Antilla Project Overview

Calisto Cobre's flagship property is the Antilla Copper Project ("Property" or "Project"), in the Apurimac Region of southern Perú – an active mining region of the country – situated approximately 8 hours by road southwest of Cusco. The Property consists of 12 exploration concessions covering approximately 7,500 hectares, and hosts existing Indicated Resources of 2.2 billion pounds of copper and Inferred Resources of 0.4 billion pounds of copper.  Calisto Cobre considers the Property to be substantially under-explored, with the main porphyry intrusion(s) driving mineralization yet to be discovered.

In December 2021, the Company purchased a 75% operating interest in the Project from Panoro Minerals Ltd. ("Panoro"), and has the ability to increase its interest to 90% by making certain additional payments to Panoro. The concessions are held free of outstanding liens or encumbrances, with the exception of a 2% net smelter return royalty ("NSR") granted in favor of Panoro.

The Property is located approximately 330 km from Cusco, traveling mainly along paved roads. There are regular scheduled flights from Lima to Cusco. The Property is located approximately 140 km by road from Abancay, capital of the Apurimac Region, where most supplies may be sourced, and adjacent to the village of Antilla.

Climate in the region of the Property is characterized by dry winters and rainy summer seasons. Project elevations in its high Andean Cordillera location vary between 2,500 meters to 4,500 meters above sea level ("masl"). Relief on the Property varies from moderate slopes to very high rugged relief along the flanks, and tops, of the ridges.

The Antilla Deposit is a copper-molybdenum porphyry deposit, located in the Andahuaylas-Yauri Belt of the high Andes of southern Perú. The Andahuaylas-Yauri Belt is located immediately south of the Abancay deflection of the Cordillera, where thrust faulting oriented dominantly north-south is deflected to strike northwest south-east. The geology of the Andahuaylas-Yauri Belt is dominated by the Andahuaylas-Yauri Batholith and Mesozoic to Early Cenozoic clastic and marine sedimentary rock. The bulk of the property is underlain by quartzite, quartz-arenite, and sandstones of the Soraya Formation. Sedimentary rocks are intruded by at least three types of intrusive rock: altered and weakly-mineralized porphyry stocks or apophyses, narrow porphyry diorite and narrow, unaltered late porphyry dikes. The altered, weakly-mineralized main porphyry is exposed to the west and east of the mineralized quartz-arenite, and as thin dykes several kilometers to the west of the Indicated and Inferred resource.

Four main mineralization types are found on the Antilla Property: primary sulfide, secondary sulfides, a leached cap, and an overburden/cover zone overlying the deposit. The secondary sulfide zone forms a relatively continuous, tabular blanket of chalcocite that generally ranges from 60 m to 120 m thick. The secondary sulfide zone is overlain by the leached cap which has an average thickness of 55 m and generally ranges from 0 m to 75 m thick.

The mineralization identified to date on the Property is consistent with a supergene enrichment blanket underlain by a primary sulfide mineralization, both hosted in the quartzite and sandstone. Mineralization is associated with an Andean-type copper-molybdenum porphyry system

Several metallurgical testwork programs have been carried out by various independent laboratories on samples of Antilla Deposit mineralization between 2006 and 2018. Preliminary studies were carried out by Laurion and Inspectorate in 2006 and 2011, respectively. In 2013, a more substantive program was undertaken by Certimin which focused on the recovery of copper and molybdenum from samples of primary and secondary mineralization using conventional flotation techniques. Lastly, a 2018 program of leaching testwork (bottle roll and column leaching) completed at Aminpro, Perú, examined the amenability of supergene zone mineralization to acid and ferric bioleach methods.

The bottle roll and column leaching testwork competed at Aminpro Laboratories, Lima, Perú in 2018 indicate that a ferric bio-heap leach process would be effective at treating mineralization from the supergene zone of this deposit. Results from the program indicate copper leach extractions of circa 75 % are achievable in cycle times of between 150 days and 175 days for 3/8" and 1" crush sizes respectively. Future trade-off studies will be required to determine the optimum economic crush size and other leach conditions.

The metallurgical testwork conducted to date indicates a phased approach to project development, with the first phase based on implementation of a ferric leach process for the recovery of copper from secondary sulfides.  Recovery of copper from any material resource of primary sulphides that might be discovered on the property would be based on a conventional mill and concentrator flowsheet.

