Which method involves extracting salt from underground rock deposits?

• A. rock mining
• B. brine solution mining
• C. solar evaporation
• D. open-pit mining

Answer: (A)

When salt exists as solid rock underground, the way to get it out is to mine the rock itself. Rock mining involves digging shafts or tunnels and removing blocks of rock that contain the salt (halite), then crushing and processing it to yield usable salt. This directly accesses the underground rock deposit and retrieves the solid mineral.

Brine solution mining, on the other hand, dissolves the salt with water underground to form a salty liquid that is pumped to the surface. Solar evaporation uses surface ponds to evaporate water from brine so the salt crystallizes, which happens above ground. Open-pit mining is a surface method used for near-surface deposits and isn’t the typical approach for extracting salt from deep underground rock. So the method that fits underground rock deposits best is rock mining.