Bentonite is a raw material mined in open pit quarries. Bentonite deposits are usually quite large, with lenticular beds, only a few meters deep. Bentonite production process features ore mining, sodium activation (if required), drying, and milling. Sodium activation is performed to convert calcium bentonite to sodium bentonite, in which calcium ions are exchanged for sodium carbonate. Through sun drying, bentonite natural moisture content of about 25-35% is reduced to around 12-16% or lower if required.