Not every mining disaster is a spectacular explosion or a flood. Some of the most common and deadly accidents in underground coal mining are far quieter: a slab of rock, hanging unseen above a working face, simply lets go. The Shyamsundarpur Colliery accident of 29 November 2006 is a textbook example. At about 5:30 am, in a depillaring panel in the Bankola Area of Eastern Coalfields Limited (ECL), a huge block of sandstone fell. Six loaders were killed, and a mining sirdar and four other loaders were injured.
This post walks through what happened, what the enquiries found and what students of mining can learn from it, especially about depillaring with caving, a method that is full of lessons about strata control. It is based on a published summary of the accident and the enquiry. I refer to officials by their roles, not by name.
A note before we begin: six families lost someone in this accident. We study it so that the same mistakes are never repeated.
The accident at a glance
| Mine | Shyamsundarpur Colliery, Bankola Area, Eastern Coalfields Limited (ECL) |
| Date and time | 29 November 2006, at about 5:30 am (third shift) |
| Place | 12B slice of a depillaring panel in the contiguous Jambad Top and Jambad Bottom seams |
| Type of accident | Roof fall |
| Casualties | 6 fatal injuries (loaders), minor injuries to one mining sirdar and four loaders |
| Production | About 375 tonnes per day from the panel |
The mine and the panel
Two thick seams, Jambad Top and Jambad Bottom, lay one above the other with a parting of only about 3 m between them. The panel was being depillared with caving in both seams at the same time, with permission from DGMS that had been granted on 3 August 2006.
| Cover, seam or parting | Thickness | Status of working |
|---|---|---|
| Cover | 55 m (hard cover 35 m) | - |
| Jambad Top seam | 2.3 to 2.5 m | Depillaring with caving |
| Parting | 3 m | |
| Jambad Bottom seam | 4.65 m | Depillaring with caving |
| Parting | 58 to 75 m | |
| Bankola seam | 4.88 m | Development with roof bolting and SDL |
| Parting | 26 m | |
| Banbahal seam | - | Water-logged |
- The seams had a cover of 55 m, of which 35 m was hard cover, and an incubation period of 4¼ months.
- The DGMS permission said the Top and Bottom sections were to be worked simultaneously, keeping the line of extraction in both vertically coincident, and a diagonal line of extraction was to be maintained. It also had a special provision that a scientific body should study and determine the parameters of induced blasting.
- Twenty-four pillars of average size 24.4 m (centre to centre) were to be extracted, and 11 had already been extracted, including the pillar where the accident occurred.
Depillaring with caving, in plain words
In bord and pillar mining, the coal is first developed into a grid of galleries leaving pillars of coal to hold up the roof. Later, in depillaring, those pillars are extracted. In depillaring with caving, the roof behind the working area is allowed to fall in a controlled way into the worked-out space, called the goaf. Pillars are often split and extracted in slices. This works well when the roof caves regularly and the lines of extraction are kept neat. It becomes dangerous when the roof is a thick, strong layer that does not cave on time, hangs over the goaf and then breaks suddenly.
What happened on the day
| Shift | What was happening at 12B slice |
|---|---|
| First shift | 14 shots were blasted in 12B slice. No tubs were loaded. |
| Second shift | Seven loaders were engaged and only 6 tubs were loaded. They then left the face and worked elsewhere until the end of the shift. |
| Third shift | 11 empty tubs were supplied, and 8 loaders loaded 11 tubs from 12B slice and left. About 9 more tubs arrived at about 3:30 am, and the same gang loaded 6 of them by 5 am. Then 13 loaders together started loading the remaining 3 empty tubs from the face. |
At 5:30 am, a roof fall suddenly occurred. It overrode the goaf edge and extended all the way to the working face, killing 6 loaders and injuring a mining sirdar and four loaders. The fall also extended into the slice which had joined. It was a fall of fine-grained massive sandstone measuring 9 m by 5.5 m by 0.9 m. That is about 45 cubic metres, which, at a typical sandstone density of around 2.4 tonnes per cubic metre, would be roughly 100 tonnes. (This weight is my rough estimate, not a figure from the report.)
Rescue and recovery
- On hearing of the accident, the manager, safety officer, colliery assistant manager and the back shift under-manager went down the mine.
- Rescue and recovery began immediately, with the support at the accident site being strengthened at the same time, for the protection of the rescuers.
- Manpower, tools and appliances for breaking the stones were brought from adjoining mines, and the work continued round the clock.
- Senior officials and rescue teams arrived. The Director (Technical) of Coal India and the Technical Secretary to the Chairman reached the mine at about 12:30 pm on 30 November 2006 and inspected the site.
- The first body was recovered at about 4:30 pm on 30 November 2006, and the sixth body by 9 pm on 1 December 2006.
- The Chairman of Coal India inspected the site on 2 December 2006 and discussed the causes and circumstances with unit, area and headquarters management.
Compensation and relief
- To the dependants of each victim: Life Cover Scheme payment of Rs 40,000, ex-gratia of Rs 30,000 and funeral expenses of Rs 750.
- Cheques for compensation were deposited with the Compensation Commissioner.
- An ex-gratia of Rs 3 lakh to the family of each victim, announced by the Minister for Coal, was paid.
- Cheques for gratuity were prepared for disbursement.
- One dependant of each victim was offered employment.
The enquiry
An enquiry ordered by the CMD of ECL was started by the CGM (T and MS), the Technical Secretary to the CMD and officials of the Internal Safety Organisation (ISO). A scientist from CMRI joined the enquiry to study the roof behaviour technically and recommend measures to prevent a repeat. DGMS withdrew the depillaring permission and began its own enquiry. Because the incubation period had been crossed, the panel was sealed off.
