The concept of the strip ratio is pivotal in the domain of open-pit mining, serving as a barometer for the economic viability of a mining operation. It is the mathematic expression of the volume of overburden or waste material required to be handled in order to extract a unit volume of ore. In other words, it represents the balance between the amount of material that must be moved and the amount of valuable mineral that is gained in the process.
The strip ratio, often expressed as a ratio such as “3:1,” signifies that three tonnes of waste must be excavated to access one tonne of ore. This seemingly simple fraction is a beacon that guides mining companies’ strategic decisions, illuminating the path to profitability or loss.
A lower strip ratio indicates that less waste is to be removed per tonne of ore, hinting at a more cost-effective mining environment. Conversely, a higher strip ratio suggests an operation where the cost of removing waste could potentially outweigh the benefits of the ore extracted.
This ratio is not static; it evolves with the life of the mine. In the initial phases of a mine’s development, the strip ratio may be relatively low as the surface ore is accessed. However, as mining progresses deeper, the overburden increases, thus inflating the strip ratio and challenging the economic calculus of continued operation. It is a dynamic figure that reflects the changing face of the mine’s geology and the fluctuating costs of operation(Lyall, 2023).
Reference:
Lyall, I. (2023, November 7). Mining 101: Strip ratio – the key to open-pit mining. Proactiveinvestors NA. https://www.proactiveinvestors.com/companies/news/1032093/mining-101-strip-ratio-the-key-to-open-pit-mining-1032093.html
