Supergene mineral deposits form a significant proportion of certain global mineral resources. For some metals, such as aluminium, iron, niobium, nickel and cobalt, supergene deposits predominate, providing 50–100% of global supply. For others, they are regionally important, e.g., oxidized zones on sediment-hosted copper-cobalt deposits of the African Copperbelt; or relatively minor surface enrichments that provide cash flow in the early stages of mine development, exemplified by lateritic and saprolitic gold overlying orogenic quartz-sulfide-carbonate systems and epigenetic systems in more juvenile terranes. Some are niche deposit types of local importance, such as palaeochannel uranium, or by-products of multi-commodity deposits that supplement the yield of the principal ore.