lectric drills for blasting to drop the face. Once dropped, manual labor was used to load coal onto the conveyor parallel to the face and to place wooden roof props to control the fall of the roof.
Such low-technology longwall mines continued in operation into the 1970s. The best known example of this was the New Gladstone Mine near Centerville, Iowa. This longwall mine did not even use a conveyor belt, but relied on ponies to haul coal tubs from the face to the slope mining where a hoist hauled the tubs to the surface.
Longwall mining has been extensively used as the final stage in mining old room and pillar mines. Room and pillar is a mining system in which the mined material is extracted across a horizontal plane, while "pillars" of untouched material is left to support the overburden, leaving open areas or "rooms" underground. It is usually used for relatively flat-lying deposits, such as those that follow a particular stratum. When used in this context, longwall mining can be classified as a form of retreat mining, a term used to reference the final phase of an underground mining.
The gate road along one side of the block is called the maingate or headgate; the road on the other side is called the tailgate. Where the thickness of the coal allows, these gate roads have been previously developed by continuous miner units, as the longwall itself is not capable of the initial development. In thinner seams the advancing longwall mining method may be used. In this system the gate roads are formed as the coal face advances. Only the maingate road is formed in advance of the face. The tailgate road is formed behind the coal face by removing the stone above coal height to form a roadway that is high enough to travel in. The end of the block that includes the longwall equipment is called the face. The other end of the block is usually one of the main travel roads of the mine. The cavity behind the longwall is called the goaf, goff, or gob.
Fresh air travels up the main gate, across the face, and then down the tail gate. 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 shear