🔹 1. Introduction

Monsoon is the most dangerous season for mines in India.
Almost 70% of inundation accidents have occurred during or just before monsoon due to:

• Heavy rainfall
  
• Flooding of rivers
  
• Breach of dams/tanks
  
• Poor drainage
  
• Failure of bunds
  
• Pump breakdown
  
• Sudden surface runoff
  

DGMS mandates compulsory pre-monsoon inspections and strict surface water control measures for all mines.
🔹 2. Pre-Monsoon Inspection (DGMS Mandatory)

Every mine must carry out a full-scale inspection BEFORE the monsoon begins.
This inspection includes:
⭐ 2.1 Inspection of Mine Plans

• Water Danger Plan updated
  
• Old working boundaries verified
  
• Check survey of water bodies
  

⭐ 2.2 Inspection of Surface Water Bodies

As per document: rivers, nallas, tanks, dams, lakes must be inspected.Danger from water and Inundatio…Look for:

• Cracks in embankments
  
• Erosion signs
  
• Low-lying areas
  
• Overflow risks
  

⭐ 2.3 Drainage System InspectionDrainage must be:

• Deep
  
• Clear
  
• Unblocked
  
• Capable of carrying floodwater
  

⭐ 2.4 Embankment (Bund) InspectionBunds must be:

• Strong
  
• Reinforced
  
• Raised where necessary
  
• Without cracks
  

⭐ 2.5 Sump & Pump Chamber InspectionCheck:

• Silt removal
  
• Pump foundations
  
• Standby pumps
  
• Emergency power backup
  

⭐ 2.6 Machinery Readiness

• Pumps tested
  
• Hoses checked
  
• Valves functional
  

🔹 3. Surface Water Control Measures (As per DGMS)
⭐ 3.1 Construction of Bunds

Bunds should be:

• High enough to prevent overflow
  
• Compacted and watertight
  
• Inspected daily during monsoon
  

⭐ 3.2 Diversion DrainsPurpose:

• Prevent stormwater from entering pits
  
• Carry away runoff water
  

Drains must be:

• Well sloped
  
• Lined if possible
  
• Free from obstruction
  

⭐ 3.3 Garland Drain SystemA garland drain surrounds the mine to prevent water entry.
⭐ 3.4 Catch DrainsSmall drains above slopes to catch and redirect rainwater.
⭐ 3.5 Pumping ArrangementDGMS guidelines require:

• Main pumps
  
• Standby pumps (100% standby)
  
• Emergency pumps
  
• Independent power source
  

🔹 4. Pumping & Dewatering Preparedness
⭐ 4.1 Sump CapacitySumps must hold at least 2–3 hours of peak inflow.
⭐ 4.2 Standby PowerGenerators must start automatically in case of power failure.
⭐ 4.3 Daily Pumping RecordsPumping logs must be maintained.
⭐ 4.4 Pump TestingAll pumps must be tested for:

• Full load
  
• Suction efficiency
  
• Delivery pressure
  

🔹 5. Emergency Preparedness (DGMS Requirements)
⭐ 5.1 Water Inrush Alarm SystemFloat-switch alarms installed in:

• Sumps
  
• Pump chambers
  
• Approaching waterlogged zones
  

⭐ 5.2 Withdrawal ProcedureA clear & rehearsed escape plan.
⭐ 5.3 Trained ManpowerMiners trained in:

• Emergency water escape
  
• Refuge area identification
  
• Communication procedure
  

⭐ 5.4 Communication SystemMust remain active even during:

• Power failure
  
• Pump breakdown
  

🔹 6. Special Monsoon Rules for Opencast Mines
⭐ 6.1 Highwall StabilityCheck for:

• Weakening
  
• Cracks
  
• Water seepage
  

⭐ 6.2 Pit Bottom DrainageMust be sloped toward sumps.
⭐ 6.3 Haul Road DrainageRoads should be:

