Gases

Question 0

1. Air
2. Chemical symbol
3. Composition
4. Density relative to air
5. Characteristics
6. Effect on persons and animals
7. Combustibility
8. Flammable (Explosive) limits in air
9. Detection
10. Where found in mines
11. Remarks

Answer 0

2. _____
   3.Unpolluted air is a mixture containing 20.94 percent oxygen, 78.94 percent nitrogen,
   0.03 percent carbon dioxide,
   0.93 percent argon
   0.002 miscellaneous inert gases
   Water vapor depending on humidity
3. 1.0
4. Colorless
   Odourless
   Tasteless
5. See constituent gases
6. Supports combustion
7. Non flammable
8. See constituent gases
9. Ventilated workings
10. Compressed air used in some mining operations

Question 1

1. Oxygen
2. Chemical symbol
3. Composition
4. Density relative to air
5. Characteristics
6. Effect on persons and animals
7. Combustibility
8. Flammable (Explosive) limits in air
9. Detection
10. Where found in mines
11. Remarks

Answer 1

2. O2
3. _____
4. 1.11
5. Colourless
   Odorless
   Tasteless
6. Essential to life. Deficiency leads to asphyxia, the early symptoms of which are dizziness, palpitation, breathlessness and weakness of limbs. With more severe deficiency there is unconsciousness and eventually cessation of breathing, life endangered below 16 percent. Permissible lower limits for coal mines in Queensland is 19 percent
7. Not combustible in air but is that constituent of air which supports ordinary combustion.
8. Non flammable Oxygen is the essential gas used in all mine rescue breathing apparatus. When liquid or compressed oxygen comes into contact with organic or other easily oxidisable materials, an explosion can take place
9. Can be measured using electrochemical sensors such as those in hand held gas monitors or by gas chromatography
10. A constituent of normal air. One third of the gas evolved during battery charging us oxygen. Must not be confused with air.
11. ____

Question 2

1. Nitrogen
2. Chemical symbol
3. Composition
4. Density relative to air
5. Characteristics
6. Effect on persons and animals
7. Combustibility
8. Flammable (Explosive) limits in air
9. Detection
10. Where found in mines
11. Remarks

Answer 2

2. N2
   3.______
3. 0.97
4. Clourless
   Odourless
   Tasteless
5. Non-poisonous but does not support life. Essential diluting to oxygen for life.
6. Incombustible in air
7. Non- Flammable
8. Can be measured using gas chromatography
9. A constituent of air and some “damps”
10. In gas analysis of mine atmospheres “nitrogen, etc.” , includes other inert gases which are present in small amounts, eg. Argon

Question 3

1. Hydrogen
2. Chemical symbol
3. Composition
4. Density relative to air
5. Characteristics
6. Effect on persons and animals
7. Combustibility
8. Flammable (Explosive) limits in air
9. Detection
10. Where found in mines
11. Remarks

Answer 3

2. H2
3. _____
4. 0.07
5. Colorless
   Odorless
   Tasteless when pure
6. Non-poisonous but does not support life
7. Burns with bluish flame in air or oxygen, forming water vapour
8. Forms flammable mixtures with air. Lower flammable limit is 4 percent and upper flammable limit is 74 percent
   9.can be measured using gas chromatography
9. Found behind seals for a few days after a mine fire is sealed off. Two thirds of the gas evolved during battery charging is hydrogen, which is usually accompanied by an irritant electrolyte mist. Can result from the reaction between acidic water and galvanized pipe.
10. Indicative of mine hearings or fires.

Question 4

1. Carbon Dioxide
2. Chemical symbol
3. Composition
4. Density relative to air
5. Characteristics
6. Effect on persons and animals
7. Combustibility
8. Flammable (Explosive) limits in air
9. Detection
10. Where found in mines
11. Remarks

