The Minister of Mines or any other Minister to whom the President may, from time to time, assign the administration of this Act may, by order, prohibit or restrict the exportation of base minerals from Zimbabwe in accordance with section 3. “Base minerals” means coal and all other minerals and mineral substances, and includes coke and all such slimes, concentrates, slags, tailings and residues as are valuable and contain base minerals as defined, but does not include precious metals, precious st