasisextremelylow(generally710%CH4),whichisinthehazardousexplosiverangeformethane/airmixtures(between5and15%CH4inair).LongerhorizontalinmineboreholesdrilledintothegobwouldseemanobviousimprovementtotheshortholescurrentlydrilledatLiuzhuang. Forexample,asearlyas1998attheXieqiaomine, located just to the east of Liuzhuang, a horizontal borehole 360 m in length wassuccessfullydrilledusinganAustraliandirectionallycontrolled1000mrateddrill.31.7.8 VentilationAt Liuzhuang centralized cross ventilation was utilized during the early stage of mining,ventilating the mainandauxiliary shafts. Two maintrackcrosscut lineswere employed: thecentral

Track

Line

and

the

air

inflow

cross

cutline.

The

mine

employs

an

exhaust

system

with

a

surfacemountedmainventilationfan. ManufacturedintheUnitedKingdombyHowden,thefanis2.8mindiameterandhasaflowcapacityof20,000to28,000m3/min.Starting August 31, 2006, the mine commissioned two auxiliary ANN2884/1400N axialflowblowers,with2MWmotorcapacityandhydraulicallyadjustablerotors.Slope shafts (Central Plastic Machine and Gangue Plastic Machine slope shafts) provideventilationtotheminingfaceandtunnelingareas. Ventilationairexitsthroughtwocrosscutshafts. Thefirstminingfacearea,developedinSeam131,wasventilatedwith2,520m3/min,freshairpassingthroughthecentraltrackcrosscuttoalltunnelingzones. Attheearlystageofmining,onlyfiveroadtunnelingfaceareas,threeminingfaceareas,andonecombinedminingface area were present, thus the ventilation requirement was about 13,080 m3/min.

3Yuan,Liang;Zhang,Liqing;Li,Ping;andZhou,Deshui,1998. UndergroundCoalbedMethaneDrainageintheHuainanMining

Area. ProceedingsoftheInternationalWorkshoponCoalbedMethaneRecoveryandUtilization,November1213,1998,Beijing,China.



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Ventilation control for the mine was established primarily through the use of permanentventilationshaft,adjustableventilationshaft,andairdiversionwalls.Currently,theminehastwomethanepumpingstations,oneontheeastsideandoneonthewest. Ontheeasternarea,fourpumpswithacapacityof415m3/minhavebeeninstalled. Onthewestside,fourpumpsarescheduledtobeinstalledduring2010;twomorepumpsaretobeinstalledlater.In 2007 Liuzhuang mine drained 10.8 million m3 (20.5 m3/min) of methane, increasing toapproximately13millionm3(24.7m3/min)in2008. Theconcentrationofthedrainedmethaneislow,usuallylessthan10%CH4. DuringtheJuly2008prefeasibilitystudyvisit,allcapturedmethanewasbeingventedtotheatmosphere.

1.7.9

CMMUtilization

Currently,noneoftheCMMbeingdrainedatLiuzhuangmineisbeingutilized. SDICXinjihasbeenevaluating (buthad not yetdecided on) the use of Shenglimanufacturedreciprocatingengines that are capable of using lowquality CMM fuelwith 710% CH4 concentration. Theprojectasoriginallyenvisionedwouldgenerateatotalof4.0MW,comprising8unitsx0.5MW.Powergeneratedwouldbeusedmainlybythemine.VentilationairmethanemitigationorutilizationdoesnotappeartobepracticalatLiuzhuangmine. Themethaneconcentrationintheventilationairisonlyabout0.02%CH4. Whilesuchalow VAM concentration is favorable for mining safety purposes, it is significantly below theeconomiclimitforVAMmitigationorutilization.

1.7.10 MethaneEmissionsThe Liuzhuang mine currently emits an estimated total 30.9 m3/min (1.6 MMcfd or 0.41MtCO2e/yr). These CMM emissions originate from two main sources. The most importantcomponentofmethaneemissionsisthe24.7m3/minof710%puritymethanethatisdrainedviatheboreholeandvacuumsystem. Anadditional6.2m3/minofverylowconcentrationVAM(average0.02%CH4)isalsoemitted.



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1.8 ConclusionsandRecommendationsThethreeSDICXinjiminessharesimilargeologiccharacteristicsaswellascertainminingandcoalminemethanedrainagechallenges. Theprefeasibilityevaluationindicatedthateachminecould

qualify

as

acandidate

for

amore

detailed

CMM

feasibility

study.

