The most important of these was the Compañía Española de Minas del Rif S.A., working large superficial masses of specular hematite. Setolazar Company, working the Navarrete mine, had an extensive concession estimated to contain more than 4 million tons of iron ore. The Compania Norte Africano had a monthly output of 200 tons of lead ore from pockets near the surface, in addition to calamine estimated to contain 40% zinc.