Accidents Due to Failures of Coal and Ore Handling Plants in Mines – DGMS Guidelines & Preventive Measures

🧾 DETAILED NOTES

1️⃣ Introduction

Coal Handling Plants (CHP) and Ore Handling Plants (OHP) are vital surface installations in mining operations where bulk material is transported, crushed, screened, and stacked. However, DGMS accident reports show that 10–15% of surface industrial accidents occur in these plants due to mechanical failures, unsafe maintenance, and human error. Major incidents involve conveyor belt entrapment, chute blockages, crusher jamming, and electrical faults.

2️⃣ Common Causes of Accidents

(A) Mechanical Failures: Conveyor belt snap or pulley failure; Broken idlers, rollers, or belt slippage; Crusher jam and rotor imbalance; Structural collapse of trestles or trusses.

(B) Electrical & Control Failures: Short circuits due to poor insulation; Improper earthing or overload; Faulty interlocks and emergency stop systems.

(C) Operational & Human Errors: Working near running conveyors; Non-compliance with Lockout/Tagout (LOTO) during maintenance; Poor communication; Lack of supervision.

(D) Material & Structural Hazards: Chute or hopper blockages; Dust explosions in enclosed areas; Failure of transfer towers or stacker boom breakage.

3️⃣ DGMS Regulations & Circulars

Reference	Description
CMR 2017, Reg. 126 & 127	Maintenance and operation of mechanical appliances.
MMR 1961, Reg. 124 & 125	Safety of material handling equipment.
DGMS Circular 6 of 2003	Safety precautions in conveyor belt operation.
DGMS Circular 3 of 2005	Standard Operating Procedures (SOPs) for CHP/OHP.
DGMS Tech Circular 2 of 2015	LOTO system and energy isolation practices.
DGMS Circular 4 of 2010	Preventive maintenance and inspection schedules.

4️⃣ Preventive Measures

(A) Safe Design and Layout: Provide walkways and handrails along conveyors; Install emergency stop switches (pull cords) at every 10–15 m; Guarding of all rotating/moving parts.

(B) Maintenance & Inspection: Strict Lockout/Tagout (LOTO) during repair; Daily mechanical and electrical inspection logbooks; Monthly safety audit.

(C) Operational Safety: Start-up alarms before conveyor start; No person allowed to cross under running belts; Only trained operators to handle control panels.

(D) Fire & Dust Control: Use of flame-proof motors in coal areas; Install belt fire sensors and deluge systems; Proper dust suppression and housekeeping.

5️⃣ DGMS Recommendations

All mines must have a Standard Operating Procedure (SOP) for CHP/OHP.
LOTO implementation before any repair or jam clearance.
Supervisors to ensure safe clearance of blockages only with isolation and permit.
Safety audit and vibration monitoring of stackers/reclaimers quarterly.
DGMS-approved training module for mechanical maintenance personnel.

6️⃣ Case Study (DGMS Investigation 2017)

A fatal accident occurred in a coal handling plant when a worker attempted to clear a blocked chute without isolation. The conveyor started automatically due to interlock failure.

DGMS Findings: No LOTO system implemented; Inadequate supervision and absence of start-up alarm.

Recommendations: Mandatory interlocking and LOTO system; Red-tag permit for confined or maintenance work.

⚙️ QUICK ONE-LINERS (Revision Points)

DGMS Circular 6/2003: Conveyor belt safety.
LOTO – Lockout/Tagout – compulsory during maintenance.
Emergency pull cord every 10–15 m along conveyors.
CMR Reg. 126–127: Mechanical maintenance rules.
DGMS Circular 3/2005: SOP for CHP/OHP.
DGMS Circular 2/2015: Energy isolation and lockout.
Belt snap, pulley failure = major mechanical hazards.
No person allowed under running conveyor.
Fire prevention by flameproof motors and sprinklers.
Mandatory quarterly mechanical safety audit.

🧮 DESCRIPTIVE MODEL QUESTION

Q. Describe the common causes and preventive measures for accidents due to failure of coal or ore handling plants in mines as per DGMS guidelines.

Answer:
Accidents in coal and ore handling plants are mainly due to mechanical failures (e.g., conveyor belt snap), poor maintenance, and unsafe practices (e.g., clearing jams without isolation). DGMS Circulars 6/2003 (Conveyors) and 3/2005 (SOPs) specify that all systems must have emergency pull cords, guarding, and strict LOTO (Lockout/Tagout) procedures during maintenance (as per Circular 2/2015). Preventive measures include regular inspections (CMR 126-127), dust suppression, fire protection, and comprehensive operator training to ensure a safe working environment.

