Lomitas Negras, Arizona

Lomitas Negras is a porphyry copper project ~20 kilometers south of the San Manuel mine in central Arizona. Rimming the valley are exposed structural segments of Laramide-age porphyry copper systems in the San Manuel and Copper Creek districts, as well as at Oracle Ridge. The property is located under post-mineral cover, with the exception of several small outcrops. One outcrop consists of Paleozoic limestone which contains base metal mineralization and distal porphyry-related alteration. 

Three targets are suggested by coincident geologic, geophysical and geochemical anomalies. EMX has completed three RC pre-collar drilling through the post-mineral cover, and has 32 permitted drill sites. During the pre-collar drilling, a unit interpreted to be equivalent to the older gravels at San Manuel was intersected and contained a high proportion of altered and mineralized porphyry dike fragments and altered granite.

*Nearby mines and deposits provide context for the project, but do not necessarily indicate similar size, styles or grade of mineralization within the project.


Geological map of area surrounding Lomitas Negras project. Click to Enlarge


Mineralization in the altered Escabrosa limestone on the Lomitas Negras project. Clockwise from upper left: Cu-oxide and wulfenite (Mo); galena and wulfenite; chalcocite, wulfenite and Cu-oxide. Click to Enlarge