Key Considerations for Gold Extraction through Crushing and Heap Leaching in Gold Mines

Gold extraction through crushing and heap leaching is a widely - adopted method in the gold mining industry. To ensure high - efficiency extraction, environmental compliance, and operational safety, several crucial aspects need to be taken into account.

1. Analysis of Ore Properties

Mineral Composition

A comprehensive understanding of the gold content and associated minerals in the ore is essential. This analysis helps determine whether the heap leaching method is suitable. For example, if the ore contains certain refractory minerals, additional pretreatment may be required.

Particle Size Distribution

The particle size of the crushed ore must be uniform. An overly large or small particle size can significantly impact the leaching efficiency. Large particles may prevent the leaching solution from effectively contacting the gold - bearing minerals, while small particles can lead to the formation of fines, which impede solution penetration.

2. Crushing Process

Crushing Equipment

Selecting the appropriate crushing equipment is crucial. Jaw crushers and cone crushers are commonly used. These crushers can effectively reduce the ore to the required particle size.

Particle Size Control

Typically, the particle size of the crushed ore is controlled within 10 - 30 mm. A particle size larger than this range may lower the leaching rate, while a smaller size may generate excessive fines, hampering the leaching process.

3. Preparation of Heap Leaching Sites

Site Selection

Choose a flat and impermeable site to prevent solution leakage, which could cause environmental pollution.

Impermeability Treatment

Lay an impermeable membrane to prevent leaching solution from seeping into the ground, protecting groundwater resources.

4. Selection and Application of Leaching Agents

Leaching Agents

Sodium cyanide solution is a commonly used leaching agent. The concentration of sodium cyanide should be strictly controlled within 0.05% - 0.1%. An overly high concentration increases costs, while an insufficient concentration reduces the leaching rate.

pH Value Control

Maintain the pH value of the leaching solution between 10 and 11. This helps prevent the decomposition of cyanide, ensuring the effectiveness of the leaching process.

5. Heap Leaching Operations

Heap Height Control

The height of the heap is usually maintained between 3 and 6 meters. An overly high heap can impede solution penetration, while a low heap reduces production efficiency.

Spraying Intensity

The spraying intensity should be controlled at 5 - 10 L/m²·h. Excessive spraying leads to solution loss, while insufficient spraying affects the leaching efficiency.

6. Management of Leaching Solutions

Leaching Solution Collection

Ensure the effective collection of leaching solutions to avoid losses and environmental pollution.

Leaching Solution Recycling

Recycling leaching solutions can improve gold recovery rates and reduce reagent consumption.

7. Environmental Protection

Wastewater Treatment

Leaching solutions must be treated before discharge to avoid environmental pollution.

Tailings Disposal

Properly handle the tailings after leaching to prevent secondary pollution.

8. Safety Management

Cyanide Management

Cyanide is highly toxic. Implement strict management measures to prevent leakage and poisoning incidents.

Personnel Protection

Operators should wear protective equipment and receive regular training to ensure safe operation.

9. Equipment Maintenance

Regular Inspection

Regularly inspect crushing, spraying, and other equipment to ensure their normal operation.

Timely Repair

Repair any malfunctioning equipment promptly to avoid production disruptions.

10. Cost Control

Reagent Cost

Optimize the use of reagents to reduce costs.

Energy Consumption Control

Optimize the crushing and spraying processes to minimize energy consumption.

In conclusion, gold extraction through crushing and heap leaching requires a comprehensive consideration of ore properties, process parameters, environmental protection, and safety management. By doing so, gold recovery rates can be improved, while ensuring sustainable development in the gold mining industry.