Belt Conveyor System – Components, Function & Design | DGMS Mechanical Notes

🧾 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, due to mechanical failure, human error, poor maintenance, or inadequate supervision, serious accidents and structural collapses can occur — resulting in injury, fire, or loss of life.

2️⃣ DGMS Concern

DGMS has repeatedly observed that plant machinery and conveyor systems in mines are often operated without adequate guarding, maintenance, or inspection schedules. Most fatal and serious accidents in CHP/OHP arise due to: Entanglement in conveyor belts, Structural failure, Fire incidents, Collapse of transfer towers, and Electrical short circuits. DGMS mandates preventive inspections, competent supervision, and lockout-tagout (LOTO) systems to ensure safe plant operations.

3️⃣ Legal Framework

Reference	Description
The Mines Act, 1952 – Sec. 23	Ensures worker safety during machinery operation.
CMR 2017 – Reg. 99, 130, 131	Safety provisions for mechanical and electrical installations.
DGMS Tech. Circular 05/2017	Safety in conveyor belt and material handling plants.
DGMS Circular (Mech.) No. 08/2018	Maintenance and guarding of CHP/OHP systems.
IS 7155 (Part 1–4)	Design and safety requirements for conveyor systems.

4️⃣ Major Causes of Failures and Accidents

Lack of proper guarding on conveyors.
Failure of pulleys, belts, or gearboxes due to poor maintenance.
Overloading and material spillage leading to structural stress.
Corrosion and fatigue in support structures.
Inadequate lubrication or misalignment of rotating parts.
Fire hazards due to overheated bearings or coal dust.
Untrained personnel working during plant running conditions.

5️⃣ Common Accident Types

Type of Accident	Example
Entanglement	Worker caught in conveyor pulley or drive unit.
Fall from Height	Collapse of walkway or transfer tower.
Fire & Explosion	Ignition of coal dust in conveyors.
Structural Failure	Belt structure or chute collapse.
Electrical Shock	Faulty cable, ungrounded panel.

6️⃣ DGMS Safety Recommendations

All moving machinery must have guards, railings, and covers.
LOTO (Lockout/Tagout) system mandatory during maintenance.
Regular inspection and greasing of pulleys, motors, and bearings.
Fire-fighting systems and detectors near transfer points.
Structural integrity test every 6 months.
Emergency stop switches (pull cords) at every 30 m along conveyors.
Training and authorization before operating plant machinery.
Use dust suppression and proper illumination.

7️⃣ Structural and Mechanical Integrity

DGMS requires annual certification of the CHP/OHP structure and foundations by a qualified structural engineer. Mechanical systems (gearboxes, pulleys, drives) must be inspected by a competent mechanical engineer at least once every quarter. Records of such inspections should be maintained.

8️⃣ Fire Safety Measures

Provide automatic sprinklers and fire hydrants near belt drives.
Maintain 2–3 fire extinguishers per 100 m of conveyor.
Install flameproof motors in dusty areas.
Conduct fire mock drills every 3 months.
Remove accumulated coal dust daily.

9️⃣ Case Study

In a 2022 coal handling plant accident, a worker was fatally injured while cleaning under a running conveyor. Investigation found: Absence of LOTO and inadequate supervision. DGMS ordered: Suspension until compliance with safety systems, guard installation, and retraining of all operators.

⚙️ QUICK ONE-LINERS (Revision Points)

DGMS Circular 05/2017 – Conveyor & CHP safety.
CMR 2017 Reg. 131 – Electrical safety in plants.
LOTO – Mandatory for all maintenance jobs.
Inspection frequency – Quarterly for mechanical parts.
Structural check – Every 6 months.
Fire detection & sprinklers – Compulsory in CHP.
Guards required on all pulleys & belts.
Training for all CHP/OHP workers mandatory.
No cleaning under running conveyors.
DGMS Circular 08/2018 – Plant guarding requirements.

🧩 DESCRIPTIVE MODEL QUESTION & ANSWER

Q. Explain the causes and preventive measures of accidents due to failure of coal/ore handling plants in mines.

Answer:
Accidents in coal and ore handling plants mainly occur due to mechanical failures (e.g., conveyor entanglement), structural collapse, poor maintenance, and lack of guarding. DGMS Circular 05/2017 mandates the use of guards, LOTO systems, and periodic inspection by competent persons. Preventive measures include regular lubrication, fire detection (Reg. 172), proper illumination, and operator training. Structural audits (every 6 months) and quarterly mechanical checks are essential to avoid breakdowns.

