The Cerro Amarillo project is a Cu-(Mo-Au) property in west central Argentina which contains a cluster of five distinct porphyry style intrusive-hydrothermal systems, namely:
- Cerro Apero;
- Vaca de Cobre;
- Cerro Choro;
- Cajon Grande; and
- La Blanca.
Substantial mineralisation of several styles has been identified at surface in each system except Cerro Choro. Moreover, these porphyry systems are clustered along a northeast-trending structural corridor on the property which transects the southern extension of the orogen-parallel, Miocene-Pliocene metallogenic belt that also hosts the El Teniente, Los Bronces, Los Pelambres, and Altar porphyry copper deposits.
Location and Infrastructure
The project covers an area of 168 km2 close to the border with Chile in southern Mendoza Province in the Department (County) of Malargüe. The property lies in the mountains of the Andean Cordillera at an average elevation of 3,000 MASL and has a relative relief of some 1,800 m from 2,000 MASL to 3,800 MASL. Much of the project area receives snow from May to November each year resulting in a practical field season of some five months from early December to late April. The town of Malargüe is the nearest major service centre lying 53 km southeast of the property. The town is the seat of local government and is also a service centre for the petroleum industry. It hosts the province's only technical mining school and is served by a towered airport with a 2,650 m paved runway.
Public roads pass to both the north and west of the property, although there are no vehicular roads or tracks within the property boundaries; all access to date has been via horseback, on foot, or by helicopter. Ample water resources for the project can be found either on the property or in the Rio Grande which flows along the western boundary of the property. High voltage transmission lines lie within reasonable distance from the project area to support future mine development.
Geology and Mineralisation
The Cerro Amarillo project area covers part of the northwest margin of the Neuquén Basin which developed as a back-arc rift during late Triassic time and then filled with a transgressive sedimentary sequence during the Jurassic and Cretaceous time. The Neuquén Basin was subsequently intruded by intermediate igneous rocks and covered by associated volcanics during two periods of magmatic activity from the late Miocene to early Pliocene. Large porphyry style mineralisation systems are known to be associated with both magmatic events.
Geology within the project area includes an eastern domain of acid volcanics that represent basement to the Neuquén Basin, a central domain of sediments that represent the lower parts of the Basin fill and a western domain of andesites that represent the Miocene-Pliocene volcanic activity. The sediments and volcanics have shallow westerly dips. Boundaries between the domains may represent unconformable contacts or thrust faults. A suite of dioritic to dacitic porphyry intrusives occurs in several small complexes that intrude all three domains. These intrusives are thought to represent the Pliocene igneous event.
Large scale "porphyry style" hydrothermal alteration and mineralisation systems are associated with four of the five identified intrusive complexes on the property. These systems are: the Cajon Grande, Vaca De Cobre, La Blanca and Cerro Apero prospects. All four prospects contain intrusive hosted stockworks and hydrothermal breccia. Skarn style mineralisation has developed at the Cerro Apero and Cajon Grande prospects where intrusives have intersected carbonate-bearing stratigraphy. Similar skarns may have developed at the La Blanca prospect below the current level of exposure.
The mineralised porphyry complexes define a remarkably linear northeast trend that is at a high angle to north trending regional structures. This trend may reflect a crustal level structure that has controlled magma transport for the intrusive complexes. The intersection of such transcurrent structures with orogen-parallel structures is thought to be important in controlling the location of many major porphyry mineralisation systems in plate margin environments. In this regard, the Cerro Amarillo project shares many characteristics of world-class porphyry copper deposits: first of all, it comprises a cluster of porphyry occurrences much the same as at Los Bronces, Escondida, Chuquicamata, and Collahuasi in Chile as well as the Vicuña project and the cluster of porphyry deposits in the Alumbrera district in Argentina; secondly, it lies on the southern extension of the Miocene-Pliocene metallogenic belt which hosts the behemoth deposits of El Teniente and Los Bronces of similar geological age; and, thirdly, this mineral district straddles the transition zone between Andean segments --in this case between steep subducting segment and the flat slab segment-- a feature which the other camps of behemoth deposits have in common.
Summary of Exploration Work
Meryllion carried out the fieldwork over two field seasons, 2011/2012 and 2013/2014. The work comprised:
- prospecting and sampling over much of the property;
- detailed mapping over Cerro Apero, Vaca de Cobre, Cerro Choro, Cajon Grande, and La Blanca;
- geochemical sampling on grids over Cajon Grande and Vaca de Cobre as well as talus sampling along scree slopes and crests at la Blanca and Cerro Choro;
- induced polarisation surveying over Cajon Grande and Cerro Apero; and
- helicopter-borne magnetic and radiometric surveying over the Cerro Amarillo property.
This work led to discovery of the La Blanca, Vaca de Cobre, and Cerro Choro porphyry systems in addition to better definition of mineralisation at the previously known Cerro Apero and Cajon Grande systems. Some of the results of this work are shown in the figures below.
All four mineralisation systems have good potential to contain substantial copper, gold and, possibly, molybdenum mineralisation. Surface exploration to date has identified targets worthy of drill testing in each of the four major prospects. A series of 14 drill holes totalling 5,300 m has been planned to test these targets.
Due to the topography at Cerro Amarillo, the drill campaign will utilize helicopter-portable rigs. A base of operations will be established on the property to support helicopter operations, drilling, logging, and on-going exploration activities. An Environmental Impact Report for Stage II Exploration (ie, drilling operations) has been submitted to the relevant authorities of the Province of Mendoza and is awaiting ratification which is anticipated in the fall of 2014 with the drill program expected to commence in December 2014.
A report on the project entitled "Technical Report on the Cerro Amarillo Project, Mendoza Province, Argentina, NI 43-101 Report" dated July 28, 2014 is available here
All scientific and technical information set out above has been approved by Dr Willem Fuchter PGeo, President and Director of Meryllion Argentina SA, an indirect, wholly owned subsidiary of Meryllion, and a Qualified Person as defined under National Instrument 43-101.