Stripping Ratio
The ratio of waste rock that must be removed to access ore in an open-pit mine, expressed as tonnes of waste per tonne of ore.
Detailed Definition
Stripping ratio is the amount of waste rock (overburden) that must be removed to access and extract ore in an open-pit mining operation. It is a key economic metric for surface mines.
Calculation: Stripping Ratio = Waste Tonnes ÷ Ore Tonnes
Example: If 5 tonnes of waste must be removed for every 1 tonne of ore, the stripping ratio is 5:1.
Types of stripping ratios
Overall Stripping Ratio: Total waste divided by total ore over mine life.
Instantaneous Stripping Ratio: Current ratio at any point in mine development.
Cutoff Stripping Ratio: Maximum ratio that remains economically viable.
Economic implications: - Higher ratios = higher mining costs - Affects cutoff grade determination - Influences pit design and depth - Changes over mine life
Factors affecting stripping ratio: - Deposit geometry and depth - Pit wall angles (slope stability) - Ore grade and value - Mining and processing costs - Commodity prices
Optimizing stripping ratio through pit design is essential for maximizing mine economics.
Related Terms
Mining Claim
A parcel of land for which a claimant has asserted a right of possession and the right to develop and extract mineral resources.
Ore
Rock or material from which valuable minerals or metals can be profitably extracted.
Feasibility Study
A comprehensive engineering study evaluating the technical and economic viability of mining a mineral deposit.