Mining Vehicle & Underground Equipment worked example

Spare Parts Inventory with average daily parts issue rate from stores of 600 units / day: a worked example in mining vehicle & underground equipment

This worked example runs the spare parts inventory numbers for a tougher week than the baseline: average daily parts issue rate from stores of 600 units / day instead of the typical 1,200 units / day. Estimate spare parts inventory for mining vehicle and underground equipment using production-ready inputs so teams can plan replenishment and safety stock using actual usage and lead time.

The inputs for this scenario

  • Average daily parts issue rate from stores: 600 units / day (the input this scenario stresses; the baseline uses 1,200)
  • Supplier replenishment lead time: 85 days (held at the documented default)
  • Safety stock cushion on lead-time demand: 1.1 units (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Spare parts inventory cycle stock = spare parts inventory daily usage × spare parts inventory lead time.
  • Protected days of supply works out to 6.42 days at these inputs, and this is the headline figure for the scenario.
  • Unprotected days works out to 7.06 days at these inputs.
  • Inventory works out to 600 pieces at these inputs.
  • Daily usage works out to 85 pieces / day at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where average daily parts issue rate from stores sits at 1,200 units / day and the headline result is 12.83 days, this scenario comes in 50% below the baseline at 6.42 days.
  • Use it when setting reorder quantities and min/max levels for consumable and rotable spares in a mine's central or satellite stores. A result at this level usually justifies acting on the stressed input before touching anything else, because every other figure in the table is downstream of it.

Results at a glance

  • Protected days of supply: 6.42 days (headline result)
  • Unprotected days: 7.06 days
  • Inventory: 600 pieces
  • Daily usage: 85 pieces / day

Run it with your numbers

  • To rerun this with your own numbers, open the live Spare Parts Inventory calculator, set average daily parts issue rate from stores to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.