DGMS (Tech.) Circular 02/2010: Complete Guide to Slope Stability & Monitoring

📘 DGMS (Tech.) Circular No. 02 of 2010 – Systematic Slope Monitoring in Opencast Mines

1. Background / Need for the Circular

Opencast mining trend in India → Deeper and larger pits with greater stripping ratios.

Increasing bench heights (30–45 m) and final pit slopes (>200 m in depth) → Higher risk of slope instability.

Failures in overburden dumps and highwalls had caused fatal accidents and production loss.

Therefore, DGMS mandated a scientific and systematic monitoring programme for all OC mines.

2. Objectives

Detect early warning signs of slope failure.

Develop a scientific monitoring system (not just visual inspection).

Ensure design & slope stability analysis by geotechnical experts.

Establish responsibility & accountability at the mine level.

Integrate emergency preparedness & response system.

3. Applicability

Coal and metalliferous mines, where:

Final pit depth >100 m.

Bench height >10 m.

Steep and composite slopes exist.

External OB dumps >30 m height.

Special focus on mines in weak geological formations (shales, weathered sandstone, lateritic rocks, etc.).

4. Systematic Slope Monitoring Programme (SMP) DGMS mandates every OC mine to maintain an SMP document, covering: A. Visual & Routine Monitoring

Look for:

Tension cracks on slope crest.

Bulging toe at slope bottom.

Seepage or wet patches → Indicates high pore pressure.

Small rockfalls / boulder dislodging.

All staff (overman, supervisor, workers) must be trained to recognize and immediately report abnormalities.

B. Scientific Monitoring (Instrumentation) (Compulsory in large mines)

Inclinometers → Detect slope tilt.

Extensometers → Measure displacement inside rock mass.

Piezometers → Measure pore water pressure → Very crucial in rainy season.

Prism Monitoring using Total Station → High accuracy ground movement detection.

Ground Based Radar (GBR) → Real-time slope monitoring (advanced mines).

LiDAR Scanning → 3D model of pit & slope movement over time.

Seismographs → To study vibrations due to blasting.

C. Survey & Geotechnical Inputs

Bench configuration to be based on Rock Mass Rating (RMR), Slope Mass Rating (SMR), or k-ratio method.

Slope design to be approved by geotechnical expert from CMPDIL/IBM/IITs/NITs or similar institutions.

Record of:

Bench height, width, slope angle.

Factor of Safety (FoS) of each slope (should be ≥ 1.2 for working slopes, ≥ 1.5 for final slopes).

D. Dump Monitoring

Dumps prone to flow slides and rotational slips.

Guidelines:

Dump height should not exceed recommended design.

Benching of dumps mandatory (6–10 m height benches).

Maintain catch drains, garland drains, and slope vegetation to control water.

Instrumentation monitoring for large dumps >30 m.

E. Monitoring Frequency

Shift-wise (Daily): Visual inspection → cracks, seepage, falls.

Weekly: Formal slope monitoring by Asst. Manager & Surveyor.

Quarterly: Geotechnical review + Report.

Annually: Comprehensive slope stability assessment by scientific agency.

5. Reporting & Records

Mines must maintain:

Slope Monitoring Register – Daily/weekly readings.

Instrumentation data logs – Graphs of displacement, tilt, pressure.

Slope stability maps – Updated annually.

Report to DGMS:

Annual Slope Stability Report.

Immediate reporting of any abnormal readings or near-failure incidents.

6. Emergency Preparedness

Slope Failure Emergency Action Plan (EAP):

Safe withdrawal routes.

Alarm system (siren).

Communication plan.

Assembly points outside danger zone.

Regular mock drills for workforce.

7. Roles & Responsibilities

Mine Manager – Overall in charge of slope monitoring.

Geotechnical Engineer – Design & technical monitoring.

Surveyor – Accurate measurements & records.

Overman/Foreman – First-level reporting of cracks/instability.

DGMS Officials – Verification & enforcement.

8. Case Learnings (Why Important)

Several accidents in coalfields (SECL, MCL, SCCL) were due to dump failures after rainfall.

Example:

Rajmahal Coal Mine, Jharkhand (2016) – Dump slide caused multiple fatalities.

SCCL Mines – Highwall failures during monsoon.

