Manganese ores occur in four main types in North America.
(1) Primary carbonate (e.g. Molango)
(2) Battery-active oxides (e.g. Molango supergene zone)
(3) BIF-associated (e.g.Cuyuna)
(4) Volcanic-associated (e.g. Autlan)
Molango, in the Mexican state of Hidalgo, is the only signifcant Mn-only commercial deposit. Many smaller deposits were mined up through the Second World War, but they are for the most part exhausted or uneconomic. The Cuyuna iron deposit produces considerable Mn as a by-product. Several small karst-hosted deposits were mined in Nova Scotia in the late 1800s.