Datasheet: Gold Ore Crushing Equipment – A Comprehensive Technical Overview

Document Control: DS-GOC-001
Revision: 2.1
Date: October 26, 2023
Classification: Public Technical Specification

1.0 Executive Summary

Gold ore processing is a capital-intensive and technically demanding operation, where the comminution (crushing and grinding) circuit typically accounts for the single largest share of both capital expenditure (CAPEX) and operational expenditure (OPEX). The primary objective of the crushing stage is to reduce run-of-mine (ROM) ore to a size suitable for downstream milling, while simultaneously liberating gold-bearing minerals from the gangue matrix. The selection and configuration of crushing equipment are therefore critical determinants of overall plant efficiency, recovery rates, and profitability. This datasheet provides a detailed, objective analysis of the core equipment used in gold ore crushing circuits, covering operating principles, key specifications, application suitability, and technological advancements.

2.0 Introduction to Gold Ore Comminution

Gold ores vary significantly in mineralogy (e.g., free-milling vs. refractory), hardness (as measured by Bond Work Index, Unconfined Compressive Strength), abrasiveness, moisture content, and clay presence. These characteristics dictate the crushing strategy. A typical three-stage crushing circuit for hard rock gold ores consists of:

1. Primary Crushing: Coarse reduction of ROM ore (up to 1500mm) to 150-250mm.
2. Secondary Crushing: Further reduction to 40-80mm.
3. Tertiary Crushing: Final size reduction to produce a mill feed of 6-20mm (P80).

The trend towards pre-concentration methods like sensor-based ore sorting has also influenced crusher placement and duty.

3.0 Primary Crushing Equipment

Primary crushers handle the largest feed size and must possess high capacity, robustness, and reliability.

3.1 Gyratory Crushers

• Operating Principle: A long spindle with a hardened steel mantle gyrates within a concave bowl liner. Crushing action is a combination of impact, attrition, and compression.
• Key Specifications:
  • Feed Opening: 500mm to 1500mm.
  • Capacity: Up to 10,000 t/h+.
  • Reduction Ratio: Typically 5:1 to 8:1.
  • Power Draw: Very high (400 kW to over 1000 kW).
• Advantages for Gold Ore: Highest capacity for large-scale operations; continuous action leading to high throughput; handles slabby material well; generally lower maintenance cost per ton than jaw crushers in high-tonnage applications.
• Disadvantages: High capital cost; complex installation requiring deep foundation; sensitive to feed segregation; not easily relocated.
• Leading OEMs: Metso Outotec (Superior™), FLSmidth (TS Gyratory Crushers), ThyssenKrupp.

3.2 Jaw Crushers

• Operating Principle: A fixed jaw and a reciprocating moving jaw create compression as material is nipped and crushed.
• Key Types: Single-toggle (simpler design, higher capacity) and Double-toggle (more robust for extremely abrasive material).
• Key Specifications:
  • Feed Opening: 800mm x 600mm up to 2000mm x 1500mm.
  • Capacity: Up to 1,500 t/h.
  • Reduction Ratio: Lower than gyratory (~4:1 to 6:1).
  • Power Draw: High (90 kW to over 600 kW).
• Advantages for Gold Ore: Lower initial cost; simpler foundation requirements; excellent for abrasive ore; effective at handling high clay content with less risk of packing; suitable for underground installations.
• Disadvantages: Lower capacity than comparable gyratories; cyclic loading can cause fatigue; higher wear part consumption in some abrasive ores.
• Leading OEMs: Metso Outotec (Nordberg® C Series), Sandvik Mining & Rock Solutions.

4.0 Secondary & Tertiary Crushing Equipment

These stages focus on producing consistent product size for optimal grinding mill feed.

