What is a Mine?
Mining sites, in majority, are classified as confined space. The air within the mine can be contaminated by the presence of other gases such as carbon monoxide, hydrogen sulphide, methane, and excess of carbon dioxide.
Due to the space being confined these gases are not always able to disperse and can therefore build up in the mine, and because of their combustible, explosive and toxic qualities this is a serious issue that threatens occupational health within the mining industry.
What are 'Damps'?
Typically in the mining industry workers will refer to gas exposure as "damps".
These damps are produced or released during mining operations including drilling and blasting, by mining machinery such as diesel and petroleum motors, and by other means such as the decay of timbers, the after effects of mine fires, and chemical processes such as oxidation.
A dangerous mine atmosphere is one that is toxic or explosive and there are several damps that create this kind of atmosphere. They are Firedamp, Black damp, White damp and Stinkdamp.
What is Firedamp?
Methane (CH4) is a colourless, odourless, highly flammable, and highly explosive noxious gas. It occurs naturally in coal seams and shale deposits and is a major component of the natural gas that we burn for energy.
Methane gas accumulates in “pockets” of the coal. As the pockets are penetrated by the mining machinery the gas seeps into the pit where explosive mixtures of methane can form.
Methane has a density relative to air because it’s much lighter than air it tends to accumulate at higher levels within enclosed spaces where little ventilation exists to disperse it.
What is Blackdamp?
Carbon dioxide (CO2) is a colourless, noxious gas that only gives off a slight acrid smell at higher concentrations making it very hard to identify through human senses.
Carbon dioxide forms through the decomposition of organic materials, such as rotting mine timbers, as well as through human and animal respiration.
The coal itself, once exposed to the air of a mine, will begin to absorb oxygen and exude carbon dioxide. With a heavier density relative to normal air, carbon dioxide will accumulate in lower-lying areas within the mine.
The accumulation of black damp in a mine is caused predominantly by poor ventilation however other factors can be attributed such as the temperature, the amount of exposed coal, and the type of coal.
What is Whitedamp?
White damp is a mixture of poisonous gases found in coal mines and is predominantly made up of carbon monoxide (CO).
It is colourless, odourless, and tasteless making it very hard for a human to detect. It is commonly referred to as a “silent killer”.
Carbon monoxide is a product of the incomplete combustion of carbon. In coal mines, large quantities of CO are generated during the oxidation of coal, and during mine fires or explosions. It will then be present in what miners call afterdamp - the resulting noxious gases given off by these fires, explosions, or blasting.
What is Stinkdamp?
Stinkdamp is the mining term given to hydrogen sulfide (H2S) due to its characteristic smell of rotten eggs. Hydrogen sulfide is a highly poisonous, flammable, colourless, and as mentioned, pungent-smelling gas. It has only ever been found in trace amounts in mines - but it can be lethal in even small concentrations. It is produced from the decomposition of iron pyrites in a mine due to the presence of water and how they interact.
In lower levels, it will irritate the eyes, nose, and throat, as it increases it has a narcotic effect on the nervous system causing headache, dizziness and difficulty breathing. Prolonged low exposure can lead to bronchitis, pneumonia, migraine, and loss of motor control.
At higher levels of exposure H2S suppresses oxygen in the blood and tissues resulting in paralysis of the respiratory system and ultimately death in severe cases.
Portable Gas Monitors
Portable Gas Monitors play an essential role when referring to the mining industry. The benefits are that you are able to monitor accurate individual exposure when the monitor is located on the front of their upper body.
You can also place Portable Gas Monitors in expected high-exposure areas to monitor potential sources of toxins or use Area Monitors.
"I think I may need Safety Instrumentation Monitoring, but I don’t know anything about it!"
You don’t need to understand Safety Instrumentation Monitoring to be safe at work! If you are unsure whether you need a monitor, please call one of the team on the below number.
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