Fatal Accident Due to Roof Fall in Underground Coal Mine – DGMS Investigation & Preventive Measures

🏗️ DETAILED NOTES

1️⃣ Introduction

Roof fall is one of the most common and deadly hazards in underground coal mines. According to DGMS accident statistics (2014), a significant percentage of fatalities were caused by collapse of roof or sides, primarily due to poor roof support, inadequate examination, and failure to follow support plans.

2️⃣ DGMS Findings (2014)

Major Cause: Insufficient or delayed support installation.

Contributing Factors: Over-extraction and wide spans between supports; Poor quality of timber or props; Water seepage and weak roof strata; Inadequate supervision or early withdrawal of support.

Affected Areas: Bord & pillar workings, depillaring panels, junctions, and inclines.

DGMS Observation: 90% of roof fall accidents were preventable through proper roof monitoring and timely support installation.

3️⃣ Legal Provisions

Regulation / Rule	Description
CMR 2017 – Reg. 99	Support of working places
Reg. 100	Withdrawal of supports
Reg. 101	Systematic Support Rules (SSR)
Reg. 102	Precautions during depillaring
Reg. 106	Duties of competent persons
Mines Act, 1952 – Sec. 23	Duties related to mine safety

4️⃣ Causes of Roof Fall

Non-installation or removal of support before time.
Delay in setting supports near the working face.
Poor condition of timber or bolts.
Wide gallery width or overhanging roof.
Non-adherence to systematic support rule (SSR).
Lack of supervision during loading or depillaring.

5️⃣ Preventive Measures

Proper Support Installation: Immediate setting of props/bolts within 1.5 m of the face.
Systematic Support Rules (SSR): Follow approved SSR for each seam.
Strata Monitoring: Use tell-tales, extensometers, and convergence indicators.
Adequate Lighting: Ensure illumination for roof visibility.
Training: Educate workers on early signs of roof movement.
Supervision: Supervisory presence during support installation and removal.
Roof Bolting: Mechanized bolting for improved safety.

6️⃣ DGMS Recommendations

DGMS advised all mine managers to conduct special safety drives focusing on roof support practices. A review of SSR was mandated, especially in depillaring panels. All future roof monitoring must include instrumented observations and risk-based classification of areas. DGMS Circular No. 02/2016 on roof fall prevention reiterated these standards.

7️⃣ Lessons Learned

Issue Identified	Corrective Action
Delayed support installation	Install supports immediately after cutting
Poor supervision	Ensure competent person presence
Weak strata	Apply grouted bolts & steel girders
Non-adherence to SSR	Strict compliance and review
Untrained labor	Conduct practical training sessions

⚡ QUICK ONE-LINERS

Roof fall = top cause of fatalities in underground mines.
Reg. 99–102 of CMR 2017 govern roof support.
DGMS Circular 02/2016 covers roof safety. (Note: Original text mentioned 06/2014 for SSR)
Supports must be within 1.5 m of face.
Telltales used for roof movement monitoring.
Depillaring areas highly prone to roof falls.
SSR must be mine-specific and DGMS-approved.
Weak roof → use steel supports or bolts.
Roof fall risk increases with poor supervision.
Continuous monitoring = key to prevention.

🧠 DESCRIPTIVE QUESTION & ANSWER

Q. Discuss the DGMS guidelines and lessons learned from the fatal accident involving four persons due to roof fall in an underground coal mine.

Answer:
A fatal accident occurred in an underground coal mine where four persons lost their lives due to a sudden fall of roof during depillaring operations. Investigation by DGMS revealed that roof support installation was inadequate, and the Systematic Support Rule (SSR) was not followed strictly. The roof strata were weak, and tell-tales were not installed for early detection of movement.

Key Findings: Supports were not installed immediately after extraction; Roof inspection by the competent person was not thorough; Supervision during shift change was poor.

Regulations Referenced: CMR 2017, Reg. 99–102 (Support, SSR, Withdrawal); DGMS Circular 02/2016 (Roof fall control measures).

