🔹 1. Introduction

Inundation accidents in Indian mines have caused major disasters such as Chasnalla (1975), Ledo, Damua, and Gaslitand.
Many were due to:

• Poor planning
  
• Inadequate precautions
  
• No water danger plan
  
• Failure to detect old waterlogged workings
  
• Violation of statutory safety rules
  

🔹 2. Water Danger Plan (Mandatory)

A Water Danger Plan (WDP) is a statutory plan showing:Danger from water and Inundation…

✓ All surface water bodies(Rivers, tanks, lakes, dams, reservoirs)

✓ All underground waterlogged areas(Old workings, goaf areas, flooded galleries)

✓ Probable points of inrush(Faults, dykes, cracks)

✓ Statutory distances (120 m / 60 m line)

✓ Pump chambers & sumps

✓ Barriers and protective pillars

✓ Proposed development & approach directionThis plan is updated every six months or whenever new information is available.
🔹 3. Statutory Safety Distances

DGMS mandates two important safety lines when approaching waterlogged areas:
⭐ A. Warning Line – 120 mAt 120 m from the boundary of old waterlogged workings:

• Mining must proceed with caution
  
• Special drilling (probe holes) must begin
  
• Speed of advance is restricted
  
• Water danger precautions intensified
  

⭐ B. Statutory Restriction Line – 60 mAt 60 m, the following are mandatory:

✓ Work must be stopped unless permission is obtained

✓ Only supervised probing is allowed

✓ Exploration must be carried out by:

• Boreholes
  
• Pilot galleries
  
• Water bore tests
  

✓ Barrier thickness is assessedThis line is strictly enforced by DGMS.

🔹 4. Precautions Before Approaching 

Waterlogged WorkingsAs per your document:Danger from water and Inundatio…

✔ 1. Detailed Survey of Plans

Old plans must be compared, and discrepancies corrected.
✔ 2. Exploration by Drilling

Probe/drill holes:

• Ahead of the working face
  
• On roof and floor
  
• Vertical & inclined
  
• At intervals of 3–5 m
  

✔ 3. Establishing a Large Cautionary ZoneArea between warning line and restriction line is treated as high danger zone.
✔ 4. Ventilation AdjustmentsTo prevent water vapor accumulation & airblast hazards.
✔ 5. Reduced Advance RateAdvancement of face should be slow and strictly regulated.
✔ 6. Withdrawal PlanA clear exit route must be available at all times.
🔹 5. Precautions for Surface WaterWhen working under rivers, tanks, or lakes:Danger from water and Inundatio…
✔ 1. Maintain Watertight EmbankmentsWell-compacted bunds must be built around quarries.
✔ 2. Drainage SystemDeep drains should divert stormwater away from mine edges.
✔ 3. Pumping CapacityPumps must be capable of discharging normal inflow + heavy rainfall.
✔ 4. Regular InspectionBefore monsoon and after every heavy rainfall.
✔ 5. No Working During Flood WarningOperations must stop if flood alert issued by authorities.

🔹 6. Precautions for Underground Water
✔ 1. Leave Adequate BarriersBarrier thickness based on:

• Depth
  
• Pressure
  
• Rock strength
  

✔ 2. Approach Dykes and Faults CarefullyFaulted zones may be water-charged.
✔ 3. Pump Chambers & SumpsKept ready with:

• Standby pumps
  
• Emergency power
  
• Alarms
  

✔ 4. Systematic DewateringOld workings must be dewatered stepwise under expert supervision.

🔹 7. Emergency Preparedness

✔ 1. Water Inrush Alarm SystemAutomatic float alarms installed.
✔ 2. Withdrawal ProceduresWorkers must be trained to withdraw through safe route immediately.
✔ 3. Communication SystemTwo-way communication system must be available.
✔ 4. Protective Structures

• Bulkheads
  
• Stoppings
  
• Ventilation doors
  

🔹 8. Text Diagram – Water Danger Zones
Old Waterlogged Workings [========================]
120m Warning Line -------------------- (Caution Zone)
60m Statutory Line -------------------- (No Working Without Permission)
Working Face O O O O O

