Mine Drainage & Water Management in Box Cut Areas – DGMS Exam Notes

                                      🏗️ Introduction

In opencast mining, the box cut acts as the first excavation — often below natural drainage level.
Accumulated rainwater, seepage, and groundwater inflow can lead to slope instability, dump erosion, and equipment accidents.
To counter this, CMR 2017 Regulations 127–131 and DGMS Circulars define standards for mine drainage, sump design, pump capacity, and water safety.
This topic is vital for DGMS First Class & Second Class Manager exams (Coal & Metal – Restricted/Unrestricted).

⚙️ 1. Sources of Mine Water

• Rainfall & Surface Runoff: Direct inflow during monsoon.
• Groundwater Seepage: Through fractured strata.
• Process Water: From washing, drilling, or dust suppression.
• Leakage: From pipelines, sumps, or hydraulic systems.

🧠 DGMS Exam Tip: Always mention “seepage + rainfall + process discharge” when defining mine water sources.

⚒️ 2. Regulation 127–131 (CMR 2017) – DGMS Water Management Provisions

Regulation	Subject	Key Requirement (Simplified)
Reg. 127	Precautions against Inundation	Water danger plan, borehole drilling, barriers between old workings.
Reg. 128	Pumping and Sump Design	Minimum capacity = 4 hours inflow; sump at lowest level.
Reg. 129	Precautions in Opencast Mines	Proper drainage slope, sump location, pumping arrangements.
Reg. 130	Pump House Construction	Pumps protected from flooding; duplicate standby provided.
Reg. 131	Notice of Inundation	Immediate reporting to DGMS and emergency rescue.

💡 3. DGMS Guidelines for Effective Mine Drainage

1. Sump Design:
• Must hold 4 hours of maximum inflow.
• Provided with sedimentation traps for silt removal.
• Located at lowest working level.
2. Pump Arrangement:
• Two pumps (one standby) with automatic switchover.
• Electrical protection and flood alarms mandatory.
3. Drainage Gradient:
• Minimum 1 in 100 slope toward sump.
• Lined channels for stormwater.
4. Safety Provisions:
• Pumps installed above highest flood level.
• Proper fencing and lighting near sump.
• Cables & starters must be flameproof.
5. DGMS Circulars:
• Tech Circular 02/2010 – Drainage & slope monitoring.
• Circular 10/2020 – Lightning & electrical safety near sumps.

⚖️ 4. Mine Water Handling & Environmental Measures

• ETP (Effluent Treatment Plant): Removes oil, grease, and suspended solids.
• Recycling: Treated water reused for dust suppression and drilling.
• Monitoring: pH, TDS, and oil content checked as per SPCB norms.
• Emergency Pumping: Backup diesel units to handle sudden inflow.

📋 5. DGMS Exam Focus Areas

• Sump design capacity & gradient
• Regulation 127–131
• Pump standby rule
• Water hazard precautions
• CMR emergency reporting procedure

🧠 Quick One-Liners for Revision

• CMR 2017 Reg. 127–131 → Water management in mines.
• Minimum sump capacity = 4 hours inflow.
• Drainage slope = 1 in 100.
• Duplicate pump = mandatory standby.
• DGMS Circular 02/2010 → drainage and slope.
• Notice of inundation → must be sent immediately to DGMS.
• Sump must be at lowest working level.

🧾 25 DGMS-Based MCQs – Mine Drainage & Water Management

Q1. The main purpose of mine drainage is to:
A. Increase groundwater recharge
B. Prevent flooding of workings
C. Maintain ventilation
D. Supply water to colony
E. Clean HEMM
Answer: B.
Solution: Drainage ensures safe and dry working conditions.

Q2. Regulation 127–131 of CMR 2017 deals with:
A. Mine water management
B. Dust suppression
C. Power supply
D. Firefighting
E. Blasting safety
Answer: A.
Solution: These regulations define standards for water safety and pumping.

Q3. Minimum sump capacity should hold water for at least:
A. 1 hour
B. 2 hours
C. 4 hours
D. 6 hours
E. 8 hours
Answer: C.
Solution: Reg. 128 mandates storage of 4 hours inflow volume.

Q4. Sump in an opencast mine must be located:
A. At highest bench
B. At central level
C. At lowest working level
D. Near haul road
E. Beside dumps
Answer: C.
Solution: Water naturally flows to lowest point ensuring drainage efficiency.

Q5. Drainage gradient for haul roads must be:
A. 1 in 10
B. 1 in 25
C. 1 in 50
D. 1 in 100
E. 1 in 200
Answer: D.
Solution: Standard gradient for safe drainage and erosion control.

