Calculate coal stripping ratio from overburden and coal volume or thickness, and find break-even ratio from coal price, cost and waste removal.
Coal Stripping Ratio Formula
The following formula is used to calculate the stripping ratio for a given volume of overburden and volume of coal.
Variables:
- SR is the stripping ratio
- Vo is the volume of overburden
- Vc is the volume of coal
For the volume mode, divide overburden volume by coal volume after converting both to the same volume unit. Inverse modes solve either volume from a known volume ratio. A thickness ratio approximates this result only for the same footprint and comparable geometry. The break-even mode instead divides net coal value (selling price minus coal mining and processing cost per mass unit) by waste removal cost per volume unit. Its result is volume per coal mass, not volume per volume; coal density is needed to compare these two bases.
What is a Stripping Ratio?
Stripping ratio describes waste or overburden removed per quantity of coal. This page labels the geometric volume / volume ratio separately from the economic volume / mass allowance. All else equal, a larger ratio means more waste handling; the ratio alone does not establish profitability. In the break-even mode, US short ton means 2,000 lb and metric tonne means 1,000 kg. Prices and coal costs share that basis; the simplified allowance excludes other charges.
How to Calculate Stripping Ratio?
The following steps outline how to calculate the stripping ratio.
- First, determine the volume of overburden (Vo).
- Next, determine the volume of coal (Vc).
- Finally, convert both volumes to the same unit and calculate SR = Vo / Vc. Coal volume must be positive.
- After inserting the values and calculating the result, check your answer with the calculator above.
Example Problem :
Use the following variables as an example problem to test your knowledge.
Volume of overburden (Vo) = 500 m³
Volume of coal (Vc) = 250 m³. Therefore SR = 500 / 250 = 2:1 (volume / volume).
