Critical Minerals in The Cuba Manganese Deposits, Cuba Manganese Mining District, Sandoval County, New Mexico
— Virginia T. McLemore

Reexamination of the mineral resources in the Cuba Manganese district, north of the town of Cuba in Sandoval County, New
Mexico, is warranted in light of today’s economic importance of critical minerals, which are essential in most of modern electronic devices,
including batteries, electric cars, wind turbines, and computer chips. Critical minerals are defined as nonfuel mineral commodities that are
essential to the economic and national security of the United States and are from a supply chain that is vulnerable to global and national
supply disruptions. Manganese is classified as a critical mineral because there is no current manganese production in the United States
and supply chain disruptions are likely. Total production from four small sedimentary manganese deposits in the Cuba Manganese district
amounted to 3,786 long tons of manganese ore (grades of 36–41 wt% MnO). The Cuba manganese deposits formed in small, local lacustrine-
deltaic environments in the San Jose Formation, where anoxic waters mixed with shallow oxygen-rich waters and created reducing
conditions that allowed manganese to precipitate. Although, the deposits in the Cuba Manganese district have manganese concentrations
similar to economic deposits elsewhere in the world (>39 wt% MnO), the known Cuba manganese deposits are small in tonnage and have no
economic potential at this time. There is potential for finding additional subsurface sedimentary manganese deposits in the area, but they are
likely to be small in tonnage and uneconomic because the local stratified, lacustrine-deltaic environments in the San Jose Formation that host
the manganese deposits are too small to host the millions of tons of manganese ore needed to form an economic deposit. Arsenic, barium,
and cobalt (other critical minerals) concentrations are elevated in the Cuba deposits, but the concentrations are too low to be economic.
There are no additional critical minerals known in the Cuba Manganese mining district.