A longwall miner (or longwall shearer) is a huge deep mining machine used in underground coal mining. The longwall miner pulls a steel plow
or rotating drum
back-and-forth across a long face of coal. The sheared coal then falls onto a conveyor
for removal from the mine. The longwall miner has a hydraulically operated re-inforced steel canopy
which holds up the mines roof and protects the miners. As the longwall miner cuts deeper into the coal seam
, the shield advances allowing the unsupported roof to collapse behind the cut, often causing subsidence
above ground. A typical longwall miner can have a capacity of up to 2,000 tons of coal per hour.
To view a photo of a longwall miner see: