π Items Requiring DGMS Special-Order Approval β Full List & Explanation
Under the DGMS Approval Policy β Second Revision 2016, several mining equipment, protective devices, and explosive materials require Special Order Approval from DGMS before use in Indian mines. These items carry high safety risk, especially in:
Underground coal mines
Gassy seams (Degree I, II & III)
Hazardous zones (Zone 0/1/2)
Explosion-prone areas
Hence, DGMS mandates testing, certification, factory inspection and periodic renewal.
πΉ 1. What is Special-Order DGMS Approval? Special-Order Approval applies to equipment that:
May cause sparks, heat, ignition
Operate in gassy underground mines
Pose risks of fire, explosion, electrical shock
Are crucial for life safety & rescue
Fall under the Mines Act, CMR/RMAMR
Use without DGMS approval is illegal and punishable.
πΉ 2. List of Items Requiring DGMS Special-Order Approval
The following categories must be DGMS-approved:
β A. FLAMEPROOF (FLP) EQUIPMENT β βEx dβ Rated Used in underground coal mines & hazardous zones. Includes:
FLP motor
FLP switchgear & starters
FLP junction boxes
FLP lighting fittings
FLP cable glands & terminations
FLP LHD/SDL/Locomotive electrical parts
FLP remote controls
FLP battery boxes
FLP transformers
FLP telephones
These must pass CIMFR flameproof testing.
β B. INTRINSICALLY SAFE (IS) EQUIPMENT β βEx ia / Ex ibβ Used for instrumentation & low-energy circuits. Includes:
Gas detectors (Methane, CO, Oβ)
Cap lamps
IS communication systems
Portable analyzers
Mine phones
Sensors & telemetry units
Environmental monitoring equipment
Refuge chamber monitoring systems
These require ETDC/ERTL testing.
β C. EXPLOSIVES & ACCESSORIES Explosives require approval under the Explosives Act + DGMS. Includes:
Permitted explosives (class P1/P3)
Non-permitted explosives
Detonators (IEDs, delay, electric & non-electric)
Cord relays
Detonating fuse
Cast boosters
Bulk emulsion systems
Blast initiation devices
Electronic detonators
DGMS ensures safety in underground coal environments.
β D. MINERβS SAFETY EQUIPMENT & RESCUE DEVICES Items include:
Self-Contained Self-Rescuer (SCSR)
BG-174A / BG-4 Breathing Apparatus
Life jackets
Rescue line, harnesses
Oxygen self-rescuers
Escape sets
Refuge chambers
These items must meet EN, IS and DGMS rescue standards.
β E. MINING MACHINES WITH ELECTRICAL SYSTEMS Equipment operating on electrical power underground:
Shuttle cars
LHDs / SDLs
Battery electric vehicles (BEVs)
Flameproof locomotives
Drill machines
Pump starters
Belt conveyor electricals
Every electrical component inside the machine must be DGMS approved.
β F. COMMUNICATION & MONITORING EQUIPMENT Including:
Leaky Feeder Systems
Wireless communication devices
Mine phones
Gas monitoring instruments
Continuous miner communication system
Man-riding telephones
Proximity warning systems (PWS)
Personnel tracking systems
β G. POWER & ENERGY SYSTEMS Examples:
Flameproof battery chargers
IS battery management systems
UPS systems
Power supplies for coal mines
Sub-station equipment (for UG installations)
β H. CABLES & ACCESSORIES
Armoured trailing cables
Mining cables (Category 1 & 2)
Cable couplers
Cable glands
Termination kits
Must comply with BIS + DGMS standards.
β I. PERSONAL PROTECTIVE EQUIPMENT (PPE) Certain high-risk PPE require DGMS approval:
Helmets (IS 2925)
Cap lamps
Respiratory devices
Protective clothing for hot/explosive zones
β J. AUTOMATION & MONITORING SYSTEMS
Longwall automation packages
Shearer monitoring systems
Dragline & shovel control systems
Underground environment monitoring systems (CO, CHβ, Oβ)
πΉ 3. Why These Items Need Special-Order Approval?
