Telemonitoring Systems in Underground Coal Mines – DGMS Requirements, Features & MCQs

🧾 DETAILED NOTES

1️⃣ Introduction

Dust generation during drilling in mines—both underground and opencast—poses a major health hazard, contributing to silicosis, pneumoconiosis, and other respiratory diseases among miners. To minimize dust exposure and protect worker health, DGMS mandates approved dust suppression/prevention systems on all drilling machines. Approval is essential before any such system is allowed for use in any mine.

2️⃣ Types of Drilling Machines Requiring Dust Control

Dust control systems are compulsory for all types of drilling machines used in mining operations, including: Jack hammer drill, DTH (Down the Hole) drill, Wagon drill, Coal/rock drill, Long-hole drill, Roof bolting drill, Surface blast-hole drill, and all other drilling HEMM.

3️⃣ Types of Dust Suppression / Prevention Systems

Wet Drilling System: Delivers water through the drill rod directly to the cutting face. Reduces dust by 70–90%. Requires adequate water pressure (≥3–5 kg/cm²).
Dry Dust Collection System (DCS): Vacuum-based system using Suction hood, Cyclone separator, and Bag filter / Cartridge filter. Used where water is not feasible.
Water Mist or Spray System: Nozzle-based fine mist spray deployed at the drill collar to reduce airborne dust during collaring.
Vacuum Extraction System: Creates continuous negative pressure to capture dust at the source.

4️⃣ DGMS Approval Requirements

To obtain DGMS approval, a dust suppression system must pass stringent tests and meet several criteria:

Performance: Control dust within DGMS-prescribed limits; Filter efficiency ≥ 98–99% (for dry systems); Airflow rate 150–300 CFM.
Safety & Reliability: No leakage of dust; Hoses must have adequate pressure rating (≥3–5 kg/cm²); Robust construction.
Operational: System must activate automatically during drilling; Must not be bypassed by the operator; Warning alarms for low water pressure / DCS failure.

5️⃣ Technical Specifications (DGMS Standard)

System	Key Specification
Wet Drilling	Water pressure: ≥ 3–5 kg/cm²; Flow rate: 3–10 L/min
Dry Dust Collector	Filter efficiency: ≥ 98–99%; Airflow rate: 150–300 CFM
Cyclone Separator	Must remove ≥ 90% of coarser dust

6️⃣ Maintenance Requirements

Regular and meticulous maintenance is crucial for continuous effectiveness:

Clean or replace filters regularly.
Check water pressure and flow rate daily.
Replace torn hoses and seals.
Ensure cyclone separators are routinely emptied and cleaned.
Test suction efficiency periodically.
Maintain logbook of system performance.

⚡ QUICK ONE-LINERS (REVISION)

DGMS approval is mandatory for all drilling machine dust suppression systems.
Wet drilling can reduce respirable dust by 70–90%.
Dry dust collectors commonly integrate cyclone + bag filter.
The minimum recommended water pressure for wet drilling is 3–5 kg/cm².
Approved systems must work automatically during drilling.
Filter efficiency must be ≥ 98–99% for respirable dust.
Silicosis prevention is the main objective of health control.
Typical airflow rate for dry dust collectors ranges from 150–300 CFM.
Hoses must withstand pressure and vibration.
Daily pre-shift inspection of dust suppression systems is compulsory.

🧠 DESCRIPTIVE MODEL ANSWER

Q. Describe the features and approval requirements of dust suppression/prevention systems used in drilling machines in mines.

Answer:
DGMS mandates approved dust suppression systems on all drilling machines to prevent occupational diseases like silicosis. The systems, primarily Wet Drilling (water injection ≥ 3–5 kg/cm²) or Dry Dust Collectors (cyclone + bag filters), must be highly efficient. DGMS approval requires demonstrated performance (dust reduction efficiency, 98–99% filtration efficiency), safety features (automatic activation, inability to bypass), and structural reliability. The system must function continuously during drilling, and all components must be maintained regularly (daily checks of water pressure, periodic cleaning of filters) to ensure compliance with CMR 2017 Reg. 123.

