Haul road design

1. Venkat

2. 2
•HAULROADS:Duringthe
lifeofthepitahaulroad
mustbemaintainedfor
access.
•
HAULROAD-SPIRAL
SYSTEM:Haulroadis
arrangedspirallyalongthe
perimeterwallsofthe
pit.
HaulRoadDesign

3. 3
•HAULROAD–SWITCH
BACKSYSTEM: Zigzagpattern
ononesideofthepit.
•
HAULROADWIDTH:Function
ofcapacityofthe roadandthe
sizeoftheequipment.Haulroad
width mustbeconsideredinthe
overallpitdesign.
HaulRoadDesign

4. 4
HaulRoadEffectonPitLimits

5. 5
ConsiderationsforHaulRoad Design
•Visibility
•Stoppingdistances
•Verticalalignment
•Horizontalalignment
•Crosssection
•Runaway-vehiclesafety
provisions

6. 6
SightDistancesandStopping
Distances
•Verticalandhorizontalcurvesdesigned
consideringsightdistanceandstopping
distance
•
•
Sightdistanceistheextentofperipheralarea
visibletothevehicleoperator
Sightdistancemustbesufficienttoenable
vehicletravelingatagivenspeedtostop
beforereachingahazard

7. 7
SightDistancesandStopping
Distances
•Onverticalcurves,roadsurfacelimitssight
distance
•
•
•
Unsafeconditionsremediedbylengtheningcurve
Onhorizontalcurves,sightdistancelimitedby
adjacentbermdike,rockcuts,trees,etc;
Unsafeconditionsremediedbylayingbackbankor
removingobstacles

8. 8
SightDistanceDiagrams
Sightdistancediagramsforhorizontalandverticalcurves

9. 9
StoppingDistances
•Stoppingdistancesdependontruckbreaking
capabilities,roadslopeandvehiclevelocity
•Stoppingdistancecurvescanbederived
basedonSAEservicebreakmaximum
stoppingdistances

10. 10
StoppingDistance
Characteristics
Forexample,
stopping
distance
characteristics
ofvehiclesof
200,000to
400,000pounds
GVW

11. 11
StoppingDistances
•Priortofinalroadlayout,manufacturersof
vehiclesthatwillusetheroadshouldbe
contactedtoverifytheservicebrake
performancecapabilities

12. VerticalAlignment
•Establishmentofgradesandverticalcurvesthat
allowadequatestoppingdistancesonallsegments
ofthehaulroad
•Maximumsustainedgrades
•Reductioningradesignificantlyincreasesvehicleuphillspeed
•Reductioningradedecreasescycletime,fuelconsumption,stress
onmechanicalcomponentsandoperatingcosts
•
•
Reductioningradeincreasessafedescentspeeds,increasing
cycletime
Thebenefitsoflowgradesoffsetbyconstructioncostsassociated
withlowgrades
12

13. 13
VehiclePerformanceChart

14. 14
VehicleRetarderChart

15. 15
VerticalAlignment
•Maximumsustainedgrades
•Somestateslimitmaximumgradesto15to20%and
sustainedgradesof10%
•Mostauthoritiessuggest10%asthemaximumsafe
sustainedgradelimitation
•Manufacturerstudiesshow8%gradesresultinthe
lowestcycletimeexclusiveofconstruction
consideration

16. 16
VerticalAlignment
•Maximumsustainedgrades
•Propertyboundaries,geology,topography,climate
mustbeconsideredonacasebycasebasis.
•Loweroperatingcostsmustbebalancedagainsthigher
capitalcostsoflowgrades.
•Trucksimulatorsandmineplanningstudiesoverthe
lifeofmineshouldbeusedtomakethedetermination
oftheappropriategrades

17. VerticalCurves
•Verticalcurvessmoothtransitionsfromone
gradetoanother
•Minimumverticalcurvelengthsarebasedon
eyeheight,objectheight,andalgebraic
differenceingrade
17