Q6. Which DGMS Circular covers drainage and slope stability?
A. 02/2010
B. 03/2015
C. 01/2021
D. 04/2018
E. 06/2023
Answer: A.
Solution: Tech Circular 02/2010 is the core reference for slope and water control.

Q7. Pumping arrangement in a mine must have at least:
A. One pump
B. Two pumps (one standby)
C. Three pumps
D. Portable units only
E. None
Answer: B.
Solution: Standby pump is mandatory to ensure continuous drainage.

Q8. Electrical switchgear near sump should be:
A. Weatherproof
B. Flameproof
C. Both A & B
D. Only dustproof
E. Non-insulated
Answer: C.
Solution: Flameproof + weatherproof equipment prevents fire hazards.

Q9. Notice of inundation must be sent to DGMS:
A. Within 7 days
B. Within 48 hours
C. Immediately
D. After inspection
E. After dewatering
Answer: C.
Solution: Immediate reporting under Reg. 131 is mandatory.

Q10. Drainage channels should be:
A. Earthen
B. Lined and graded
C. Randomly dug
D. Closed
E. Temporary
Answer: B.
Solution: Lined drains prevent erosion and ensure smooth flow.

Q11. Pump capacity is decided based on:
A. Rainfall intensity and inflow rate
B. Type of dumper
C. Lighting arrangement
D. Fuel supply
E. Labour availability
Answer: A.
Solution: Designed as per peak inflow and rainfall analysis.

Q12. Flood alarm systems must be installed:
A. At wash bay
B. At workshop
C. At pump house and sump area
D. At office
E. None
Answer: C.
Solution: Helps alert operators in case of water rise.

Q13. Sedimentation traps in sumps are used for:
A. Oil separation
B. Dust control
C. Silt and sand settling
D. Cooling water
E. None
Answer: C.
Solution: Prevents pump damage from sediments.

Q14. pH of discharged mine water should be:
A. 2–4
B. 4–6
C. 6–9
D. 9–11
E. Neutral only
Answer: C.
Solution: As per CPCB and DGMS environmental norms.

Q15. The gradient of haul roads and drainage channels ensures:
A. Lighting
B. Flow of water
C. Smooth traffic only
D. Reduced production
E. None
Answer: B.
Solution: Slope ensures gravitational water flow toward sump.

Q16. The sump design and drainage plan form part of:
A. SSR (Standing Safety Report)
B. Wage Register
C. Mine Closure Plan
D. Notice Board
E. Survey Plan
Answer: A.
Solution: SSR includes all slope, drainage, and sump design details.

Q17. DGMS recommends standby pumps be tested:
A. Monthly
B. Weekly
C. Daily
D. Quarterly
E. Annually
Answer: C.
Solution: Regular testing ensures readiness during emergencies.

Q18. Cables near sump should be:
A. Underwater
B. Shielded and raised
C. Bare
D. Underground
E. Open
Answer: B.
Solution: Prevents short circuits during flooding.

Q19. Maximum slope angle for sump wall stability:
A. 30°
B. 45°
C. 60°
D. 75°
E. Vertical
Answer: B.
Solution: A 45° angle ensures stable excavation of sump sides.

Q20. Emergency pumping capacity should handle:
A. 25% inflow
B. 50% inflow
C. 100% inflow
D. 150% inflow
E. None
Answer: D.
Solution: Emergency system must exceed normal inflow capacity.

Q21. Oil-water separators are installed to:
A. Save electricity
B. Prevent pollution
C. Collect oil for reuse
D. Reduce pH
E. None
Answer: B.
Solution: They prevent contamination of surface and groundwater.

Q22. Stormwater from box cut area must be directed:
A. Into working benches
B. Into drainage channel and sump
C. Onto spoil dump
D. To workshop area
E. None
Answer: B.
Solution: Ensures runoff does not erode slopes or benches.

Q23. DGMS requires a pumping logbook to be:
A. Maintained weekly
B. Maintained daily
C. Maintained monthly
D. Submitted yearly
E. None
Answer: B.
Solution: Daily pumping record ensures operational accountability.

Q24. Water hazard classification in coal seams is based on:
A. Gas emission
B. Old workings & inflow potential
C. Roof quality
D. Mine depth
E. Gradient
Answer: B.
Solution: Water danger classification considers previous inundation data.

Q25. DGMS inspection frequency for mine drainage systems:
A. Weekly
B. Monthly
C. Quarterly
D. As per risk category
E. None
Answer: D.
Solution: Inspections vary depending on mine risk classification and DGMS schedule.

✅ Conclusion

Efficient mine drainage prevents water-related disasters and supports safe production.
Compliance with CMR 2017 Reg. 127–131, proper sump design, and standby pumping systems are critical for DGMS audit readiness.
A well-planned drainage network saves lives, machinery, and ensures uninterrupted mining operations.

📢 

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