Gold Heap Leaching: A Cost-Effective Solution for Low-Grade Ores

 Gold mining is constantly evolving, with new technologies helping to make production more efficient and sustainable. One of the most effective methods for processing low-grade gold ore is heap leaching (HL) — a flexible and economical solution that allows miners to extract gold at a reduced cost while maintaining scalability.

Unlike traditional gold extraction processes that require intensive milling and high operating costs, heap leaching makes use of crushed ore stacked into large heaps. These piles are then irrigated with a leaching solution (typically cyanide), which slowly dissolves the gold. The resulting pregnant solution is collected and processed further through methods such as carbon adsorption or zinc powder displacement to recover pure gold.

Why Heap Leaching?

• Low production cost – Ideal for smaller mines and low-grade ores that would otherwise be uneconomical.

• Fast setup – Production can begin quickly, without the need for large-scale infrastructure.

• Flexibility – Heap leaching operations can handle tens of thousands of tons, making it adaptable to both small and large projects.

• Sustainability – Recycling of leaching solution reduces waste and improves environmental performance.

How It Works:

1. Ore preparation – The ore is crushed (30–50mm) and either directly stacked or pelletized into larger lumps.

2. Heap construction – The leaching site is carefully prepared with geomembrane lining and drainage to prevent leakage and ensure solution collection.

3. Leaching process – Cyanide solution is sprayed or infiltrated through the heap, dissolving gold over multiple cycles.

4. Gold recovery – The pregnant solution is treated with activated carbon or zinc powder to extract gold, while barren solution is recycled back into the heap.

This method has proven especially valuable for small mines and low-grade deposits that are unsuitable for conventional processing. By lowering operational costs and improving adaptability, heap leaching continues to play a vital role in the modern gold industry.

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