4.1 Cone Crushers

• Operating Principle: Similar to gyratory but with a shorter spindle supported at both top and bottom. The crushing chamber is defined by the mantle and concave liners.
• Key Types:
  • Standard/Coarse Head: For secondary crushing.
  • Short Head/Fine Head: For tertiary/quaternary crushing.
  • HPGR-fed Cone Crushers (“Tertiary Pebble” duty): Specialized for handling HPGR product.
• Key Specifications:
  • Max Feed Size: ~250mm down to ~80mm.
  • Product P80 Range: Can be as fine as <10mm in closed circuit.
  • Capacity: Up to ~2000 t/h.
  • Advanced Features: Hydroset system for CSS adjustment under load; ASRi™/Intelligent Control systems for automated optimization.
• Advantages for Gold Ore**: Highly efficient particle-on-particle interparticle crushing minimizes liner wear; produces well-shaped product with fewer fines generation compared to impactors; highly controllable product size distribution crucial for downstream recovery processes like gravity concentration or leaching heap construction.

4.2 High-Pressure Grinding Rolls (HPGR)

This technology has transitioned from alternative to mainstream in gold circuits.

• Operating Principle: Two counter-rotating rolls compress a bed of material at extremely high pressure (>50 MPa up to >300 MPa), causing micro-fractures and particle weakening (“pre-weakening”).
  **Key Specifications:
  Roll Diameter/Width: Upwards of 2.4m x 1.6m.
  Operating Pressure: Configurable based on ore competency.
  Specific Throughput: m³/h per meter roll width.
  Advantages for Gold Ore: Significant energy savings (~20-30%) vs SAG/Ball milling when used as tertiary/quaternary crusher or in place of primary ball milling (“HPGR-Stirred Mill” circuit); generates micro-cracks improving leach kinetics in certain oxide ores; produces more fines which can benefit heap leach operations or reduce grinding load.
  Disadvantages*: High capital cost initially but strong OPEX payback through energy savings); sensitive tramp metal damage requiring robust protection systems.

5 .0 Auxiliary & Mobile Crushing Equipment

5 .1 Impact Crushers

(Horizontal Shaft Impactors – HSI , Vertical Shaft Impactors – VSI)
– Application in Gold : More common in softer , non-abrasive oxide gold ores or as part of aggregate production from waste rock . VSI s are excellent sand makers but generate excessive fines unsuitable conventional milling circuits .
– Key Consideration : Generally higher wear costs hard , abrasive sulphide gold ores limiting their use primary comminution stages.

5 .2 Mobile & Semi-Mobile Crushing Stations

– Concept : Primary crusher(s ) mounted on tracked/wheeled frames or modular semi-mobile platforms connected via shiftable conveyors .
– Advantages : Reduced haulage distances open-pit mines lowering truck fleet costs ; flexibility mine plan changes ; faster commissioning .
– Configuration : Often utilize jaw gyratory crushers large capacity units.

6 .0 Technological Advancements & Smart Crushing

Modern gold ore crushing goes beyond mechanical hardware:

–Advanced Process Control Systems : Integrated platforms use real-time data from sensors measuring power draw , pressure , cavity level , CSS adjust machine parameters optimize throughput , product size energy efficiency automatically .

–Predictive Maintenance Analytics : Vibration analysis , lubrication monitoring wear modeling predict liner changes component failures minimizing unplanned downtime .

–Digital Twin Simulation : Plant designers operators simulate entire circuits using software like Metso Outotec’s Bruno™ FLSmidth’s ECS/ProcessExpert test scenarios optimize flowsheet before physical installation .

–Wear Part Metallurgy : Development ultra-high manganese steels composite materials ceramic-metal matrix liners dramatically extending service life abrasive gold ores reducing operating costs safety risks associated frequent changeouts .

7 .0 Selection Criteria Summary

Choosing correct equipment requires holistic analysis :

8 .0 Conclusion

The modern gold ore crushing circuit is sophisticated engineered system where equipment selection directly impacts metallurgical performance financial return investment ROI ). No single solution fits all deposits ). Trend moving towards integrated energy-efficient circuits combining robust primary gyratory/jaw crushers with highly controlled cone crushers HPGR technology all managed advanced automation controls maximize recovery minimize environmental footprint ). Continuous innovation materials science digitalization ensuring sector remains efficient sustainable meeting global demand precious metal while managing increasingly complex lower-grade deposits ).

Disclaimer This datasheet intended informational purposes only represents general technical overview specific equipment selection must involve detailed metallurgical testwork feasibility studies consultation qualified engineering professionals Actual specifications subject change manufacturer models.