Cerro Hermoso Project
Overview & Highlights
Cerro Hermoso is located in the Puno Region of southern Peru. The property lies 60 km from the city of Juliaca and 5 km northwest from the supply town of Santa Lucia. The property lies in a north-west trending mineral belt known for numerous gold, silver and copper deposits.
Cerro Hermoso Project Highlights
- Host to a large, energetic mineral system with multiple targets and bulk tonnage potential.
- Located along trend of regional epithermal and carbonate replacement deposits.
- Extensive sampling and mapping completed to date.
- Exploration model and targets well-defined.
- Preparing for 2018 Drilling.
The Property is comprised of two mining concessions covering a total of 988 Has. Miramont has an option to acquire 100% of the mining concessions by making property payments totaling US$3.5 million through September 2020. Surface rights are held in both private and community hands. The company has reached agreement to access the property and conduct exploration activity including drilling.
Cerro Hermoso is accessed year-round via a two-lane highway that runs from Juliaca to Arequipa. Elevations range from 4,070 to 4,400 m.a.s.l..
The property is near the town of Santa Lucia where Miramont has established camp facilities. Most services and supplies can be found here or in Juliaca about an hour’s drive away. Water for exploration work is readily available from the Verde River flowing through the Property, subject to required permitting. The nearest point to connect the Property to the national power grid three-phase system is 6 km away near Santa Lucia.
The Cerro Hermoso project is found in the Santa Lucia district along the eastern flank of the Cordillera Occidental on the edge of the altiplano that separates the Cordilleras Occidental and Oriental in southern Peru. Nearby deposits include Berenguela, San Gabriel, Limon Verde and Tacaza .
The project geology is dominated by the Cerro Hermoso diatreme (an explosive volcanic pipe) which cuts through older formations of volcanic flows and underlying lying limestone units. The Tacaza Group Volcanics of late Oligocene age outcrop throughout the property area, and consist of andesite flows. Underlying the Tacaza is the Cretaceous Ayavaca limestone which are known to be mineralized.
Intrusive rocks (hornblende diorite) are emplaced throughout the Santa Lucia District and are associated with precious and base metal mineralization (Berenguela, Limon Verde Mine). Hornblende diorite stocks and dikes are found along the northern margin of the Cerro Hermoso diatreme.
The Tacaza Group also includes the Cerro Hermoso Formation – felsic, lithic-rich tuffs and breccias produced by phreato-magmatic explosions during the formation of the diatreme. This volcanic vent cuts earlier Ayavaca Limestone and Tacaza volcanics. The Cerro Hermoso diatreme is the dominant geologic feature and is related to the multiple styles of gold, silver and copper mineralization found on the property.
Historic development of the property consisted of mining a series of high-grade veins and other structures formed in a concentric ring along rim of the diatreme. Approximately 750,000 tons at an average grade of 15 oz/t, Ag, 1% Cu, 2% Zn, 2% Pb and 1.0 g/t Au were mined.
The property is centered around the large, 1.4-kilometre-diameter Cerro Hermoso diatreme which hosts extensive mineralization. Miramont has identified three priority targets for further exploration and initial drilling.
Central Breccia Zone
This zone is found within the heart of the diatreme. The formation of gold-bearing hydrothermal breccia, the potential host-rock for mineralization, is extensive. Three separate phases of breccia have been identified all of which host gold. Historic channel sampling in the central breccia resulted in 43 meters averaging 1.8 g/t. Selective sampling by Miramont has confirmed the channel sample results and expanded the Central Breccia zone. The high value for gold is 18.4 g/t while 87 of 178 samples collected were greater than 0.1 g/t.
Other outcrops of mineralized breccias have been found up to 800 meters away. This indicates the widespread presence of gold and the extensive tonnage potential of this receptive host rock.
The Stockwork Zone
The stockwork zone lies just outside the northern rim of the diatreme. It is a 500 by 400 meter area of extensive stockwork veining developed within the Tacaza andesite unit. It is also adjacent to an outcropping hornblende diorite intrusion. Finally all of this appears to be contained within a separate fault-block concentric to the diatreme margin.