However,

the

Liuzhuang

minestoodoutasaparticularlyattractivecandidateforseveralreasons,including:

1) TheLiuzhuangmineisthenewestandmostmodernofthethreeSDICXinjiEnergyoperatedmines,havingbeeninproductionforonlythreeyears.

2) Ithasthelargestlongwallpanelsbeingdevelopedofthethreemines,measuring250mby1800m,offeringspaceforadvancedlongholedrillingstrategies.

3) Liuzhuanghasthelargestdesignedcapacity(8milliont/year),aswellasrecoverablereserves(679milliont)andthelongestservicelife(61years).

4) It has the largest total methane resources, estimated at 69 billionrecoverablereserveof23billionm3. m

3 with a5) Mine management has installed an extensive realtime monitoring system of

methanedrainage,coalproduction,andothermineproductionrelatedstatistics.6) Liuzhuang has experimented with surface drilled gob wells with some success,

indicating that alternative degasification systems could be employed that wouldproducehigherconcentrationsofmethane.

7) The ARI teams initial finding is that long horizontal borehole drilling intothe gobzoneabovetheminedcoalseamscoulddramaticallyimprovemethanerecoveryandconcentration.

8) Additional improvements inboreholesealingeffectivenessandthe integrityofthepipelinesystemcouldboostmethanequalityseveralfold.

9) Oncegasflowandquality is improved, largermoreefficientreciprocatingenginescould be applied for power generation, with more reliability and efficiency gainsoverthecurrentlessreliablelowconcentrationunits.

Section2through10ofthisreportprovideadetailedfeasibilitystudyoftheproposedCMMdrainageandutilizationimprovementprojectatLiuzhuangmine.



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SECTION2GeologicAnalysisandResourceAssessment

GeologicAnalysisandResourceAssessment 2i


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SECTION2CONTENTS2.1 Introduction.............................................................................................................. 212.2 LocationandRegionalTectonics............................................................................... 21

2.2.1 HuainanCoalField................................................................................................................2 32.3 LiuzhuangMineGeologyandResourceAssessment................................................215

2.3.1 MineAreaDescription.......................................................................................................2 152.3.2 LiuzhuangMineGeology....................................................................................................2 152.3.3 LiuzhuangMineCoalProperties........................................................................................2 232.3.4 LiuzhuangMineCoalandCMMReserves ..........................................................................224

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SECTION2FIGURESFigure21: LiuzhuangMineLocationinrelationtotheEastChinaCoalRegion...................22Figure22: StratigraphicLithofaciesofEastCentralChina...................................................23Figure23: StructureMapofHuainanCoalField................................................................... 24Figure24: TotalCoalThicknessDistributionintheHuainanCoalField...............................25Figure25: Vitrinite Reflectance Distribution in the Huainan Coal Field............................... 26Figure26: GasContentVersusDepthintheHuainanCoalField.........................................27Figure27: AdsorptionIsothermsforHuainanCoals............................................................. 29Figure28: GasContentDistributioninHuainanCoalField................................................210Figure29: CoalMiningDistrictsintheHuainanCoalField................................................. 211Figure210: CBMExplorationWellsandResourceEstimationBlocksinthe

HuainanCoalField............................................................................................. 212Figure211: GasInPlaceDistributionintheHuainanCoalField.......................................... 213Figure212: StructureandDepthtoSeam131atLiuzhuangmine.....................................216Figure213: StructureandDepthtoSeam211atLiuzhuangMine.....................................216Figure214: StructuralCrossSection15................................................................................ 217Figure215: ExpandedSectionofNSCrossSectionacrossLiuzhuangmine.......................218Figure216: StratigraphicColumnshowingCoalSeamDistributioninthe

LiuzhuangCoalField.......................................................................................... 219Figure217: CoalCoreholeLog3032(DepthInterval654689m)........................................ 221Figure218: CoalCoreholeLog3032(DepthInterval741774m)........................................ 222

SECTION2TABLESTable21: Gas Content Data from Huainan Coal Field Districts........................................... 28Table22: 2003EstimateofCBM/CMMResourcesintheHuainanCoalField..................213Table23: 2009EstimateofCBM/CMMResourcesintheHuainanCoalField..................214Table24: Industrial(proximate)analysesofSeams131and112atLiuzhuangmine.... 223Table25: EstimatedCoalandCMMReservesatLiuzhuangmine....................................224

