Accidents Due to Dumper Braking and Steering Failures in Mines – DGMS Guidelines, Causes & 25 MCQs

🧾 DETAILED NOTES

1️⃣ Introduction

In opencast mines, dumpers and tippers are the backbone of material handling operations. However, failure of braking and steering systems has caused several fatal accidents involving runaway vehicles, tip-over incidents, and collisions. DGMS mandates strict inspection, maintenance, and operator training to minimize such risks.

2️⃣ Legal Framework

Reference	Description
CMR 2017 – Reg. 96	Maintenance of HEMM and periodic examination of brakes and steering systems. (Note: Reg 96 is Transport, Reg 99/108/126 are more relevant)
DGMS Circular (Tech) 2 of 2010	Safety standards for dumpers, dozers, and tippers.
DGMS Circular (Tech) 1 of 2014	Mandatory testing of braking systems in heavy machinery.
CMR 2017 – Reg. 108	Precautions for transportation within mines.
The Mines Act, 1952 – Sec. 18	Safety in operation and maintenance of machinery.

3️⃣ Common Causes of Accidents

Failure of service or parking brakes due to poor maintenance.
Hydraulic system leakage or air-locks.
Worn-out brake liners or discs.
Steering failure due to hydraulic leakage or pump malfunction.
Improper tire pressure or damaged linkages.
Operator error – excessive speed on gradients or untrained driving.
Neglect in daily pre-start checks and periodic maintenance.

4️⃣ Types of Braking Systems in Dumpers

Type	Description	DGMS Requirement
Service Brake	Primary brake used during motion	Must stop vehicle within prescribed distance
Parking Brake	Holds vehicle stationary on gradient	Must hold at least 16% gradient
Retarder / Secondary Brake	Assists braking during downhill run	Mandatory for large dumpers (>100T)

5️⃣ Steering System Overview

Consists of hydraulic power steering, pumps, hoses, and linkages. DGMS mandates redundant steering system or fail-safe feature in large dumpers. Steering oil level, pressure, and mechanical linkages must be inspected daily.

6️⃣ DGMS Safety Recommendations

Daily pre-start checks of brakes and steering by operator.
Fortnightly testing of braking efficiency under Engineer supervision.
Brakes must stop vehicle from 20 km/h within 15 m distance.
Steering system must be fail-safe, i.e., automatically locks or stops on failure.
No dumper to be operated with hydraulic oil leakage or warning light ON.
Maintain logbooks of repairs, inspections, and test results.
Operators to be trained as per MVTR 1966 and DGMS safety training schedule.

7️⃣ Case Example

In 2021, a 60T dumper lost control on a haul road gradient due to total brake failure, resulting in one fatality. DGMS investigation found contaminated brake fluid, untrained operator, and no daily inspection record. Following this, DGMS re-emphasized functional checks before every shift and maintenance certification by engineer.

⚙️ QUICK ONE-LINERS (Revision Points)

Reg. 96 (CMR 2017): Maintenance of machinery and HEMM. (Note: Reg 126/127 are more specific).
DGMS Circular 2/2010: Safety for dumpers and tippers.
Service brake, parking brake, and retarder mandatory.
Steering system must be fail-safe.
Brake efficiency test – 15 m stopping distance from 20 km/h.
Hydraulic leakage = machine to be stopped immediately.
Daily pre-start inspection by operator.
Engineer to certify brake & steering condition weekly.
Training under MVTR 1966 mandatory.
Logbook entries essential for DGMS compliance.

🧩 DESCRIPTIVE MODEL QUESTION

Q. Explain the causes and preventive measures of dumper accidents due to brake and steering system failures in mines as per DGMS guidelines.

Answer:
Dumper accidents in mines often occur due to brake or steering failures caused by poor maintenance, hydraulic leakage, and untrained operation. According to CMR 2017 Reg. 96/108 and DGMS Circular 2/2010, all dumpers must be inspected daily, and braking systems must be tested fortnightly. Service, parking, and retarder brakes are mandatory for dumpers above 100T capacity. Steering systems must be fail-safe, and defects must be reported immediately. Proper training, maintenance logbooks, and pre-start checks can prevent such accidents.

🧮 25 DGMS-Based MCQs

Q1. Regulation related to dumper maintenance and safety:

Solution: Regulation 96 of CMR 2017 (Transport of Men and Material) and Regulation 126/127 (Maintenance) broadly cover HEMM safety.

