Mirasol Resources announced to provide an exploration update on the 100% owned Rubi copper, molybdenum and gold porphyry project located adjacent to the world class El Salvador mining district in Region III of northern Chile.
The 13,350 hectare Rubi property is prospective for copper mineralization where Mirasol has identified multiple stand alone porphyry Cu targets. Recent geological evaluation identified additional conceptual Cu-Au targets and a new outcropping precious metal target which returned rock chip assays of up to 6.9 grams per tonne gold. Recently, Mirasol staked additional claims to secure extensions of exploration targets at Rubi. The Company is actively seeking a joint venture partner to advance this project and is conducting field reviews with a select group of mid to first tier copper producers as the initial step in the joint venture process.
At the district scale, the Rubi project is centered within a cluster of world class porphyry Cu-Mo-Au deposits that in some instances include associated epithermal gold deposits. These include the historic El Salvador and the Potrerillos mines as well as the Inca del Oro porphyry development project. Published geology suggests the intrusive and mineralized system at Rubi maybe part of the Paleocene to early Eocene age mineral belt that has produced a series of world class porphyry Cu and epithermal Au deposits in Northern Chile.
The Rubi project encompasses a 10 kilometer diameter gravel covered pampa surrounded by altered volcanic and intrusive rocks and hosts several outcropping zones of Cu Mo Au and base metal mineralization. The eastern margin of the project is marked by a large arcuate fault zone thought to represent the ring fracture faults of a mineralizing caldera system. The alteration and geochemical patterns at Rubi are suggestive of a large zoned porphyry epithermal mineral district with a number of possible mineralized centers indicated.
Previous drilling was undertaken over parts of the Rubi project during the 1990's but did not test the principle targets identified by Mirasol. Many of the historic holes drilled into the gravel cover to test for covered porphyry mineralization, apparently were stopped in gravel short of reaching basement. Over 50% the claims area shows no evidence of historic exploration including some of the outcropping mineralized targets identified by Mirasol. There is no evidence of systematic ground electrical geophysical surveys over the Rubi project and the project is not covered by any publicly available modern aeromagnetics surveys.
Mirasol has identified a series of outcropping and covered conceptual targets at Rubi. The Lithocap target is an area of intense advanced argillic alteration and silicification that may cover in excess of 9 square kilometers. Rock chip sampling by Mirasol geologists identified a central zone with wide spread anomalous Mo peak assay of 250 parts per million ppm Mo low grade Cu and localized higher grade secondary Cu in narrow veins and breccias. The alteration and geochemical signature of this target is characteristic of the barren alteration lithocap that can form over or lateral to, a high sulphidation and porphyry Cu Mo Au system. Localized historic drilling on the southern edge of the Lithocap zone has not tested Mirasol's target.
Quebrada del Salado is an epithermal gold and silver target associated with a felsic dike swarm that extends north from the Lithocap target. Small-scale historic gold workings are intermittently exploited on the dike margins over a 1.1 kilometer strike length in a series of near surface, oxidized quartz carbonate veins. Reconnaissance rock chip sampling of the dumps and workings has returned anomalous gold, silver, manganese and base metal results indicative of a precious metal intermediate sulphidation epithermal system. The average gold grade of the 10 samples collected to date is 2.7 gram per tonne Au with a peak assay of 6.9 gram per tonne Au. ASTER alteration processing shows argillic alteration extends for several kilometers along the dike swarm and suggests that the mineralized zone could be more extensive than currently recognized in outcrop. Epithermal precious metal deposits are known to form on the edge porphyry districts. Some of these deposits contain significant gold and silver resources. There has been no previous modern exploration identified over the Quebrada del Salado vein zone.
The Portezuelo porphyry Cu-Mo target is a 2.5 by 1.5 kilometer area of multiphase granodiorite to rhyolite intrusive and dike complex. Rock chip sampling and mapping shows widespread anomalous Cu values and Mo values (peak assay of 310 ppm Mo) associated with porphyry style sheeted veins and disseminated mineralization. Five historic shallow reverse circulation holes were drilled at the prospect by CODELCO Chile, the state mining corporation. Preliminary field evaluation by Mirasol suggests the historic drill holes have not have been optimally placed to test the mineralization.
Additional conceptual covered porphyry and exotic Cu targets are suggested by alteration vectors and low level anomalous Cu-Mo surface chip geochemistry at the Corner Zone and Pampa del Inca prospects. Drilling of these types of gravel covered targets in Chile has led to the discovery of a number of porphyry deposits over recent decades. Systematic geophysics of the gravel-covered areas at Rubi is required to filter and prioritize targets prior to drill testing.