18. 18
StoppingDistancevs.Vertical Curve
Forexample,
verticalcurve
controls9fteye
height(usually
minimumheight
forarticulated
haulagetrucksof
200,000to
400,000poundof
GVW)

19. HorizontalAlignment
•Dealsprimarilywithdesignofcurvesand
considerspreviouslydiscussedradius,width,
andsightdistanceinadditionto
superelevation
•Crossslopesalsoshouldbeconsideredinthe
design
19

20. 20
Curves,Superelevation,and
SpeedLimits
•Superelevationgraderecommendationsvary
butshouldbelimitedto10%orlessbecause
oftractionlimitations
•
•
Dependingonmagnitudeofthesidefriction
forcesatlowspeed,differentvaluesare
suggestedforsmallradiuscurves
KaufmanandAultsuggest.04-.06fpf
(basicallythenormalcrossslope)

21. 21
Curves,Superelevation,and
SpeedLimits
•CATsuggestshigherslopeswithtraction
cautionsand10%maximumcaution
•Again,whereice,snow,andmudarea
problem,thereisapracticallimitonthe
degreeofsuperelevation

22. 22
CurveSuperelevation

23. 23
RecommendedSuperelevationRates
Ifsuperelevationisnotused,speedlimitsshouldbesetoncurves.

24. 24
Curves,Superelevation,and
SpeedLimits
•Centrifugalforcesofvehiclesoncurvesare
counteractedbyfrictionbetweentireanroadand
vehicleweightasaresultofsuperelevation
•
•
Theoretically,withsuperelevation,sidefriction
factorswouldbezeroandcentrifugalforceis
balancedbythevehicleweightcomponent
Toreducetirewear,superelevationorspeedlimits
oncurvesarerequired

25. 25
CombinationsofAlignments
•Avoidsharphorizontalcurvatureatornearthecrest
ofahill
•
•
•
•
Avoidsharphorizontalcurvesnearthebottomof
sustaineddowngrades
Avoidintersectionsnearcrestverticalsandsharp
horizontalcurvatures
Intersectionsshouldbemadeflataspossible
Ifpassingallowed,gradesshouldbeconstantand
longenough

26. 26
CrossSection
•Astableroadbaseisveryimportant
•Sufficientlyrigidbearingmaterialshouldbe
usedbeneaththesurface
•Definethebearingcapacityofthematerial
usingtheCaliforniaBearingRatio(CBR)

27. 27
CaliforniaBearingRatio

28. 28
SubbaseConstruction

29. 29
CrossSlopes
•Crossslopesprovideadequatedrainageand
rangefrom¼to½inchdropperfootof
width(approximately.02to.04footperfoot)
•Lowercrossslopesusedonsmoothsurfaces
thatdissipatewaterquicklyandwheniceor
mudisaconstantproblem

30. 30
CrossSlopes
•Highercrossslopespermitrapiddrainage,
reducepuddlesandsaturatedsub-base,and
areusedonroughsurfaces(graveland
crushedrock)orwheremudandsnoware
notaproblem
•Highcrossslopescanbeparticularly
problematicwithiceorsnowonhighgrades
(+5%)

31. 31
RecommendedRateof
Cross-Slope Change
Slopechangeshouldbegradual.

32. 32
Width
•Onstraightortangentsegments,width
dependson
•Vehiclewidth
•Numberoflanes
•Recommendedvehicleclearance,whichranges
from44to50%ofvehiclewidth

33. 33
MinimumRoadDesignWidths
forVariousSizeDumpTrucks

34. 34
TypicalDesignHaulRoad Width
Typical
designhaul-
roadwidth
fortwo-way
trafficusing
77.11-t(85-
st)trucks

35. 35
TypicalHaulagewaySections

36. 36
Width
•Bermheightandwidthasafunctionof
vehiclesizeandmaterialtype
•
•
•
•
Ditch(es)addedtobasicrecommendations
Runawayprovisionsmayalsoaddtowidth
Roadwideroncurvesbecauseofoverhang
Minimumturningradiusconsideredon
curves(shouldbeexceeded)