Preventive Measures: Follow SSR strictly; Use tell-tales in all depillaring panels; No work under unsupported roof; Provide roof bolting in systematic grid pattern; Regular roof safety training.

Conclusion: Strict adherence to support regulations and effective supervision can prevent recurrence of such tragic accidents. Every miner must understand that roof safety is life safety.

🎯 25 MCQs – Roof Fall Accident & DGMS Safety Rules

Q1. Which regulation of CMR 2017 deals with roof support?

Solution: Regulation 99 of CMR 2017 specifically covers the support of working places.

Q2. SSR stands for:

Solution: SSR is the acronym for Systematic Support Rule, a key element in roof control.

Q3. Tell-tales are used for:

Solution: Tell-tales are instruments specifically designed to detect and indicate movement or separation in roof strata.

Q5. Roof fall commonly occurs during:

Solution: Depillaring operations inherently destabilize the roof strata, making them high-risk areas for falls.

Q6. DGMS circular for roof fall prevention:

Solution: DGMS Circular No. 02/2016 specifically addresses measures for preventing roof fall accidents.

Q7. Roof support must be:

Solution: Timely installation of support after exposing fresh roof is crucial for preventing falls.

Q8. Minimum roof support inspection frequency:

Solution: Competent persons like Overmen/Sirdars are required to inspect the roof at the beginning of each shift.

Q9. Unsupported roof area is:

Solution: Working or travelling under unsupported roof is extremely dangerous and strictly prohibited.

Q10. Withdrawal of supports requires:

Solution: Regulation 100 of CMR 2017 outlines the procedures and permissions required for withdrawing supports.

Q11. Roof fall hazard mainly due to:

Solution: The inherent geological weakness of the roof rock is a primary contributing factor.

Q12. Roof bolting spacing depends on:

Solution: Geotechnical assessment of the rock mass rating (RMR) or similar classification determines the required bolt density and pattern.

Q13. SSR approval authority:

Solution: Systematic Support Rules must be formally submitted to and approved by DGMS.

Q14. Roof fall accident reporting under:

Solution: Regulation 9 of CMR 2017 specifically deals with the notice of accidents in coal mines. Mines Act Sec 23 covers the general duty.

Q15. Roof monitoring device:

Solution: Tell-tales are common instruments used specifically for monitoring roof movement.

Q16. Overman responsibility:

Solution: Examining the roof and sides is a primary duty of the Overman at the start of each shift.

Q17. Roof fall leads to:

Solution: Roof falls are a major cause of serious and fatal injuries in underground mines.

Q18. Depillaring involves:

Solution: Depillaring is the process of extracting the coal pillars left during the first phase of bord and pillar mining.

Q19. DGMS stresses on:

Solution: Training workers to recognize and respond to roof hazards is a key preventive measure emphasized by DGMS.

Q20. Roof fall mostly occurs in:

Solution: The geology of sedimentary coal measures often makes them more prone to roof instability compared to hard rock metal mines.

Q21. Roof bolt type used:

Solution: Resin-grouted bolts are a common and effective type of roof support used in modern mining.

Q22. Support withdrawal order given by:

Solution: Withdrawal of supports is a critical operation requiring authorization from the Mine Manager or designated competent person.

Q23. Roof fall hazard prevented by:

Solution: Adherence to approved support rules (SSR) and effective support methods like bolting are primary preventive measures.

Q24. DGMS mandates tell-tale frequency (typical guideline):

Solution: While specific spacing depends on conditions, installing tell-tales at regular intervals (like every 10m at junctions or critical areas) is a common guideline for effective monitoring. Check specific mine SSR.

Q25. Main cause of roof fall fatalities:

Solution: Working or being present under roof areas that are not adequately supported according to regulations is the direct cause of most roof fall fatalities.

🔗 INTERNAL LINKING SUGGESTIONS

Related Topic	Read More On...
Strata Control	Strata Monitoring in Longwall Workings
Safety Management	Integrated Safety Management Plan (SMP)
DGMS Circulars	DGMS Tech SOMA Circular No. 03 of 2024
Accident Investigation	Accident Investigation & Legal Framework

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