Study the given figure carefully and answer the questions that follow :
| Open-cast Mining | Shaft Mining |
|---|---|
| Used for extracting minerals that lie close to the surface. | Used for extracting minerals that lie deep below the surface. |
| Involves removal of surface layers to reach the mineral deposit. | Involves digging deep vertical shafts to access underground minerals. |
| Less expensive and less dangerous. | More expensive and riskier due to depth and safety concerns. |