| Question |
Answer |
Notes |
| Tests for this gas in structures, enclosures, or other facilities in which coal is handled or stored must be conducted at least once during each operating shift and immediately prior to any repair work in which welding or an open flame is used or a spark may be produced. |
Methane |
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| If at any time the air in any structure, enclosure, or other facility contains ____% or more of methane, changes or adjustments in ventilation must be made at once to reduce the concentration. |
1 |
|
| A gas with a specific gravity of 1.5 will do what in air? A. Rise; B. Sink; C. Nothing |
B. Sink |
Specific gravity is the ratio of the weight of a substance to an equal volume of another substance, typically water. The vapor density of a substance is the ratio of the weight of a volume of pure vapor or gas to an equal volume of dry air at the same temperature and pressure. Vapor density is also referred to as vapor specific gravity. It is expressed as a ratio where air is assigned the value of 1. Materials with a vapor density greater than 1 will be heavier than air and sink and concentrate at low-lying areas; materials with a vapor density less than 1 are lighter than air and will rise and dissipate. |
| Name one factor that affects the atmosphere in a mine. |
Vehicles; people; fires; ventilation |
|
| Besides oxygen, name three common mine gases. |
Carbon monoxide; carbon dioxide; oxides of nitrogen; methane; hydrogen sulfide; sulfur dioxide; radon |
|
| An increase in temperature will cause a gas to do what if all other variables are constant? A. Escape; B. Contract; C. Expand |
C. Expand |
|
| In a permit-required confined space, gas monitoring should be done in what order? A. Toxic, flammable, oxygen; B. Oxygen, flammable, toxic; C. Oxygen, toxic, flammable; D. Flammable, oxygen, toxic |
B. Oxygen, flammable, toxic |
The mnemonic “Test OFTen” is used to help remember the proper order. |
| Hydrogen sulfide gas has a specific gravity of 1.1895. What will this gas do in air? A. Rise; B. Sink; C. Nothing |
B. Sink |
Specific gravity is the ratio of the weight of a substance to an equal volume of another substance, typically water. The vapor density of a substance is the ratio of the weight of a volume of pure vapor or gas to an equal volume of dry air at the same temperature and pressure. Vapor density is also referred to as vapor specific gravity. It is expressed as a ratio where air is assigned the value of 1. Materials with a vapor density greater than 1 will be heavier than air and sink and concentrate at low-lying areas; materials with a vapor density less than 1 are lighter than air and will rise and dissipate. |
| A natural gas (SG = 0.65) leak is suspected in the surface shops. Where should you test for natural gas first? A. Near the ceiling; B. Waist level; C. Near the floor; D. All of the above |
A. Near the ceiling |
Specific gravity is the ratio of the weight of a substance to an equal volume of another substance, typically water. The vapor density of a substance is the ratio of the weight of a volume of pure vapor or gas to an equal volume of dry air at the same temperature and pressure. Vapor density is also referred to as vapor specific gravity. It is expressed as a ratio where air is assigned the value of 1. Materials with a vapor density greater than 1 will be heavier than air and sink and concentrate at low-lying areas; materials with a vapor density less than 1 are lighter than air and will rise and dissipate. |
| How often must gas meters be bump tested? A. Weekly; B. Monthly; C. Bi-weekly; D. Prior to each use |
D. Prior to each use |
|
| Air composed of less than _____ oxygen is considered oxygen-deficient. A. 16.5%; B. 19.5%; C. 21.0%; D. 23.0% |
B. 19.5% |
|
| Which of the following gases has the largest explosive range? A. Carbon dioxide; B. Hydrogen sulfide; C. Methane; D. Oxides of nitrogen |
B. Hydrogen sulfide |
The explosive range of hydrogen sulfide in air is 4.3 – 45%; The explosive range of methane in air is 5 – 15%. |
| Explosive limits are usually given as the _____________ of the material in the air. A. Parts per million; B. Percent by volume; C. Milligrams per cubic meter |
B. Percent by volume |
|
| What are three potential sources of CO in an underground mine? |
Fire; diesel equipment; blasting |
|
| True or false: Gas cylinders must be stored horizontally. |
False |
|
| What welding gas has the largest flammable range? A. Oxygen; B. Methanol; C. Nitrogen; D. Acetylene |
D. Acetylene |
|
| Gases expand or contract based on temperature and what? A. Volume; B. Other chemicals; C. Pressure |
C. Pressure |
|
| What percent of oxygen is required for proper combustible gas detection? A. 5%; B. 10%; C. 19.5%; D. 21% |
B. 10% |
|
| What is the most likely source of immediate danger from a fire underground? A. Radiant heat; B. Low visibility; C. Carbon monoxide; D. Hydrogen trisulphide |
C. Carbon monoxide |
|
| When we breathe, what poisonous gas do we exhale? A. Hydrogen; B. Nitrogen; C. Carbon dioxide; D. Nitrous oxide |
C. Carbon dioxide |
|
| True or false: It is acceptable to lube valves, gauges, and other parts of oxygen cylinders with oil or grease. |
False |
|
| Why do you need to know the upper and lower explosive limits of a gas? |
The maximum concentration of a gas or vapor that will burn in air is defined as the Upper Explosive Limit (UEL). Above this level, the mixture is too “rich’ to burn. The range between the LEL and UEL is known as the flammable range for that gas or vapor. |
|
| What does its vapor density tell us about a gas? |
The relative weight of a gas or vapor compared to air, which has an arbitrary value of 1. If a gas has a vapor density of less than 1, it will generally rise in the air. If the vapor density is greater than 1, the gas will generally sink in air. |
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| Which gas causes tightness across the forehead and dizziness in higher concentrations? A. Hydrogen sulfide; B. Oxygen; C. Carbon dioxide; D. Carbon monoxide |
D. Carbon monoxide |
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| True or false: The explosive range of a gas is dependent upon its concentration. |
True |
|
| An asphyxiant is a gas that what? A. Displaces oxygen in the air; B. Causes your throat to constrict; C. Causes pain and reddening of the exposed area; D. Acts on the genetic material of the cells caused uncontrolled cell growth |
A. Displaces oxygen in the air |
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