Logan slabbing machine

Logan slabbing machine

[′lō·gən ′slab·iŋ mə‚shēn]
(mining engineering)
A machine that has three cutting chains; two are horizontal—one at the base of the coal seam, the other at a distance from the floor; the third is mounted vertically and shears off the coal at the back of the cut; a short conveyor transfers the coal to the face conveyor.