🔥  25 MCQs (DGMS Pattern) with Solutions

1) Water Danger Plan must show —

a) Explosive magazines
b) Canteen room
c) All water bodies & waterlogged workings
d) Coal stockyard
e) None
Answer: c
2) Warning line is drawn at —

a) 20 m
b) 40 m
c) 120 m
d) 500 m
e) None
Answer: c
3) Statutory restriction line is at —

a) 10 m
b) 30 m
c) 60 m
d) 120 m
e) None
Answer: c
4) Work beyond 60 m line can be done only with —

a) Sirdar’s permission
b) Manager’s verbal order
c) DGMS permission
d) Electrician’s permission
e) None
Answer: c
5) Probe holes are drilled —

a) Behind the face
b) Ahead of the working face
c) In the sump only
d) In goaf only
e) None
Answer: b
6) Purpose of water danger plan —

a) Ventilation
b) Lighting
c) Prevent inundation
d) Blasting
e) None
Answer: c
7) Old workings are treated as —

a) Safe zone
b) Strong zone
c) Water danger zone
d) No danger zone
e) None
Answer: c
8) Barrier thickness depends on —

a) Gradient
b) Water pressure & depth
c) Coal grade
d) Conveyor speed
e) None
Answer: b
9) Pump chambers must have —

a) 1 pump
b) Standby pumps
c) Only handpump
d) Fans
e) None
Answer: b
10) Large cautionary zone lies between —

a) 60–120 m
b) 0–20 m
c) 20–40 m
d) 90–140 m
e) None
Answer: a
11) Bunds are built to prevent —

a) Subsidence
b) Gas outbursts
c) Surface water inflow
d) Ventilation issues
e) None
Answer: c
12) Probe holes spacing —

a) 20 m
b) 15 m
c) 10 m
d) 3–5 m
e) None
Answer: d
13) DGMS requires water danger plans to be updated —

a) Monthly
b) Every 6 months
c) Yearly
d) Daily
e) None
Answer: b
14) Embankments must be —

a) Weakly built
b) Watertight and strong
c) Temporary
d) Unmonitored
e) None
Answer: b
15) Advance under water bodies must be —

a) Fast
b) Slow and cautious
c) Random
d) Without drilling
e) None
Answer: b
16) Main cause of flooding is —

a) Gas
b) Dust
c) Neglecting waterlogged areas
d) Good blasting
e) None
Answer: c
17) Permission to cross 60 m line is granted by —

a) Foreman
b) Colliery clerk
c) DGMS
d) Seam surveyor
e) None
Answer: c
18) Water inrush alarms operate using —a) Sensors
b) Float switches
c) CCTV
d) Gas detectors
e) None
Answer: b
19) Drainage channels must be —

a) Blocked
b) Narrow
c) Deep and well maintained
d) Random
e) None
Answer: c
20) Unsafe approach to waterlogged area leads to —

a) High production
b) Inundation
c) Low humidity
d) Reduced noise
e) None
Answer: b
21) Sumps must be kept —

a) Dry
b) Free of silt
c) Filled
d) Closed
e) None
Answer: b
22) Under waterlogged areas, roof is often —

a) Stable
b) Weak and water-soaked
c) Fireproof
d) Strong
e) None
Answer: b
23) Bund inspection is especially required —

a) During winter
b) Summer
c) Before and after monsoon
d) Night shift only
e) None
Answer: c
24) Fast advance toward old workings causes —

a) Good output
b) Higher wages
c) Breakthrough into waterlogged area
d) More safety
e) None
Answer: c
25) Primary goal of WDP —

a) Increase coal price
b) Improve blasting
c) Prevent sudden water inrush
d) Increase roof height
e) None
Answer: c

 🔚 Conclusion

Water Danger Plan is a mandatory and life-saving document in all mines.
Mining near waterlogged areas must follow DGMS rules:

• Warning line (120 m)
  
• Restriction line (60 m)
  
• Probe drilling
  
• Strong barriers
  
• Adequate pumping
  
• Pre-monsoon inspections
  

Proper precautions prevent mine flooding and protect workers.

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