Cinco de Mayo is a carbonate replacement deposit (CRD) style mineral exploration project in the state of Chihuahua, Mexico. Drilling, since November 2007, has confirmed a large zone of high-grade silver, lead, and zinc mineralization. This new, buried mineral deposit is called the José Manto (a manto is coherent massive sulphide sheet). The deposit is hosted by the fossiliferous limestone Finlay Formation, with the thickest and most uniform high-grade massive sulphide intersections occurring near its upper and lower contacts. CRD deposits account for roughly 4 billion ounces or 40% of the 10 billion total silver ounces produced in Mexico. They are second only to Mexico's epithermal veins in historic silver production.