LIDSDALEOIL/GAS|SEWER|STORMWATER|POWER|WATER|TELCO

LOCATION LidsdaleNSW

CLIENT Private

PIPE710mmPE112SDR8.2HDPEand2x63mmPE100SDR11

GEOLOGY Sandstone&siltstone

LENGTH 920metres

TECHNIQUE HDD

PROJECTOVERVIEWUEAhas recently completed the constructionofparallel bores, both 920metres longwith 1,500mmofseparation. The first bore was for a 710mm water main, whilst the second bore housed two 63mmcommunication lines. Thebores ranadjacent toa coal conveyorbelt and crossedunder theCastlereaghHighway,theCox’sRiverandarailwayline.CONSTRUCTIONDuetothedistance,holevolumeandlikelyrockgroundconditions,UEAutilisedtheGallagher660drillrigtoundertakebothbores.UEAutiliseditsin-housedesignteamtodevelopaboredesignsotheunderborewouldpredominantlyremainwithinthesandstoneandsiltstonerocklayersalongthealignment.CHALLENGESUEAdevelopedtheboredesignforbothclientandRMSapproval,astheborescrossedahighway,riverandrailway.Thedesignhadtoadheretocertainlimitations,suchasbeinglocatedwellunderneaththepilesatthebridgeonCastlereaghHighway,whileensuringtheborewaswithinthepre-determinedeasement.Duetodesign limitationsandminimal spaceat theentryof theHDD,UEAproposed that spacebetween thewaterpipeandcommunicationlineborebeaminimumof1.5metres.Whereseparationbetweenthetwobores could not bemaintained horizontally, the communications bore achieved a vertical separation byincreasingthedepthwhilealsoremainingwithintheeasement.Duetovaryingsurfacelevelsandvariousspecific site restrictions, awireline systemwasemployed to track theunderbores. Theuseof awirelinesystem allowed the drill head to be tracked to a depth of 30 metres, while minimising the interactionbetweentheHDDcrewand livetraffic (bothvehicularandfreighttrains)andwaterways.Additionally,as

theprojectwascompletedduringwinter,UEAhadtocontinuallyworkthroughsubzerotemperatures.Thesubzero temperatures introduced a new challenge, requiring theHDD crew to develop newmethods tomaintain the equipment while reducing any downtime from icing – a rare occurrence in Australianconditions.COMPLETIONThetwopipelineswereinstalledsuccessfullyandwithintheallocatedtime.Thisincludedthesubmissionofallqualityassurancedocumentation(workasexecuteddrawings,NATAaccreditedhydrostatictestingandweldtestingreports) forthecommissioningof thissectionof thepipeline.Asaresult,UEAwasaskedtodesignandinstalltwofurtherboresaspartoftheproject.