1. Material Characteristics

• Hardness Variation: Mohs hardness 3-5, design for hardest conditions
• Moisture Impact: Up to 8-12% in wet seasons, require anti-clogging design
• Dust Generation: High CaCO₃ content (>95%) requires enhanced dust collection

2. Process Design Essentials

Crushing Stages Selection

Two-Stage: -30% capex | Poor particle shape (>15% flaky)
Three-Stage: Standard | Good shape (<8% flaky)
Four-Stage: Premium | Cubic shape (<5% flaky)

Flexibility: Allow space for future tertiary crusher addition

Key Equipment

• Primary: Deep-cavity jaw crusher (1:8 reduction ratio)
• Secondary/Finishing: Impact crusher for better shape, cone crusher for lower wear cost
• Critical: Crusher speed control (38-42 m/s optimal)

Screening System

• Screen Type: Polyurethane decks last 3-5× longer despite 40% higher initial cost
• Anti-Blinding: Essential due to marble dust adhesion
• Efficiency: Multi-deck screens achieve 85-92%

3. Quality Control Points

• Particle Shape: Target <10% flaky for premium aggregate
• Fines Control: 10-15% in manufactured sand (MB value <1.4)
• Dust Emission: Bag filter efficiency >99.5%, emission <20 mg/m³

4. Environmental & Safety

Dust Control System

Three-Level Approach:
1. Source: Enclosure + high-pressure spray (>4MPa)
2. Process: Covered conveyors + extraction points
3. Treatment: Bag filters + 15m stack

Noise Management

• Equipment enclosures: -15 to -20dB
• Boundary standards: Day <65dB, Night <55dB

Water Management

• 95% water recycling rate
• Sludge dewatering >60% solids

5. Automation & Energy Saving

• Control Levels: PLC + optional MES/cloud platform
• Key Monitoring: Crusher current/temperature/vibration, energy consumption
• Energy Optimization: VFDs on feeders/conveyors (-15 to 25%), IE3+ motors (+3-5% efficiency)

6. Maintenance & Accessibility

• Clearance: 1.5× equipment width around crushers
• Lifting: Dedicated hoists for each major machine
• Wear Parts: Liner change target <8 hours

7. Investment & Operations

Phased Implementation

Phase 1 (Years 1-2): 60% investment - Base capacity
Phase 2 (Years 3-4): 25% investment - Shaping/sand making
Phase 3 (Year 5+): 15% investment - Value-added products

Operational Targets

• Power: 1.0-1.3 kWh/ton
• Wear Parts: $0.7-1.1/ton
• Labor: 3-4 operators per shift (300tph)

8. Common Design Pitfalls

1. Over-Crushing: Excessive fines increase energy 30-50%
2. Undersized Screening: Causes >150% circulating load
3. Conveyor Bottlenecks: Restricts overall capacity
4. Dust System Undersizing: Actual airflow = 1.2-1.5× theoretical

9. Design Checklist

• Complete material test reports
• Reasonable crushing stage ratios (Primary 1:6-8, Secondary 1:4-6)
• Circulating load 100-120%
• Backup for critical units (feeders/screens)
• Meets local environmental standards
• Adequate maintenance access
• Remote diagnostics capability
• Energy monitoring system