Q2. DGMS Circular for HEMM safety:

Solution: DGMS Tech. Circular 2 of 2010 provides specific guidelines for the safety of dumpers, dozers, and tippers.

Q3. Major cause of dumper brake failure:

Solution: Brake failure is a complex issue, and all listed factors (overheating, leaks, air in the system) can lead to it.

Q4. Minimum gradient holding capacity of parking brake:

Solution: A gradient of 1 in 16 (approx 6.25%) is for haul roads. Parking brakes must be stronger, often required to hold at 15-20%. 16% is a common standard.

Q5. Brake efficiency test stopping distance (from 20 km/h):

Solution: DGMS guidelines often specify a maximum stopping distance of 15m from a speed of 20 km/h to pass the brake test.

Q6. Steering system should be:

Solution: A fail-safe or redundant steering system is a critical DGMS requirement to ensure the operator can control the vehicle even if the primary system fails.

Q7. DGMS recommends brake test frequency:

Solution: While daily checks are done by operators, a formal brake efficiency test by engineers is often required fortnightly (every 14 days).

Q8. Operator training governed by:

Solution: The Mines Vocational Training Rules (MVTR), 1966, mandate the training and certification of all machinery operators.

Q9. Brake fluid contamination leads to:

Solution: Contamination (with water, dirt, or wrong fluid) drastically reduces the hydraulic efficiency and boiling point, leading to failure.

Q10. Steering failure mainly due to:

Solution: Steering is a complex system; failure can result from hydraulic issues (leaks, pump failure), power loss, or mechanical linkage problems.

Q11. Runaway dumper accidents caused by:

Solution: A combination of high speed, a steep gradient, and failing brakes is the classic recipe for a runaway accident.

Q12. DGMS requires which brakes in heavy dumpers?

Solution: All three braking systems (Service, Parking, and a Secondary/Retarder) are required for safe operation.

Q13. Minimum inspection frequency by engineer:

Solution: While operators check daily, a competent engineer is required to conduct a formal inspection weekly.

Q14. Logbook maintained by:

Solution: The statutory maintenance and inspection logbook for machinery is the responsibility of the appointed Engineer.

Q15. DGMS regulation for haul road vehicle safety:

Solution: Regulation 108 of CMR 2017 specifically outlines precautions for moving vehicles on haul roads.

Q16. Failure of steering may cause:

Solution: A loss of steering control can easily lead to the vehicle running off the road (overturn) or into another vehicle (collision).

Q17. Brake system of dumper uses:

Solution: Modern dumpers use complex air-over-hydraulic systems to operate their service, parking, and retarder brakes.

Q18. DGMS requires all repairs to be:

Solution: All repairs, especially to safety-critical systems, must be properly documented, logged, and certified as safe by a competent engineer.

Q19. Before starting vehicle, operator must:

Solution: A pre-start walk-around and systems check (brakes, steering, fluids, alarms) is a mandatory duty for all HEMM operators.

Q20. Frequent failure of brakes due to:

Solution: All these factors, stemming from a harsh mining environment and poor maintenance, contribute to brake failures.

Q21. DGMS Circular 1/2014 emphasizes:

Solution: This circular specifically mandates periodic testing of brake systems on heavy machinery.

Q22. Secondary braking system called:

Solution: The retarder (hydraulic or electric) is a secondary system designed to control speed on long downhill gradients, saving the service brakes.

Q23. Steering pressure low indicates:

Solution: Low pressure in a hydraulic steering system indicates a leak, pump failure, or low fluid, which is a critical fault.

Q24. DGMS inspection of HEMM logbook:

Solution: DGMS inspectors can demand any statutory record, including machinery logbooks, at any time during an inspection.

Q25. Primary objective of dumper brake inspection:

Solution: While it aids speed control, the fundamental reason for inspection is to ensure the equipment is safe and compliant with statutory requirements.

🔗 INTERNAL LINKS

Related Topic	Read More On...
Opencast Transport	Accidents Due to Dumpers and Tippers
HEMM Safety	Safety Features in Crawler/Tyre Mounted Machinery
Dump Stability	Design & Monitoring of Pit/Dump Slopes
DGMS Circulars	DGMS Tech Circular No. 02 of 2020

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