🌊Introduction

Water hazard or inundation is one of the most serious dangers in underground and opencast mining.
Uncontrolled inflow of water from old workings, surface reservoirs, or aquifers has caused many fatal accidents in Indian mines.
DGMS enforces strict rules under CMR 2017 (Reg. 127–131) and issues technical circulars to prevent such disasters.

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⚙️ 1. Sources of Water in Mines

• Surface Water: Rainfall runoff, rivers, ponds, and water from opencast pits.
• Subsurface Water: Aquifers, faults, joints, and fissures.
• Old Workings: Abandoned water-logged areas connected by cracks or boreholes.
• Process Water: From drilling, washing plants, and hydraulic sand stowing.

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🚨 2. Causes of Mine Inundation

• Breach of Barrier Pillar between working and waterlogged areas.
• Uncontrolled surface runoff during heavy rainfall.
• Fault zones connecting aquifers.
• Improper borehole sealing.
• Failure of pumping system due to power or mechanical breakdown.

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⚒️ 3. DGMS Rules & Regulations (CMR 2017)

Regulation	Provision
Reg. 127	Manager’s responsibility for water danger precautions
Reg. 128	Precautions before approaching water-logged areas
Reg. 129	Boring of exploratory holes & supervision
Reg. 130	Design of sumps & drainage arrangements
Reg. 131	Pumping capacity, electrical safety, and standby system

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🧠 4. DGMS Circulars & Safety Practices

• DGMS Tech Circular No. 02/2010: Guidelines on mine drainage & slope stability.
• DGMS General Circular No. 03/2018: Real-time monitoring for inflow detection.
• Mandatory borehole drilling: At least 60 m ahead of advancing face near water-bearing strata.
• Barrier pillar width: Minimum 60 m (coal) or as per strata conditions.
• Emergency drills: Conducted every six months.

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📘 5. Inundation Control Measures

1. Proper Drainage Layout: Garland drains, sumps, and pumping stations.
2. Standby Pumps: Always maintained ready for operation.
3. Automatic Water Level Alarms: To detect rising levels.
4. Sealing of Old Workings: Brick/concrete bulkheads for isolation.
5. Mine Plan Updates: Regularly marked with waterlogged zones.
6. Emergency Preparedness: Evacuation plans and communication systems.

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📜 6. DGMS Case Studies

• Chasnala Disaster (1975): Water from old workings rushed into active mine → 375 deaths.
• Bansra Colliery (2011): Inrush due to unsealed borehole connection.
• Kujama Mine, Dhanbad: Water from surface quarry entered underground panel during monsoon.

👉 Each case highlighted the importance of barrier pillars, borehole drilling, and updated mine plans.

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🧩 7. DGMS Exam Relevance

This topic covers Mine Environment, Legislation & Safety sections for Coal & Metal (Restricted/Unrestricted) exams — frequently asked in both objective and oral papers.

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🎯 25 DGMS-Style MCQs – Mine Water Hazards & Inundation Control

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Q1. The main source of mine water hazard is:
A. Surface wind
B. Fault zones and old workings
C. Explosives use
D. Dust deposition
E. Ground vibration
Answer: B.
Solution: Water seeps through faults and abandoned workings.

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Q2. CMR 2017 Reg. 128 deals with:
A. Fire precautions
B. Roof supports
C. Precautions before approaching water-logged areas
D. Explosive handling
E. Ventilation layout
Answer: C.
Solution: Reg. 128 prescribes procedures for approaching waterlogged strata.

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Q3. Minimum barrier pillar thickness between old workings is:
A. 30 m
B. 45 m
C. 60 m
D. 80 m
E. 100 m
Answer: C.
Solution: 60 m barrier required to prevent inrush from old flooded areas.

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Q4. DGMS Circular 02/2010 deals with:
A. Pump efficiency
B. Dust suppression
C. Drainage and slope safety
D. Illumination in mines
E. Groundwater chemistry
Answer: C.
Solution: Covers mine drainage and slope management guidelines.

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Q5. The manager must maintain plans showing:
A. Borehole numbers only
B. All waterlogged and flooded areas
C. Coal seams only
D. Production zones
E. None
Answer: B.
Solution: Mandatory under Regulation 127 to mark flooded zones.

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Q6. Before cutting into suspected water-bearing strata, boreholes must be drilled:
A. 10 m ahead
B. 20 m ahead
C. 60 m ahead
D. 100 m ahead
E. 150 m ahead
Answer: C.
Solution: CMR 2017 Reg. 129 requires 60 m advanced boreholes.

