Ore Placement: Low-grade ore (often containing less than 0.8% copper) is hauled directly from the open pit and deposited into large "dumps" or "stockpiles," sometimes reaching hundreds of meters in height.
Irrigation: A "raffinate" solution (typically weak sulfuric acid, H2SO4) is sprayed or dripped over the top of the dump.
Collection: The "Pregnant Leach Solution" (PLS)—now rich in copper—seeps to the bottom of the dump, where it is captured by a liner system and pumped to a Solvent Extraction (SX) and Electrowinning (EW) plant to produce 99.9% pure copper cathodes.
| Feature |
Dump Leaching |
Heap Leaching |
| Ore Grade |
Lowest (often "waste" grade) |
Low to Medium |
| Preparation |
None (Run-of-Mine) |
Crushed and sometimes Agglomerated |
| Recovery Rate |
30% – 60% (very slow) |
70% – 90% (faster) |
| Cost |
Minimal (lowest OpEx) |
Moderate (due to crushing/handling) |
Process Flow:
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