Respirable Dust Measurement & Pneumoconiosis Prevention in Mines – DGMS Guidelines & 25 MCQs

🧾 DETAILED NOTES

1️⃣ Introduction

Respirable dust is one of the most serious health hazards in mining. Prolonged exposure leads to Pneumoconiosis, including Coal Workers’ Pneumoconiosis (CWP / Black Lung), Silicosis, and Mixed-dust fibrosis. DGMS mandates strict monitoring, measurement, and control of airborne respirable dust in mines.

2️⃣ Sources of Respirable Dust

Major sources include coal cutting by continuous miners, drilling & blasting, loading & unloading, crushing & screening, haul roads, belt conveyor transfer points, secondary blasting, and dumping & dozing operations.

3️⃣ Dust Measurement Methods (DGMS Approved)

Gravimetric Dust Sampler (GDS): Measures Total Suspended Particulate (TSP) for environmental/surface dust.
Personal Dust Sampler (PDS): Worn by workers for 8-hour sampling, measures respirable fraction (<10 micron).
Real-time Dust Monitors: Provide digital readout for continuous monitoring.
Respirable Dust Sampler with Cyclone Head: Separates dust by aerodynamic size.

4️⃣ Permissible Dust Levels (DGMS / ILO Guidelines)

Respirable dust in coal mines is typically below 3 mg/m³. If free silica content is >5%, the limit becomes stricter. Silica content is tested using XRD analysis.

5️⃣ Dust Control Measures

Water Sprays: Used on shearers, drills, and loading points; mist/fog nozzles reduce airborne dust.
Wet Drilling: Essential for silica-prone strata.
Ventilation Control: Adequate air quantity, proper face ventilation, and auxiliary fans.
Chemical Dust Suppressants: Hygroscopic agents and binding chemicals for haul roads.
Enclosures & Isolation: Enclosed cabins for operators, dust curtains at faces.
Housekeeping: Regular cleaning, belt cleaning, road sweeping.

6️⃣ Personal Protective Equipment (PPE)

IS-approved dust respirators (N-95 or higher filtration) and face masks are compulsory in high-dust zones, especially during drilling/blasting.

7️⃣ Health Surveillance

Periodic medical exams under Mines Rules 1955, including X-Ray (ILO classified) and Spirometry (lung function tests) for early identification of suspected cases. Records kept for life + 10 years.

8️⃣ DGMS Statutory Provisions

Applicable regulations include CMR 2017 – Reg. 123, 124, 125 (Dust/Ventilation); MMR 1961 – Reg. 124, 125; DGMS Technical Circulars on Dust Sampling; and Mines Act Section 23 & 25 (Health). Strict record-keeping is required.

⚡ QUICK ONE-LINERS (Revision)

Respirable dust <10 microns causes pneumoconiosis.
Silica dust is more dangerous than coal dust.
Wet drilling significantly reduces dust.
DGMS requires regular dust sampling.
Dust sampling done using Personal Dust Sampler.
Water sprays are primary engineering controls.
N-95 respirators must be used in dusty areas.
X-ray is mandatory for diagnosing pneumoconiosis.
Poor ventilation increases dust accumulation.
Haul roads must be regularly water-sprinkled.

🧠 DESCRIPTIVE MODEL Q&A

Q. Explain respirable dust measurement and the control measures required to prevent pneumoconiosis in mines.

Answer:
Respirable dust measurement is carried out using Personal Dust Samplers, gravimetric samplers, and real-time monitors to determine airborne particles below 10 microns. DGMS prescribes dust sampling frequency, silica content analysis, and permissible exposure limits. To prevent pneumoconiosis, mines must ensure wet drilling, adequate ventilation, water spraying, chemical suppressants, housekeeping, and use of dust respirators. Periodic medical examination, X-ray, and lung function tests are essential for early diagnosis. Proper monitoring, engineering controls, and health surveillance collectively minimize the risk of pneumoconiosis.

🧮 25 MCQs (Dynamic Answers A–E)

Q1. Respirable dust size is:

Solution: Respirable dust refers to particles small enough to penetrate deep into the lungs, typically less than 10 micrometers in aerodynamic diameter.