🧮 25 DGMS-Based MCQs

Q1. Major cause of accidents in CHP/OHP:

Solution: Most CHP/OHP accidents are related to machinery, conveyors, crushers (mechanical failures) or structural issues.

Q2. DGMS Circular on conveyor belt safety:

Solution: DGMS Circular 6 of 2003 specifically outlines safety precautions for conveyor belt operation. (Note: 05/2017 is also relevant, but 6/2003 is a foundational one).

Q3. LOTO stands for:

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

Q4. Structural integrity test frequency:

Solution: Regular (half-yearly) structural integrity audits are recommended to check for corrosion, fatigue, and overload damage.

Q5. Guarding required for:

Solution: All moving parts of machinery, such as pulleys, gears, and conveyor nip points, must be securely guarded.

Q6. Regulation for electrical safety in plants:

Solution: Regulation 131 of CMR 2017 details the general electrical provisions, including those for surface installations like CHPs.

Q7. Common accident type in OHP:

Solution: Entanglement in rotating or moving parts like conveyor rollers, pulleys, and belts is a very common and serious hazard in OHP/CHPs.

Q8. Fire extinguisher requirement:

Solution: Adequate fire points and extinguishers (2-3 per 100m) must be provided along the conveyor length and at drive heads.

Q9. Inspection by:

Solution: Statutory inspections of machinery must be carried out by a competent person, typically the appointed engineer.

Q10. DGMS Circular 08/2018 covers:

Solution: This circular specifically addresses the importance of proper guarding and maintenance of CHP/OHP systems.

Q11. IS standard for conveyors:

Solution: IS 7155 provides the code of practice for the design, installation, operation, and maintenance of conveyor safety.

Q12. Fire cause in CHP:

Solution: Friction from jammed rollers or overheated bearings, combined with coal dust, is a primary cause of fires in CHPs.

Q13. Operator training mandatory for:

Solution: All personnel working in the plant must receive training on its operation, hazards, and emergency procedures.

Q14. Illumination required near transfer points:

Solution: Transfer points and workshops are critical areas requiring higher illumination, typically 50 lux.

Q15. Record of inspection kept at:

Solution: Records should be readily available for inspection, typically at the plant control room or manager's office on-site.

Q16. LOTO prevents:

Solution: Lockout/Tagout (LOTO) is a procedure to ensure machinery is completely isolated from energy sources and cannot be started accidentally.

Q17. Fire mock drill frequency:

Solution: Regular emergency preparedness drills, including fire drills, are typically mandated at least once every 3 months (quarterly).

Q18. Guarding reduces:

Solution: Guards act as physical barriers to prevent body parts or clothing from getting caught in moving machinery.

Q19. Common failure point:

Solution: Transfer towers are high-stress, high-vibration areas prone to structural fatigue and material blockage, making them common failure points.

Q20. DGMS requires inspection by:

Solution: All statutory inspections must be carried out by a 'competent person' (like an engineer or safety officer) as defined in the regulations.

Q21. Fire suppression system used:

Solution: Automatic sprinklers (deluge systems) and manual hydrants are the primary fire suppression systems in a CHP.

Q22. Main goal of DGMS circular:

Solution: All DGMS circulars related to operations are aimed at preventing accidents and improving safety.

Q23. Entanglement occurs in:

Solution: Both conveyors (pulleys, idlers) and crushers (rotors, jaws) have powerful moving parts that pose a high risk of entanglement.

Q24. First-aid facility required:

Solution: First-aid facilities must be readily accessible, meaning they should be located near the active plant/control room area.

Q25. DGMS emphasizes:

Solution: A fundamental and non-negotiable safety rule in any plant is that maintenance or cleaning must never be done on running/moving machinery.

🔗 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

⚙️ Stay Safe, Stay Operational – Learn DGMS CHP/OHP Safety Rules!

Join Online Mining Exam (OME) – India’s 1st Online Mining Academy for:

CHP/OHP Accident Analysis Notes
DGMS Safety Circulars & MCQs
Real Case Studies for Exam Prep

🌐 Visit: www.onlineminingexam.com
📞 Call/WhatsApp: 9971114020

Download CHP/OHP Safety Notes & Practice 25 MCQs Now!

Online Mining Exam