El Violín SEDEX Project
Summary
El Violín is centered about 30 km southwest of Chilpancingo de los Bravos, the state capital of Guerrero, Mexico (99º18’W, 17º20’ N). The Property consists of 5 concessions that overlap a total surface area of 9583 hectares: Violín 2 Norte, Violin 2 Sur, Lupita, La Huerta and La Pastoría. Exploraciones La Plata, S.A. de C.V. (a wholly-owned subsidiary of Alphamin Resources Corporation: TSX-V:AFM), acquired 100% of the El Violín 2 Property from Minerales Monclova S.A. de C.V. in an agreement signed 20 Febuary 2009, subject to a 3% Net Smelter Return. The remaining Properties were staked directly in the name of Exploraciones La Plata.
The Property overlaps part of the Mixteca Terrane of Southern Mexico, a Middle Jurassic continental arc built on polydeformed basement rocks of the Acatlán Complex. Following the Middle Jurassic orogeny, a prolonged period of back-arc rifting and basin development is marked by deposition of Chapolapa formation quartzites and syn-sedimentary mafic sills. Sedimentary exhalative (SEDEX) massive sulfide deposits occur near the top of the Chapolapa Formation close to the capping schists of the Ixcuinatoyac (?) Formation. These are unconformably overlain by limestones of the Morelos Formation. Uplift in the latest Cretaceous resulted in deposition of Mexcala red bed sediments unconformably on top of the Morelos Limestone, and intrusion of continental granites though the section. The granitic rocks are related to copper-gold porphyry prospects at Coaxtlahuacan and Tlacotitlanapa.
Between 2006 and 2008, major soil geochemical and reconnaissance geological mapping campaigns were completed on the Property to evaluate the potential of stream sediment geochemical anomalies for copper, gold, silver, lead and zinc. In mid-2008, a combined Induced Polarization (IP) and magnetic survey was completed on a compelling copper-gold anomaly in quartz-feldspar-biotite porphyritic rocks to evaluate the potential of this area to host a significant porphyry copper-gold deposit. In March of 2009, a short follow-up field review with Dr. C. I. Godwin, C. Verley and M. Robinson was done to evaluate the new data.
One major conclusion of work completed to date is that the Property has excellent potential down-dip of exposed SEDEX mineralization at El Carrizal. On the El Violin 2 Property, SEDEX type mineralization occurs in fine-grained quartzites and cherts near the top of the fining upwards Chapolapa Formation, a more than one kilometer thick section of coarse-grained, permeable redbed clastics and synsedimentary sills. Analyses of the massive sulfides are high grade, and typically contain 5 to 10% zinc and 40 to 100 g/t silver with about 0.5 to 1% Pb+Cu.
The porphyry/skarn prospects at Tlacotitlanapa and Coaxtlahuacan are marked by large, high amplitude soil geochemical anomalies, and surface rock sampling has confirmed a bedrock source to the soil geochemistry. The average metal grade for 20 surface rock samples from the copper-rich area of Coaxtlahuacan is 0.34% Cu, 0.5 g/t Au, 6.8 g/t Ag, 20 ppm Mo, 0.36% Zn and 0.18% Pb. The average metal grade for 28 surface rocks from Tlacotitlanapa is 0.5% Cu, 0.1 g/t Au, 8.4 g/t Ag and 33 ppm Mo. In both areas, potentially ore-grade Cu-Au values occur in magnetite skarn near limestone or in quartz-magnetite veins that occur in quartz-feldspar-biotite porphyritic host rocks.