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Q7. DGMS classifies water hazard into:
A. Three categories
B. Two categories
C. Four categories
D. One category
E. None
Answer: A.
Solution: Classified as Low, Moderate, and High hazard zones.

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Q8. The Chasnala disaster (1975) was caused by:
A. Fire
B. Inrush of water
C. Explosion
D. Roof fall
E. Gas outburst
Answer: B.
Solution: Inrush of water from old workings caused massive fatalities.

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Q9. To prevent surface runoff entering opencast mine:
A. Dust suppression
B. Garland drains
C. Water sprinklers
D. Waste dumps
E. Boreholes
Answer: B.
Solution: Garland drains divert surface water away from pit.

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Q10. The minimum number of standby pumps required in a gassy mine:
A. None
B. One
C. Two
D. Three
E. Four
Answer: B.
Solution: At least one standby pump as per Reg. 131.

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Q11. Inundation emergency plan must include:
A. Rescue arrangements
B. Communication plan
C. Evacuation routes
D. All of these
E. None
Answer: D.
Solution: Comprehensive emergency plans are required by DGMS.

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Q12. During inrush risk, workers must be:
A. Withdrawn to surface
B. Instructed to continue
C. Shifted to higher level
D. Sent to sealed areas
E. Asked to increase pumping
Answer: A.
Solution: Withdrawal is mandatory to prevent casualties.

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Q13. Pumps should be inspected:
A. Daily
B. Weekly
C. Monthly
D. Quarterly
E. Annually
Answer: B.
Solution: Weekly checks by competent person are mandatory.

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Q14. The width of sump wall must be adequate to:
A. Store coal
B. Prevent collapse under pressure
C. Serve as roadway
D. Hold slurry
E. None
Answer: B.
Solution: Structural strength is critical to hold water pressure.

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Q15. Who classifies a mine as water-dangerous?
A. DGMS
B. State Government
C. Manager
D. Company engineer
E. Regional Controller
Answer: A.
Solution: DGMS classifies mines based on risk assessment.

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Q16. The purpose of sealing old workings is to:
A. Prevent ventilation
B. Stop inflow of water
C. Block transport
D. Store gases
E. None
Answer: B.
Solution: Sealing isolates waterlogged or hazardous zones.

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Q17. If water inflow exceeds sump capacity, first action is:
A. Start standby pump
B. Stop production
C. Call DGMS
D. Drain to surface
E. Do nothing
Answer: A.
Solution: Standby pump handles excess inflow immediately.

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Q18. Boreholes drilled to detect water must be:
A. Upward
B. Downward
C. Horizontal and fan-shaped
D. Random
E. Spiral
Answer: C.
Solution: Fan-shaped holes help detect water ahead of the face.

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Q19. DGMS mandates the presence of which record?
A. Weekly water inflow log
B. Ventilation report
C. Explosives ledger
D. Fire report
E. None
Answer: A.
Solution: Inflow measurement helps track drainage performance.

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Q20. DGMS requires emergency drills to be conducted:
A. Monthly
B. Quarterly
C. Every six months
D. Annually
E. Biennially
Answer: C.
Solution: Half-yearly mock drills are mandatory.

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Q21. The water danger zone must be clearly marked on:
A. Attendance register
B. Working plan
C. Training report
D. Electrical log
E. Machinery record
Answer: B.
Solution: Water danger zones are demarcated in mine plans.

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Q22. Water level indicators must be installed:
A. On surface tanks
B. Inside sumps and pump chambers
C. On conveyor belts
D. At office
E. None
Answer: B.
Solution: Indicators monitor water levels in sumps.

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Q23. The most effective means to detect rising water in old workings:
A. CO detector
B. Water level sensor
C. Methane detector
D. Anemometer
E. None
Answer: B.
Solution: Water level sensors detect inrush in advance.

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Q24. Barrier pillar strength depends mainly on:
A. Seam dip
B. Strata conditions & water pressure
C. Type of machinery
D. Lighting
E. Gradient
Answer: B.
Solution: Geological conditions determine pillar width and strength.

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Q25. DGMS must be informed of inrush incident within:
A. 2 hours
B. 6 hours
C. 12 hours
D. 24 hours
E. 48 hours
Answer: D.
Solution: Mines Act & DGMS rules require reporting within 24 hours.

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                          🧾 Conclusion 

Inundations are preventable disasters when mines follow CMR 2017, DGMS circulars, and scientific drainage planning.
Proper barrier pillars, borehole drilling, sump design, and real-time monitoring can save lives and equipment.
For DGMS exams, focus on Reg. 127–131, case studies like Chasnala, and practical applications of drainage systems.

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