Most cases → poor drainage, weak dump management, absence of systematic monitoring.

9. Safety Precautions as per Circular

Maintain catch benches at interval of 30–40 m.

Berms of minimum 1.5 m width at slope edge.

No machinery within 10 m from slope toe unless cleared.

Ensure controlled blasting techniques near final slopes.

No dumping during heavy rainfall.

10. Benefits of Implementation

Reduction in slope failure accidents.

Enhanced worker and equipment safety.

Increased productivity by reducing downtime.

Scientific database for future planning & design optimization.

11. Exam-Oriented Key Points

Circular No.: DGMS (Tech.) 02 of 2010.

Subject: Systematic Slope Monitoring in Opencast Mines.

Monitoring Levels: Visual + Instrumental + Geotechnical.

Monitoring Frequency: Daily, Weekly, Quarterly, Annual.

Factor of Safety: ≥ 1.2 (working), ≥ 1.5 (final).

Reporting: Annual report to DGMS.

Tools: Inclinometer, Extensometer, Piezometer, Total Station, Radar, LiDAR.

Responsibility: Manager + Geotechnical Engineer + Surveyor.

📘 MCQs – DGMS (Tech.) Circular 02 of 2010 (Systematic Slope Monitoring)

Q1. DGMS (Tech.) Circular No. 02 of 2010 deals with: A. Blasting practices in opencast mines
B. Systematic slope monitoring
C. Mine ventilation standards
D. Explosives handling procedures
E. Transport rules in opencast mines ✅ Answer: B
Explanation: Circular 02/2010 specifically prescribes Systematic Slope Monitoring (SSM) in opencast mines.

Q2. The main objective of slope monitoring is: A. Increase mine production
B. Ensure early detection of slope instability
C. Reduce manpower requirement
D. Replace geotechnical studies
E. Reduce overburden removal ✅ Answer: B
Explanation: The goal is early warning and prevention of slope failures, not production-related.

Q3. The slope monitoring programme (SMP) must include: A. Only blasting vibration studies
B. Only annual geotechnical survey
C. Visual, instrumentation, and geotechnical monitoring
D. Only prism monitoring
E. None of the above ✅ Answer: C
Explanation: SMP must integrate visual inspection, scientific instrumentation, and geotechnical design inputs.

Q4. Which instrument is used to monitor pore water pressure in slope mass? A. Inclinometer
B. Extensometer
C. Piezometer
D. LiDAR
E. Seismograph ✅ Answer: C
Explanation: Piezometers → measure pore water pressure, which directly affects slope stability.

Q5. For working slopes, the minimum Factor of Safety (FoS) should be: A. 1.0
B. 1.1
C. 1.2
D. 1.5
E. 2.0 ✅ Answer: C
Explanation: DGMS requires FoS ≥ 1.2 for working slopes, ≥ 1.5 for final pit slopes.

Q6. Which of the following is NOT a tool for slope monitoring? A. Total Station
B. Inclinometer
C. Extensometer
D. Piezometer
E. Flameproof switchgear ✅ Answer: E
Explanation: Flameproof switchgear is for electrical safety, not slope monitoring.

Q7. Frequency of visual inspection by mine officials should be: A. Daily (shift-wise)
B. Weekly
C. Monthly
D. Quarterly
E. Annually ✅ Answer: A
Explanation: Shift-wise/daily visual monitoring is compulsory.

Q8. Comprehensive slope stability assessment by a scientific agency should be carried out: A. Weekly
B. Monthly
C. Annually
D. Every 5 years
E. Only at mine closure ✅ Answer: C
Explanation: Annual slope stability study is mandatory.

Q9. External dump slope monitoring is essential because: A. Dumps are consolidated rock
B. Dumps consist of loose, unconsolidated material
C. Dumps are less dangerous than pit slopes
D. Dumps are always stable
E. Dumps don’t require monitoring ✅ Answer: B
Explanation: Loose dumps are prone to failures, hence systematic monitoring is required.

Q10. A common early sign of slope failure is: A. Sudden rise in production
B. Development of tension cracks
C. Reduction in water seepage
D. Increase in ore grade
E. None of the above ✅ Answer: B
Explanation: Cracks at slope crest are classic early indicators of instability.

