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Mine Gases > Mine Gases section 1 > Flashcards

Mine Gases section 1 Flashcards

1
Q

name 8 gases relevant to coal mining

A

hydrogenH2.07 methaneCH4 .55 carbonmonoxideCO .97 oxygen O2 1.11 hydrogen sulphideH2S 1.18 carbondioxideCO21.52 nitrogendioxideNO21.6 sulphurdioxideSO22.2

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2
Q

explain the effects on a person of oxygen concentrations @ 16 - 14%, 14 - 10% and 10 - 6%

A

slight nausea, increase in pulse/breathing rate, nigh/colour vision & judgement affected, abnormal fatigue on exertion : PJ, AFOE : nausea&vomiting, inability to move or cry out, loss of conciousness may occur

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3
Q

what is the minimum concentration of oxygen a cmw can be exposed to?

A

19.5%

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4
Q

what are the gas constituents of normal air and their percentages?

A

nitrogen 78.08% oxygen 20.95% argon/inert .93% water vapour/carbon dioxide .04%

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5
Q

at what percentages of oxygen do a)flammable liquids cease burning b)all flaming combustion stops c) all combustion ceases

A

a) 17% b) 10 -12% c) 2%

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6
Q

what effect does an oxygen enriched atmosphere have on the UPPER FLAMMABLE Limit of FG?

A

expands the flammable limits of a FG

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7
Q

what 2 gases are released when blasting with explosives?

A

Nitrogen dioxide N02 Carbon monoxide CO

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8
Q

how can you identify if Nitrogen Dioxide has been released during a blast?

A

a reddish brown colour in the gas fume

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9
Q

what is the TWA, Short Term Exposure Limit STEL & Immediate Danger to Health or Life IDHL for Nitrogen dioxide NO2

A

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

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10
Q

Name 4 signs or symptoms of exposure to NO2

A

feeling ill, coughing violently, symptoms of bronchitis/pneumonia, cessation of life

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11
Q

a cmw must not be exposed to an atmosphere at the mine containing a general body concentration 0f CO2 exceeding?

A

TWA - 1.25% = 12,500 ppm
STEL - 3% = 30,000 ppm

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12
Q

explain what effects occur to a person at the following concentrations of CO2?

A

2% - 5% increased in lung ventilation
4.5 - 5% - anxiety, panic, irritability
10% - toxic, depresses CNS (Central Nervous
System) violent panting, exhaustion,
headache

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13
Q

carbon dioxide CO2 is described 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 CO2 a) how is it produced and b) where is it found on a mine site?

A

a) oxidisation of coal & carbon based materials, exhaust fumes from combustion engines, blasting operations and fires
b) diesel exhaust, blast fume, spon com, inert firefighting gases

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15
Q

describe the physical and chemical properties of CO2

A

CO2 - specific gravity SG 1.2 non flammable NF colourless, slight pungent odour, soda water taste

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16
Q

describe the physiological effects of carbon dioxide CO2 at low and high concentrations

A

low - stimulates central nervous system CNS
high - depresses CNS

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17
Q

is carbon dioxide CO2 a flammable gas? if so, at what concentration?

A

it is an inert gas, non-flammable NF

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18
Q

state the long term exposure limits for carbon monoxide CO, hydrogen sulphide H2S, nitrogen dioxide NO2, sulphur dioxide SO2

A

CO - 30ppm, H2S - 10ppm, NO2 - 3ppm, SO2 - 2 ppm

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19
Q

how is the human body poisoned by carbon monoxide CO?

A

CO is absorbed 300x more readily by the body than oxygen O2 and prevents O2 from binding to the red blood cell

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20
Q

in regards to carbon monoxide poisoning, what is meant by the term blood saturation?

A

blood becomes soaked with CO that prevents the blood from taking on anymore O2 or CO

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21
Q

carbon monoxide poisoning is said to have a cumulative effect. what is meant by cumulative effect?

A

multiple small exposures to CO can build up in a person making them more susceptible to its effect

22
Q

how is carbon monoxide CO produced in coal mines? give 4 examples

A

oxidisation of coal, fires, heating, explosions and diesel engine exhaust

23
Q

is carbon monoxide CO an explosive gas? if so, at what concentration?

