Arizona Porphyries

Lomitas Negras

The Lomitas Negras porphyry copper project is located approximately five kilometers southeast of the town of San Manuel, Arizona and contains isolated altered outcrops that occur in a broad area of post-mineral cover rocks. The project area is ringed by Laramide-age intrusive rocks and porphyry copper/skarn deposits that include BHP-Billiton's San Manuel-Kalamazoo deposits (~16 kilometer north), Redhawk's Copper Creek deposit (~20 kilometers northeast), and Oracle Mining Corp.'s Oracle Ridge deposit (~10 kilometers southwest). Outcrops on the property exhibit alteration and anomalous base metal mineralization that characteristically occurs on the margins of porphyry copper systems. EMX's recognition of the importance of the altered outcrops, combined with a new interpretation of the extensional structural setting of the area, led to the identification of concealed porphyry copper-molybdenum targets beneath post-mineralization pediment cover.

EMX acquired the property and has completed geologic mapping, outcrop geochemical sampling, a soil gas hydrocarbon survey, and a property-wide ZTEM/magnetic geophysical survey, all funded by a previous partner. Three target areas with coincident geologic, geophysical, and geochemical anomalies were identified from this work, and 32 sites were permitted for drill testing. In 2013, EMX completed a three hole, pre-collar reverse circulation drilling program over two of the target areas in preparation for a follow-up diamond drilling program. Two of these pre-collar holes encountered altered porphyry and host rock fragments within the deepest pediment horizon that suggest a nearby, concealed porphyry source.

An option agreement with Kennecott Exploration Company was announced in May 2014 (see EMX news release dated May, 15, 2014). After a reconnaissance diamond drill program was completed during the third quarter, Kennecott relinquished its interest in the project, with EMX regaining 100% control.

The Lomitas Negras project is available for partnership.

Note: The nearby mines and deposits in the region provide context for EMX's Project, which occurs in a similar geologic setting, but this is not necessarily indicative that the project hosts similar mineralization.

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.