What is the most common method of underground diamond mining?

• A. Shaft mining deep underground
• B. Cave mining
• C. Room-and-pillar mining
• D. Placer mining

Answer: (B)

Underground diamond mining favors a method that handles large, bulk ore bodies with high production at lower cost. Cave mining, especially in the form of block caving, fits this well. It lets rock be undercut and allowed to break and collapse under its own weight, creating a network of voids that can be mined progressively from below. This approach enables very high production rates once the initial access is established and keeps operating costs down because it minimizes blasting and extensive ground support compared to other methods.

Shaft mining deep underground, while used in some cases, is typically more expensive and better suited to narrow veins or smaller, high-grade targets rather than massive, irregular kimberlite bodies. Room-and-pillar mining can be effective in certain deposits but often isn’t economical for the large, bulk tonnage nature of many diamonds. Placer mining, by contrast, is surface work for alluvial diamonds and isn’t an underground method, so it doesn’t apply here.