Gold Ore Crushing Circuit Design Fundamentals
Gold ore crushing circuit design must consider the unique characteristics of gold deposits — particularly the presence of coarse, gravity-recoverable gold and the requirement to avoid over-crushing that destroys valuable gold particles. This guide covers the key design considerations for efficient gold ore crushing.
Primary Crushing — Jaw vs Gyratory
The primary crusher is the first stage of size reduction, accepting run-of-mine (ROM) ore directly from the mine. For gold ore, key considerations include:
Feed Characteristics:
- Maximum lump size (typically 600-1200mm depending on blasting)
- Clay or soil contamination in weathered ores
- Coarse gold particles that can cause bridging
- Potential for hard pieces in fresh rock zones
Jaw Crusher Selection:
- Most common choice for gold mine primary crushing
- Excellent for handling variable feed conditions
- Easy to clear blockages and uncrushables
- Typical capacities: 200-2000 tph
Secondary and Tertiary Crushing
Secondary crushing typically uses cone crushers in open or closed circuit with screens. For gold ore, the goal is to produce a consistent feed size for grinding while avoiding excessive fines.
Circuit Configurations:
- Open Circuit: Simple but produces variable product size — generally not preferred for gold
- Closed Circuit with Screen: Produces consistent product size, allows recycle of oversize
- Two-Stage Closed Circuit: Secondary and tertiary crushers each in closed circuit for maximum control
Gold Ore Crushing Circuit Design
Pre-Screening and Feed Preparation
Pre-screening before grinding offers several advantages:
- Removes fine material that doesn't need grinding (increases effective grinding capacity)
- Allows separate handling of coarse gold particles
- Reduces overgrinding of gold particles
- Improves classification efficiency
Special Considerations for Gravity Gold
For gold deposits with significant gravity-recoverable gold:
- Avoid over-crushing — coarse gold is lost if ground too fine
- Consider stage crushing with intermediate gravity recovery
- Design for coarse gold retention throughout the circuit
- Use crushers that produce minimum fines (avoid impact crushers if possible)
Crushing-Classification Interface
The crushing circuit must interface properly with the grinding and classification circuit:
- Crushing product size typically 80% passing 10-20mm for ball mill feed
- Screens or hydrocyclones used for classification
- Critical to balance crushing and grinding capacities
- Cyclone feed density affects classification efficiency
WSHT provides complete gold ore crushing and grinding circuit design, with expertise in gravity gold recovery, cyanide leaching and flotation applications.
