The prospect is located in Region III, the Atacama Region, 12 km northeast of the city of El Salvador, in the Chañaral Province, Norte – Sierra Miranda & Mantos Gruesos mining district. It lies at an average elevation of 2650 meters above sea level. The central reference UTM coordinates are: 7 104 500 N, 447 250 E.
The prospect comprises 402 mining rights units located in the Diego de Almagro District, Chañaral Province, Atacama Region. The companies that currently hold mining rights in the area are SLM Nueva Esperanza, SLM Guanaco uno, SLM Royal 1 de S. Amarga, Godoy Trujillo Aliro y Ots., and Patricio Martínez Gómez
The Manto Hermoso prospect comprises mainly andesitic volcanic rocks with breccia and red volcanic sandstone intercalations, grouped into two units: the Llanta formation (Lower Cretaceous) and the Sierra Mantos Gruesos volcanic-sedimentary sequence (Cretaceous – Paleocene). These units feature intrusive igneous bodies dating back to the following periods: Upper Cretaceous-Lower Tertiary, Lower Eocene-Paleocene, and Eocene-Oligocene. The system also includes volcanic rocks with secondary magnetization resulting from their proximity to the igneous body. Meanwhile, the intrusive body is demagnetized.
Areas of mineralization-alteration are indicated at the base of the tributaries that run towards the San Juan stream; the structural framework is linked to an area of convergence of major faults, oriented NE-SW and NNW-SSE, located just to the north of the magnetic anomaly. The zone is covered with thick gravel deposits washed down from Paleozoic intrusive rocks in the highlands, running eastward up to the Sierra Castillo Fault.
Two volcanic sedimentary units have been located in the region (the Llanta formation and the Mantos Gruesos sequence), in structural contact across the Manto Hermoso Fault, which also forms a boundary for copper mineralization.
Evidence has been found for a system of faults and minor structures running on a general heading of N20°W, related with the Sierra Castillo Fault system, along which copper mineralization has occurred in calcite and quartz-calcite veins. Another system runs in a general direction of N70°W, comprising faults conjugated with the principal system (Reidel faults), which, like the previous system, affects the formation of calcite veins. The intersection of the two systems creates the best conditions for copper mineralization (Manto Hermoso Mine).
Magnetic surveys have detected magnetic alignments that could be correlated with structures mapped at the surface, indicating at least five demagnetized zones to the east of the Manto Hermoso Fault, in volcanic rock from the Mantos Gruesos sequence that could correspond to altered rock. Soil analysis results indicate the existence of two extensive copper anomalies, with values of up to 0.12% Cu. In general, a number of minor copper oxide sites exist, related to the presence of calcite and/or quartz-calcite veins. The CaO is concordant with the presence of calcite veins and with the two structural systems recognized in the area. Trench samples were taken from along the Manto Hermoso Fault and from calcite veins at the surface; chemical analysis indicates that the mineralized zone of the Manto Hermoso Fault has an average thickness of 6m and an average grade of 2.9% Cu, decreasing to below 500 ppm at the extremes.
The Manto Hermoso Mine is a vein of quartz-calcite located at the intersection of the Manto Hermoso Fault and conjugated faults, forming an elongated ore “pocket” running on a bearing of N20°W, with a surface length of 110m and an average thickness of 3m. The ore is formed from copper oxides (chrysocolla and atacamite) and sulfides (chalcocite) with calcite and quartz gangue.
The Manto Hermoso prospect shows the features of a strata-bound deposit linked to a fault system with a general NNW bearing that is probably linked to movements over the course of time of the Sierra Castillo fault system.
Geology studies are available, consisting of a surface survey at a scale of 1:5,000, geophysics studies with measurement of 53.3 km of magnetometer profiles and 28.1 km of spectral induced polarization. A geochemistry study has also been conducted, with 62 soil samples and 277 rock samples (trenches), which were analyzed for Cu, Ag, Fe2O3, CaO, NaO, K2O, and MnO. The area has also been studied with 1,380 m of trenches dug with an excavator and 4 air reverse boreholes (1,146 m).
The area’s principal mineralization is directly associated with the Manto Hermoso Fault and represented by the Manto Hermoso Mine. To the north, located outside the area, the same structure houses the mineralization of the Royal and Madona Mines.
Studies have detected evidence of mineralization to the east of the Manto Hermoso Fault, represented by traces of chalcopyrite and abundant disseminated pyrite, while exploratory drilling has not intersected with the principal structure.