Answer 4

2. CO2
3. A compound of carbon and oxygen
4. 1.53
5. Colorless has slight pungent smell and “soda-water” taste
6. Respiration is increased by CO2 in air; eg; at rest 3% doubles the respiration rate, 5% triples the respiration rate, 8% concentration will cause a person to breathe with difficulty. In concentrations of 5% to 10% or higher the gas acts as a narcotic, causing impairment or loss of consciousness . Working increases the symptoms. Concentrations above 5% in air are usually accompanied by appreciable lowering of O2 content due to carbon dioxide in the atmosphere. This increases the serious effects and may cause death. In Queensland coal mines, the maximum allowable general body concentration for CO2 is 1.25%
7. Incombustible and will not support combustion.
8. Non-flammable
9. Can best be identified and determined with detector tubes, electrochemical and infrared sensors and by gas chromatography. Accompying reduction of O2 content due to carbon dioxide in the atmosphere, will be indicated by oxygen measuring instruments.
10. a constituent of “black damp”. “After damp” or “Illawarra bottom gas”. Owing to density may, if not mixed with air, accumulate on floors and in lowest parts of workings. Gas from some outbursts is almost pure CO2
11. Formed by oxidation of combustion of coal, timber, etc and by breathing of persons and animals. Can be given off in almost pure form by strata in some coal mines and also in some metal mines or other underground workings or caves. A constituent of gases given off by mine fires and explosions and by blasting, internal combustion engine exhausts and accompanies smoke. Produced by action of acid waters on carbonate rock.

Question 5

1. Carbon Monoxide
2. Chemical symbol
3. Composition
4. Density relative to air
5. Characteristics
6. Effect on persons and animals
7. Combustibility
8. Flammable (Explosive) limits in air
9. Detection
10. Where found in mines
11. Remarks

Answer 5

2. CO
3. A compound of carbon and oxygen
4. 0.97
5. Colourless
   Odourless
   Tasteless
6. Highly insidious poison, displacing oxygen from the blood and thus depriving the brain and other vital organs of oxygen. Death may occur after one hour when exposed to 1000ppm. Where massive atmospheric concentrations occur, death may be almost immediate, without any preliminary symptoms. Early symptoms include: shortness of breath and palpitation on exertion; headache increasing in severity; judgement disturbed; loss of power in legs. As exposure continues mental confusion and collapse occur followed by unconsciousness and possibly death. In Queensland Coal Mines, the maximum allowable general body concentration for CO is 30ppm.
7. Burns with bluish flame in air, forming carbon dioxide.
8. Forms flammable mixtures with air. The lower flammable limit is 12.5 percent and the upper flammable limit is 74. Percent.
9. Can be measured using detector tubes but carbon pretube must be used in presence in concentrations above ten percent. Can also be measured using electrochemical sensors by infrared instruments and when in higher concentrations by gas chromatography.
10. Found after methane or coal dust explosions; after firing explosives; during mine fires. A small amount may be found in the exhaust gases of Diesel engines but is rapidly diluted by the ventilation of air.
11. Formed by in complete combustion of coal, timber, oil ect.. Be explosions of fire damp and some explosives. Presence in mine atmospheres usually indicates incipient heating or active fire. Constituent of “water gas”, “producer gas”, “white damp”

Question 6

1. Methane
2. Chemical symbol
3. Composition
4. Density relative to air
5. Characteristics
6. Effect on persons and animals
7. Combustibility
8. Flammable (Explosive) limits in air
9. Detection
10. Where found in mines
11. Remarks

Answer 6

2. CH4
3. A compound of carbon and hydrogen
4. 0.55
5. Colourless
   Odourless
   Tasteless
6. Non-poisonous but does not support life
7. Burns in air with blue flame forming carbon dioxide and water
8. Forms flammable mixtures with air. Lower flammable limit is 5.3 percent and upper flammable limit is 14 percent. The most easily ignited mixture is 9.8 percent.
9. Can be measured using hand held methanometers or multi gas analyses (such as passports or minigas) or by gas chromatography.
10. Owing to low density, methane may rise to roof and highest parts of mine workings if not mixed with air. Can issue from floor strata or from blowers. Methane is given off naturally from almost all coal.
11. Personnel are to be withdrawn where the general body methane concentration exceeds 2.5 percent. In Queensland mines, methane detectors fitted to plant are required to alarm and trip power as follows:
    - For auxiliary fan, the detector must activate a visible alarm and automatically trip power at 1.25%.
    - For continuous miners, the detector must activate a visible alarm at 1% and trip power at 2%.
    - For shearers, the detector must activate a visible alarm at 1% and trip power yo the cutters at 1.25% and to the machine at 2%.
    - For battery or internal combustion LHD’s the detector must activate a visible alarm at 1% and trip power/ stop engine at 2%