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2.1 IntroductionCoalminingonalargescalefirstbeganattheHuainanCoalFieldinthe1950s,whilecoalminemethane(CMM)drainagehasbeenunderwaysince1961.Today,HuainanisoneofChinaslargestand

most

important

coal

mining

and

coal

mine

methane

production

areas,

ranking

number

three

andtwo,respectively,inthecountry.ThissectiondiscussestheregionalgeologyandCMMresourcesintheHuainancoalfield. Italsoevaluates the specific conditions, challenges, and potential technical solutions for optimallydrainingandutilizingCMMatLiuzhuangmine.Understandingfirsttheregionalgeology,coalmining,andCMMdrainageconditionsandchallengesinthe largeHuainanCoalFieldisessentialforultimately improvingtheperformanceofCMMdrainageatLiuzhuangmine. ItalsohelpstoquantifythepotentialbenefitsthatimprovementsdevelopedatLiuzhuangminemayprovideforupgradingCMMdrainageattheregionsseveraldozenundergroundcoalmines.CoalmineproductionfromtheHuainanCoalFieldtotaledapproximately100milliontin2008.Assumingbasinwideaveragespecificmethaneemissionsof20m3/t,whichincludesmethanethatseepsintotheminefromadjacentnonminedseamsandfracturedsandstones,approximately2billionm3/year(200MMcfd)ofmethaneisliberatedbycoalmininginHuainan.Ofthistotal,onlyabout190millionm3/year(ornearly10%)isdrainedinCMMcollectionsystems.Of the methane drained, about 40% or 95 million m3/year is utilized, mainly as boiler fuel,residential town gas, and some power generation. In summary, methane emissions to theatmospherefromcoalminingintheHuainanCoalFieldareestimatedtobe1.9billionm3/year.Clearly, the Huainan Coal Field offers a major opportunity for improved CMM drainage andutilization.2.2 LocationandRegionalTectonicsLiuzhuang mine is located in the western portion of the Huainan Coal Field in central AnhuiProvince. TheHuainanCoalFieldispartofthemuchlargerandstructurallycomplexEastChinaCoalRegion,amajorcoaldepositwhichextendsupthelengthofeasternChinaintonortheasternChinasLiaoningandHeilongjiangProvinces(Figure21).

GeologicAnalysisandResourceAssessment 2-1


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Over the past 15 years several articles authored by Chinese researchers have described thegeology,coalminemethane,andcoalbedmethanepotentialoftheHuainanregion.1,2,3 ThissectionisbasedonARIssynthesisofotherspreviousworkaswellasourowninterpretationoftherawdata.

Figure21: LiuzhuangMineLocationinrelationtotheEastChinaCoalRegionTheEastChinaCoalRegionisatectonicallyactiveregioncharacterizedbynumerousresultsandoftenrapid,recentregionalsubsidence. ThistectonicactivityisbeingdrivenbyIndiascontinuednorthwardsubductionundertheAsiancontinentandtheresultingnortheastwardextrusionofChina. EastChinaisstructurallymuchmorecomplexthantherelativelyquiescentOrdosandQinshui basins of northcentral China. These areas have experienced mostly up and downmovement, much like in the Colorado Plateau of the U.S. The Ordos and Qinshui basin arerelativelyfreeofactivefaultingandthereforestructurallymuchsimplerthanHuainan.1

Yang,Zhongzhen;Zhang,Bingguang;andSunMaoyei(HuainanCoalMiningBureau),1995. EvaluationoftheGeologicalCharacteristicsandtheResourcesofCoalbedMethaneintheHuainanCoalField. Proceedings,InternationalConferenceonCoalbedMethaneDevelopmentandUtilization,UnitedNationsDevelopmentProgram,Beijing,China,October1995.

2Yang,Zhonzhen;Zhang,Bingguang;andSunMaoyei((HuainanCoalMiningBureau),1995. EvaluationandDevelopmentProspectsofCoalbedMethaneResourcesintheHuainanCoalBasin. ChinaCoalbedMethane,No.1,May1995.

