0891Mining of Mineral, Chemicals, and Fertilizer Materials

mining of natural phosphates and natural potassium salts; | mining of natural sulfur; | extraction of pyrite and pyrrhotite, except roasting; | mining of natural barium sulfate and carbonate (barite and witherite), natural borate, and natural magnesium sulfate (kisserite); | mining of natural pigments/earth colors, fluorspar, and other minerals primarily as chemicals. This subclass also includes | mining of guano (fertilizer made from bird or bat droppings); | mining of clay for medicinal purposes.