Carbon Dioxide in Mine Air

Many gases found in a mine during normal operating conditions can have a harmful effect on the human body if inhaled for a period of time in concentrations above the recognized safe limit. Emergencies such as fires can emit large quantities of toxic or explosive gases and create an ______ atmosphere.

The first priority for miners at the time of a mine fire is to protect themselves from these ______.

Deadly concentrations of toxic gases may be only a few parts per million (ppm). For many of us, 1 ppm is about as hard to visualize as the national debt. The following examples will help grasp what one part per million really represents and also help you think in ______ units.

Being able to identify and respond safely to these substances is a fundamental aspect of mine rescue. Upon completion of this chapter, the trainee shall be able to demonstrate understanding of:  Terms, concepts, and ______.

Many gases found in a mine during normal operating conditions can have a harmful effect on the human body if inhaled for a period of time in concentrations above the recognized safe limit. Emergencies such as fires can emit large quantities of ______ gases and create an oxygen-deficient atmosphere.

The first priority for miners at the time of a mine fire is to protect themselves from these conditions. CONCEPTS AND DEFINITIONS On The Threshold of Understanding: Toxic Chemicals Deadly concentrations of toxic gases may be only a few parts per ______ (ppm).

Acetylene forms an explosive compound with ______

Ammonia has an explosive range of ______

Ammonia's corrosive qualities will irritate the eyes, nose, throat, lungs, or moist skin and may cause considerable ______

Carbon dioxide is a colourless, odourless gas that when breathed in large quantities may cause a distinctly ______ taste.

Ammonia is stored in commercial cylinders as a ______ gas.

Acetylene has an explosive range of ______

Carbon dioxide is heavier than ______ and is often found in low places and abandoned mine workings.

Carbon monoxide is a colourless, odourless, tasteless gas that, when breathed in even low concentrations, will produce symptoms of ______.

Chlorine is a heavy, greenish yellow, non-flammable ______ that has an odour similar to chlorine bleach and is tasteless.

Hydrogen is a colourless, odourless and tasteless ______. It is highly flammable.

Hydrogen can be produced when rock is heated to ______. It is a product of incomplete combustion or distilling coal.

Hydrogen cyanide is a colourless, tasteless gas with a distinctive odour of bitter almonds. Many people cannot detect presence by odour therefore the scent alone does not provide adequate warning of hazardous ______.

Hydrogen sulphide has an explosive range of ______%

Methane is lighter than air and has an explosive range of ______%

Oxygen is required to support life and combustion. Atmospheres in the workplace should contain at least ______%

Nitrogen is a colourless, odourless, tasteless and ______ gas

Nitrogen dioxide corrodes the respiratory passages and inhaling relatively small quantities may cause ______

MAPP has an explosive range of ______%

Propane is a liquefied petroleum gas. Propane vapour is ______ than air.

Sulphur dioxide is a gas produced by heating, burning, or blasting sulphide ores. It is also produced in explosions of sulphide ore dust. Some diesel fuels also produce low amounts of sulphur dioxide when ______.

Propane may cause an oxygen-deficient atmosphere resulting in ______.

Liquid propane will expand to about ______ times its liquid volume when converting to vapour.

Sulphur dioxide may cause noxious effects before it becomes ______.

During and following fires, the two greatest hazards to life are carbon monoxide poisoning and ______ deficiency.

Polyvinylchloride (PVC)-covered belting is practically non-flammable, but when heated, PVC, synthetic rubber, and neoprene (found in rubber tires) give off ______ gas.

One source of radiation is nuclear gauges used for measuring. When responding to an incident involving this source, contact the site Radiation Safety Officer (RSO). Another source of radiation is ______, a naturally occurring element released into the mine’s atmosphere.

Hydrogen sulphide sometimes indicates the presence of ______.

Acetylene is ______ than air.

One ppm is the same as: ______ per 1,000 litres of liquid

Threshold Limit Value – Time Weighted Average (TLV-TWA) is the time-weighted average concentration for a normal eight-hour workday and a 40-hour workweek, to which nearly all workers may be repeatedly exposed without adverse health effects. Note: When TWA is not indicated, refer to the 8-hour TLV. A Concentration Equivalent (Ceq) formulae must be used for shifts longer than an eight-hour workday and a 40-hour workweek. The formula used depends on the jurisdiction in which the mine is located. 5-2 Threshold Limit Value – Short Term Exposure Limit (TLV-STEL) is the concentration to which workers can be exposed for a short period of time without suffering from: Irritation, Chronic or irreversible tissue damage, or Narcosis of sufficient degree to increase the likelihood of accidental injury, impair self-rescue or materially reduce work efficiency, provided that the daily TLV-TWA is not exceeded. The STEL is not a separate independent exposure limit. Rather, it supplements the time-weighted average (TWA) limit where there are recognized acute effects from a substance whose toxic effects are primarily of a chronic nature. STELs are recommended only where toxic effects have been reported from high short-term exposures in either humans or animals. A STEL is defined as a 15-minute exposure which should not be exceeded at any time during a work day even if the eight-hour time-weighted average is within the TLV. Exposures at the STEL should not be longer than 15 minutes and should not be repeated more than four times per day. There should be at least 60 minutes between successive exposures at the STEL. A period other than 15 minutes may be recommended when this is warranted by observed biological effects. Threshold Limit Value – Ceiling (TLV-C) is the concentration that should not be exceeded during any part of the working exposure. Combined Threshold Limit Values The air in a mine may contain a combination of different gases, which when combined may cause adverse effects and therefore must be taken into account. When two or more hazardous substances have a similar toxicological effect on the same target or system, their combined effect, rather than that of either individually, should be given primary consideration. The equation for determining the combined TLV is: $𝐶1 𝐶2 𝐶𝑛 + +⋯ = 𝐷𝑜𝑠𝑒 𝑇1 𝑇2 𝑇𝑛$ Where C is the concentration and T is the threshold limit value. If Dose is greater than 1, the TLV for the mixture has been exceeded.

Median Lethal Dose (LD 50) refers to the dose of a toxic substance that would be ______ for 50% of a test population

Median Lethal Concentration (LC 50) refers to how concentrated a toxic substance must be in an atmosphere to be ______ for 50% of a test population

Immediately Dangerous to Life and Health (IDLH) refers to a condition posing ______ danger to life or health, or a condition posing an ______ threat of severe exposure to contaminants. If a concentration of a contaminant is above the IDLH, only positive-pressure breathing apparatus should be used to enter such an atmosphere or to move someone through that atmosphere

Lower and Upper Explosive Limits refer to the minimum (LEL) and maximum (UEL) ______ of a gas or vapour in air that will ignite when exposed to an ignition source provided there is sufficient oxygen to support combustion