3Liu,Dameng;Yao,Yanbin;Tang,Dazhen;Tang,Shuheng;Yao,Che;andHuang,Wenhui(ChinaUniversityofGeosciences),2009. CoalReservoirCharacteristicsandCoalbedMethaneResourceAssessmentinHuainanandHuaibeiCoalfields,SouthernNorthChina. InternationalJournalofCoalGeology,v.79,p.97112.



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Mainlyforthisreason,advancedCMMdrainagetechniquesthatarebeingsuccessfullyemployedinstructurallysimple(i.e.,notfaultedandfolded)andstable(strong,intactcoal)portionsofShanxiProvince (e.g., the Sihe mine) and in particular the 1000m long inseam borehole drillingtechnology importedfromNorthAmericaandAustralia arenotnecessarilyappropriate forLiuzhuangandotherminesinEastChina.2.2.1 HuainanCoalFieldThe Huainan Coal Field is a major coal mining region in eastcentral China. Huainan is thesouthernmost coal field in the East China Coal Region. Covering a total surface area ofapproximately3,000km2,theHuainanCoalFieldmeasuresabout100kmeasttowestandabout25to30kmnorthtosouth. ItcomprisesseveraldozenlargeundergroundcoalminestargetingPaleozoicagecoaldeposits.CoalStratigraphy.ThecoaldepositsintheHuainanCoalFieldarefoundmainlywithinthePermianShihezi Formation, with a few economically less vital seams also occurring in the underlyingPermianShanxiFormation(Figure22).(NotethattheShiheziFormationisayoungerunitthanthecoalbearingCarboniferousTaiyuanandPermianShanxiFormationsfurthertothenorthinHenanand Shanxi Provinces.) These coal seams were formed in a mostly paralic delta facies withnumerousdepositionalcycles. Approximately32to40individualcoalseamstotalingupto42mnetcoalthicknessoccurwithinanoverall350mthickcoalbearingsequence.Ofthese,about9to18seamsareconsideredtobeofmineablethicknessandlateralcontinuity,thoughinagivenminetypicallyonlyseveralindividualseamsaremined.

Figure22: StratigraphicLithofaciesofEastCentralChinaGeologicAnalysisandResourceAssessment 2-3


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Regional Structure. The Huainan Coal Field is an eastwest trending depression containingPaleozoiccoaldeposits(Figure23). Majorfaultsandfoldsinthebasinalsotrendeastwestandcontrolcoaldepthdistribution. SignificantfoldsincludethePanAnticlineintheeast,theXieliSynclineinthesoutheast,andtheXieqiaoSynclineinthesouthwest,wheretheLiuzhuangmineissituated. Depthtocoalrangesfromlessthan300mdeepinthewestcentralportionofthebasintoover2,000mdeepatitsfareasternedge. CoaldepthatLiuzhuangminerangesfrom400mdeep inthenorthtowellover1000mdeep inthesouth. Notethataboutadozencoalbedmethaneexplorationwellshavebeendrilledinthebasinsince1992,fiveofwhicharelocatedonARIsstructuremap,butnoneofthemarelocatedneartheLiuzhuangmine.

Figure23: StructureMapofHuainanCoalField



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CoalThickness. Totalcoalthicknessreachesamaximum33minthenortheasternportionofHuainanCoalField(Figure24). Liuzhuangmine,locatedinthewesternportionofHuainanCoalField,hasmoderatetotalcoalthicknessofapproximately25m,whichisstillconsideredaverysubstantialcoaldeposit. AsizeableareajusttothenorthofLiuzhuangmineiscompletelydevoidofcoal,havingbeendenudedofPermiansedimentaryrocksduringtheancientupliftanderosionaleventthatcreatedthePermianQuaternaryunconformity.Coalthicknessincreasesagaintomorethan30minthestructuraldepressionjustsouthofLiuzhuangmine.NotethatonlyasmallfractionofthiscoaldepositiscurrentlyminedatLiuzhuang. TheextensivecoaldepositsintheLiuzhuangmineareacouldenablecoal(andCMM)productiontobeincreasedsignificantly.

