A type of sub-surface mining

A type of sub-surface mining

• A. Rift Valley
• B. Shaft Mining
• C. Shield Volcano
• D. Sea-floor Spreading

Answer: (B)

Sub-surface mining means extracting minerals from below the ground, using tunnels and shafts instead of digging large open pits. A vertical shaft is sunk from the surface down to the ore, and miners reach and extract the ore from there through connected levels. This is the classic underground mining method. The other terms describe natural geological or tectonic features, not mining methods: a Rift Valley is a landform created by tectonic plates pulling apart; a Shield Volcano is a volcanic structure formed by steady lava flows; sea-floor spreading is the process of new ocean crust forming at mid-ocean ridges. Because they are not mining techniques, they don’t fit the concept of sub-surface mining.

Sub-surface mining means extracting minerals from below the ground, using tunnels and shafts instead of digging large open pits. A vertical shaft is sunk from the surface down to the ore, and miners reach and extract the ore from there through connected levels. This is the classic underground mining method.

The other terms describe natural geological or tectonic features, not mining methods: a Rift Valley is a landform created by tectonic plates pulling apart; a Shield Volcano is a volcanic structure formed by steady lava flows; sea-floor spreading is the process of new ocean crust forming at mid-ocean ridges. Because they are not mining techniques, they don’t fit the concept of sub-surface mining.