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Coal Mine Gases > Gases > Flashcards

Gases Flashcards

1
Q

Name 8 gases relevant to the coal mining industries, chemical symbol, and specific gravity.

A

Name of Gases Chemical symbol Specific gravity
Hydrogen H2 0.07
Methane CH4 0.55
Carbon monoxide CO 0.97
Oxygen O2 1.11
Hydrogen Sulphide H2S 1.18
Carbon Dioxide CO2 1.52
Nitrogen Dioxide NO2 1.6
Sulphur Dioxide SO2 2.2

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2
Q

Oxygen. Explain the effect.

A

A. 16-14%- Slight increase in pulse and breathing rate, night and colour vision and judgement affected, Abnormal fatigue upon exertion
B. 14-10%- Poor judgement, abnormal fatigue upon exertion
c. 10-6%- Nausea, vomiting, inability to move or cry out, loss of consciousness may occur.

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3
Q

Minimum concentration of oxygen which coal mine worker can be exposed

A

19.5%

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4
Q

Gases that constitute normal air & percentages

A 
Oxygen	                      20.95 %
Nitrogen	                     78.08 %
Carbon dioxide	      .04 %
Argon/Inert gases	  .93 %
Water vapour	         0-3%
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5
Q

What percentage of oxygen

a) Flammable liquid cease
b) All flaming combustion ceases
c) All combustion ceases

A

Flammable liquid cease 17%
All flaming combustion ceases 10-12%
All combustion ceases 2%

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6
Q

What effect does atmosphere enriched with oxygen have on Upper flammable limit.

A

Expands the flammable limits of a flammable gas.

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7
Q

Name 2 Gases released when blasting.

A

Nitrogen dioxide

Carbon Monoxide

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8
Q

How do you identify if nitrogen dioxide has been released in a blast

A

Reddish brown colour in gas fume.

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9
Q

For nitrogen dioxide what is the:
TWA
STEL
IDHL

A

TWA- 3ppm (0.0003%)
STEL- 5ppm
IDHL- 20ppm

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10
Q

Name 4 signs or symptoms of exposure to Nitrogen Dioxide.

A
  1. Feeling ill
  2. Coughing violently
  3. Symptoms of bronchitis and pneumonia
  4. Death
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11
Q

Carbon Dioxide

A person must not be exposed to an atmospheric concentration at a coal mine containing a general body concentration of carbon dioxide exceeding?

and convert the % to ppm of above:

A

a) TWA of 1.25% - 12500 ppm

b) STEL 3.0 % - 30000 ppm

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12
Q

Explain the effect of the following CO2 concentrations on a person:

a) 2%-
b) 4.5-5%
c) 10%

A

a) 2%- 50% increase in lung ventilation
b) 4.5-5%- Anxiety, panic, irritability
c) 10%- Toxic, depresses CNS, violent panting, exhaustion, headache

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13
Q

Carbon dioxide is regarded as a hot gas due to its low thermal conductivity, explain:

A

Due to its insulating properties it gives a feeling of warmth

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14
Q

Carbon dioxide:

a) How is it produced
b) Where is it found in a coal mine

A

a) OXIDISATION of COAL and CARBONACEOUS MATERIAL, diesel exhausts, blasting operations, fires
b) Diesel exhausts, fires, spon com, fire fighting inert gas, Breathing..

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15
Q

Describe the physical and chemical properties of CO2:

A

Colourless, slight pungent odour. Soda water taste.

Non-flammable.

SG of 1.52

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16
Q

Describe the physiological effects of carbon dioxide at high and low concentrations

A

Low- STIMULATES the CNS. (Central Nervous System)

High-DEPRESSES the CNS
Affects lungs and breathing passage

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17
Q

Is CO2 a flammable gas

A

Not Flammable

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18
Q

State the long-term exposure limit concentrations for:

a) Carbon Monoxide
b) Hydrogen Sulphide
c) Sulphur dioxide
d) Nitrogen Dioxide

A

a) Carbon Monoxide: 30ppm
b) Hydrogen Sulphide: 10ppm
c) Sulphur dioxide: 2ppm
d) Nitrogen Dioxide: 3PPM

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19
Q

Carbon Monoxide

How is the body poisoned by CO Carbon monoxide

A

CO is absorbed 300 times more readily than 02 and prevents 02 from binding to the red bloods cells.

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20
Q

In regard to CO what is meant by the term “blood saturation”

A

Blood becomes saturated with CO preventing the blood from taking on any more O2 or CO

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21
Q

CO is said to have a cumulative effect. What is meant by cumulative effect

A

CO can build up in a person from multiple, small exposures to CO,

Making the person more susceptible to its effect.

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22
Q

4 Examples of how CO is produced in a coal mine

A

OXIDISATION
HEATINGS / FIRE
EXPLOSIONS
DIESEL ENGINES

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23
Q

Is CO an explosive gas

And at what concentration

A

Yes – 12.5% to 74.% explosive range

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24
Q

Name 6 signs or symptoms of CO poisoning

A 
Impairment of visual threshold, 
Unsteady gait, 
Becoming silent,
Rosy/Flushed Face, 
Heavy feeling in legs, 
Headache, nausea
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25
Q

State the chemical & physical properties of CO

A

HIGHLY POISONOUS GAS
C. O. T.
FLAMMABLE GAS
SG of 0.97.

