Exposure to dust in stone grinding mills is a significant occupational health hazard, primarily due to the inhalation of crystalline silica dust, which can lead to serious respiratory diseases like silicosis, chronic obstructive pulmonary disease (COPD), and even lung cancer. Below are key aspects of dust exposure in stone grinding mills:
1. Sources of Dust in Stone Grinding Mills
– Grinding & Crushing: Stone milling generates fine particulate matter (PM10 and PM2.5) from the abrasion of stones.
– Material Handling: Loading, unloading, and transporting raw materials (e.g., grains, spices, or minerals) can release dust.
– Maintenance Activities: Cleaning and repairing equipment can disturb settled dust.
2. Health Risks
– Silicosis (from silica in stone dust) – irreversible lung scarring.
– Lung Cancer & COPD – long-term exposure increases risk.
– Asthma & Bronchitis – irritation from fine particles.
– Eye & Skin Irritation – contact with abrasive dust.
3. Regulatory Exposure Limits
– OSHA Permissible Exposure Limit (PEL):
– *Respirable crystalline silica*: 50 µg/m³ (8-hour TWA).
– *Total dust*: 15 mg/m³ (general industry).
– NIOSH Recommended Exposure Limit (REL):
– *Silica dust*: 25 µg/m³ (8-hour TWA).
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4. Control Measures
# (A) Engineering Controls
– Local Exhaust Ventilation (LEV): Install hoods near grinding points to capture dust at the source.
– Wet Methods: Use water suppression to reduce airborne dust.
– Enclosed Systems: Automate processes to minimize worker contact.
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# (B) Administrative Controls
– Work Rotation: Reduce individual exposure time.
– Housekeeping: Regular wet cleaning to prevent dust accumulation.
– Training: Educate workers on hazards and PPE use.
# (C) Personal Protective Equipment (PPE)
– N95 Respirators (or higher, like P100 for silica).
– Goggles & Face Shields for eye protection.
– Coveralls & Gloves to prevent skin contact.
5. Monitoring & Medical Surveillance
– Conduct regular air sampling for silica and respirable dust levels.
– Provide health check-ups for workers (che