Question 7

1. Hydrogen Sulphide
2. Chemical symbol
3. Composition
4. Density relative to air
5. Characteristics
6. Effect on persons and animals
7. Combustibility
8. Flammable (Explosive) limits in air
9. Detection
10. Where found in mines
11. Remarks

Answer 7

2. H2S
3. A compound of Hydrogen and Sulphur
4. 1.19
5. Colourless, sweetish taste, powerful unpleasant odour resembling that of rotten eggs. Nasal sensitivity to odour decreases with continued exposure to high levels.
6. Very poisonous. Atmospheric concentrations between 20 parts per million (0.002%) and 50 parts per million (0.005%) may irritate the eyes. Higher concentrations above 500 parts per million (0.05%) act on the nervous system, causing rapid loss of consciousness and early death. Very high concentrations may cause immediate death. In Queensland coal mines, the maximum allowable general body concentration for H2S is 10ppm.
7. Burns with blue flame in air, forming sulphur dioxide and water.
8. Forms flammable mixture with air. Lower flammable limit 4.5%, upper flammable limit 45%.
9. Can best be determined and identified with a detector tube. Can be measured using electrochemical sensors (passports and minigas). Odour is detectable at less than 1 part per million (0.0001%) in air; at 50 parts per million (0.005%) odour is powerful but rapidly lost due to nose becoming insensitive, so one must never rely on odour as a warning of dangerous concentrations of the gas.
10. May be given off by certain strata or from stagnant water and hearings.
11. It’s presence is usually due to natural chemical action on pyrites or other sulphide. Sometimes it is due to heating of coal or strata containing sulphides.

Question 8

1. Sulpur Dioxide
2. Chemical symbol
3. Composition
4. Density relative to air
5. Characteristics
6. Effect on persons and animals
7. Combustibility
8. Flammable (Explosive) limits in air
9. Detection
10. Where found in mines
11. Remarks

Answer 8

2. SO2
3. A compound of sulphur and oxygen
4. 2.26
5. Colourless, acid taste, pungent “burning sulphur” smell.
6. Poisonous, mainly by irritation of the respiratory tract, on which actions may be delayed. 20 parts per million (0.002%) in air causes irritation of eyes and coughing. Concentration of 400 parts per million (0.04%) to 500 parts per million (0.5%) are dangerous to life for short exposures. In Queensland coal mines, the maximum allowable general body concentration for SO2 2ppm.
7. Incombustible
8. Non-flammable
9. Can be identified and determined with detector tubes. It’s typical odour can be detected by smell at 3 parts per million (0.0003%) to 5 parts per million (0.0005%) but is rapidly lost due to nose becoming insensitive so one must never rely on odour as a warning of dangerous concentrations of the gas. May also be measured using electrochemical sensors.
10. In vicinity of heating, very small quantities may occur in sulphide metal mines due to slow oxidation of purification material.
11. Usually formed by heating or burning of coal containing sulphur compounds or of “brassy tops” in an adequate air supply.

Question 9

1. Nitrogen Dioxide
2. Chemical symbol
3. Composition
4. Density relative to air
5. Characteristics
6. Effect on persons and animals
7. Combustibility
8. Flammable (Explosive) limits in air
9. Detection
10. Where found in mines
11. Remarks

Answer 9

2. NO2
3. A compound of nitrogen and oxygen
4. 1.6
5. If sufficiently dense is reddish brown in colour ( concentrations resulting not likely in coal mines) acrid smell; acid taste.
6. Poisonous - highly irritant to the lungs and air passages, but action often delayed some hours. Dangerous concentrations may be inhaled without causing significant discomfort at the time. A concentration of 100 parts per million (0.01%) in air, which is the least amount able to cause coughing, is dangerous if inhaled for only a few minutes. Any atmosphere in which NO2 is noticeable by either smell, irritation or colour, should be regarded as dangerous. In Queensland coal mines the maximum allowed general body concentration go NO2 is 3ppm.
7. Incombustible, but will support combustion
8. Non-Flammable
9. Can be identified and determined with detector tubes and electrochemical sensors.
10. In working places immediately after shot firing. A small amount is found in the exhaust gases of Diesel engines but is rapidly diluted and dispersed by ventilated air.
11. The formation of this gas in dangerous quantities is usually due to the detonation or burning of explosives and due to diesel equipment if poorly ventilated or improperly maintained.