Q11. Which technology provides real-time slope movement detection? A. Total station
B. Ground-based radar (GBR)
C. Compass survey
D. Tape measurement
E. Barometer ✅ Answer: B
Explanation: GBR detects slope movement in real-time with high accuracy.

Q12. Catch benches are provided in slopes mainly for: A. Drainage of water
B. Stopping rockfalls and sliding material
C. Supporting haul roads
D. Allowing machinery parking
E. Increasing slope angle ✅ Answer: B
Explanation: Catch benches intercept falling material and improve slope safety.

Q13. In slope monitoring, LiDAR technology is used for: A. Measuring pore pressure
B. Mapping 3D slope surfaces
C. Detecting vibrations
D. Studying blasting fumes
E. Checking machine health ✅ Answer: B
Explanation: LiDAR produces 3D terrain/slope models for deformation studies.

Q14. Who holds overall responsibility for slope monitoring in a mine? A. Overman
B. Surveyor
C. Mine Manager
D. Geotechnical Engineer
E. DGMS Inspector ✅ Answer: C
Explanation: Mine Manager is legally responsible, though technical support is from surveyor & geotechnical expert.

Q15. Which condition is most dangerous for slope stability? A. Dry summer
B. Heavy rainfall with poor drainage
C. Winter season
D. Controlled blasting
E. Final slope benched ✅ Answer: B
Explanation: Rain increases pore water pressure → slope failure risk.

Q16. In systematic slope monitoring, survey records must include: A. Bench height & slope angle
B. Type of explosives used
C. Output per shift
D. Workers’ attendance
E. Fuel consumption ✅ Answer: A
Explanation: Bench geometry + slope stability parameters must be recorded.

Q17. A slope with FoS = 1.0 indicates: A. Stable condition
B. Marginally stable, failure possible
C. Very safe slope
D. Excessively safe slope
E. Not applicable ✅ Answer: B
Explanation: FoS = 1.0 → resisting = driving forces → slope is critically stable.

Q18. Dump benches should normally be: A. 1–2 m
B. 6–10 m
C. 20–30 m
D. 40–50 m
E. Not benched at all ✅ Answer: B
Explanation: DGMS recommends 6–10 m benches in OB dumps.

Q19. In case of slope movement detection, first action should be: A. Continue operations
B. Evacuate men & machinery
C. Increase excavation rate
D. Reduce blasting charge
E. Do nothing until failure occurs ✅ Answer: B
Explanation: Immediate withdrawal of men & machines is the first emergency action.

Q20. Which circular mandates slope monitoring in Indian opencast mines? A. DGMS Tech. 01/2005
B. DGMS Tech. 02/2010
C. DGMS Tech. 03/2019
D. DGMS Tech. 04/2015
E. MMR 1961 Rule 190A ✅ Answer: B
Explanation: 02/2010 is the slope monitoring circular.

Q21. Controlled blasting near final slopes is required to: A. Improve coal grade
B. Minimize slope disturbance
C. Increase slope angle
D. Reduce haul road length
E. Increase powder factor ✅ Answer: B
Explanation: Controlled blasting reduces vibrations → prevents slope weakening.

Q22. Slope Monitoring Cell in a mine is constituted under the: A. DGMS Inspector
B. Surveyor
C. Mine Manager
D. IBM Authority
E. Mining Engineer at DGMS HQ ✅ Answer: C
Explanation: Mine Manager forms a slope monitoring cell as per circular.

Q23. Which is a non-instrumental method of slope monitoring? A. Prism survey
B. Extensometer
C. Visual observation
D. Inclinometer
E. Piezometer ✅ Answer: C
Explanation: Visual inspection is a basic non-instrumental method.

Q24. Emergency Action Plan (EAP) for slope failure should include: A. Safe withdrawal, alarm, communication
B. Production schedule revision
C. Mine closure proposal
D. Increase in manpower
E. Only DGMS reporting ✅ Answer: A
Explanation: EAP includes safe evacuation, alarm system, communication & mock drills.

Q25. The biggest advantage of systematic slope monitoring is: A. Higher output per man shift
B. Reduced diesel consumption
C. Early warning → prevention of slope failure
D. Reduction in blasting cost
E. Lesser haul road maintenance ✅ Answer: C
Explanation: The ultimate purpose is early detection of instability → save lives + property.

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