BIZOMAT MAKEOS · Materials
Stockpile Haulage Plan (Pile Mass, Truck Loads, Loading Time, Ground Pressure)
How much material is in this stockpile, how many truck loads and loader passes will it take to move it, and is the ground under the pile strong enough?
Plan for moving a conical or ridge-shaped stockpile of bulk material: pile height from the angle of repose, volume and mass (as the stockpile weight tool), truck loads at the payload, loader bucket passes at the bucket size and fill factor, loading time at the cycle time, and the peak ground pressure under the highest point of the pile against the allowable bearing pressure.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Pile shape | choice | Round cone or a ridge with sloping ends. |
| Base diameter (cone) | m | Base diameter of a conical pile. |
| Base width (ridge) | m | Base width of a ridge pile (the shorter side). |
| Base length (ridge) | m | Base length of a ridge pile. |
| Angle of repose | ° | Angle of repose of the material (about 30–40° for most granular materials). |
| Bulk density | kg/m³ | Bulk (loose) density of the material. |
| Truck payload | t | Legal payload of one truck. |
| Loader bucket size | m³ | Rated (heaped) bucket capacity of the loader. |
| Bucket fill factor | % | Share of the rated bucket actually loaded each pass. |
| Loader cycle time | s | Time for one loader cycle (dig, travel, dump, return). |
| Allowable ground bearing pressure | kPa | Allowable bearing pressure of the ground under the pile (from a geotechnical assessment). |
What each input means
Open an input to see what it is, its units, the worked example and the common mistakes, with a small diagram.
What this means: Pile shape
- What it is
- The shape of the pile: a cone on a round base, or a ridge on a rectangular base with sloping sides and ends.
- Units and format
- Choose one of 2 options from the list: Conical (round base); Ridge (rectangular base).
- Example
- The form opens with “Conical (round base)” selected as a worked example. Choose the option that matches your case.
What this means: Base diameter (cone)
- What it is
- The diameter of the round base of a conical pile. Used only for the conical shape.
- Units and format
- Enter a number in m: metres. The form accepts 0.000001 m to 1000 m. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 10 m as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Pile volume and mass rise with the cube of the base diameter.
What this means: Base width (ridge)
- What it is
- The shorter side of the rectangular base of a ridge pile, which sets its height. Used only for the ridge shape.
- Units and format
- Enter a number in m: metres. The form accepts 0.000001 m to 1000 m. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 6 m as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- It must be the shorter side; the tool rejects a width greater than the length.
What this means: Base length (ridge)
- What it is
- The longer side of the rectangular base of a ridge pile. Used only for the ridge shape.
- Units and format
- Enter a number in m: metres. The form accepts 0.000001 m to 10000 m. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 20 m as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
What this means: Angle of repose
- What it is
- The slope the material naturally settles at when tipped into a free pile, measured from the horizontal.
- Units and format
- Enter a number in °: degrees of angle. The form accepts 10° to 60°. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 35° as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Pile height, volume and peak ground pressure rise with tan θ.
What this means: Bulk density
- What it is
- The loose bulk density of the material in the pile, including the voids between particles.
- Units and format
- Enter a number in kg/m³: kilograms per cubic metre. The form accepts 100 kg/m³ to 5000 kg/m³. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 1600 kg/m³ as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
What this means: Truck payload
- What it is
- The legal load one truck may carry, from its registration or the haulage contractor.
- Units and format
- Enter a number in t: tonnes. The form accepts 0.000001 t to 1000 t. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 20 t as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Get it right
- Tonnes: 1 t = 1000 kg.
What this means: Loader bucket size
- What it is
- The rated (heaped) bucket capacity of the loader, from its specification sheet.
- Units and format
- Enter a number in m³: cubic metres. The form accepts 0.000001 m³ to 100 m³. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 2 m³ as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
What this means: Bucket fill factor
- What it is
- The share of the rated bucket volume actually carried on each pass, which depends on the material and the operator.
- Units and format
- Enter a number in %: percent: the number is read as a percentage, so type 8 for 8 %. The form accepts 30% to 120%. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 90% as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
What this means: Loader cycle time
- What it is
- The time for one complete loader cycle: dig, travel, dump and return.
- Units and format
- Enter a number in s: seconds. The form accepts 0.000001 s to 3600 s. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 40 s as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
- Effect on the result
- Loading time rises in direct proportion.
What this means: Allowable ground bearing pressure
- What it is
- The allowable bearing pressure of the ground under the pile, from a geotechnical assessment.
- Units and format
- Enter a number in kPa: kilopascals. The form accepts 0.000001 kPa to 10000 kPa. Required: the tool does not calculate until every input is valid.
- Example
- The form opens with 100 kPa as a worked example. It is an illustration, not a recommended value: replace it with your own figure.
Method and formulas
- Cone: h = (D ÷ 2) tan θ, V = π D² h ÷ 12; ridge: h = (A ÷ 2) tan θ, V = A h (3B − A) ÷ 6 (as the stockpile weight tool).
- Truck loads = mass ÷ payload (rounded up); bucket passes = volume ÷ (bucket × fill) (rounded up); loading time = passes × cycle.
- Peak ground pressure = ρ g h under the highest point.
- Example: the pile is 3.501 m high, 146.65 t; moving it takes 8 truck loads and 51 loader passes (0.56667 h).
Limitations
- Ideal pile shape at the angle of repose; real piles are often flatter or have a flat top.
- Bulk density varies with moisture and compaction.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Plan removal of a gravel, coal or ore stockpile
- Estimate a stockpile’s tonnage for inventory
- Check ground bearing under a new pile
Who it is for
- Site supervisors
- Plant engineers
- Logistics planners
What you get
- Pile height, volume and mass
- Truck loads, loader passes and loading time
- Peak ground pressure against the allowable
Interpreting the result
- The pressure under the peak of a pile is three times the average: check the ground there.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 382–383. Topic reference; no source tables or recommended settings are reproduced.
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Open the Stockpile Haulage Plan (Pile Mass, Truck Loads, Loading Time, Ground Pressure) calculator