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Approval of Mine Lighting Systems, Fixtures & Signal Lights – DGMS Guidelines & 25 MCQs

🧾 DETAILED NOTES

1️⃣ Introduction

Proper lighting is vital for safe and efficient mining operations, both on the surface and underground. Inadequate or unsafe lighting systems have caused accidents due to poor visibility, glare, or electrical sparks in hazardous areas. Therefore, DGMS mandates approval of all types of lighting fixtures, fittings, and signal lights used in mines, including those on HEMMs (Heavy Earth Moving Machinery) and other mobile equipment.

2️⃣ DGMS Safety Concern

DGMS emphasizes that all lights, fixtures, and electrical systems used in gassy underground and oil/gas fields must be flameproof (FLP) or intrinsically safe (IS) to prevent ignition of flammable gases. For surface mines, lighting systems must comply with electrical safety and illumination standards to prevent glare and electrical hazards.

3️⃣ Legal Framework

Reference	Description
The Mines Act, 1952 – Sec. 23	Employer’s responsibility for worker safety.
CMR 2017 – Regulation 131 & 132	Electrical lighting and illumination standards.
DGMS Circular (Tech.) No. 08/2019	Guidelines for approval of lighting systems in mines.
DGMS Circular (Elec.) No. 04/2014	Electrical safety in HEMM lighting and signaling.
IS: 2148 & IS/IEC 60079-1	Standards for flameproof enclosures.

4️⃣ Objective

Ensure all lighting fixtures in mines meet safety standards.
Prevent ignition hazards in gassy or oil mines.
Maintain adequate visibility for workers.
Reduce glare, shadows, and accidents during night operations.
Regulate approval process through DGMS testing and certification.

5️⃣ Types of Lighting Systems in Mines

Type	Description	Application
Fixed Lighting	Installed on poles, conveyors, workshops.	Surface mines, plants.
Mobile Lighting	Mounted on HEMMs, dumpers, shovels.	Opencast working zones.
Portable Lamps	Rechargeable hand lamps or cap lamps.	Underground workings.
Signal & Indicator Lights	On machinery or haul roads.	HEMMs, plants.
Explosion-Proof Lights	Flameproof fittings in gas zones.	Underground coal/oil mines.

6️⃣ DGMS Approval Requirements

All lighting systems must be approved by DGMS after compliance testing under relevant BIS/IEC standards.

⚙️ Approval Process:

Manufacturer submits application to DGMS (Electrical Division) with specifications.
Sample sent to Testing Authority (e.g., CIMFR, CMERI, ERTL, CPRI).
Testing includes: Insulation resistance, Flameproof/thermal endurance, IP protection, vibration, and illumination/glare tests.
Test report reviewed by DGMS.
Upon compliance, DGMS issues Type Approval Certificate.

7️⃣ Lighting on Board HEMMs and Machinery

All headlights, tail lights, and signal lights on HEMMs must be DGMS-approved.
Lights must withstand vibration, dust, and moisture.
Flashing amber lights required for moving equipment.
Brake and turn indicator lights must be visible from 50 meters.
Wiring must be properly insulated and secured.

8️⃣ Lighting in Underground Mines

Use intrinsically safe (IS) or flameproof (FLP) lights only.
Voltage level must not exceed 110 V in gassy zones.
Lamps must meet IS/IEC 60079-1 standards.
Cap lamps must be IS-approved and regularly maintained.

9️⃣ Minimum Illumination Standards (as per DGMS)

Location	Minimum Lux Level
Underground haulage road	5 lux
Coal face	10 lux
Opencast haul road	15 lux
Workshops / plants	50 lux
Office / Control room	100 lux

⚙️ QUICK ONE-LINERS (Revision Points)

DGMS Circular 08/2019 → Lighting approval guidelines.
Regulation 131 (CMR 2017) → Mine lighting provisions.
HEMM lights must be DGMS-approved.
IS 2148 → Flameproof standard.
Intrinsically safe lights used underground.
Voltage ≤ 110 V in gassy zones.
Headlights visible ≥ 50 m.
LED lights encouraged by DGMS.
Lux standard: 10–50 lux typical for workings.
Testing labs: CIMFR, CPRI, ERTL.

🧩 DESCRIPTIVE MODEL QUESTION & ANSWER

Q. Explain the DGMS procedure for approval and safe use of lighting systems in mines.

Answer:
DGMS requires that all lighting fixtures and systems used in mines (HEMMs, plants, underground) be tested and approved. The manufacturer must submit samples to DGMS-approved labs (like CIMFR/CPRI) for testing against standards like IS 2148 (Flameproof) or IS/IEC 60079-1 (Intrinsically Safe). After reviewing the test report, DGMS issues a Type Approval Certificate. For safe use, mine management must ensure correct installation (e.g., voltage < 110V in gassy zones), maintain illumination levels as per Reg. 131, and conduct regular inspections.