Causes, as found by the ISO enquiry
- Improper line of extraction in the top and bottom sections of the panel, causing irregular breakage of the roof in the goaf.
- Verticality of extraction not maintained between the top and bottom sections (the top section was being advanced), leading to irregular caving of the goaf.
- Over-splitting of pillars in the entire panel, in both sections.
- Lag of advance supports as per the Systematic Support Rules (SSR).
- No convergence recorder in the panel. The system for measuring convergence was missing, so the possibility of an early warning of the roof collapse was largely lost.
Recommendations of the ISO
- Massive immediate roof: where the roof is massive, as in the top section of the Jambad Top seam, any rib or stook that cannot be taken out or judiciously reduced should be blasted down.
- Induced blasting with 2.4 m long holes had been used to help the roof cave, but only with the aim of preventing air blast. It would have no effect on the caving behaviour of the immediate roof. Goaf inspection showed big boulders that had parted off from a weak zone, as seen in the past. A detailed study of weak zones and their effect on caving should be made when planning extraction in this kind of situation.
- The DGMS permission said induced blasting should be practised if the hanging roof in the goaf exceeded 60 square metres. The ISO felt this condition appeared impracticable.
- A faster rate of retreat can avoid an impending goaf fall that affects people.
- Splitting of pillars should be restricted to a maximum of 2 pillars ahead of the place under extraction. The DGMS permission had reduced it to one pillar, so DGMS should be persuaded to allow splitting up to two pillars.
- The conditions of the DGMS permission should be followed.
DGMS remarks in the Coal India Safety Committee meeting
- A study of the cavability of the roof had been done at a cost of Rs 3 lakh. But an instrument costing only Rs 10,000 that was needed to monitor roof behaviour had not been provided.
- The slice was being taken from both directions, within the slice as well as from the original gallery, and this resulted in the accident.
Lessons for mining students and workers
- Spend the small amount on monitoring. A Rs 3 lakh study was done, but a Rs 10,000 instrument was missing. Cheap monitoring tools such as convergence recorders can give the early warning that saves lives.
- Respect the line of extraction. When two seams are worked together, the lines of extraction must stay in step. Irregular lines create irregular goaf breaks and unpredictable roof falls.
- Do not over-split pillars. Splitting limits exist because over-reduced pillars carry load unevenly. The general rule in the regulations is a maximum of two pillars ahead. You can see how that rule is tested in the WCL Mining Sirdar 2023 paper.
- Know your roof. A thick, strong sandstone roof will hang until it breaks. Understanding how rock fails is basic to ground control. Read Rock Failure Theories in Mining to see why.
- Keep support in step with the work. Advance supports must keep up as per the support rules.
- Limit the people under the risk. Thirteen loaders were gathered at one face to load the last three tubs, and when the fall came it hit them all. Fewer people for a shorter time under a doubtful roof is a rule worth following.
- Permission conditions are not paperwork. They are designed to manage specific risks, and when a condition is impractical, the answer is to ask for it to be changed, not to ignore it.
- Understand the caving behaviour before you start, including weak zones, and plan the extraction around them.
For the legal framework, see our explainer on DGMS CMR 2026, and for exam practice try the Geology MCQs for Mining Engineering.
More to read on this blog
- Ground control and rock mechanics articles
- Mining methods, including longwall mining
- Blasting and explosives, for the background to induced blasting
- Mining SOPs and mine safety articles
- Mining history, for more case studies
Test yourself: 8 quick MCQs
- A. Western Jharia Area, BCCL, 6 September 2006
- B. Bankola Area, ECL, 29 November 2006
- C. Barka-Sayal Area, CCL, 15 June 2005
- D. Singareni, 13 October 2006
Show Answer
- A. 6
- B. 2
- C. 14
- D. 50
Show Answer
- A. That only the top seam be worked
- B. That they be worked in different years
- C. That they be worked simultaneously with the line of extraction vertically coincident
- D. That no stowing be done
Show Answer
- A. 1 m x 1 m x 1 m
- B. 50 m x 50 m x 5 m
- C. 0.5 m x 0.5 m x 0.1 m
- D. 9 m x 5.5 m x 0.9 m
Show Answer
- A. Convergence recorder
- B. Anemometer
- C. Tele-monitoring of methane
- D. Water gauge
Show Answer
- A. Zero pillars
- B. One pillar
- C. Two pillars
- D. Five pillars
Show Answer
- A. Because it was out of coal
- B. Because of flooding
- C. To save money
- D. Because the incubation period had been crossed
Show Answer
- A. To increase coal production
- B. To prevent air blast only
- C. To remove water
- D. To strengthen the roof
Show Answer
Frequently asked questions
What happened at Shyamsundarpur Colliery?
On 29 November 2006, a large fall of massive sandstone occurred in a depillaring panel in the Jambad Top and Bottom seams, killing six loaders and injuring five other people.
What was the main cause?
According to the ISO enquiry, irregular extraction lines between the top and bottom sections led to irregular caving of the goaf and a sudden heavy fall of the roof. Over-splitting of pillars, a lag of advance supports and the absence of a convergence recorder also contributed.
What is induced blasting?
Blasting the roof to help it cave in a controlled way. Here it was used mainly to prevent an air blast, and the ISO said it would not change how the immediate roof caved.
What is an incubation period?
The time within which coal left in a goaf can begin to heat spontaneously. If a panel has crossed it, it is usually sealed off.
Disclaimer: this article is an educational summary of a published account of the accident and its enquiry. It is not a legal document. For exact findings and for legal purposes, please refer to the official reports.
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