These notes are included as a reference for the cycle time calculations.
Cycle Time
Cycle time is defined as the time for a truck to complete one return trip between any two points on the haul.
TheoreticalTruckCycleTime = SpotAtLoader + TruckLoadTime + LoadedTravelTime + SpotAtDump + DumpTime + UnloadedTravelTime + RechargeTravelTime + RechargeTime + TKPHDelay TruckCycleTime = TheoreticalTruckCycleTime + Queue
Loader Load Time
Loader Load Time is defined as the time taken to load one truck payload. This makes it equal to the total swing time plus any delays between loading, such as the truck spot time.
LoaderLoadRate = TruckPayload / LoaderLoadTime LoaderLoadTime = FirstPassDelay + NumBuckets * BucketCycleTime
Truck Load Time
Truck Load Time is defined as the time taken to fill the truck, exclusive of truck spot time. It is assumed that the truck is backing up under a full bucket, which makes Truck Load Time exclude the first bucket swing.
TruckLoadRate = TruckPayload / TruckCycleTime TruckLoadTime = (NumBuckets – 1) * BucketCycleTime
Truck Matching
The Nominal Number of Trucks is calculated as the ratio of Final Loader Rate (after overrides) over Theoretical Truck Rate (excluding queue time).
NominalNumTrucks = FinalLoaderRate / TheoreticalTruckRate
This number is then rounded or replaced according to the Truck Matching Method and any truck number overrides.
Truck Queue Time & Loader Hang Time
If the digger is over trucked, then there will be queue time.
Queue = NumTrucks * LoaderLoadTime - TheoreticalTruckCycleTime
If the digger is under trucked, then there will be loader idle time / hang time.
LoaderIdleTime = TheoreticalTruckCycleTime - NumTrucks * LoaderLoadTime
TKPH Delay
TKPH delays are calculated from the axle weights and truck speeds according to the formulas available in Michelin and Bridgestone handbooks.
Note that Michelin provides a temperature coefficient for calculating TKPH at different temperatures. This coefficient can sometimes be negative if the average haul speed is below 5 kilometres per hour. Essentially this means that there are no TKPH delays.
Cycles Per Charge
For trucks with Power Source set to Battery, this is the number of cycles that can be completed on a single charge.
It is roughly calculated by just dividing the battery capacity by the net energy usage per cycle.
In the special case of Battery Capacity = 0, there are infinite cycles per charge.
When Battery Capacity is not the special value of 0, the cycles per charge are more precisely calculated as:
Effective Capacity = Max(0, Battery Capacity - (Recharge Travel Time * Battery Usage While Travelling To Recharge))
if (Net Usage > Effective Capacity) {
Charges Per Cycle = RoundUp(Net Usage / Effective Capacity)
Cycles Per Charge = 1 / Charges Per Cycle
} else {
Cycles Per Charge = RoundDown(Effective Capacity / Net Usage)
}
Recharge Time and Recharge Travel Time per cycle
Then the Recharge Time and Recharge Travel Time per cycle are calculated using Cycles Per Charge from above as just:
Recharge Time Per Cycle = Single Recharge Time / Cycles Per Charge. Recharge Travel Time Per Cycle = Single Recharge Travel Time / Cycles Per Charge.
See also: