Mining from surface, removing waste rock to reach ore — the cheapest way to move large tonnages and the most visible.
A surface mining method where ore is extracted from an open excavation. Open-pit mining is suitable for deposits near the surface and is generally less expensive than underground mining but creates larger environmental footprints.
Open-pit economics live or die on the stripping ratio. Every tonne of waste is a tonne paid for and never sold, and as a pit deepens that ratio worsens, which is what eventually ends the mine rather than the ore running out.
Look for the pit shell in a technical study and the strip ratio at depth, not just the average. A project with a 2:1 average and 6:1 in its final years has most of its value in the early phases.
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