A

yes, it is explosive
explosive range is 12.5 % - 74 %

24
Q

name 6 signs and symptoms that would be associated with carbon monoxide CO poisoning

A

1) impairment of visual threshold 2) nausea/headache 3) rosy/flushed face 4) becoming silent 5) unsteady gait 6) heavy feeling in legs

25
Q

state the chemical and physical properties of carbon monoxide

A

CO - SG 0.97 flammable, highly poisonous
COT - Colourless/Odourless/Tasteless

26
Q

what is the ignition temperature of methane CH4?

A

537’C Australian Standard

27
Q

what is the minimum concentration of oxygen O ( at normal atmosphere ) for a methane CH4 explosion to occur?

A

12.2 %

28
Q

is methane CH4 poisonous?

A

non-toxic, will not support life

29
Q

state the chemical and physical properties of methane CH4

A

CH4 - SG 0.55
Flammable, COT

30
Q

what is the explosive range of methane CH4 in normal air and ambient temperature?

A

5 % - 15 %

31
Q

what is the most easily ignited % of methane CH4 from a heated surface in a mixture of air & CH4?

A

5 % - 6 %

32
Q

explain the term “Lag of Ignition”

A

time period that a flammable gas mixture is in contact with a heat source prior to an ignition taking place. it is dependant on gas concentration and temperature of heat source

33
Q

what is the Lag of Ignition for methane CH4 at 5% - 6%?

A

2 seconds

34
Q

explain how methane CH4 is produced and found on a mine site?

A

a) produced naturally during peat to lignite transformation
b) found in almost al coal seams & some coal bearing strata

35
Q

what effect can the presence of coal dust suspended in the atmosphere have on the LEL of methane CH4?

A

can lower the LEL from 5% to 0%

36
Q

what percentage of methane CH4 is recognised as the most explosive in air?

A

9.5%

37
Q

what effects does the increase of ambient temperature have on a flammable gas/air mixture?

A

increases the upper explosive limit UEL and lowers the lower explosive limit LEL

38
Q

state where hydrogen sulphide H2S could be found on the mine?

A

stagnant water, seam gas, spon com in coal containing pyrites

39
Q

what is the concentration of hydrogen sulphide H2S that causes dizziness, excitement, nausea, dryness & pain in nose/throat/chest, coughing and irritation of mucus membranes?

A

250 - 600 ppm

40
Q

explain the chemical and physical properties of hydrogen sulphide H2S?

A

H2S SG 1.18
Flammable, colourless, rotten egg smell, sweetish taste

41
Q

state the physiological effects hydrogen sulphide H2S has on a person

A

toxic, irritates eyes,throat and respiratory tract, narcotic effect on the central nervous system CNS

42
Q

is hydrogen sulphide H2S a flammable gas? if so, at what percentage in air?

A

4.3% - 45% flammable limit
auto ignition temp of 260’C

43
Q

state the chemical and physical properties of sulphur dioxide

A

SO2 - SG 2.2 N-F
colourless, suffocating pungent odour, almost intolerable acidic taste

44
Q

state the physiological effects sulphur dioxide SO2 has on a person

A

extremely poisonous, irritates lungs and respiratory passage, intolerable to breathe at certain concentrations

45
Q

where does sulphur dioxide occur on the mine site?

A

spon com in coal containing sulphur, diesel exhaust emissions, burning rubber

46
Q

is sulphur dioxide SO2 a flammable gas? if so, at what percentage?

A

no, it is incombustible and non-flammable

47
Q

state the chemical and physical properties of nitrogen dioxide

A

NO2 - SG 1.6 N-F (will support combustion)
reddish brown colour
acrid smell, acid taste

48
Q

state the maximum exposure limit for nitrogen dioxide NO2

A

short term exposure limit STEL 5 ppm

49
Q

how does nitrogen dioxide occur at the mine?

A

shotfiring
component of diesel exhaust

50
Q

although nitrogen dioxide is N-F what does it support?

A

combustion

51
Q

state the physiological effects nitrogen dioxide NO2 has on the body

A

extremely poisonous
coughing
seriously irritates lungs, eyes, respiratory tract
symptoms of acute bronchopneumonia
cessation of life

Mine Gases (3 decks)

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