37. 37
HaulagewayWidthsonCurves

38. 38
SafetyProvisions-Berms
•Triangularortrapezoidalmadebyusinglocal
material
•Standsatnaturalangleofreposeofconstruction
material
•Redirectsvehicleontoroadway
•Minimumheightatrollingradiusoftire

39. 39
Berms
•Largerbouldersbackedwithearthenmaterial
•Nearverticalfacedeflectsvehicleforslight
anglesofincidence
•Problemswithdamageandinjuryand
availabilityofboulders
•Minimumheightofboulderatheightoftire
allowingchassisimpact

40. 40
RunawayProvisions
•Withadversegradessomesafetyprovisionshould
beintegratedtopreventrunawayvehicles
•
•
•
Primarydesignconsiderationisrequiredspacing
betweenprotectiveprovisions
Drivermustreachasafetyprovisionbeforetruck
travelingtoofasttomaneuver
Maximumpermissiblespeeddependsontruck
designconditionsandoperator

41. 41
RunawayProvisions
•Maximumpermissiblespeed,equivalent
downgrade,andspeedatbreakfailuredetermine
distancebetweenrunawaytrucksafetyprovisions
•Forexample,atanequivalentdowngradeof5%and
amaximumspeedof40mph,
SpeedatFailure
ProvisionSpacing
10 mph
1,000ft
20 mph
800ft
(KaufmanandAult)

42. 42
RunawayPrecautions

43. 43
MedianRunaway-Vehicle
ProvisionBerms
•Vehiclestraddlescollisionbermandrides
vehicletostop
•
•
•
Madeofunconsolidated-screenedfines
Criticaldesignaspectsspacingbetween
bermsandheightofberm
Heightgovernedbyheightofundercarriage
andwheeltrackgovernedbylargestvehicle

44. 44
MedianRunaway-Vehicle
ProvisionBerms
•Requiresmaintenanceinfreezingconditions
•Agitationtopreventdamagetovehicle
•Maycoverberminhighrainfallareas

45. 45
EscapeLanes
•Goodtoolforstoppingrunawaybut
expensivetoconstruct
•
•
Entrancefromroadisimportant;spacing,
horizontal,verticalcurveandsuperelevation
areallconsideredindesign
Decelerationmainlybyadversegradeand
highrollingresistancematerial

46. 46
EscapeLanes
•Lengthafunctionofgradeandspeedat
entranceandrollingresistance
•Stoppingbylevelsectionmedianberm,sand
orgravelormudpits,roadbumpsormanual
steering

47. 47
EscapeLanes

48. 48
Maintenance
•Theroadsurfaceis
deformedbytheconstant
poundingofhaulage
vehicles.
•Agoodroadmaintenance
programisnecessaryfor
safetyandeconomics.

49. 49
SafetyConsiderations
•Dust,potholes,ruts,depressions,bumps,and
otherconditionscanimpedevehicular
control.

50. 50
EconomicConsiderations
•Thewearoneverycomponentisincreasedwhena
vehicletravelsoveraroughsurface.
•Ifthevehiclebrakesconstantly,unnecessarylining
wearoccursaswell.

51. 51
DustControl
•Dustmayinfiltratebrakes,airfilters,
hydrauliclifts,andothercomponentsof
machinery.
•Theabrasiveeffectofdustwillresultin
costlycleaningorreplacementofthese
items.

52. 52
DeteriorationFactors
•Weather
•Vehiclesfollowa
similarpath
•Spillage

53. 53
MotorGraders
•Amotorgrader
shouldbeusedto
maintaincrossslopes,
removespills,andto
fillandsmooth
surfacedepressionsas
theyoccur.

54. 54
RoadDrainage
•Toavoidoverflow,roadsideditchesand
culvertsshouldbeperiodicallycleaned.
•Avoiderosionorsaturationofsubbase
materials.

55. Thanks