Adequate drainage system design for heap leaching structures

Area of Science:

• Mining Engineering
• Geotechnical Engineering
• Environmental Engineering

Background:

• Heap leaching operations can experience increased acid levels, leading to operational issues.
• Elevated pore acid pressure in heaps poses a significant risk of heap-slides, endangering the mine environment.
• Effective drainage system design is critical for mitigating these risks and improving hydrometallurgical processes.

Purpose of the Study:

• To develop an optimum design for a heap leaching drainage system.
• To evaluate factors influencing acid level increases and pore acid pressure.
• To propose a method for calculating drainage layer thickness and auxiliary pipe diameters.

Main Methods:

• Determining gravelly drainage layer thickness using empirical equations.
• Calculating internal diameter for slotted polyethylene pipes, considering overburden pressure and pipe deformation.
• Applying the proposed design to a heap structure at Sarcheshmeh copper mine.

Main Results:

• An optimized drainage system design was developed for heap leaching structures.
• The design accounts for factors contributing to increased acid levels and pore pressure.
• Calculated results were compared with existing equations, validating the proposed approach.

Conclusions:

• The proposed drainage system design positively impacts mine environment and economics.
• Proper drainage design is essential for preventing heap-slides and ensuring operational stability.
• The study provides a practical approach for designing effective heap leach drainage systems.