Introduction

Pumping systems in coal and metal mines are vital for keeping workings dry and preventing inundation. DGMS mandates specific safety standards under CMR 2017 (Reg. 127–131) and the CEA Rules, 2010. Proper electrical safety ensures pumps operate without risk of fire, shock, or explosion.

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⚙️ 1. Overview of Mine Pumping Systems

• Purpose: To remove accumulated water from sumps, galleries, and shafts.
• Types of Pumps Used in Mines:
• Centrifugal Pumps – most common type for mine drainage.
• Submersible Pumps – for flooded sections.
• Positive Displacement Pumps – used for small-scale drainage.
• Layout: Main pump installed at pit bottom; auxiliary pumps placed at intermediate levels.
• Standby Arrangement: One standby pump must always be available.

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⚡ 2. DGMS Electrical Safety Requirements

• All electrical installations must comply with CEA Rules, 2010.
• Switchgear must be flameproof in gassy seams.
• Earth leakage protection (ELCBs) mandatory on all equipment.
• All cables must be PVC insulated, armoured, and flameproof.
• Automatic tripping on overload, short circuit, or phase imbalance.
• Regular testing and record maintenance required by Manager and Electrical Supervisor.

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🔋 3. Key DGMS Circulars on Pumping & Electrical Safety

Circular	Year	Subject
Tech Circular No. 02	2010	Slope stability & drainage safety
Tech Circular No. 10	2020	Lightning protection and grounding
General Circular No. 03	2018	Real-time telemetry and electrical monitoring
Tech Circular No. 06	2024	Training of electrical supervisors & electricians

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🧯 4. Emergency & Inspection Rules

• Regular inspection of all pumps and motors by competent person.
• Overload relay and emergency switch must be tested weekly.
• Cable joints must be sealed with epoxy compounds.
• Proper communication between surface and underground pump house required.

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🧩 5. DGMS Exam Relevance 

This topic covers CMR Reg. 127–131, CEA Rules, 2010, and DGMS Circulars – all important for Legislation & General Safety Papers in both Coal and Metal exams.

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⚡ 25 DGMS-Style MCQs – Mine Pumping & Electrical Safety

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Q1. The main function of mine pumps is to:
A. Drain gases
B. Remove accumulated water
C. Supply compressed air
D. Control ventilation
E. Circulate oil
Answer: B.
Solution: Pumps prevent water accumulation and mine flooding.

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Q2. The standby pump in mines must be:
A. Smaller in size
B. Always ready for use
C. Used occasionally
D. Portable only
E. Surface-mounted
Answer: B.
Solution: Regulation 131 requires one standby pump in running condition.

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Q3. Electrical switchgear in underground mines must be:
A. Open type
B. Flameproof type
C. Semi-open type
D. Normal industrial type
E. Explosion-prone type
Answer: B.
Solution: Flameproof switchgear prevents ignition in gassy atmospheres.

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Q4. DGMS requires pump motor circuits to be protected against:
A. Vibration
B. Overload & short circuit
C. Dust accumulation
D. Overheating only
E. Corrosion
Answer: B.
Solution: Regulation 131 mandates overload and short-circuit protection.

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Q5. Minimum sump capacity should hold water equivalent to:
A. 6 hours inflow
B. 12 hours inflow
C. 24 hours inflow
D. 36 hours inflow
E. 48 hours inflow
Answer: C.
Solution: CMR Reg. 130 specifies 24-hour pumping volume.

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Q6. Pumps used in gassy seams must have:
A. Flameproof motor and starter
B. Ordinary motor
C. Open type fan cooling
D. Air-cooled drives only
E. None
Answer: A.
Solution: DGMS mandates flameproof equipment in gassy mines.

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Q7. The electrical supervisor’s daily report must include:
A. Fan efficiency
B. Voltage and current readings
C. Attendance of workers
D. Production details
E. None
Answer: B.
Solution: Electrical load readings help detect faults and overloads.

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Q8. The CEA Rules, 2010 are enforced under:
A. Mines Act 1952
B. Electricity Act 2003
C. DGMS Notification 2017
D. CMR 2017
E. Metalliferous Mines Regulation 1961
Answer: B.
Solution: Electrical safety in mines is governed by the Electricity Act 2003.

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Q9. Earthing resistance in mines should not exceed:
A. 1 ohm
B. 2 ohms
C. 5 ohms
D. 10 ohms
E. 20 ohms
Answer: C.
Solution: Standard DGMS limit for earth resistance ≤ 5 ohms.

