Dust, Noise & Health

Long-term health hazards in mining: respirable dust and crystalline silica, coal workers' pneumoconiosis, diesel particulate matter, noise and hearing loss, whole-body vibration, and heat. Learn exposure limits, noise dose calculations, dust control methods and health surveillance.

Occupational diseases — silicosis, black lung, hearing loss — have harmed more miners than accidents. They develop slowly and are irreversible, so prevention through engineering controls and monitoring is essential.

An analogy

Dust and noise are silent thieves: each shift takes a little lung or hearing capacity, and you only notice years later.

Dust and silica

Respirable particles (< 10 µm) reach deep lungs. Crystalline silica (quartz) causes silicosis and lung cancer; coal dust causes pneumoconiosis. Limits are low: respirable silica 0.025–0.1 mg/m³ depending on jurisdiction.

Dust control

Water sprays and wet drilling, dust extraction and filters on drills and crushers, ventilation, enclosed pressurised cabins, conveyor transfer enclosures, road watering and suppressants, and respirators as last resort.

Noise

Drills, crushers, fans and mobile equipment exceed 85 dB(A). Every 3 dB doubles sound energy and halves permissible time. Controls: quieter equipment, enclosures, cabins, distance, then hearing protection. Audiometric testing detects early loss.

Diesel, vibration and heat

Diesel particulate matter (DPM) is a carcinogen — controlled by low-emission engines, filters, ventilation and electrification. Whole-body vibration from haul roads causes spinal injury — control by road maintenance and seat suspension. Heat stress is covered in ventilation.

Formulas

• Permissible time (3 dB exchange): T = 8 / 2^((L − 85)/3)
• Noise dose: D = Σ C_i / T_i × 100 %
• 8-h TWA: L_TWA = 85 + 10 log₁₀(D/100)
• Silica exposure: C_q = respirable dust × quartz fraction

Worked example: Noise dose

Given: 4 h at 91 dB(A), 4 h at 85 dB(A)

Find: Dose and TWA.

• T(91) = 2 h, T(85) = 8 h
• D = 4/2 + 4/8 = 2.5 = 250 %
• TWA = 85 + 10 log 2.5 = 89 dB(A)

Answer: 250 % dose — hearing protection and engineering controls needed

Worked example: Silica exposure

Given: Respirable dust 1.5 mg/m³ with 8 % quartz; Limit 0.05 mg/m³

Find: Silica exposure and ratio.

• C_q = 1.5 × 0.08 = 0.12 mg/m³
• Ratio = 0.12/0.05 = 2.4

Answer: 2.4× the limit — must cut dust by ≥ 58 %

Common mistakes

• Wrong: Relying on respirators and earplugs first. — Right: Engineer the exposure down; PPE is last.
• Wrong: Measuring only total dust. — Right: Measure respirable fraction and quartz content.

Applications

• Exposure monitoring: Personal dust pumps and noise dosimeters.
• Engineering controls: Dust extraction and cabin filtration.
• Health surveillance: Lung function tests, X-rays, audiometry.

Key takeaways

• Silica, coal dust, DPM, noise, vibration, heat.
• T = 8/2^((L − 85)/3); D = Σ C/T.
• Engineering controls first.
• Monitor and do health surveillance.

Going further

• Real-time dust monitors: Continuous personal dust monitors (CPDM).
• Exposure modelling: Similar exposure groups and statistics.
• Electrification: Removing DPM with battery equipment.