e. Once past the face the air is no longer fresh air, but return air carrying away coal dust and mine gases such as methane, carbon dioxide, depending on the geology of the coal. Return air is extracted by ventilation fans mounted on the surface. A series of seals are erected as mining progresses to maintain goaf gas levels. 
Typically to avoid coal in the goaf spontaneously combusting, goaf gases are allowed to build up so as to exclude oxygen from the goafed area. This means that there is an explosive goaf fringe between the face and the goaf at all times requiring constant monitoring, which can become dangerous for miners if coal companies neglect or ignore safety precautions.
The longwall equipment includes:
- A number of hydraulic jacks, called powered roof supports, chocks or shields, which are typically 1.75m wide and placed in a long line, side by side for up to 400 m in length in order to support the roof of the coalface. An individual chock can weigh 30-40 tonnes, extend to a maximum cutting height of up to 6 m and have yield rating of 1000-1250 tonnes each, and hydraulically advance itself 1m at a time.
- The coal is cut from the coalface by a machine called the shearer (power loader). This machine can weigh 75-120 tonnes typically and comprises a main body, housing the electrical functions, the tractive motive units to move the shearer along the coalface and pumping units (to power both hydraulic and water functions). At either end of the main body are fitted the ranging arms which can be ranged vertically up down by means of hydraulic rams, and onto which are mounted the shearer cutting drums which are fitted 40-60 cutting picks. Within the ranging arms are housed very powerful electric motors (typically up to 850 kW) which transfer their power through a series of lay gears within the body the arms to the drum mounting locations at the extreme ends of the ranging arms where the cutting drums are. The cutting drums are rotated at a speed of 20-50 revs/min to cut the mineral from coal seam.
- The shearer moves along the length of the face sat upon the armoured face conveyor, driving through a chainless haulage system (which resembles a ruggedised rack and pinion system especially developed for mining),Previous to chainless haulage systems, a heavy duty chain was run the length of the coal face for the shearer to pull itself along the face. The shearer moves at a speed of 10-30m/min depending on cutting conditions. The AFC on which the shearer sits, is placed in front of the powered roof supports, and the shearing action of the rotating drums cutting into the coal seam, disintegrates the coal this being loaded onto the AFC. The coal is removed from the coal face by a scraper chain conveyor called the AFC to the main gate. Here it is loaded onto a conveyor belt and transported to the surface, usually via a network of conveyor belts.
- At the main gate the coal is usually reduced in size in a crusher, and loaded onto the first conveyor belt by the beam stage loader (BSL).
As the shearer removes the coal, the AFC is snaked over behind the shearer and the powered roof supports move forward into the newly created cavity. As mining progresses and the entire longwall progresses through the seam, the goaf increases. This goaf collapses under the weight of the overlying strata. The strata approximately 2.5 times the thickness of the coal seam removed collapses and the beds above settle onto the collapsed goaf. This collapsing can lower surface height considerably, causing serious problems like changing the course of rivers and severely damage building foundations.
The advantages of longwall mining include:
- better resource recovery (about 80% compared with about 60 percent for room and pillar method).
- safety of the miners enhanced by being under the hydraulic roof supports when they are extracting coal.
The disadvantages of longwall mining include:
- surface subsidence, which may considerably alter the landscape above the mine which can damage natural or man-made structures or features.
- deterioration in groundwater