DGMS Tech. Circular No. 02 of 2020
Subject: Guidelines for Systematic Monitoring of Slopes in Opencast Mines
Published Year: 2020

πŸ“˜ Detailed Notes (Exam-Oriented)
1. Background

  • Slope failures in opencast mines can cause:
    • Fatal accidents (fall of overburden, dump slides).
    • Damage to HEMM, infrastructure, haul roads.
  • Factors affecting slope stability: geology, water seepage, blasting, equipment vibration, slope geometry, dump design.
  • This circular gives guidelines for systematic slope monitoring to prevent slope failures.
2. Key Hazards in Slopes
  • Bench failure (localized).
  • Overall slope failure (large-scale slide).
  • Dump collapse (external dump or backfill failure).
  • Triggering factors: rainfall, blasting vibrations, poor drainage, weak strata.
3. Monitoring Guidelines
  1. Geotechnical Investigations
    • Study of rock/soil strength, joints, bedding planes.
    • Slope stability analysis using geotechnical software.
  2. Design Parameters
    • Bench height, width, and slope angle designed based on investigations.
    • Catch benches for rockfall protection.
  3. Drainage & Water Control
    • Proper surface drainage to avoid waterlogging.
    • Sumps, pumping systems, garland drains.
  4. Instrumentation & Monitoring
    • Slope monitoring devices:
      • Total station, prism reflectors
      • Ground-based radar
      • Inclinometers, extensometers, piezometers
    • Regular visual inspection by competent persons.
  5. Survey & Data Recording
    • Periodic survey of slopes.
    • Records maintained for monitoring trends.
  6. Warning & Safety System
    • Trigger levels for slope movement defined.
    • Evacuation procedures if slope movement exceeds safe limits.
  7. Blasting Control
    • Controlled blasting near slopes.
    • Use of delay detonators & reduced charge per delay.
4. Responsibilities
  • Mine Manager: overall responsibility for slope stability.
  • Geotechnical Engineer: design & monitoring of slopes.
  • Surveyor/Overman: regular inspection & reporting.
5. Importance
  • Prevents catastrophic slope failures.
  • Ensures safety of men & machinery.
  • Compliance with Reg. 106 & 107 of CMR 2017 (benches, dumps, slopes).
6. Exam-Oriented Key Points
  • Circular 02 of 2020 = Systematic Slope Monitoring.
  • Tools: total station, radar, piezometer, inclinometer.
  • Drainage is key to slope safety.
  • Bench design must be based on geotechnical study.
  • Evacuation if slope movement crosses threshold.
πŸ“ 25 MCQs – DGMS Tech.
Circular No. 02 of 2020: Guidelines for Systematic Monitoring of Slopes in Opencast Mines

Q1. Circular 02 of 2020 deals with:
A) Methane safety in underground mines
B) Systematic slope monitoring in opencast mines
C) Safe blasting practices
D) Railway siding safety
E) Dust monitoring
βœ… Answer: B
Explanation: This circular provides guidelines for systematic slope monitoring to prevent slope/dump failures in opencast mines.


Q2. Slope failures in opencast mines can cause:
A) Roof fall accidents
B) Dump slides and bench collapse
C) Damage to HEMM & infrastructure
D) Fatal accidents to workers
E) All of the above
βœ… Answer: E
Explanation: Slope failure is hazardous because it causes dump slides, bench collapse, machinery damage, and fatalities.


Q3. Which of the following is a factor in slope instability?
A) Weak geological strata
B) Water seepage & rainfall
C) Blasting vibrations
D) Poor design of benches
E) All of the above
βœ… Answer: E
Explanation: All listed factors contribute to slope failure, especially in monsoon & weak strata.


Q4. Bench design parameters include:
A) Height of bench
B) Width of bench
C) Slope angle of bench
D) Catch benches
E) All of the above
βœ… Answer: E
Explanation: Bench geometry depends on height, width, slope angle, and provision of catch benches.


Q5. Catch benches are provided to:
A) Drain water
B) Arrest falling rocks
C) Support blasting operations
D) Control dust
E) None of the above
βœ… Answer: B
Explanation: Catch benches trap loose rocks and prevent them from rolling onto lower benches.


Q6. Drainage around slopes should include:
A) Garland drains
B) Sumps
C) Pumping systems
D) All of the above
E) None
βœ… Answer: D
Explanation: All drainage measures are needed to keep slopes dry and stable.


Q7. Which instrument measures slope movement in real-time?
A) Extensometer
B) Ground-based radar
C) Piezometer
D) Inclinometer
E) None
βœ… Answer: B
Explanation: Radar-based monitoring detects slope movement continuously and gives early warnings.


