A Neoproterozoic epithermal gold deposit—The Haile gold mine, South Carolina, USA

Abstract

Abstract The Haile gold mine is located in southern Lancaster County, South Carolina, near the town of Kershaw. Gold was discovered at the site in 1827, and four periods of mining have yielded 360,000 ounces of gold. The mine is located between the past producing Ridgeway and Brewer mines that, when all are combined, constitute a significant amount of historical gold production in the southeastern United States. These mines are hosted within Neoproterozoic to lower Cambrian Carolina terrane rocks and are dominated by volcanic and epiclastic units that have experienced greenschist facies metamorphism. Saprolitic weathering is present in the near-surface portions of the deposit and is locally covered by Cretaceous-aged Coastal Plain sediments. The gold mineralization at the Haile mine is hosted within silicified meta-sediments containing fine-grained disseminated pyrite and pyrrhotite and is a replacement type-epithermal deposit. Re-Os ages from molybdenite associated with the mineralization indicate that the deposit formed shortly after major, arc-related volcanic activity. Haile currently has a measured and indicated resource of 4.03 million ounces at an average grade of 1.77 g/t Au with an additional inferred resource of 801,000 ounces at an average grade of 1.24 g/t Au. Included in the resource is a reserve of 2.02 million ounces of gold at an average grade of 2.06 g/t. Mine construction began in May 2015, and gold production is expected by the end of 2016. The construction cost is expected to be US$380 million. Ore will be extracted from eight open pits with mill extraction and the current mine life is 14 years.