Botswana Ash (Pty) Limited produces soda ash and salt from their mine at Sua Pan in northern Botswana. The primary market for soda ash is the glass industry in South Africa. Salt products are also sold within the continent.
The Alrode site in Johannesburg has three soda ash storage silos, 15 m (50 ft.) wide and 25 m (83 ft.) high. The silo inventory was being measured manually by a dip test method, whereby a weight was dropped on a tape into the vessel and the distance to the surface read. Because the soda ash is a solid, it did not lie flat. Plus, since the silo was quite wide, several measurements were needed to get a representative average level.