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Q10. Flameproof enclosures are tested as per:
A. IS 2148
B. IS 2312
C. IS 3043
D. IS 5571
E. IS 732
Answer: A.
Solution: IS 2148 specifies flameproof enclosure testing.

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Q11. Overload relay testing should be carried out:
A. Daily
B. Weekly
C. Monthly
D. Quarterly
E. Yearly
Answer: B.
Solution: Weekly testing ensures protection system reliability.

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Q12. The main reason for pump motor failure in mines is:
A. Improper ventilation
B. Overload and moisture ingress
C. Dust deposition
D. Excess temperature
E. Pump misalignment
Answer: B.
Solution: Moisture and overloads cause insulation breakdown.

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Q13. The DGMS circular for lightning protection is:
A. 03/2018
B. 10/2020
C. 06/2024
D. 02/2010
E. 01/2015
Answer: B.
Solution: Circular No. 10 of 2020 deals with lightning protection systems.

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Q14. All switchgear must have:
A. Flameproof body
B. Proper identification plate
C. Short-circuit relay
D. All the above
E. None
Answer: D.
Solution: Proper identification and protection are DGMS requirements.

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Q15. Water hazard classification is based on:
A. Seam thickness
B. Inflow rate
C. Type of pump
D. Depth of sump
E. Gradient of haul road
Answer: B.
Solution: Classification is based on rate of inflow and source.

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Q16. The degree of hazard due to water is assessed by:
A. DGMS Inspector
B. Manager
C. Regional Controller of Mines
D. Surveyor
E. State Government
Answer: A.
Solution: DGMS inspectors assess and categorize water hazard level.

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Q17. Electrical cables in water-logged zones must be:
A. Armoured, flameproof, and waterproof
B. Aluminium-coated
C. Rubber-insulated only
D. Temporary type
E. Bare
Answer: A.
Solution: Must withstand water, mechanical damage, and fire risk.

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Q18. The power supply to pumps must be automatically cut off when:
A. Overpressure occurs
B. Methane exceeds 1.25%
C. Rain starts
D. Ventilation stops
E. Fan restarts
Answer: B.
Solution: DGMS requires automatic power cut when methane >1.25%.

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Q19. Regulation 131 of CMR 2017 specifically deals with:
A. Training of electricians
B. Pumping arrangements
C. Drainage boreholes
D. Methane detection
E. Explosion risk areas
Answer: B.
Solution: Reg. 131 covers pumping and electrical safety arrangements.

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Q20. Pump capacity should exceed normal inflow by:
A. 10%
B. 20%
C. 25%
D. 30%
E. 50%
Answer: C.
Solution: Safety margin of 25% ensures emergency handling.

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Q21. The installation of pumps and motors must be inspected by:
A. Manager only
B. Electrical Supervisor
C. Regional Inspector
D. DGMS Officer
E. None
Answer: B.
Solution: Electrical supervisor ensures compliance with CEA rules.

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Q22. The use of aluminum conductors in gassy mines is:
A. Allowed
B. Prohibited
C. Allowed with approval
D. Only for surface use
E. Recommended
Answer: B.
Solution: Aluminium can spark and is prohibited underground.

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Q23. For opencast drainage, DGMS recommends:
A. Garland drains & pumping stations
B. Borehole sealing
C. Dump storage
D. Explosive blasting
E. Reclamation ponds
Answer: A.
Solution: Drains divert runoff and prevent slope erosion.

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Q24. The term “telemetry” in DGMS context refers to:
A. Data transfer of environmental parameters
B. Temperature measurement
C. Lighting control
D. Load control
E. Communication only
Answer: A.
Solution: Telemetry transmits gas, voltage, and current data to surface.

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Q25. CEA Rule 29 covers:
A. Insulation resistance testing
B. Earthing
C. Shock prevention
D. Lightning protection
E. Circuit breaker design
Answer: A.
Solution: Rule 29 mandates periodic insulation resistance testing.

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🧾 Conclusion 

 Proper mine pumping and electrical safety are critical to prevent inundation, fire, and electrocution risks.
Compliance with CMR 2017 Reg. 127–131, CEA Rules 2010, and DGMS circulars ensures both equipment reliability and worker protection.
Every DGMS aspirant must master pump layout, sump design, cable safety, and regulation references.

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