Noise Control in Mining Operations
Noise is a significant occupational hazard in mining and processing plants. Crushing, screening, conveying and grinding equipment can produce noise levels exceeding 100 dB(A) — well above the 85 dB(A) exposure limit enforced by most regulatory agencies. Effective noise control protects workers and ensures regulatory compliance.
Understanding Noise Regulations
Key Exposure Limits:
- OSHA (USA): 90 dB(A) TWA for 8 hours, 85 dB(A) action level
- EU Directive: 87 dB(A) peak limit, 80 dB(A) lower action level
- Australia: 85 dB(A) LAeq,8h standard exposure
- South Africa: 85 dB(A) occupational exposure limit
Noise Sources in Crushing Plants
Crushers: 95-110 dB(A) at operator position
- Material impact on crushing surfaces
- Drive system (motor, belts, gears)
- Structural vibration and resonance
Screens: 90-105 dB(A)
- Vibration mechanism
- Material impact on screen media
- Structure-borne noise transmission
Conveyors and Feeders: 85-100 dB(A)
- Material impact at transfer points
- Belt friction and idler rotation
- Motor and drive noise
Noise Control in Mining Plants
Engineering Noise Control Solutions
1. Enclosures and Barriers:
- Acoustic enclosures around crushers (reduces noise by 10-25 dB)
- Sound-absorbing panels on control rooms and operator cabins
- Acoustic curtains for temporary high-noise areas
2. Damping and Isolation:
- Rubber isolation mounts for crushers and screens
- Damping compounds on structural panels
- Flexible connectors on conveyors and pipework
3. Low-Noise Equipment:
- Rubber screen media reduces noise by 5-10 dB vs steel
- Rubber-lined chutes and transfer points
- Synchronous belt drives vs V-belts for noise reduction
Noise Monitoring Program
Establish a systematic noise monitoring program:
- Initial baseline survey — map noise levels across the plant
- Personal dosimetry for operators in high-noise areas
- Annual re-surveys and when plant changes occur
- Post-control effectiveness verification
Hearing Protection Program
While engineering controls reduce noise at source, hearing protection remains essential:
- Earplugs (NRR 20-33 dB) — suitable for most areas
- Earmuffs (NRR 22-30 dB) — easier to fit consistently
- Dual protection (plugs + muffs) for very high noise areas (>105 dB)
- Fit-testing to ensure adequate protection
WSHT incorporates noise control measures in our plant designs and can provide noise assessments and engineering solutions for existing operations.
