Status: Available for Option
The El Valle target is a volcanic related epithermal vein hosted Au, Ag system.
Location and Setting
The property is located in northeastern Sonora, 26 km east of Southern Copper’s La Caridad mine, in an area dominated by the north trending mountain ranges of the prolific Sierra Madre Occidental.
El Valle consists of two mining claims totalling 502 Ha. Two small internal claims totalling 53 Ha exist within El Valle and are the site of previous underground mining.
An internal claim mined during the 1940s focused on a large 2 to 8 meter wide quartz vein which forms a low sulfidation epithermal deposit containing pyrite, chalcopyrite and galena. An inclined shaft reaches at least 20 meters into the subsurface and mine workings open wide into a grand salon. This vein extends 400 meters into Millrock’s El Valle claim group. Similar epithermal quartz veins and silicified crests are located both north and south of historic mine workings on Millrock claims.
Young rhyolite tuffs deposited over deformed and altered Cretaceous volcanic rocks of the upper Tarahumara formation cover the surface at El Valle. The Tarahumara formation is cut by hypabyssal Tertiary to Oligocene andesites, which were potentially responsible for mineralization in the area. The emplacement of gold bearing quartz veins was followed by Miocene extension and the formation of the Baucarite conglomerate found in the surrounding valleys.
Structure and Alteration
Typical basin and range structures in the area have produced faulting along northwest oriented structural fabric parallel to the former continental margin. El Valle along with the La Caridad mines are located within horst blocks. Within the claim east-west and northeast tending quartz veins have been traced for up to 400 meters. A large alteration zone is moderately silicified and oxidized and contains stockwork veins along the same structural trend.
Mineralization is found in east west trending quartz veins and silicified bodies containing pyrite, chalcopyrite and galena. These veins are characterized by epithermal textures. Minerals found in the area include pyrite, chalcopyrite and galena.
Conclusions and Recommendations
Previous mining and evidence form recent field investigations suggests the possibility that a volcanic hosted epithermal vein system may be responsible for anomalous gold and silver values in rock samples at El Valle. Recommendations include structural and alteration mapping and stream sediment and rock geochemistry to determine the extent of the mineralized area. This should be combined with or followed by Induced polarization geophysics to target anomalous zones at depth and future drill holes.
“THE TECHNICAL INFORMATION WITHIN THIS DOCUMENT HAS BEEN REVIEWED AND APPROVED BY GREGORY A. BEISCHER, PRESIDENT & CEO OF MILLROCK RESOURCES INC. MR. BEISCHER IS A QUALIFIED PERSON AS DEFINED IN NI 43-101.”