Regional Geologic Context
The South Grass Valley Project lies along the same inferred deep-seated structural corridor as the Grass Valley Project to the north, which heads south southwest from Barrick Gold Corp.’s Cortez Property, a series of large Carlin-type gold deposits primarily hosted in deeper lower plate bedrock.
- 50 km (32 miles) south-southwest of Barrick Gold Corp.’s (TSX:ABX) Cortez Property, one of the world’s largest and lowest cost gold mines (proven and probable reserves: >15,000,000 oz Au – includes Pipeline and Cortez).
At the project scale, initial geologic mapping has established the presence of lower plate carbonate rocks outcropping within and adjacent to the Project claim boundary. For scale, the air photos below show the size of the footprint for the upper and lower Cortez Hills Breccia Zones (>5 million ounces gold), as well as a section grid (each square is approximately one mile by one mile).
Regional Air Magnetic Geophysics
The regional air magnetic geophysics dataset identifies several broad areas of anomalous magnetization. Specifically, the granitic intrusive rocks of Jurassic age that outcrop in the SW corner of the image below are associated with a broad magnetic response interpreted to be related to similar-aged intrusive bodies at depth and located elsewhere in the region.
At the Cortez Hills gold deposits to the north, the Jurassic-aged, Mill Canyon stock is spatially associated with, and believed to be important in preparing the ground for later, Tertiary–aged, Carlin-Type gold mineralization. Prospect pits within carbonate rocks adjacent to the granitic intrusive rocks located in the SW corner of the image are associated with contact metasomatic mineralization similar to that associated with the Mill Canyon stock adjacent to the Cortex Hills Breccia deposit.
Regional Gravity Geophysics
The regional gravity geophysics dataset for the South Grass Valley Project area delineates large areas of shallow bedrock adjacent to lower plate carbonate outcrop. Specifically, the orange areas in the image below are interpreted to be underlain by bedrock covered by less than 300 metres (1,000 feet) of sand and gravel.
Together, the regional geologic context, the project scale mapping, and the regional geophysics datasets suggest the possibility that lower plate rocks associated with mineralization could be present at economic depths at the South Grass Valley Project.