⛏️ Stripping Ratio Calculator

What Is Stripping Ratio?

Stripping ratio expresses how much waste (overburden) must be removed to access each unit of ore or pay material. A 3:1 ratio means 3 cubic yards of waste for every 1 cubic yard of ore.

How It Affects Mine Economics

Every unit of overburden costs money to drill, blast, excavate, haul, and dump — but generates no revenue. A higher stripping ratio directly increases the cost per tonne of ore produced. At some point, the stripping ratio becomes so high that the operation is no longer economical — this is the break-even stripping ratio.

Typical Ratios by Commodity

• Coal (surface mining): 1:1 to 6:1 — low commodity price demands low ratios
• Copper porphyry: 1:1 to 4:1 — moderate; large-scale operations absorb higher ratios
• Gold: Can exceed 10:1 — high commodity price justifies more waste removal
• Iron ore: Typically 1:1 to 3:1 — bulk commodity, very sensitive to ratio
• Diamonds: Often very high — value per tonne supports it

How Stripping Ratio Changes Over Time

As a pit deepens, the stripping ratio often increases — you must remove more and more overburden from steeper pit walls to access ore at depth. Pit design engineers optimize the pit slope and pushback sequence to manage the cumulative stripping ratio over the mine's life.