🧮 25 MCQs (Dynamic Options A–E)

Q1. Dust suppression in drilling machines is mandated by:

Solution: CMR 2017 (Regulation 123) is the core statutory regulation mandating adequate measures for dust control.

Q2. Wet drilling systems achieve what percentage of dust reduction?

Solution: Wet drilling is a highly effective primary control, capable of reducing airborne dust levels by 70% to 90% or more.

Q3. What is the minimum water pressure required for wet drilling as per DGMS?

Solution: Adequate water pressure (3–5 kg/cm²) is required at the drill bit for effective dust suppression.

Q4. Which component is NOT part of a typical dry dust collection system?

Solution: A water injection pump is specific to wet drilling systems, not dry dust collection.

Q5. What is the minimum filter efficiency required for dry dust collectors?

Solution: High filter efficiency (98–99%) is crucial for capturing fine respirable dust particles and achieving statutory compliance.

Q6. Which DGMS regulation generally covers dust control for workers' safety?

Solution: Regulation 123 of CMR 2017 is the specific rule detailing precautions against dust.

Q7. What airflow rate is typically required for dry dust collectors?

Solution: An adequate airflow rate must be adequate to capture all dust effectively, typically falling within the 150–300 CFM range for most drills.

Q8. The primary purpose of a water mist or spray system at the drill collar is to:

Solution: Water mist systems focus on suppressing the dust generated when starting the borehole (collaring).

Q9. Which drilling machine specifically mentioned requires a dust control system?

Solution: DGMS mandates dust control measures for all types of drilling machines used in mine environments.

Q10. Cabin HEPA filters protect the operator from:

Solution: High-Efficiency Particulate Air (HEPA) filters are used to clean the air entering the cabin, protecting the operator's lungs from respirable dust.

Q11. The main objective of dust suppression:

Solution: The fundamental objective of dust control is to minimize the amount of harmful airborne particulate matter.

Q12. Wet drilling system uses:

Solution: Wet drilling relies on water injection directly through the drill bit to trap and suppress dust.

Q13. Cyclone separator removes dust using:

Solution: The cyclone creates a vortex, using centrifugal force to spin out and separate heavier dust particles.

Q14. DGMS inspections include:

Solution: Checking the functionality and records of the dust suppression system is a mandatory part of a DGMS audit.

Q15. Water injection reduces dust by:

Solution: Water injection is highly effective, achieving significant dust reduction (70% or more).

Q16. Drilling without dust suppression is:

Solution: Operating a drilling machine in a mine environment without a functional, approved dust control system is a statutory violation.

Q17. Respiratory diseases are caused by:

Solution: Inhaling airborne contaminants, specifically dust, is the root cause of occupational respiratory diseases like pneumoconiosis.

Q18. Main component of DCS (Dry Dust Collector System):

Solution: The bag filter or cartridge filter is the main component responsible for capturing the fine respirable dust.

Q19. DGMS requires dust control in:

Solution: Dust control is an occupational health requirement applicable to all mine working environments (coal and metal).

Q20. Water pressure should be checked:

Solution: Proper water pressure is essential for effective suppression, making a daily pre-shift check mandatory.

Q21. Silicosis is:

Solution: Silicosis is a fibrotic disease affecting the lungs, caused by crystalline silica dust.

Q22. Dust sampling report stored in:

Solution: The results of dust sampling are statutory records kept in a dedicated Dust Survey Register.

Q23. Silica dust mainly found in:

Solution: Metal and hard rock mines, which drill through quartz-bearing rock, have a high risk of silica exposure.

Q24. Real-time monitors give:

Solution: Real-time monitors use photometers to provide an immediate measurement of airborne dust concentration.

Q25. Pneumoconiosis is:

Solution: With proper engineering controls and health surveillance, pneumoconiosis is entirely preventable.

🔗 INTERNAL LINKS

Related Topic	Read More On...
Occupational Health	Occupational Health Survey (Dust) – DGMS Notes
Medical Surveillance	Dust Diseases: Silicosis & Pneumoconiosis
CMR Regulations	CMR 2017 Part 2 - Working & Supervision Rules
HEMM Safety	Safety Features in Crawler/Tyre Mounted Machinery

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