Business Processes Operation phase
Mining
The ores are mined after making an optimal mining plan for the target copper deposit. Open pit mining, by which ores are extracted from stepped walls near the earth surface, is the mainstream method for large-scale mines currently in operation.
Ore processing
The extracted copper ores are processed in different ways depending on its types (copper sulfide ores or oxide ores).
Copper sulfide ores
Before processing
Copper sulfide ores
Copper grade: 1% or less
Processing method
Crushing and Grinding
The extracted copper ores (diameter of several tens centimeters) are crushed and ground to several tens of microns.
Flotation
Utilizing the wettability of mineral surfaces depending on given conditions, the target ores are separated into a copper-rich portion and another portion. The ground ore/water slurry from the grinding circuit is conditioned with some reagents and air blow, then agitated for producing bubbles. Using the principle of attaching sulfide ores to the bubbles, copper ores are concentrated to 20-40% Cu through the flotation process and then transported to smelters.
After processing
Oxide ores
Before processing
Oxide ores
Copper grade: 1% or less
Processing method
Leaching
Copper oxide ores normally exhibit high dissolution by weak acidic solution. Utilizing this property, these ores are stacked on a pad and sprayed weak acidic solution over the pad, and then copper is leached for a few months.
SX-EW (Solvent Extraction-Electrowinning)
After extracting copper ions from copper-bearing acid solution mixing with organic solvent, then the pure copper (99.99% Cu) is recovered by electrowinning.
After processing
Refined copper
Purity 99.99%