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Engine Loads
Average engine loads for idle, spotting, dumping and trolley assisted operation can be measured from the haul truck’s on-board management systems (such as VIMS, KOMTRAX, etc).
Acceleration
Acceleration limits are measured in “kilometres per hour per second”. The defaults are set to a conservative standard and should be updated from field observations.
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When measuring the limits of braking, ask the operators about the best practices for reducing load spillage and road maintenance.
Traction
The coefficient of traction is the maximum percentage of the normal component of the truck's weight on the driven axle(s) which can be used to accelerate or decelerate the truck. Braking reliance on traction applies another coefficient, which specifies how close the truck driver will approach skidding when decelerating. More traction means that a truck can use faster acceleration and braking without skidding. If traction is so low that a truck would spin its wheels on the ramp, then Haul Infinity will report a “steep segment” error.
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Adjust the coefficient of traction to match the conditions on your site.
Retarder
Applying brakes with too much force can cause premature brake failure, reduce tyre life expectancy, increase road maintenance costs and/or cause strut damage from digging potholes in the road surface. The default max use of retarder is set to 70% as a conservative estimate of safe operating behaviour. Consider your truck types and maximum ramp gradients when setting the max use of retarder.
Rolling Resistance
Tools > Project Settings > General > Network Defaults
Rolling resistance is the force (as a percentage of gross vehicle weight) required to propel a vehicle at constant speed over level terrain, caused by the tire climbing up out of the depression created by its own load.
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TKPH Constants
Refer to the TKPH rating tables provided by your tyre manufacturer.
Trolley Assist Curves
Rimpull is the total linear force that a vehicle can exert on the ground. Also called “tractive effort,” it is the axle torque divided by the distance from the axle to the road surface.
Power (N*m/s) = Rimpull (N) * Velocity (m/s)
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Take careful note to use the right units if doing conversions. Haul Infinity uses kilograms of force (kgF) as the default unit of rimpull measurement.
Fuel Curves
Haul truck fuel curves are digitized from the original equipment manufacturer’s handbooks. Operating fuel curves should be updated with measurements from the fleet on-board monitoring systems.
Single Lanes
Haul Infinity does not support traffic simulations. Truck fleet allocation is calculated on the assumption of a continuous flow of traffic between the source and destination.
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For full mine site traffic simulation, Alastri recommends running Simio in conjunction with Haul Infinity. Visit www.simio.com for more information about discrete event simulation.
Time and Motion Studies
Haul Infinity cycle times can be calibrated with time and motion studies in the field.
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