Underground mine ventilation provides a flow of air to the underground workers of a mine with sufficient volume to dilute and remove dust and noxious gases (typically NO_x, SO₂,

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...

, CO₂ and CO) and to regulate temperature. The source of these gases are equipment that runs on

diesel engine The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compr ...

s, blasting with

explosives An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...

, and the orebody itself. Regulations often require airflow to be distributed within mines to improve

air quality Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...

. The largest component of the operating cost for mine ventilation is

electricity Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

to power the ventilation fans, which may account for one third of a typical underground mine's entire electrical power cost.

Types of ventilation

Flow-through ventilation is the main ventilation circuit for the mine. Air enters the mine from the surface via a shaft, ventilation raise or

adit An adit (from Latin ''aditus'', entrance) or stulm is a horizontal or nearly horizontal passage to an underground mine. Miners can use adits for access, drainage, ventilation, and extracting minerals at the lowest convenient level. Adits are a ...

. The air is distributed through the mine via internal ventilation raises and ramps, and flows are controlled by regulators and permanently mounted ventilation fans. An auxiliary ventilation system takes air from the flow-through system and distributes it to the mine workings via temporarily mounted ventilation fans, Venturi tubes and disposable fabric or steel ducting. Auxiliary fan and duct systems may be either forcing systems, where fresh air is pushed into mine headings, or exhausting systems that draw out contaminated air.

Ventilation control

Sufficient volume of air is required for proper ventilation. A bulk of electric power is required for driving fans. By installing variable speed control air quantity can be optimized hence the power. At every place in the mine where persons are required to work or pass, the air should not contain less than 19% of oxygen or more than 0.5% of carbon dioxide or any noxious gas in quantity likely to affect the health of any person. The percentage of inflammable gas does not exceed 0.75% in the general body of the return air of any ventilating district and 1.25% in any place in the mine.

Regulations

The volume (expressed in

cubic feet per minute The cubic foot (symbol ft3 or cu ft)
, . is an Cubic metre per second, cubic meters per second) of air required to ventilate an underground mine is determined by

mining engineers Mining is the extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a la ...

based on a wide variety of parameters. In most countries minimum requirements are outlined by law, regulation or standards. However, in some developing countries the mandated ventilation requirement may be insufficient, and the mining company may have to increase the ventilation flow, in particular where ventilation may be required to cool the ambient temperature in a deep hot mine, however auto-compression must also be taken into account. As per CMR 153-2-(i)(2017), in every ventilating district not less than six cubic meters per minute of air per person employed in the district on the largest shift or not less than 2.5 cubic meters per minute of air per daily tons output whichever is larger, passes along the last ventilation connection in the district which means the inbye-most gallery in the district along which the air passes.

Heating

temperate climates In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ra ...

ventilation air may need to be heated during winter months. This will make the working environment more hospitable for miners, and prevent freezing of workings, in particular water pipes. In

Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

mines, where the mining horizon is above the

permafrost Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below ...

, heating may not take place to prevent melting the permafrost. "Cold mines" such as

Raglan Mine Raglan Mine is a large nickel mining complex in the Nunavik region of northern Quebec, Canada. It is located approximately south of Deception Bay. Discovery of the deposits is credited to Murray Edmund Watts in 1931 or 1932. It is owned and ope ...

and

Nanisivik Mine Nanisivik Mine was a zinc-lead mine in the company town of Nanisivik, Nunavut, north of the Arctic Circle on Baffin Island. It was Canada's first mine in the Arctic. The mine first opened on 15 October 1976 and permanently closed in September ...

are designed to operate below 0 °C. The

wet bulb temperature The wet-bulb temperature is the lowest temperature that can be reached under current ambient conditions by the evaporation of water only. It is defined as the temperature of a parcel of air cooled to saturation (100% relative humidity) by the ...

in any working place does not exceed 33.5 °C and where the wet bulb temperature exceeds 30.5 °C arrangements are made to ventilate the same with a current of air moving at a speed of not less than one meter per second.

Tunnels

In underground mining, long

tunnel A tunnel is an underground or undersea passageway. It is dug through surrounding soil, earth or rock, or laid under water, and is usually completely enclosed except for the two portals common at each end, though there may be access and ve ...

s require efficient ventilation systems to protect miners' health and safety.

Ventilation shaft In subterranean civil engineering, ventilation shafts, also known as airshafts or vent shafts, are vertical passages used in mines and tunnels to move fresh air underground, and to remove stale air. In architecture, an airshaft, also known ...

s are critical in these setups, as they introduce fresh air into deeper sections and expel contaminated air. These shafts are typically placed at regular intervals along the tunnel to ensure that airflow reaches all parts of the mine. This distribution of airflow is essential for diluting hazardous gases, such as

and

carbon monoxide Carbon monoxide (chemical formula CO) is a poisonous, flammable gas that is colorless, odorless, tasteless, and slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the si ...

, which can accumulate in confined spaces and pose serious risks of explosion or poisoning. In addition to air quality, tunnel ventilation plays a key role in

temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...

regulation. Heat generated by mining equipment and geological factors can make underground conditions extremely hot. Effective ventilation helps to maintain a more manageable temperature, enabling miners to work in safer, more comfortable conditions. Modern mine ventilation systems often combine both natural ventilation (using pressure and temperature differences to create airflow) and mechanical ventilation methods (using fans to circulate air) to optimize performance. Dust control is another important function of tunnel ventilation. Dust particles generated by drilling and blasting can impair visibility, clog equipment, and harm respiratory health. By directing fresh air through the tunnels, ventilation systems help to reduce dust concentration, improving air quality and visibility. Advanced ventilation designs are tailored to the specific layout and depth of the mine, ensuring that airflow requirements are met throughout the entire tunnel network.

References

{{Authority control Underground mining Mine ventilation