Q8. A piezometer is used to measure:
A) Slope angle
B) Water/groundwater pressure
C) Dust level
D) Rock temperature
E) Bench height
βœ… Answer: B
Explanation: Piezometers measure pore water pressure, a key factor in slope stability.


Q9. An inclinometer is used to measure:
A) Vertical crack displacement
B) Angular tilt of slope
C) Water seepage
D) Gas content
E) None
βœ… Answer: B
Explanation: Inclinometers monitor angular displacement/tilt of slopes.


Q10. An extensometer is used to measure:
A) Rock pressure
B) Slope crack movement/displacement
C) Dust in air
D) Gas concentration
E) None
βœ… Answer: B
Explanation: Extensometers measure crack widening and slope displacement.


Q11. Ground-based slope radars are useful because:
A) They reduce dust
B) They provide real-time monitoring & alarms
C) They detect gas
D) They calculate production
E) None
βœ… Answer: B
Explanation: Radars continuously scan slopes and provide real-time alerts.


Q12. Main responsibility for slope stability lies with:
A) Workers
B) Mine Manager
C) DGMS Inspector only
D) Contractors
E) None
βœ… Answer: B
Explanation: Mine Manager is legally responsible for slope stability, supported by geotechnical engineers.


Q13. Which blasting method is safest near slopes?
A) Random blasting
B) Controlled blasting with delay detonators
C) Overcharging
D) Blasting without stemming
E) None
βœ… Answer: B
Explanation: Controlled blasting minimizes vibration impact on slope stability.


Q14. Water seepage in slopes can be controlled by:
A) Drainage channels
B) Dewatering systems
C) Grouting
D) All of the above
E) None
βœ… Answer: D
Explanation: All listed measures help reduce seepage & pore pressure.


Q15. During monsoon, slope failure risk increases due to:
A) Dust
B) Gas accumulation
C) Rainfall & water infiltration
D) High wind only
E) None
βœ… Answer: C
Explanation: Water infiltration reduces slope shear strength, increasing risk.


Q16. Survey of slopes should be:
A) Done once every 5 years
B) Periodic & properly recorded
C) Optional
D) Done during accidents only
E) None
βœ… Answer: B
Explanation: Regular survey & data recording are mandatory for slope safety.


Q17. Regulation covering slope stability in coal mines is:
A) Reg. 106–107, CMR 2017
B) Reg. 150, MMR 1961
C) Reg. 31, OMR 2017
D) Factory Act
E) None
βœ… Answer: A
Explanation: CMR 2017 (Reg. 106–107) prescribes safety for benches & dumps.


Q18. Trigger levels in slope monitoring are used for:
A) Maintenance planning
B) Evacuation decision
C) Blasting permission
D) Dust control
E) None
βœ… Answer: B
Explanation: If slope movement exceeds trigger level β†’ workers evacuated.


Q19. Dumps in opencast mines should be:
A) Constructed systematically
B) Monitored like slopes
C) Properly drained
D) All of the above
E) None
βœ… Answer: D
Explanation: Dumps require same safety as pit slopes.


Q20. Which person plays key role in slope design & monitoring?
A) Geotechnical engineer
B) Blaster
C) Electrical supervisor
D) Ventilation officer
E) None
βœ… Answer: A
Explanation: Geotechnical engineer studies slope design & safety.


Q21. Radar slope monitoring provides advantage of:
A) Night-time & all-weather monitoring
B) Real-time alerts
C) Large coverage area
D) All of the above
E) None
βœ… Answer: D
Explanation: Radars are accurate, 24Γ—7, and give advance warnings.


Q22. Failure of external dump is considered:
A) Roof fall
B) Slope failure
C) Gas accident
D) Fire hazard
E) None
βœ… Answer: B
Explanation: Dump failure is classified as slope failure.


Q23. A bench collapse affecting only one working place is called:
A) Overall slope failure
B) Bench failure
C) Dump slide
D) Controlled slide
E) None
βœ… Answer: B
Explanation: Bench failure is localized slope failure.


Q24. Why is slope monitoring critical in opencast mines?
A) To increase production
B) To ensure slope safety and prevent accidents
C) To reduce manpower
D) To measure coal quality
E) None
βœ… Answer: B
Explanation: Purpose is safety of men & machinery.


Q25. Main aim of Circular 02 of 2020 is:
A) Improve blasting output
B) Guidelines for systematic slope monitoring
C) Train electrical supervisors
D) Introduce mechanization
E) None
βœ… Answer: B
Explanation: Objective = systematic monitoring of slopes in opencast mines.


βœ… Memory Hack:
πŸ‘‰ β€œ2 = 2 Sides of a Slope” β†’ Circular 02 of 2020 = Slope Monitoring.


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