Definition and Scope
Mobile crushing plants are self-contained, transportable installations designed for on-site size reduction of rock, concrete, demolition waste, and recycling materials. They integrate primary or secondary crushing equipment with screening units in a modular frame structure, enabling deployment across multiple locations without permanent infrastructure. Typical feed sizes range from 0–1,500 mm depending on crusher type; product outputs span 0–100 mm in graduated fractions.
Machine Types and Configurations
Plants are classified by primary crusher type: jaw crushers (compression-based, suited for hard stone and concrete; throughput 50–500 tph), impact crushers (impact-based, for softer to medium materials; 40–400 tph), and cone crushers (secondary stage, 100–600 tph). Configurations include single-stage units for primary reduction only, or multi-stage plants combining crusher + vibrating screens for classified product streams. Typical plant weight ranges 25–150 t for jaw-based units, 30–200 t for impact systems.
Drive Systems and Power Requirements
Mobile plants employ diesel engines (most common), electric motors with generator sets, or hybrid configurations. Diesel units typically consume 15–45 L/h depending on load and crushing intensity. Electric-driven plants require 90–250 kW from external grid or on-board generator (30–150 kVA). Hydraulic systems operate at 210–280 bar for jaw actuation and screen vibration control.
Screening and Product Classification
Integrated vibrating screens (dual or triple-deck) separate material into 2–4 product fractions. Screen aperture sizes (typically 4–80 mm) determine gradation. Fines handling systems manage 0–4 mm material through separate conveyors or discharge chutes. Typical screening capacity matches crushing output to prevent bottlenecks (40–300 tph throughput).
Mobility and Transport
Units mount on wheeled chassis (2–3 axles, 18–40 t axle load per local regulations) or crawler undercarriages for soft-ground deployment. Telescopic conveyors extend 6–12 m for product stockpile formation. Setup time averages 30–90 minutes; tear-down 20–40 minutes. Transport height restrictions typically 4.0–4.5 m require lowered crusher head or collapsible hoppers.
Operational Efficiency and Dust Control
Production rates depend on material type, hardness, and gradation targets: hard stone 80–150 tph, recycled concrete 60–120 tph, soft materials 100–250 tph. Dust suppression employs water spray systems (50–200 L/h mist application) or complete enclosure with bag filters (efficiency >99.5% for particles >5 μm). Noise emissions typically 78–88 dB(A) at 1 m distance, managed via engine shrouds and vibration dampening.
Fuel Consumption and Operating Costs
Specific fuel consumption ranges 0.5–1.2 L per tonne of material crushed, depending on material hardness and utilization rate. Maintenance intervals occur every 500–1,500 operating hours. Jaw lining costs represent 2–8% of total operating cost; screen mesh replacement every 200–1,000 running hours. Hourly operating costs (fuel, wear parts, labor) range 80–250 EUR/h depending on plant size and material.
Regulatory and Environmental Compliance
Plants must comply with EU Directive 2006/42/EC (Machinery Directive) for electrical and mechanical safety. Air emissions follow local dust ordinances (Germany: TA Luft). Water discharge (from dust control) requires settling tanks or closed-loop recycling systems. Noise limits enforce 75–82 dB(A) in sensitive zones during operating hours. Weighing systems (optional) must meet OIML R 50 for certified tonnage documentation.