• Cross-drained
  
• Water-free
  
• Non-slippery
  

🔹 7. Special Monsoon Rules for Underground Mines
⭐ 7.1 Airshafts & AditsMust be protected from flooding.
⭐ 7.2 Stoppings & BulkheadsMust be checked for water tightness.
⭐ 7.3 Waterlogged Old WorkingsApproach prohibited during monsoon unless DGMS permits.
🔹 8. Text Diagram – Monsoon Precaution Structure
Surface Water Sources --------------------------- | Rivers | Tanks | Nallas | --------------------------- ↓ Diversion Drains ↓ Garland Drain ↓ Bunds / Embankments ↓ Mine Sump & Pumps ↓ Safe Working & Emergency Plan
🔥  25 MCQs (DGMS Pattern) with Answers
1) Pre-monsoon inspection is —

a) Optional
b) Only for UG mines
c) Mandatory for all mines
d) Done every 5 years
e) None
Answer: c
2) Bunds are constructed to —

a) Prevent dust
b) Increase production
c) Stop surface water entering mines
d) Store explosives
e) None
Answer: c
3) Standby pump requirement —

a) 25%
b) 50%
c) 100% standby
d) 10%
e) None
Answer: c
4) Sumps must be free of —

a) Machinery
b) Silt
c) Workers
d) Roof bolts
e) None
Answer: b
5) Automatic alarm system uses —

a) Fans
b) Lights
c) Float switches
d) Blasters
e) None
Answer: c
6) Drainage channels must be —

a) Narrow
b) Unlined
c) Clear & deep
d) Zigzag
e) None
Answer: c
7) Pump chamber inspection required —

a) Once a year
b) Before monsoon & weekly during monsoon
c) Once in 5 years
d) Never
e) None
Answer: b
8) Bund failure leads to —

a) Noise
b) Gas outburst
c) Sudden flooding
d) Roof bolting
e) None
Answer: c
9) Purpose of garland drain —

a) Increase coal production
b) Prevent rainwater entering mine
c) Gas monitoring
d) Support roof
e) None
Answer: b
10) Sump can hold ________ of peak inflow

a) 1 hour
b) 2–3 hours
c) 6 hours
d) 10 hours
e) None
Answer: b
11) Surface water danger highest during —

a) Summer
b) Winter
c) Monsoon
d) Post-monsoon
e) None
Answer: c
12) Embankments must be inspected —

a) Yearly
b) Daily
c) Before & after rains
d) Never
e) None
Answer: c
13) Emergency power supply is —

a) Optional
b) Mandatory for pumps
c) For office only
d) For lighting only
e) None
Answer: b
14) Opencast drain is called —a) Ventilation stoppage
b) Garland drain
c) Manhole
d) Goaf
e) None
Answer: b
15) Probe holes are required when —

a) Checking gas
b) Approaching waterlogged areas
c) Installing props
d) Surveying seam
e) None
Answer: b
16) Monsoon preparedness includes —

a) Extra blasting
b) Pump testing
c) More diesel use
d) Roof bolting only
e) None
Answer: b
17) Sudden inflow of water can cause —

a) Better ventilation
b) Air blast
c) Low humidity
d) High temperature
e) None
Answer: b
18) Drainage must be provided —

a) Above buildings
b) Inside magazines
c) Around the mine boundary
d) On the roof
e) None
Answer: c
19) Sump must be cleaned —

a) Never
b) Regularly to remove silt
c) Once in 10 years
d) During blasting
e) None
Answer: b
20) Water pumps should be tested —

a) Every 6 years
b) Regularly, especially before monsoon
c) Never
d) After mine closure
e) None
Answer: b
21) Surface water enters OC mine due to —

a) Strong bunds
b) Poor drainage
c) Ventilation
d) Explosive fumes
e) None
Answer: b
22) Slope stability reduces due to —

a) Dry strata
b) Water seepage
c) More coal
d) Good blasting
e) None
Answer: b
23) Inundation preparedness includes —

a) More explosives
b) High production targets
c) Emergency withdrawal plan
d) High blasting
e) None
Answer: c
24) Excess rainfall may cause —

a) Better ventilation
b) Good illumination
c) Bund overtopping
d) Smooth roads
e) None
Answer: c
25) Primary aim of pre-monsoon inspection —a) Increase manpower
b) Higher blasting
c) Prevent flooding & ensure safety
d) Reduce haulage
e) None
Answer: c
                     🔚 Conclusion

Pre-monsoon inspections and surface water control are critical for preventing mine inundation.
Proper drainage, strong embankments, adequate pumping, and emergency preparedness significantly reduce flooding risk and protect lives.

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