Q2. Pneumoconiosis is caused by:

Solution: Pneumoconiosis is a group of interstitial lung diseases caused by the inhalation of mineral dust, leading to fibrosis.

Q3. Dust sampling in mines uses:

Solution: Personal Dust Samplers (PDS) are worn by workers to measure their actual exposure to respirable dust.

Q4. Silica content is measured by:

Solution: X-ray Diffraction (XRD) analysis is used to determine the crystalline silica content in dust samples.

Q5. Wet drilling helps to:

Solution: Wet drilling introduces water to the drill bit, suppressing dust at the source and preventing it from becoming airborne.

Q6. N-95 masks provide protection from:

Solution: N-95 respirators are designed to filter out at least 95% of airborne particles, including respirable dust.

Q7. DGMS requires dust surveys:

Solution: Regular dust surveys are mandated to continuously monitor exposure levels and ensure controls are effective.

Q8. Main cause of pneumoconiosis:

Solution: Pneumoconiosis is the general term for lung diseases caused by the inhalation of mineral dusts.

Q9. Water spraying reduces:

Solution: Water sprays cause dust particles to coalesce and fall out of the air, reducing airborne concentrations.

Q10. Free silica is dangerous because:

Solution: Crystalline silica (free silica) is a known cause of silicosis, a severe and often progressive lung disease.

Q11. Dust curtains used at:

Solution: Dust curtains are used at the mine face or other active areas to confine dust to a smaller zone, allowing ventilation to remove it more effectively.

Q12. Haul roads controlled by:

Solution: Regular water sprinkling or application of chemical suppressants on haul roads is vital to prevent dust generation from vehicle movement.

Q13. Personal dust sampler worn for:

Solution: Personal dust samplers are typically worn for the full shift (8 hours) to capture a representative sample of a worker's exposure.

Q14. Dust diseases classified by:

Solution: The International Labour Organization (ILO) provides a classification system for chest X-rays used in diagnosing pneumoconiosis.

Q15. Excessive dust leads to:

Solution: Excessive inhalation of respirable dust leads to debilitating lung diseases.

Q16. Respirable dust contains:

Solution: Respirable dust is defined by its small size (fine particles) that bypass the body's natural filters.

Q17. Dust suppression chemicals:

Solution: Chemical suppressants (like hygroscopic salts) work by binding dust particles to the ground or making them heavier.

Q18. PDS measures:

Solution: The Personal Dust Sampler (PDS) measures the respirable dust level to which an individual worker is exposed.

Q19. Silicosis affects:

Solution: Silicosis is a lung disease resulting from the inhalation of crystalline silica dust.

Q20. Most dust is generated at:

Solution: The highest generation points are where the rock or coal is broken (face, drilling, crushing).

Q21. Dust inhalation risk increases with:

Solution: Poor ventilation allows dust to accumulate and remain suspended in the working atmosphere.

Q22. Dust sampling report stored in:

Solution: All dust sampling results must be recorded in the statutory Dust Survey Register.

Q23. Silica dust mainly found in:

Solution: Metalliferous mines (especially those cutting quartz or hard rock) have a higher risk of crystalline silica exposure than coal mines.

Q24. Real-time monitors give:

Solution: Real-time monitors provide an immediate digital measurement of the current dust concentration.

Q25. Pneumoconiosis is:

Solution: With proper engineering, administrative, and PPE controls, pneumoconiosis is entirely preventable.

🔗 INTERNAL LINKS

Related Topic	Read More On...
Occupational Health	Occupational Health Surveillance Guide
Medical Forms	Medical Examination Formats (Form O & Others)
Ventilation	Mine Ventilation System & Air Quality Control
Mines Rules	Medical Re-examination (Rule 29K)

🫁 Prevent Dust Diseases – Learn DGMS Dust Control Standards!

Get 100+ mining safety blogs & MCQs at Online Mining Exam – India’s 1st Online Mining Academy.

DGMS Dust Control & Health Safety Notes
25 MCQs with Answers
Real Case Studies & Circular References

🌐 www.onlineminingexam.com
📞 9971114020

Download Dust Control Notes & Practice 25 MCQs Now!

Online Mining Exam