05---Friday---Gasses Questions 1 Flashcards
With a volumetric type sensor what effects will an higher reading of CO2 than normal have on the O2 reading?
The presence of CO2 at 1% will have an increased reading of 0.1% O2 P 182 black rescue book
Is a volumetric sensor affected by variations in atmospheric pressure?
No it is not affected by altitude , pressure, Temperature or relative humidity
How is nitrogen detected in Queensland?
Gas Chromatograph
What is the formulae for CO make?
CO make in Litres= 0.06 x PPM C0 x M3/sec ventilation flow
what is Grahams ratio?
This is the ratio of CO produced to O2 consumed and is directly proportional to the temp of the coal
What is morris ratio?
it is a measure of the amount of O2 absorbed by the coal and the amount of oxidation produced
What is Carbon monoxide / carbon dioxide ratio?
It is based on the change in ratio of CO produced to CO2 produced as a function of the coal temp.
What is the nose point for Methane?
12.2-O2 5.9-CH4
Where is nitrogen stored underground?
Behind seals / Transormer Tanks
What is meant by lag of ignition?
The gas must be in contact with the heat source for a definate time for the ignition to take place.
What are the main processes used to detect Methane? 3 listed
Catalytic oxidation, Thermal conductivity, Infrared
Which Process is more suitable when O2 is deficient or other gasses are present?
Infrared techniques
What is the normal measurement range for the wheatstone bridge or pellister catalytic oxidation principle?
0 to 5 % XAM 5000
Name two methods portable for detecting Co underground?
Tube detectors Electrochemical sensor
Is the electrochemical sensor used to detect Co cross sensitive to other gases?
Yes it is cross sensitive to Hydogen, ethylene and hydrogen sulphide. (Black rescue book page 150)
How will the lack of O2 affect the reading using a electrochemical sensor when sampling carbon Monoxide?
The sensor requires O2 to be able to oxidise the Gas
Name one sensor used to dectect CO” Must be portable?
Infrared cell portable detector 0 to 5 %
Why is hydrogen not suitable for testing by the electrochemical sensor?
Because of the cross sensitivities encounted by hydrogen cell make it unsuitable for use in mining.
At what percentage of oxygen does all Flamable liquids cease to burn?
16%
At what percentage of oxygen does all Flaming combustion cease?
12.50%
At what percentage does all combustion cease?
2%
How much O2 is present in normal Air?
20.93 by volume
What effect does an atmosphere enriched with oxygen have on the UEL of Flammable Gases?
Reduces the Explosive limit
What effect does Nitrogen have on the Human body in normal Atmosphere?
It has no effect on the Human body at normal atmospheric Pressure
Will nitrogen support life?
No
Where is nitrogen stored underground in a coal mine?
Transformers
Why is correct nitrogen pertentage critical/important in grahams ratio?
GGGGG
What is the minimum concentration of Oxygen for a methane explosion.
12.40%
What is the most easily ignited mixture of methane in air (by electric arc)?
7 to 8 %
Methane has a lag long time when compaired to most other gasses What is the lag time for 5 to 6% of methane/air mixture?
Two seconds
State the methane legal limits for Men withdrawn?
2.50%
State the methane legal limits for Diesel machinery shut down?
1.25
State the methane legal limits for diesel vehicles withdrawn?
1.00%
State the methane legal limits forPower disconnected?
2.00%
State the methane legal limits for Face Machinery Shearer ?
Face Machine 1.25% trips cutters to Longwall Shearer 2% trips all power to Longwall shearer
State the methane legal limits for Face Machinery Miner ?
Continuious miner, coal cutter, Tunnel boring, power trip ABM25 2%
State the methane legal limits for Auxillary Fan Power up?
less than 2%
What effect does high concentrations of CO2 have on the central nervous system?
It depresses the central nervous system
What effect does low CO2 percentages have on the Body?
Its a stimulant to the Central Nervous System and to the Respiratory system i.e.it makes you breath.
How much more soluble is carbon dioxide absorbed into the blood than oxygen?
20 Times
What does the term hypoxia mean ?
Lack of oxygen
What gasses and percentages does carbogen contain?
Oxygen 96% carbon dioxide 4%
What is Carbogen used for?
Resusitation /refrigeration/fire extinguishers
What is the most explosive concentration of Carbon monoxide?
29%
Where is CO2 generated or found in a coal mine. Name 4 places
Breating, afterdamp, Blackdamp, coal seam gas, mine fires, explosions , diesel fumes.
Is CO2 soluble in water?
Yes quite soluble in water
What is the chemical symbol for hydrogen?
H2
What is the Specific gravity for CO2
1.53
What is the nose point for methane
12.2 O2 5.9 CH4
What is ther nose point for Hyrogen?
5.1 O2 4.3 H2
What is the nose point for Carbon Monoxide?
6.1 O2 13.8 CO
When taking a bag sample how full should the bag be?
3/4 capacity
Sample tubes into stopped off areas should extend how many meters into the goaf
100m
When should samples be taken from stoppings?
When the barometer is falling
When a sample Bag has tested for what gas will it have to be destroyed?
Hydrogen
Describe how you would take a sample from a tube extending 100m into a stopped off area?
Ensure that the sample tube is flushed at least 3 times the internal diameter
List the information to be detailed on a sample tag?
Where the sample was taken, Date, Time, Barometer Reading, Spot or General sample, Other Information
