🏗️ Detailed Notes
1️⃣ Introduction
Lock Out & Tag Out (LOTO) is a critical safety system that ensures machines and electrical systems are completely de-energized before maintenance or repair. In mines, where equipment such as conveyors, pumps, crushers, and drilling machinery operate under high voltage or pressure, failure to isolate energy can result in fatal accidents. DGMS mandates LOTO under Regulation 123(2) of Coal Mines Regulations, 2017, Regulation 126 of MMR 1961, and various DGMS Technical Circulars on electrical and mechanical safety.
2️⃣ Meaning of Lock Out & Tag Out
| Term | Definition |
|---|---|
| Lock Out | Physical isolation of energy sources using lock devices to prevent accidental energization. |
| Tag Out | Placement of warning tags or labels indicating that the equipment is under maintenance and must not be operated. |
3️⃣ Purpose of LOTO in Mines
- Prevent unexpected energization of machinery.
- Protect maintenance and electrical workers.
- Ensure compliance with DGMS & OSHA-equivalent standards.
- Avoid electrocution, entrapment, or mechanical movement.
- Promote systematic energy control during shutdowns.
4️⃣ Types of Hazardous Energy in Mines
- Electrical Energy – Motors, cables, transformers.
- Mechanical Energy – Conveyors, belts, crushers.
- Pneumatic Energy – Compressed air lines.
- Hydraulic Energy – Pumps and drilling rigs.
- Thermal Energy – Boilers, furnaces, diesel engines.
- Chemical Energy – Fuel storage or battery systems.
5️⃣ DGMS Legal Framework
| Provision | Description |
|---|---|
| CMR 2017 – Reg. 123(2) | Before repair/maintenance, energy source must be isolated. |
| MMR 1961 – Reg. 126(1)(c) | No electrical work unless the circuit is isolated and locked off. |
| DGMS Circular (Tech.) No. 06/2013 | Guidelines for electrical safety and lock-out procedures. |
| DGMS Circular (Tech.) No. 08/2015 | Safe work practices for maintenance in mines. |
6️⃣ Standard LOTO Procedure (Step-by-Step)
- Preparation: Identify all energy sources. Notify affected personnel.
- Shutdown: Turn off power or equipment normally.
- Isolation: Disconnect or de-energize using switch, valve, or circuit breaker.
- Lockout: Apply padlocks and lockout hasps on each energy source.
- Tagout: Attach a visible tag indicating “DO NOT OPERATE – UNDER MAINTENANCE”.
- Verification: Test zero energy condition using meters or try-start method.
- Maintenance: Proceed with work only after verifying isolation.
- Re-energization: Remove tools, clear personnel, remove locks/tags, and restore power.
7️⃣ Roles & Responsibilities
| Personnel | Duties |
|---|---|
| Manager | Ensure LOTO policy implementation. |
| Engineer (Electrical/Mechanical) | Authorize isolation and lockout. |
| Supervisor | Verify zero energy before starting work. |
| Workmen/Technicians | Follow LOTO checklist before maintenance. |
8️⃣ LOTO Equipment Used in Mines
- Safety Padlocks (color coded).
- Lockout Hasps (for multiple users).
- Circuit Breaker Locks.
- Ball Valve Lockouts.
- Danger Tags / Permit Tags.
- Isolation Boards.
9️⃣ DGMS Best Practices
- Every mine must have a written LOTO policy.
- Maintain LOTO Register signed by authorized engineers.
- Conduct periodic training for maintenance workers.
- Never bypass or share locks.
- Display LOTO instructions near all MCC panels.
⚡ Quick One-Liners (Revision Points)
- LOTO = Lock Out Tag Out.
- Ensures complete energy isolation.
- Regulation 123(2), CMR 2017 – Energy shutdown before maintenance.
- No person shall work on live circuit.
- Lock prevents re-energization; Tag warns others.
- DGMS Circular 06/2013 – Electrical LOTO guidelines.
- Verification ensures zero energy condition.
- Each worker uses personal lock.
- LOTO register is mandatory.
- Failure in LOTO leads to fatal accidents.
🧠 Descriptive Model Question & Answer
Q. Explain the purpose, procedure, and DGMS requirements of Lock Out & Tag Out (LOTO) system for energy shutdown in mines.
Answer:
The Lock Out & Tag Out (LOTO) procedure is a systematic safety method for isolating hazardous energy sources before any maintenance or servicing work. It ensures that equipment remains completely de-energized and cannot be accidentally started.
As per Regulation 123(2) of the Coal Mines Regulations, 2017 and Reg. 126 of MMR 1961, no person shall repair or work on machinery unless the power is isolated, locked out, and tagged. The LOTO process involves identifying energy sources, isolating them, applying padlocks, placing warning tags, and verifying zero energy before work begins.
Authorized engineers and maintenance staff must record all activities in a LOTO Register. DGMS Circulars (Tech.) No. 06/2013 and 08/2015 emphasize LOTO implementation in all mines to prevent electrocution, entanglement, and unexpected machine motion. Thus, the LOTO system is a vital part of mine electrical and mechanical safety, ensuring zero harm and complete energy control during maintenance.
🎯 25 MCQs – LOCK OUT & TAG OUT (LOTO)
Q1. LOTO stands for:
Q2. Main purpose of LOTO:
Q3. Regulation requiring isolation before maintenance:
Q4. DGMS Circular for electrical lockout:
Q5. Tag in LOTO indicates:
Q6. Before starting maintenance, the equipment must be:
Q7. Common LOTO equipment:
Q8. DGMS LOTO register maintained by:
Q9. Testing zero energy means:
Q10. LOTO prevents:
Q11. Color of danger tag:
Q12. Each worker must:
Q13. “Tag Out” means:
Q14. LOTO applied to:
Q15. Who can remove lock/tag?
Q16. DGMS Circular 08/2015 relates to:
Q17. LOTO register contains:
Q18. LOTO policy ensures:
Q19. Re-energization done after:
Q20. LOTO is mandatory during:
Q21. Each lock should have:
Q22. Lock & tag must be placed at:
Q23. If multiple workers work on same equipment:
Q24. Removing tag without authorization leads to:
Q25. Primary benefit of LOTO:
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