Thor Copper Project
Commodity: Copper and Gold
Location: Sonora, Mexico
Size: 128 km²
Option: Available for partnership
The Thor Copper Project is located within the Arizona - Sonora Copper Mining Belt is host to over 40 major Cu-Mo porphyry deposits, including the world-class, Cananea and La Caridad copper mines currently being operated by Grupo Mexico. The Thor property was acquired for its extensive geochemical and associated color anomalies, which is interpreted by Riverside to represent the basal portions of an eroded porphyry-related lithocap making it the prime target for a new significant copper discovery. This part of Sonora is rich in copper potential where extensional tectonics has created the potential for shallow, bulk tonnage discoveries. Within these areas of more recent crustal extension pediment valley fill often covers post-mineral faulting creating ‘buried copper porphyries’, as documented by Riverside’s President, John-Mark Staude, who described this condition in his 1995, Ph.D. thesis on the mineralization of Sonora, Mexico.
The 128 sq km Thor Project is located 130 km SW of the La Caridad Mine (1,800 Mt @ 0.45% Cu, 0.02% Mo) and has good access via paved highways from the city of Hermosillo and the nearby town of Ures, Sonora. An electrical power-line and a source of water are nearby. Riverside has developed positive working relationships with the local community and ranchers that has facilitated our exploration activities on the property.
Riverside controls 100% of the Thor mineral concession and has completed an initial four-hole drill program into two of the six target areas with funding from Antofagasta Minerals. The results from this first 1,400 metre diamond core drilling program was successful in finding a mineralized porphyry system. Additional work is now required to further test and follow up of other targets. Drill cores and all other exploration data generated to date, including Aster image analysis, ground magnetics surveying, petrographic and geochronology studies are available for review by interested parties. Riverside has already used this information to outline six targets which warrant further exploration.
The Thor project is located at the southern end of the Aconchi Batholith Complex, which is composed of several intrusive phases of both Laramide (65 to 55 Ma) and post-Laramide (42-36 Ma) ages. About 15 km to the southwest is the Mazatan Metamorphic Core Complex, comprising Paleozoic and older rocks that display ductile and brittle-ductile structural features similar to those found in the Catalina Core Complex, located north of Tucson, Arizona around a cluster of copper mines in Arizona. The Mazatan Core Complex was formed approximately at the same time as the Basin and Range extensional geomorpho-tectonic province of Southwestern U.S.A. and Northwestern Mexico. Pronounced tilting of structural blocks and rotation of normal faults are a characteristic feature of the Basin and Range province and have been observed on the Thor property. Recognition of such structural features has enabled Riverside geologists to define high-potential copper porphyry targets that are ready for drilling.
The project area is located in the central portion of the Aconchi batholith complex which has been affected by extensional faults that have formed a NNW-oriented, 15 km long by 1.5 to 3.5 km wide graben structure. Upper Cretaceous-Paleocene felsic and intermediate volcanic rocks along with Paleozoic carbonate and siliciclastic sedimentary rocks exist within the limits of the graben. The volcanic rocks occur in the northern part of the down-faulted block, while the older sedimentary rocks are exposed more in the south where deeper erosion has occurred. Both of these rock sequences have stratigraphic equivalents that host porphyry copper deposits elsewhere in the Arizona-Sonora mineral province. The geology and the pro-mining working environment make the Thor Project a excellent place for making a discovery.