How do you calculate underground duty cycle time?

Divide the workload by the completion rate to get base time, then multiply by one plus the allowance. With 120 trips at 12 per minute that is 10 hours base, and a 10% allowance gives 11 hours required.

Why apply a delay allowance to duty cycle time?

Face-measured rates ignore tramming up grades, queuing at the dump, ventilation doors and operator changes. The allowance converts an idealized base time into a realistic, schedulable figure; here 10% turns 10 hours into 11.

What is a good delay allowance for underground haulage?

Short, well-laid-out headings run 8-12%, while long tramming distances, single-lane sections or congested dumps push it to 20-30%. Track actual versus planned cycles to calibrate your own number.

What does the base duty cycle time represent?

It is the theoretical minimum, 10 hours in the example, assuming the equipment never waits. It is useful as a benchmark but should never be used directly for scheduling.

Can I use this for a fleet rather than one machine?

Yes, if the completion rate is the combined effective rate of the fleet. For mixed machines or shared dumps, model each unit separately because the allowance differs by route.

How do I reduce required duty cycle time?

Raise the completion rate by shortening tramming distance or adding a passing bay, or cut the allowance by smoothing dump queues and ventilation-door delays. Both push the 11-hour figure down.

Mining Vehicle & Underground Equipment calculator

Underground Duty Cycle Calculator

Underground duty cycle time tells you how many hours a loader, shuttle car or haul truck will actually take to clear a defined workload once tramming, queuing and dump delays are folded in. Mine planners and shift supervisors use it to size haulage fleets against a production target and to check whether a heading can be cleared inside one shift. It matters because raw throughput rates measured at the face always overstate real output: ramp grades, ventilation doors, charge-out queues and operator changeovers eat into every cycle. By applying a delay allowance to the base time, this calculator gives a defensible required cycle time you can schedule against instead of an optimistic best-case number.

What this calculator does

Estimate underground duty cycle for mining vehicle and underground equipment using production-ready inputs so teams can plan labor hours, schedule the work, or check whether the job fits the available shift time.
Use it when underground duty cycle in mining vehicle and underground equipment is changing rate or allowance and you want to see the impact.
It computes base duty cycle time as workload divided by completion rate, then inflates it by a delay allowance to give the required time.

Formula used

Base underground duty cycle time = underground duty cycle workload ÷ underground duty cycle completion rate
Required underground duty cycle time = base underground duty cycle time × allowance factor

Inputs explained

Loads or trips to move underground:
Trips completed per minute at the face:
Tramming, queuing and delay allowance:

How to use the result

Use it when planning a shift's haulage, sizing a fleet to a production target, or sanity-checking whether a heading clears within available hours.
A single allowance percentage cannot capture a heading where one constraint (say a single ventilation door) dominates; for those, model the bottleneck explicitly.

Current U.S. benchmarks

U.S. light vehicles sell at a 16.9 million annual rate (BEA, Jun 2026), up 4.1% from a year earlier, the volume signal for automotive supply chains.
Steel mill PPI stands at 348.53 (BLS, May 2026), up 6.7% from a year earlier. New factory orders are up 2.3% year over year (Census).
The U.S. has 11,691 transportation equipment establishments employing about 1,682,910 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate underground duty cycle time? Divide the workload by the completion rate to get base time, then multiply by one plus the allowance. With 120 trips at 12 per minute that is 10 hours base, and a 10% allowance gives 11 hours required.
Why apply a delay allowance to duty cycle time? Face-measured rates ignore tramming up grades, queuing at the dump, ventilation doors and operator changes. The allowance converts an idealized base time into a realistic, schedulable figure; here 10% turns 10 hours into 11.
What is a good delay allowance for underground haulage? Short, well-laid-out headings run 8-12%, while long tramming distances, single-lane sections or congested dumps push it to 20-30%. Track actual versus planned cycles to calibrate your own number.
What does the base duty cycle time represent? It is the theoretical minimum, 10 hours in the example, assuming the equipment never waits. It is useful as a benchmark but should never be used directly for scheduling.
Can I use this for a fleet rather than one machine? Yes, if the completion rate is the combined effective rate of the fleet. For mixed machines or shared dumps, model each unit separately because the allowance differs by route.

Last reviewed 2026-05-12.