High-Magnesium Dolomites in South-Central New Mexico

Magnesium is an important critical mineral used in a wide range of industrial products and materials. It is used in the manufacture of certain medicines, fertilizers, electronics, and batteries. Magnesium is utilized as an alloying agent of aluminum to improve mechanical capabilities; aluminum-magnesium alloys are useful in airplane and car construction, where strong lightweight materials are critical. China has much of the processing capacity and is the largest global producer of both magnesium compounds and magnesium metal. Demand for magnesium has increased because of use in car parts and batteries. Although magnesium is found in many minerals, dolomite, magnesite, brucite, carnallite, and olivine are of major commercial importance. In New Mexico, magnesium is produced solely for fertilizer as langbeinite from the Carlsbad Potash District. At least one company is considering producing magnesium from dolomite near Deming. In addition to providing significant yields of magnesium, dolomites are also used as crushed rock in construction as a soil additive and iron smelting. In order to consider mining dolomites for magnesium, the dolomites need to be “high-purity”. We define high-purity dolomites as containing at least 15% MgO. We find that certain dolomites in south-central New Mexico, including those within the Florida and Organ Mountains, contain economically significant grades of magnesium (12-22% MgO). High-purity dolomites exist near Silver City, Deming, and Las Cruces, locations that are feasible for transport and extraction. High-purity dolomite deposits in south-central New Mexico, the mining of which could occur in the future, remain the most plentiful source of magnesium in the state. Research is ongoing as magnesium-rich sites are found and described for any potential future mining activity.