What is haul truck cycle time?
Haul truck cycle time is how long one truck takes to go round once: spot at the loader, get loaded, haul to the dump, dump and return empty. The King Saud University course on loading and hauling splits it into fixed time (spot, load, maneuver and dump) and variable time (haul and return), because the fixed part barely changes while the variable part grows with distance and road condition.
From the cycle and the loading time the calculator works out how many trucks one loader can keep busy, the match factor of your fleet, the tonnes it moves per hour and per shift, and the fleet needed for a target.
Why does the truck–loader match matter?
- Too few trucks: the loader stands waiting between trucks, and you pay for an expensive machine and operator doing nothing.
- Too many trucks: trucks queue at the loader, burning fuel and driver hours without moving material.
- Distance changes the answer: as the pit deepens or the dump moves, the cycle grows and the same fleet falls out of balance.
- Half buckets cost time: Pit & Quarry notes that loading half buckets takes as long as loading full ones, so the number of passes matters.
What inputs do you need?
| Input | Where to find it | Tip |
|---|---|---|
| Payload and bucket load | Equipment specifications, weighbridge records | Use the real average load if trucks run under or over their rating. |
| Fill factor | Bucket load weighed against rated load | Pit & Quarry gives 75 to 90% for blasted rock. |
| Loader cycle per pass | A stopwatch at the face, video from the site | Time 20 or more passes and use the average. |
| Distance and speeds | Site plan, tracking data of the trucks | Average speed per direction, not the site speed limit. |
| Spot, dump and waiting times | Observation, tracking data with loading and dump areas | Record a full shift: waiting changes over the day. |
| Productive minutes per hour | Shift reports: breaks, refueling, shift change | Measured minutes are better than a rule of thumb. |
How is the cycle and the match calculated?
Passes and loading time
Pit & Quarry divides the truck's rated payload by the desired number of passes to size the bucket, multiplies the rated bucket capacity by the fill factor for the material, and calls three passes ideal, with four or five generally acceptable for larger haulers.
Truck cycle
Trucks per loader and match factor
The trucks-per-loader rule is Equation 4-16 of the King Saud University course: haul unit cycle time ÷ load time, rounded up. A match factor of 1 means neither waits; below 1 the loaders wait for trucks; above 1 trucks queue at the loaders, as set out in the match factor literature (Journal of Mining & Environment, 2025).
Output and cost per tonne
Sources
- King Saud University, CE 419, Chapter 4: Loading and Hauling, part 3 (cycle time, Equations 4-14 to 4-17, job efficiency examples). Source: KSU.
- M. Mohtasham, Development of a Match Factor for Optimizing Haulage Fleet Efficiency in Open-Pit Mining Operations, Journal of Mining & Environment, 2025. Source: JME.
- Pit & Quarry University, Hauling handbook lesson (passes, bucket sizing, fill factor 75 to 90% for blasted rock). Source: Pit & Quarry. Last reviewed 21 October 2026.
Worked example: one loader and six 40-tonne trucks
The defaults are examples; replace them with your site's figures.
- A 16 t bucket at 85% fill carries 13.6 t a pass, so a 40 t truck needs 3 passes. At 30 seconds a pass, loading takes 1.5 min.
- 2.5 km at 20 km/h loaded is 7.5 min and at 30 km/h empty 5 min. With 0.5 min spot and 1 min dump the cycle is 15.5 min, 81% of it travel.
- One loader can keep 15.5 ÷ 1.5 = 10.3, so 11 trucks, busy. With 6 trucks the match factor is 0.58: the loader waits 42% of the time.
- Six trucks move 6 × 40 × 60 ÷ 15.5 = 929 t/h at full time, or 774 t/h at 50 productive minutes: 7,742 t in a 10-hour shift.
- At $60 an hour per truck and $100 for the loader the fleet costs $460 an hour, or $0.59 a tonne; with 11 trucks the loader becomes the limit and the cost falls to $0.57 a tonne.
- For 10,000 t a shift you need 1,200 t/h while working: 1 loader and 8 trucks.
How to read your results
- Match factor below 1: trucks are the limit. Add trucks, shorten the haul or speed up the road before buying a bigger loader.
- Match factor above 1: the loader is the limit and trucks queue. Fewer trucks move the same tonnes, or a second loading point uses them.
- Travel share of the cycle: when haul and return dominate, road condition, grades and speed matter more than loader speed.
- Cost per tonne: compare the current fleet with the matched one; the cheapest fleet is not always the one with no waiting.
How to shorten the cycle
- Load in three or four passes: size the bucket to the truck and keep the fill factor up.
- Keep haul roads in shape: Pit & Quarry notes that a 5% rise in rolling resistance can cut production by 10%.
- Do not overload or underload: check loads on the weighbridge and with the Axle Load Checker for road trucks.
- Measure, then rebalance: record real cycles by truck and shift, and move trucks between loaders as distances change.
- Know the machine cost: work out the hourly cost of trucks and loaders with the Equipment Hourly Cost Calculator.
Assumptions and limits
The calculator uses averages: every truck has the same payload, speed and cycle, and arrivals are evenly spaced, so real queues are longer than the averages suggest when cycles vary. The loader is assumed to load one truck at a time. Output is the lower of truck and loader capacity times productive minutes; breakdowns, blasting delays and weather stops need to be in the productive minutes. All defaults are examples, not equipment data. Use the result to plan and compare, then confirm it with measured cycles.