🧮 25 DGMS-Based MCQs (5 Options Each)

Q1. DGMS Circular for lighting approval:

Solution: DGMS Circular (Tech.) No. 08/2019 provides the updated guidelines for approval of lighting systems.

Q2. Flameproof standard for lighting fixtures:

Solution: IS 2148 is the Indian Standard for flameproof enclosures of electrical apparatus.

Q3. Voltage limit in underground gassy zone:

Solution: To enhance safety in gassy zones, the voltage for systems like lighting is often restricted to 110 V.

Q4. Intrinsically safe standard:

Solution: IS/IEC 60079-1 (Flameproof) and 60079-11 (Intrinsic Safety) are the relevant standards. IS 2148 is also used for flameproof. (Note: The prompt's answer for IS/IEC 60079-1 is 'A', but 60079-1 is for Flameproof 'd', while 60079-11 is for Intrinsic Safety 'i'. IS 2148 is also Flameproof. Given the options, and acknowledging the potential typo in the prompt's data, IS/IEC 60079-1 is the most plausible intended answer for explosion protection standards.)

Q5. Testing lab for lighting systems:

Solution: CIMFR (Central Institute of Mining and Fuel Research) is a premier DGMS-approved lab for testing mining equipment.

Q6. HEMM lights must be:

Solution: All electrical fittings on HEMM, including lights, must be of a type approved by DGMS.

Q7. Minimum illumination at coal face:

Solution: A minimum of 10 lux is generally specified for working faces in underground coal mines.

Q8. Regulation for illumination:

Solution: Regulation 131 (General electrical provisions) and 132 (Illumination) of CMR 2017 cover lighting standards.

Q9. Signal light color for moving HEMM:

Solution: An amber (yellow) flashing beacon is the standard warning light for moving HEMM. Red is for reversing.

Q10. Lux level for workshop:

Solution: Workshops and plants require a higher level of illumination, typically 50 lux, for safe maintenance work.

Q11. Cap lamps used in:

Solution: Cap lamps are the primary personal lights for all personnel working in underground mines.

Q12. DGMS approval ensures:

Solution: The entire approval process is focused on ensuring the equipment is electrically and mechanically safe for the mine environment.

Q13. Fixed lighting used in:

Solution: Fixed lighting refers to permanently installed lights in stationary areas like plants, workshops, and along conveyors.

Q14. DGMS Circular 04/2014 covers:

Solution: This circular specifically addresses electrical safety aspects of HEMM, including lighting and alarms.

Q15. BIS standard for cables:

Solution: IS 1554 (Part 1) is the Indian Standard for PVC insulated heavy-duty electric cables.

Q16. Lux level on opencast haul road:

Solution: Opencast haul roads require adequate illumination for safe HEMM movement, typically 15 lux.

Q17. Lighting failure risk:

Solution: The most direct consequence of lighting failure is poor visibility, which leads to a high risk of accidents.

Q18. Oil mines use:

Solution: Oil mines are hazardous areas requiring explosion-proof equipment, such as intrinsically safe (IS) or flameproof (FLP) fittings.

Q19. Light inspection frequency:

Solution: Regular weekly inspections by competent electrical staff are necessary to check for damage, dirt, and functionality.

Q20. DGMS approval certificate validity:

Solution: A DGMS Type Approval is generally valid for as long as the product's design and manufacturing standard do not change.

Q21. Cap lamp voltage:

Solution: Cap lamps are low-voltage DC devices, typically operating in the 6 to 12 Volt range from a battery.

Q22. Flameproof light used in:

Solution: Flameproof (FLP/Ex 'd') enclosures are specifically required in areas where flammable gas may be present (i.e., gassy mines).

Q23. Portable lights must be:

Solution: Portable lights (like cap lamps or hand lamps) rely on rechargeable batteries for power.

Q24. Illumination measured in:

Solution: Lux is the standard unit of illuminance (light intensity falling on a surface).

Q25. Main purpose of DGMS approval:

Solution: The DGMS approval process is entirely focused on ensuring the equipment is safe to use in the specific mine environment.

🔗 INTERNAL LINKS

Related Topic	Read More On...
Electrical Safety	Electrical Safety, Accident Investigation & Legal Framework
HEMM Safety	Safety Features in Crawler/Tyre Mounted Machinery
Opencast Lighting	Standards of Illumination in Opencast Mines
DGMS Circulars	DGMS Training Syllabus for Electrical Engineers

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