Figure24: TotalCoalThicknessDistributionintheHuainanCoalField



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CoalRank.Thethermalmaturity(rank)ofcoalisamajorcontrolonitsmethanesorptioncapacity,as well as its cleat and permeability development. Figure 25 shows ARIs map of vitrinitereflectance(Ro)distributionintheHuainanCoalField,ameasureofthermalmaturity. Vitrinitereflectancereachesamaximumof0.85%ineasternHuainanCoalField,equivalenttomediumvolatilebituminouscoalrank. Liuzhuangminehasrelatively lowRoofapproximately0.72%,representinghighvolatilebituminousAcoalrankand indicatingsomewhat lowergasstoragecapacity.

Figure25: VitriniteReflectanceDistributionintheHuainanCoalField



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GasContentandSaturation.CoredesorbedusingtheU.S.BureauofMines(USBM)methodfromsurfacecoreholes,locatedinareasundisturbedbymining,istheonlyreliablemeasurementofcoalseamgascontent. Inminemeasurementofgascontentusingshortboreholes(


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Table21showsgascontentdatafromvariouscoaldistrictsoftheHuainanCoalField,tabulatedbyindividualcoalseam. TheLiuzhuangmineislocatedintheXieqiaodistrict,whereSeams112and132 have average gas contents of 7.96 and 7.25 m3/t, respectively, at a depth of 1,000 m.However,muchofthegascontentdatacollectedinthisareaareprobablynotbasedonthemorerobustUSBMmethodandthereforearesuspect. GascontentishigherinthePanjiandXieliareasofeasternHuainan,about11m3/tat1,000mdepth.

Gas Content by Seam

(m3/t d.a.f. basis)

Coal District Depth Range (m) 1 8 11-2 13-2

Xieqiao West

700

1000

1200

1000

1200

1500

5.05

6.71

7.01

3,19

5.89

7.75

2.75

5.75

7.00

4.72

6.74

7.45

Xieqiao

700

1100

1200

1000

1200

1500

-

6.09

6.20

8.11

8.45

8.60

-

7.96

8.23

6.82

7.25

-

Guqiao900

1100

1200

10001200

1500

-8.71

11.18

10.4512.58

14.05

7.518.70

10.10

8.1510.13

11.10

Panji

700

1000

1200

-

1000

1200

1500

>1500

-

11.44

12.48

13.10

13.07

14.38

14.45

14.45

8.20

10.11

11.88

12.10

8.59

9.93

11.75

12.40

Zhuji

900

1000

1200

-

1000

1200

1500

>1500

-

-

9.73

12.80

7.65

10.39

13.98

14.30

5.22

6.27

8.07

11.39

-

8.90

11.55

12.10

Xieli

900

1000

1200

-

1000

1200

1500

>1500

-

7.90

10.13

4.80

-

11.27

14.46

4.65

9.75

10.45

11.95

5.10

8.45

9.68

11.00

5.13

Zhangou10001200

-

12001500

>1500

2.013.22

4.80

2.744.03

4.65

2.843.56

5.10

1.953.55

5.13

Madian

1000

1200

-

1200

1500

>1500

-

3.28

4.75

2.23

4.45

5.01

-

3.23

4.25

2.21

3.99

5.00

Table21: GasContentDatafromHuainanCoalFieldDistrictsSorptionisothermmeasurementsindicatethatcoalseamsintheHuainanCoalFieldgenerallyhavegascontentlevelsthataresignificantlybelowthetheoreticalsorptivecapacityofthecoalseams.Thus, the coals are in an undersaturated state (Figure 27). Extensive dewatering would benecessarytoelicitmethanedesorptionandeventualproductioninaverticalorhorizontalsurfaceCBMwell.(Coalminedevelopmentreducesreservoirpressuretonearatmosphericlevels,soCMMproductionisnotasaffectedbyreservoirundersaturation.)PanjianticlineareaineasternHuainanCoalFieldisthemostsaturatedareaofHuainan,withgascontentdataapproachingthesorptionisotherm. TheXieliportionofsoutheasternHuainanisseverelyundersaturated. LiuzhuangmineinwesternHuainanisslightlyundersaturated,withgascontentintherangeof7m3/tplottingbelowthesorptionisothermcurveat9to11m3/t.GeologicAnalysisandResourceAssessment 2-8


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Figure27: AdsorptionIsothermsforHuainanCoalsReddatapointsaregascontentsmeasuredusingtheformerMinistryofCoaldesorptionmethod,whichusessmallersamplesandshorterdesorptiontime,thusislessreliable.GreendataaremorerecentgascontentsmeasuredusingtheUSBureauofMinesdesorptionmethod. Thisutilizeslargercoalsamplesanddesorbsforamuchlongertime,resultinginmorereliable(andgenerallyhigher)values.