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26
Q

Methane

What is the ignition temperature of Methane

A

537 C. - Aust Standard

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27
Q

What is the MINIMUM concentration of OXYGEN (at norm temp) for methane explosion to occur

A

12.2%

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28
Q

Is methane poisonous

A

NOT POISONOUS but WILL NOT SUPPORT LIFE

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29
Q

State physical and chemical properties of methane

A

Colourless, Odourless,Tasteless
Flammable gas.
CH4 - SG of 0.55.

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30
Q

What is the explosive range of methane (in normal air and temp)

A

5-15%

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31
Q

What is the most easily ignited % of methane from a HEATED SURFACE in a mixture of CH4 and air

A

5-6%

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32
Q

Explain “lag on ignition”

A

The time period that a FLAMMABLE GAS MIXTURE is in contact with a HEAT SOURCE prior to an IGNITION taking place.
DEPENDENT on CONCENTRATION of GAS and TEMPof HEAT SOURCE.

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33
Q

What is the lag on ignition for methane at 5-6%

A

2secs

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34
Q

Explain how methane is produced
+
Where it is found

A

Produced naturally during the PEAT to LIGNITE transformation

Found in almost all coal and some coal bearing strata.

35
Q

What effect can the presence of coal dust suspended in the atmosphere have on the LEL of methane

A

Can lower LEL from 5 - 0%

36
Q

What % of METHANE is recognised as the MOST EXPLOSIVE in AIR

A

9.5% of MIXTURE

37
Q

What effect does the increase in ambient temp have on a flammable gas/air mixture

A

Increase in Explosive Limit of the Upper Explosive Limit (UEL)
Decrease in Explosive Limit of the Lower Explosive Limit (LEL)

38
Q

Hydrogen Sulphide

State where H2S can be found at a coal mine

A

Stagnant water,
Spon com in coal containing PYRITES,
Seam gas

39
Q

What concentration of H2S causes dizziness, excitement, nausea, dryness & pain in the nose, throat chest and irritation of the mucous membranes

A

250-600ppm

40
Q

Explain the physical & chemical properties of H2S

A 
TOXIC
COLOURLESS
ROTTEN EGG SMELL
SWEETISH TASTE
H2S - SG 1.18- Flammable
41
Q

State the physiological effects of H2S on a person

A

Toxic gas.

IRRITATES the EYES and RESPIRATORY TRACT and has a NARCOTIC EFFECT on the NERVOUS SYSTEM.

42
Q

Is H2S flammable and a what percentage in air

A

It has an AUTO IGNITION TEMP of 260°C

FLAMMABLE RANGE 4.3% - 45%

43
Q

Sulphur Dioxide

State the chemical & physical properties of SO2

A 
\: Toxic. -NF
Colourless 
SUFFOCATING PUNGENT  odour 
Almost intolerable acidic taste. 
SG of 2.2. - SO2
44
Q

State the physiological effects of SO2 has on a person

A

EXTREMELY POISONOUS
Affects LUNGS
IRRITATES EYES and RESPIRATORY PASSAGE
INTOLERABLE to BREATHE at certain concentrations.

45
Q

Where does SO2 occur at a coal mine

A

SPON COM / Heatings in coal containing SULPHUR
DIESEL EXHAUST EMISSIONS
BURNING RUBBER

46
Q

Is SO2 a flammable gas

A

It is INCOMBUSTIBLE and NON FLAMMABLE

47
Q

Nitrogen Dioxide

  1. State the chemical and physical properties of NO2:
A

Reddish brown colour, an acrid smell and acid taste.
SG of1.6. NO2
Although incombustible and non-flammable, it Will SUPPORT COMBUSTION

48
Q

State the maximum exposure limit concentration of NO2

A

STEL is 5ppm

49
Q

How does Nitrogen dioxide occur at a coal mine.

A

Component of diesel exhausts, shotfiring

50
Q

Although NO2 is not flammable,

What does it support

A

Combustion

51
Q

State the physiological effects of NO2

A

Extremely poisonous. Coughing. Seriously irritates the lungs and respiratory passages.
Symptoms of acute bronchopneumonia.
Death.

