The Haile Gold Mine was the largest gold producer east of the Mississippi River prior to 1942. It is currently the only producing gold mine in the Southeastern United States.
Current development involves the mining and heap leaching of some 1000 TPD. Carbon is employed as a recovery medium. Due to its clayey nature and excessive fines in the oxide ore, agglomeration using Portland cement is required prior to leaching. The ore ranges in screen size from two inches to -200 mesh.
The ore consists of micron free gold and auriferous pyrite/limonite in a quartz sericite gangue. Minor associated minerals include molybdenite, arsenopyrite, pyrrhotite, copper sulfides, sphalerite, rutile, and topaz (Spence and others). The gold bearing zones vary from massive pyrite sulfide lenses to highly siliceous lenses or streaks with more or less pyrite.
The highly weathered nature of the ore in addition to its rather high clay content enabled easy mining in the oxide zone, but mandated agglomeration of the ore for successful heap leaching.
Undersize from the crusher is conveyed back to the screen feed conveyor, joins the screen undersize, and drops into a Davis Pug Mill. Originally, the cyanide solution was added to the ore in the pug mill to get it into the system as soon as possible. It is currently being added to the ore at the agglomerator. Upon leaving the pug mill the ore is conveyed to the agglomerator via a 24 inch (609.6mm) conveyor that passes over a Ramsey belt scale.
Agglomerated ore is discharged from the agglomerator onto a 24 inch (609.6mm) conveyor belt that is made up of several segments to allow lengthening or shortening as required. A Van Meter type automatic sampler is incorporated in this conveyor system to provide automatic sampling of the ore being leached. The belt conveyors discharge onto a short stacking conveyor which builds a small surge pile. Another rubber tired loader transfers the ore from this surge pile a short distance to the main heap building stacker conveyor.
Construction of the heaps with the stacker conveyor has provided good to excellent percolation of the cyanide solution through the heap and with the agglomeration of the ore has enabled good recoveries of the gold and silver in relatively short time. Average leach cycles on the oxide ore thus far have averaged 4 to 6 weeks. Recoveries are estimated at 90+ percent.
