Shares of 10 Shillings. purple. No 6730. Folds. A copper mine in the Copperbelt province of today's Zambia (previously part of British-controlled Rhodesia). After WWI, the company began exploring a flotation process to extract copper from low grade ores. The company closed its mines in 1931. However, the Bwana M'Kubwa settlement also wrote history during WWII : thousands of Polish refugees found shelter there and a Polish WWII Memorial still commemorates this life-saving effort.