Area1:PanjianticlineareaofeasternHuainanCoalField.ThisareaisthemostsaturatedportionofHuainan,withgascontentdataapproachingthesorptionisotherm.

Area2:TheXieliportionofsoutheasternHuainanisseverelyundersaturated. Area3:LiuzhuangmineinwesternHuainanisslightlyundersaturated.Gascontentinthe

rangeof7m3/tplotsbelowthesorptionisothermcurveat9to11m3/t.GeologicAnalysisandResourceAssessment 2-9


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GascontentdistributionvarieswidelyacrosstheHuainanCoalField(Figure28). Gascontentreachesamaximum23m3/tinthePanjiminingarea,easternHuainanCoalField. TheLiuzhuangminehascomparativelylow(butstillsubstantial)gascontentof7to8m3/t. This isbecauseLiuzhuangisrelativelylowinrankandalsoissomewhatlesssaturatedthanthecoaldepositsofeasternHuainan.

Figure28: GasContentDistributioninHuainanCoalFieldGasOrigin. Coalbedmethane 13CvaluesintheHuainanCoalfieldgenerallyarelessthan 55,whichindicatesabiogenic(ratherthanthermogenic)origin. However,thevitrinitereflectancelevel(Ro=0.82%~0.97%)indicatesthatthecoalalreadyhaspassedthroughtheearlybiogenicgasstageandalreadyreachedthestageofthermogenicmethanegeneration.Therefore,itislikelythatCBMintheHuainanCoalFieldismainlysecondarybiogenicgas. TheYanshanianorogenycauseduplift,erosion,anddegassingofthePermiancoalbearingsequence.BiogenicresaturationofmethanemayhaveoccurredaftermorerecentregionalsubsidenceandthedepositionofthethickQuaternaryoverburden,whichelevatedformationpressureandallowedadsorptionofbiogenicmethane.GeologicAnalysisandResourceAssessment 2-10
http:///reader/full/0.82%~0.97http:///reader/full/0.82%~0.97http:///reader/full/0.82%~0.97


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CoalReserves&Resources. TheHuainanCoalFieldcontainsprovencoalreservesofabout15.3billionmetrictonnes(t). Thereareafurther10.8billiontofdetailedexplorationcoalreserves. Inadditiontothesefairlyconservativeofficialreserveestimates,highresolutionseismicsurveysindicatethereisanadditional80billiontofcoalpresentatdepthsshallowerthan2,000m,ofwhich30billiontisshallowerthan1,200mand20billiontisshallowerthan1,000m. ThisisalargeresourcebaseandHuainanislikelytoremainamajorcoalproducingareaformanydecadestocome.Figure29showsthe29currentandplannedcoalminingdistrictsthathavebeendevelopedintheHuainanCoalField. LiuzhuangmineislocatedwithintherelativelynewlyestablishedXieqiaominingdistrict(BBonARIsmap),inthewesternportionofHuainanabout70kmwestofHuainancity.

Figure29: CoalMiningDistrictsintheHuainanCoalFieldThecurrentdepthofcoalminingatHuainanismostlyintherangeof300to700m. However,miningisexpectedtodeepenincomingdecadesto1,000manddeeper.GiventhatgascontentintheHuainanCoalFieldincreasessignificantlybelowabout700m,methaneemissionsareexpectedGeologicAnalysisandResourceAssessment 2-11


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tocontinuerising. Manyminesthatarenotcurrentlyexperiencingseveredrainagechallenges,includingtheLiuzhuangmine,couldexperiencemarkedlyhighergaslevelsastheytargetcoalsdeeperthanabout700m.CoalMineMethaneandCoalbedMethaneResources. In2003theHuainanCoalMiningGroupestimatedcoalbedmethaneresourcesintheHuainanCoalField,includingtheLiuzhuangminearea(Figure210).4 Basedonthedistributionofcoalthicknessandgascontent,HCMGestimatedtheHuainanCoalFieldhasapproximately593billionm3(20.9Tcf)ofCBMandCMMresources(Table22

Documents

Final Feasibility Study Liuzhuang