The Mineral Resources for the Antilla Deposit are an Indicated Resource of 295.1 Mt at 0.33% copper, 0.008% molybdenum: and an Inferred Resource of 66.3 Mt at 0.27% copper, 0.007% molybdenum. Mineral Resources are reported by copper cut-off grades between 0.11% Cu and 0.24% Cu depending on domain and are constrained by the optimized pit shell. The effective date of the Mineral Resources is 10 May 2022. The block grades were estimated by the OK interpolation method on capped composite copper and molybdenum grades. No recoveries have been applied to the interpolated grade estimates.

Indicated and Inferred Mineral Resources of the Antilla Project, within an optimized pit shell, are as follows:

On June 26, 2018, Panoro filed on SEDAR the Technical Report on the PEA for the Antilla Copper Project Heap Leach and SX/EW Operation, authored by Moose Mountain Technical Services Ltd. ("MMTS"), Tetra Tech Inc. ("Tetra Tech") The results of the 2018 PEA Update were announced by Panoro in a May 14, 2018, news release. 

The 2018 PEA Update development scenario was based on conventional shovel and truck open pit mining at 20,000 tpd, and multi-lift, valley-fill heap leach operations over a 16.5-year mine life. The base case analysis used a US$ 3.05/lb long term copper price and copper recoveries of 72.5%, assuming a ferric leach processing method.

Key parameters and inputs to the 2018 PEA Update, reflecting prevailing prices and costs at the time are presented below.

The 2018 PEA reflected capital and operating cost estimates for the Antilla Project developed to a level of accuracy of +/-50%, considered suitable for a PEA-level study, reflecting input costs prevailing at the time.

Calisto Cobre considers that substantial exploration upside opportunities on the Property exist in three broad categories:

1. Supergene Resource Addition - Delineation of additional supergene mineralized tonnages beneath the current supergene mineral resource, where a number of drill holes terminate in supergene material. Extensions to these holes and deeper drilling in these areas has the potential to encounter additional supergene mineralization at depth.  In addition, compilation of a more robust multi-parameter geometallurgical model may better refine the understanding of the supergene-hypogene boundary and likely transition zone, potentially adding leachable material to the Project inventory.
2. The potential for lateral extension of the supergene resource is strongly supported by drilling on the margins of the deposit. This is particularly evident in the north and northeast where drill holes on the edge of the deposit remain strongly mineralized and have no follow up drilling further north, north east or east.
   
   Lateral extensions are also supported by historical surface geochemical sampling indicating widespread anomalous copper values in the areas adjacent to the current resources to the east, northeast and north, as well as in other areas of the property to the west of the known deposit.
   
   
3. Primary Porphyry Exploration - Possible discovery of primary mineralization tonnages at depth adjacent to the Antilla deposit, and/or elsewhere within the concession package.
   
   Calisto Cobre has conducted a program of re-processing, interpretation, and integration of legacy geophysical data from the 2003 to 2004 timeframe to develop modern 3D magnetic susceptibility and 3D chargeability models, to support drill targeting for both supergene and primary mineralization. Primary magnetite contents of the Antilla host sedimentary sequence are negligible and hence magnetic false positive are unlikely, giving high confidence that magnetic anomalies are related to alteration and/or intrusions. Similarly, the Soraya Formation host contains negligible primary pyrite and therefore IP chargeability false positives are unlikely.
   
   Both the IP chargeability and magnetic susceptibility models conform well with observed geology in both historic drill core and on surface, and provide compelling targets for further work:
   • The magnetic and chargeability anomalies on the east and northeast of the mineral resource area, in the vicinity of minor mapped porphyry intrusion, indicate the presence of elevated pyrite and magnetite alteration.
   • The magnetic anomaly to the west of the supergene mineral resource area is associated with porphyry outcrop and magnetite-bearing potassic alteration in rare deep drilling.
   • The chargeability anomaly in the West target area is closely associated with pyrite observed in outcrop and the sparse drilling. The magnetic anomalies in the same area are not well exposed nor drilled, however magnetite-bearing potassic alteration is noted in two historic shallow drillholes in the vicinity.
   
   The image below shows the orientation of the sections shown above through the resource and adjacent areas.
   
   
   The example cross section shown below, demonstrates magnetic susceptibility highs that may be associated with primary intrusions.
   
   
   The same section across the IP model shows chargeability highs associated with the presence of pyrite, in relation to both supergene zones and potential primary targets to the west of the current resource.
   
   

Calisto is currently reviewing all available data to refine plans for exploration work under these three broad categories.