ABSTRACT
Since its first appearance in 1954, the shearer has undergone continuous changes both in capability and structural design. In the 1980s, Joy Technologies developed the 4LS double-ended ranging drum shearer which was thinner, with module construction, for ease of maintenance. It was a multi-motor machine as opposed to previous single-motor ones. Just like the shield support’s capacity, the shearer’s capacity also increased continuously prior to 2010 and stabilizes since then. Increased power allows the mining technology to apply to thinner and/or dirtier coal seams. The shearer is used in all coal seams thicker or mining heights larger than 60–66 in. A double-ended ranging drum shearer cuts coal either uni-directionally or bi-directionally and will cut clear at both ends of the panel and into the headgate or tailgate. After being cut off by the shearer, the coal is loaded by the cutting drum itself onto the armored face conveyor, which runs the whole face width endlessly.