🧩 25 DGMS-Based MCQs

Q1. Major cause of accidents in CHP/OHP:

Solution: CHP/OHP accidents are predominantly related to machinery, including conveyors, crushers, and structures.

Q2. DGMS Circular on conveyor belt safety:

Solution: DGMS Circular 6 of 2003 specifically outlines safety precautions for conveyor belt operations.

Q3. LOTO stands for:

Solution: LOTO (Lockout/Tagout) is the standard safety procedure for isolating energy sources during maintenance.

Q4. Emergency pull cord spacing along conveyors:

Solution: Pull cords must be easily accessible, with 10-15m being a common standard spacing.

Q5. Regulation for mechanical maintenance in mines:

Solution: Regulations 126 & 127 of CMR 2017 deal with the appointment of engineers and the safe maintenance of mechanical appliances.

Q6. DGMS Circular 2 of 2015 deals with:

Solution: This circular provides detailed guidelines on the standards for energy isolation and LOTO procedures.

Q7. Conveyor belts should be guarded to:

Solution: Guarding prevents workers from coming into contact with moving parts like rollers, idlers, and the belt itself.

Q8. Fire detection in CHP must include:

Solution: A comprehensive fire detection system in a CHP uses multiple types of sensors (heat, smoke, CO for smoldering) for early detection.

Q9. SOP stands for:

Solution: SOP stands for Standard Operating Procedure, a key document in safety management.

Q10. DGMS Circular 3/2005 relates to:

Solution: This circular specifically mandates the preparation and implementation of SOPs for CHPs and OHPs.

Q11. LOTO should be implemented during:

Solution: LOTO is a safety procedure specifically for maintenance, repair, or cleaning to prevent accidental startup.

Q12. Working under running conveyor is:

Solution: This is an unsafe act and is strictly prohibited due to the risk of falling material or belt failure.

Q13. DGMS Circular 4/2010 emphasizes:

Solution: This circular highlights the importance of having scheduled preventive maintenance plans for machinery.

Q14. Start-up alarm should sound at least:

Solution: A pre-start audio-visual alarm (hooter/siren) is required for a sufficient duration (e.g., 10-15 seconds) to warn people.

Q15. Dust control in CHP is achieved by:

Solution: Water sprinklers and mist sprays at transfer points are the primary methods for dust suppression in CHPs.

Q16. Flameproof motors are used to:

A. Save energy B. Prevent fire/explosion C. Increase speed D. None

Solution: Flameproof (Ex 'd') enclosures prevent an internal spark from igniting external flammable dust or gas.

Q17. Conveyor belt inspection frequency:

Solution: Daily pre-shift inspections of critical machinery like conveyors are a standard requirement.

Q18. DGMS accident reports show __% of surface accidents in CHP:

Solution: CHPs/OHPs are significant contributors to surface accidents, typically in the 10-15% range.

Q19. Stackers/reclaimers require vibration monitoring:

Solution: Quarterly vibration analysis is a standard predictive maintenance practice for large rotating machinery like stackers.

Q20. SOP must be approved by:

Solution: The Mine Manager is responsible for framing and approving all Standard Operating Procedures (SOPs) for the mine.

Q21. Electrical short circuits are caused by:

Solution: All three are common causes of electrical faults. Poor insulation and moisture break down resistance, while overload generates excessive heat.

Q22. Permit-to-work system is part of:

Solution: The Permit-to-Work system is a formal administrative control, often part of the LOTO procedure, and detailed within the SOP.

Q23. Crushers must have:

A. Guards and interlocks B. Overload sensors C. Both A & B D. None

Solution: Safety requires both physical guards (for moving parts) and control interlocks (like overload sensors) to prevent damage and accidents.

Q24. DGMS recommends fire drills in CHP at least:

A. Once a month B. Once every 3 months C. Twice a year D. Annually

Solution: Quarterly (every 3 months) fire drills are a standard requirement for high-risk areas like CHPs.

Q25. Key principle of CHP safety:

Solution: A safe CHP relies on a combination of good maintenance, well-trained personnel, and strict adherence to safety procedures like LOTO.

🔗 INTERNAL LINKS

Related Topic	Read More On...
LOTO	Lockout/Tagout (LOTO) Procedures in Mines
HEMM Safety	Safety Features in Crawler/Tyre Mounted Machinery
Safety Management	Integrated Safety Management Plan (SMP)
Electrical Safety	Electrical Safety & Accident Investigation

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