52
Q

Gas Sensors/Detectors
Type of gas sensors:
Oxygen O-GE Carbon monoxide-3- M-EGIT
Carbon dioxide -2- D-IGT Methane-2- M-ITG cc Nitrogen -GC
Hydrogen Sulphide H-EGT Sulphur dioxide S-EGT
Hydrogen - GC Nitrogen dioxide N-EGT

A

Oxygen - GC. EC
Carbon monoxide-EC GC IR TUBE

Carbon dioxide-  IR, GC, Tube							
Methane- IR, Thermal, GC, CC						
Nitrogen-  GC								
Hydrogen Sulphide- EC, GC, Tube							
Sulphur dioxide-   EC, GC, Tube

Hydrogen. - GC
Nitrogen dioxide. - EC, GC, Tube

53
Q

How often does the gas detector have to be fully calibrated to NATA standard

A

Every 6 Months

54
Q

How often does the gas detector have to be tested using known levels of gases

A

Before each shift

55
Q

Electronic multi gas detectors can be cleaned using what

A

Damp soft cloth / bristle brush

56
Q

What could high [condensation] humidity do to an Oxygen sensor reading

A

Cause sensor to fail

57
Q

Why is it not advisable to breath over sensors

A

Moisture from exhaled breath can poison O2 sensor

58
Q

State 2 advantages of an infrared methane sensor has over a catalytic combustion methane sensor

A
  1. NOT DEPENDANT of Oxygen

2. NOT CROSS SENSITIVE

59
Q

What should the oxygen sensor of a handheld gas detector read

A

20.95

60
Q

What is the MINIMUM oxygen level required for correct operation of a catalytic combustion sensor ( CC )

A

10%

61
Q

What is the normal MEASURING RANGE range for a Wheatstone Bridge or Pellistor (catalytic oxidation principle) type methanometer

A

0% to 5% of LEL

62
Q

Name 2 gases that could cause “cross Interference” on CO sensor

A
  1. H2S

2. SO2

63
Q

What does T90 refer to when using a personal gas detector

A

The time taken to reach 90% of the test gas concentration of no more than 30secs

64
Q

What gas detector is used to detect “Volatile Organic Compounds” VOC’s

A

PID (Photoionization Detector)

65
Q

What does intrinsic safety mean when using a gas detector

A

One which is intended for use in a potentially explosive atmosphere

66
Q

When should you use a pump style gas detector

A

Remote sampling

Confined Space

67
Q

What are the effects of air velocities on gas detectors

A

Displaces gases and does not give true reading

68
Q

Miscellaneous

Where could Methane be found on surface mine

Name 3 areas

A

1: Seam Gas - Blasting
2: Sewage - Drill Holes
3: Produced NATURALLY during PEAT to LIGNITE transformation

69
Q

Where could Nitrogen Dioxide be found on a surface mine

A

Blast flume,

Diesel exhaust

70
Q

Areas where Sulphur dioxide could be found

A

When sulphur is in coal/spon com

71
Q

What are the 5 factors that must occur simultaneously for an explosion to occur

A
  1. Oxygen
  2. Fuel
    3 .Heat
  3. Suspension
  4. Confinement
72
Q

Where can carbon monoxide can be found on the surface.

Name 2

A
  1. Heatings -Fires - Spon Com

2. Diesel exhaust - Explosions

73
Q

What 2 gases can be found in confined spaces at CHPP

A
    • Hydrogen Sulphide. H2S
    • Carbon Monoxide. CO
    • Oxygen. O2
    • MIBC (Floculant? )
74
Q

What gases can be found when an inversion layer occurs

A

All seam gases

75
Q

What gases can be found when a product cylinder leaks

A

Whatever is inside the cylinder etc. (LPG, Acetylene)

76
Q

What risk control method is used at your mine when responding to the detection of flammable & toxic gases

A

TARP (Trigger Action Response Plan)

77
Q

When coal heats gases appear at characteristic temps,

Name 6

A
  1. Carbon dioxide CO
  2. Carbon monoxide CO2
  3. Methane CH4
  4. Hydrogen H2
  5. Ethane
  6. Hydrocarbons
78
Q

Convert 400PPM to %

A

0.04%

79
Q

What must occur for a person working more than the stated hours for applicable long term exposure limits

A

The TWA standard will need to be adjusted to the Recognised Standard

80
Q

What is the applicable long term exposure limit concentration for various atmospheric contaminants

A

Define long term exposure for hours in a day and hours in a week. 8hr / 40hr week

81
Q

What is the maximum general body concentration of CARBON DIOXIDE a person can be exposed if a continual personal monitoring method is used

A

TWA- 1.25% = 12500 ppm

STEL- 3% = 30000 ppm

82
Q

What should be recorded when taking gas readings in the excavations.

Name 6

A
  1. Person name
  2. Gas type
  3. Location
  4. Time
  5. Date
  6. Weather conditions
83
Q 
Abbreviations
CNS- Central Nervous System
SG- Specific Gravity
COT- Colourless, Odourless, Tasteless
EC- Electrochemical
PID- Photoionization Detector
GC- Gas Chromatograph
IR- Infrared
TWA- Time Weighted Average
STEL- Short Term Exposure Limit
LEL- Lower Explosive Limit
UEL- Upper Explosive Limit
NF- Non Flammable
A 
Abbreviations
CNS- Central Nervous System
SG- Specific Gravity
COT- Colourless, Odourless, Tasteless
EC- Electrochemical
PID- Photoionization Detector
GC- Gas Chromatograph
IR- Infrared
TWA- Time Weighted Average
STEL- Short Term Exposure Limit
LEL- Lower Explosive Limit
UEL- Upper Explosive Limit
NF- Non Flammable

Coal Mine Gases (1 decks)

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