(39) Petrography of Replacement Minerals in the Horseshoe Deposit, Haile Gold Mine, Lancaster, South Carolina

The venerable Haile Gold Mine in the Albemarle Sequence of the Carolina Slate Belt is currently in production under the Australian-based Oceana Gold Corp., although successful exploration by Canadian based Romarco Minerals... [ view full abstract ]

The venerable Haile Gold Mine in the Albemarle Sequence of the Carolina Slate Belt is currently in production under the Australian-based Oceana Gold Corp., although successful exploration by Canadian based Romarco Minerals Inc. began there in 2007. The origin of the Haile gold deposits has been the subject of much debate, and it has been variably interpreted as a syngenetic or syntectonic gold deposit. Most recently, it has been classified as a low-sulfidation disseminated gold deposit. The Haile gold deposit is composed of numerous ore bodies, and this study addresses petrographic aspects of the Horseshoe ore body, discovered in 2010 by Romarco Minerals Inc. The Horseshoe ore body is unique in that it is of higher grade than the Palomino and Mustang ore bodies, controlled at depth, and will be the only underground gold mined in the Southeastern US. Samples collected from a transect across the ore boundaries and from the relatively high grade ore itself were studied to understand the types of mineral alteration that border this deposit (i.e., seritization, chloritization, albitization), how these alteration assemblages change with proximity to the ore deposit, and to determine if the gold itself is associated with particular sulfides. Petrographic observations show potassic overprinting and seritization within the ore body, and chloritic alteration in and out of the ore zone. Magnetite and chalcopyrite were also found bordering the ore zone. These findings will inform genetic models for the Haile gold deposit and exploration efforts of other Horseshoe-type deposits.