Agnes Gold, South Africa
Commercial-scale GEOCOAT® Plant
The first commercial GEOCOAT® heap operated at the Agnes Mine near Barberton, South Africa from 2003 until the mine was shutdown in 2006 due to the owner's financial problems. At the time, the mine was owned and operated by African Pioneer Mining, a subsidiary of Metallon Corporation. The Agnes Mine processed a sulfidic-refractory gold ore from an underground mine, and produced about 25,000 oz/year gold. The 3-year operation of the GEOCOAT® plant proved the technology at commercial scale.
In 2009, the mine was sold to new owners; the GEOCOAT® plant could be restarted to treat highly refractory concentrates planned to be produced by exploiting the Princeton orebody.
Agnes Mine
Overview of Agnes GEOCOAT® Operation
GEOCOAT® First Gold
Heap Stacking
Stacker
The general design criteria for the GEOCOAT® facility at the Agnes Mine include:
|
As Built Design Specifications |
|---|---|
| Stacking Rate | 34.5 tph |
| Concentrate Rate | 4.6 tph |
| Biooxidation Time | 60 days |
| Irrigation Rate | 10-30 L/m2/hr (80 m3/hr) |
| Solution Application | Wobbler® sprinklers |
| Aeration Equipment | Centrifugal fan – 3 x 360 m3/min at 2.5 kPa |
| Air Distribution | Perforated pipes in drain rock base |
| Pad Dimensions | 50 x 120 m |
| Heap Dimensions | 6 x 45 x 60m |
| Pond Capacity | 7000 m3 |
| Stacking Method | Slewing radial stacker with automated materials handling |
| Concentrate Recovery | Front-end loader, trommel, thickener |
| Gold Recovery | CIL - six 20 m3 tanks |
| Effluent Disposal | Heap bleed solution neutralized by mixing with carbonate flotation tails. Cyanide in CIL residue destroyed using excess acid bleed. |
| Performance Monitoring | Solution analysis, solids sampling, and temperature monitoring. |