Stockwork veining here consists of a patchy to pervasive, crisscrossing network of quartz veinlets. Mineralization at surface is mostly oxidized metal sulfides although occasional fresher sulfide grains can be seen.
The Stockwork Zone has significant silver, copper, and gold mineralization throughout the area (see geochem maps). Values as high as 500 g/t Ag, 3.9% Cu and 10 g/t Au have been found here. Of a total 79 samples collected in this area 67 had more than 10 g/t Ag, 29 had more than 0.1% copper and 13 had greater than 0.5 g/t Au.
The combination of intrusive activity, structural setting and widespread mineralization makes this an excellent target.
Carbonate Replacement Zone
This zone is known from a review of investigations carried out by previous operators of the Santa Barbara mine. Development on lower levels (approx. 200 meters below surface) encountered carbonate replacement deposits (CRD’s) within the underlying Ayavaca limestone unit. Values up to 6.9% Zn, 6.6% Pb and 6.2 oz/t Ag have been found in multiple horizons.
Examination of old mine dump material has identified massive sulfide in limestone as well as some possible marble/skarn. This latter is an indication of skarn formation where limestone comes into contact with intrusive rock. Skarn deposits, such as the nearby Tintaya and Las Bambas Mines, can be major precious and base-metal producers.
Miramont geologists have identified other target areas within the concessions. These are currently defined as secondary but may be upgraded to priority as new mapping, geochemical sampling and geophysical information become available.
Geochemical anomalies in all target areas for gold, silver and copper are shown in these maps.
Miramont conducted ground magnetic, conductivity (full waveform distributed array– AG DAS) and resistivity studies over much of the concession. The survey has been successful in identifying different rock types, structural controls and most importantly, shows significant correlation between surface mineralization and the location of the chargeability and magnetic highs in the subsurface. These results reinforce Miramont’s understanding of the project’s geology and will be a significant aide in drill hole targeting.
Stockwork Zone This area is dominated by a high chargeability (IP) and high resistivity signature that extends to depth. Coincident with these anomalies is an area of high magnetic susceptibility. The magnetic high, together with the IP/Resistivity anomalies, support Miramont’s interpretation that the Stockwork Zone is sitting on top of a large potentially mineralized intrusive body.
Central Breccia Zone An elevated chargeability and resistivity signature extends in a north-south direction underlying the areas with the best surface gold anomalies. This is a possible indication that surface mineralization extends into the subsurface. Magnetic susceptibility lows within the diatreme itself identify several internal source areas. This supports Miramont’s interpretation that multiple pulses of explosive hydrothermal activity indicating a long-lived and energetic system formed the diatreme.
Carbonate Replacement Zone High chargeability (IP) coupled with high resistivity has been identified trending from the Carbonate Replacement Zone to the southern boundary of the Stockwork Zone. This has good continuity at depth and is coincident with a magnetic low that may indicate a limestone host. The geophysical signature taken together with the geologic interpretation suggests both the occurrence of sulfide minerals and presence of limestones consistent with carbonate replacement mineralization.
Figure X – Image of chargeability as a horizontal slice 200 meters below surface. Note the formation of a chargeability high under the Stockwork Zone as well as the north-south, finger-like high under the Central Breccia Zone.
Figure Y – Image of resistivity as a horizontal slice 200 meters below surface. Note the resistivity low extending from the Carbonate Replacement Zone into the Stockwork Zone. This may result from the presence of limestone at depth. Together with the coincident Chargeability high (image above) may indicate a carbonate replacement environment.
Figure Z – Image of magnetic susceptibility taken as a horizontal slice 200 meters below surface (Magnetic Vector Inversion of Perpendicular Factor). Note the strong magnetic high underlying the Stockwork Zone. Taken together with the coincident chargeability anomaly this may indicate a buried sulfide-bearing intrusion in the subsurface.
Miramont is planning a 3500-5000 meter drill program for the first half of 2018. All three priority targets (Central Breccia, Stockwork and Carbonate Replacement Zones) will be tested. The company is in the final stages of acquiring the necessary drill permits. Under current Peruvian regulations Miramont has requested 20 drill pad locations.