From Extraction to 99% Pure Gold
1. Gold Mining in South Africa
South Africa gold mines are deep level mines reaching depths of over three kilometres.
2. Going Underground
Miners go underground in shaft cages and then walk or take trains to the work face. When sinking a new shaft they descend in buckets, called kibbles.
3. Safety Equipment
All miners wear hard hats, boots and carry battery lights and, when appropriate, use personal protective equipment like ear plugs, goggle and respirators.
Miners work in teams in low, narrow work places called stopes. Their first task is to ensure the stope is safe by barring down loose rocks and installing support structures. Then they begin to drill.
5. Ore Extraction
Holes are drilled in the gold-bearing reef using a pneumatic rock drill. These holes are filled with explosives and timed with igniter cord and fuses to ensure a pre-determined sequence of blasts. The area is blasted in order to free the gold-bearing rock from the face. This rock is then scraped awat from the stope into box holes, where it is drawn off into hopper, or small railway cars, hauled by locomotives.
6. Ore Transport
Ore is hoisted from the lowest underground level of the mine in skips and then transported to the gold plant by rail hopper or conveyor belts.
7. Crushing and Milling
Ore is crushed and then milled to a fine powder.
8. Leaching and Carbon-in-Pulp
Gold is leached from slurry by means of dilute cyanide solution. Carbon is used to absorb gold form the solution. This is called “carbon-in-pulp” process.
9. Gold Recovery Process
The carbon particle are screened from the pulp and chemically treated to produce a pure solution of electrowinning.
10. Smelting of Gold
The cathode sludge is dried and smelted in an electric furnace to produce gold bars of 90% purity.