Because they involve:
High explosion risk
High voltage
Methane-rich atmosphere
Life-critical use
Electrical arcing danger
Fire hazard
DGMS approval certifies:
Safety standards β
Performance reliability β
Explosion-proof design β
Quality management system β
πΉ 4. Testing Requirements for Special-Order Items
β FLP Equipment
Pressure/Explosion test
Spark test
Temperature rise test
Ingress protection
Impact test
β IS Equipment
Energy limitation test
Short-circuit protection
Over-voltage test
Intrinsic safety test
β Explosives
Gallery test
VOD test
Fume test
Cartridge strength
πΉ 5. Renewal Requirements
Manufacturers must submit:
Updated test reports
QMS/ISO documentation
Production records
Performance field reports
No-deviation affidavit
π₯ 25 MCQs (DGMS Pattern) with Answers
1) Flameproof equipment rating β
a) Ex n b) Ex e c) Ex d d) Ex p e) None Ans: c
2) IS equipment rating β
a) Ex d b) Ex ia / Ex ib c) Ex p d) Ex t e) None Ans: b
3) Gas detectors require β
a) General order b) Special order approval c) No approval d) Field test only e) None Ans: b
4) CIMFR tests β
a) IS circuits b) Soil c) FLP equipment d) Diesel engines e) None Ans: c
5) Permitted explosives classification β
a) P0 b) P1, P3 c) P5 d) PA e) None Ans: b
6) SCSR stands for β
a) Safety Cable Support b) Self-Contained Self-Rescuer c) Speed Control System d) Survey Control Standard e) None Ans: b
7) Battery vehicles used underground must be β
a) Wooden body b) FLP/IS certified c) Petrol-based d) Uncertified e) None Ans: b
8) Cap lamps fall under β
a) General items b) Office supplies c) Special-order items d) Mechanical items e) None Ans: c
9) Flameproof cable glands must follow β
a) IS 555 b) IS/IEC 60079-1 c) IS 230 d) AISC e) None Ans: b
10) Detonators require approval from β
a) Police b) Mine manager c) DGMS & Explosives Dept. d) Mining engineer e) None Ans: c
11) Rescue equipment approved by β
a) College b) Private labs c) DGMS d) Mines Board e) None Ans: c
12) Intrinsic safety ensures β
a) Explosion b) Spark creation c) No ignition from circuits d) More voltage e) None Ans: c
13) Methane detectors are β
a) Optional b) Mandatory in UG mines c) For labs only d) For coal washeries e) None Ans: b
14) Gallery test is done for β
a) Ventilation b) Permitted explosives c) Roof bolting d) Gas drainage e) None Ans: b
15) Underground lighting fittings must be β
a) Tubelights b) CFL c) Flameproof type d) Normal streetlights e) None Ans: c
16) Cast boosters are used in β
a) Conveyor belts b) Blasting c) Ventilation d) Drainage e) None Ans: b
17) FLP enclosures prevent β
a) Sunlight b) Internal explosion reaching outside c) Airflow d) Gas emission e) None Ans: b
18) SCSR life (shelf) β
a) 1 year b) 3 years c) 5β10 years d) 20 years e) None Ans: c
19) Gas monitors must be calibrated β
a) Monthly b) Yearly c) As per manufacturer (typically monthly/quarterly) d) Never e) None Ans: c
20) FLP stands for β
a) Flood Lamp Protection b) Flameproof c) Full Load Protection d) Frequency Load Point e) None Ans: b
21) IS stands for β
a) Indian Standard b) Intrinsically Safe c) Internal Supply d) Industrial Safety e) None Ans: b
22) PPE requiring approval includes β
a) Shirts b) Trousers c) Helmets, cap lamps d) Shoes e) None Ans: c
23) Electronic detonators require β
a) Motor license b) Vehicle permit c) Manager signature d) DGMS testing e) None Ans: d
24) Mine telephones used UG must be β
a) Normal phones b) IS type c) Smartphone d) WIFI e) None Ans: b
25) Special-order approval is needed because equipment may β
a) Lower cost b) Increase salary c) Ignite methane/coal dust d) Save fuel e) None Ans: c
π Conclusion
Special-order equipment plays a critical role in mine safety, especially in underground coal mines where methane, coal dust, and electrical hazards are common. DGMS ensures:
Only tested, certified, and safe equipment is used
Risk of fires/explosions is minimized
Mines comply with national standards
Workers remain protected
Every mining professional must know this list thoroughly.
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