THE RIDGEWAY AND HAILE GOLD DEPOSITS: SIMILARITIES AND DIFFERENCES IN THEIR STYLES OF GOLD MINERALIZATION AND GEOLOGIC EVOLUTION WITHIN THE CAROLINA TERRANE, SOUTH CAROLINA, USA

The Ridgeway Gold Mine, SC, operated from 1988 to 1999, pouring 1.45 million ounces (Moz) of gold from ore averaging 0.032 opt Au. OceanaGold Corporation is reopening the historic Haile Gold Mine (Haile), located 46km northeast of Ridgeway in Lancaster Co, SC, and this company will pour ~2Moz from ore averaging 0.06 opt Au over 14 yrs.

Both Ridgeway and Haile are epithermal gold deposits, hosted by metasiltstone/metagreywacke of the Richtex fm, and stratigraphically underlain by Persimmon Fork fm felsic metavolcanics. Both deposits contain an alteration/mineralization assemblage that includes silicification, potassic alteration, brecciation, accessory molybdenite, and micron to submicron-sized gold associated with fine grained, mostly disseminated pyrite. Both deposits are greenschist grade; contain a pervasive slaty cleavage associated with folding of bedding and mineralized zones, and display evidence of still younger fold-related deformation. Alkaline dikes ~311ma crosscut the Haile, as do similar dikes and other, basaltic dikes at Ridgeway. Mesozoic diabase and lesser felsic dikes cut both deposits.

Ridgeway preserves an east-west striking, steeply dipping and south-younging stratigraphy that includes a rift-related basalt sequence located between the Persimmon Fork and Richtex fms. Foliations at Ridgeway are moderate north dipping except in the North Pit, where Alleghanian (?) folding/faulting has warped the deposit into a synform. At Haile, the host Richtex metasediments lie structurally beneath the older felsic metavolcanics (no rift basalts are present), young downwards, and represent an overturned, shallow northeast plunging fold that predates the crosscutting slaty cleavage/fold event. Variations in the alteration assemblages, stratigraphy, and geologic evolution of these two deposits are discussed in this presentation.