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How is potash mined by underground mining?

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A periodic table element box for potassium shows atomic number 19, symbol K, atomic weight 39.0983, electron configuration [Ar]4s1, and name potassium. Icons indicate it is an alkali metal, solid at room temperature, body-centered cubic crystal structure, and has strongly basic higher-valence oxides. A key explains the symbols for alkali metals, solid state, body-centered cubic structure, and strong basicity. — potassium Properties of potassium.

In traditional underground mining for potash, the extraction process involves using mechanical boring and explosives to remove ore from evaporite deposits. Once the ore is excavated, it is transported to the surface for crushing and refining.1

Depending on the specific geological conditions, two primary systems are often employed for flat-lying deposits like potash:

Room-and-pillar mining: This system creates a checkerboard pattern by driving parallel drifts and connecting them at regular intervals. Pillars of ore are left in place to support the overlying rock, though some may be removed once mining reaches the deposit's boundary.2
Longwall mining: In this method, the ore body is divided into rectangular panels. A cutting machine moves along a "longwall" face under the protection of movable hydraulic supports. As the machine cuts the mineral, an armoured conveyor transports it away, and the supports are advanced, allowing the roof behind the canopy to cave in.3

Because potash is a relatively soft rock, it is well-suited for these mechanical cutting techniques.3