The system will mine a metallurgical coal seam with height of 1 to 1.2 m (39 to 47 inches), and the face length will be 240 m (787 ft). The Cat GH800 plow will be paired with a Cat armored face conveyor using PF3 line pans, and the Cat PMC-R roof support control system will manage roof support advance. Automation enhances safety—there is no need for an operator to be at the coal face during operation.
In China, automated plow longwall faces from the Caterpillar predecessors, DBT and Bucyrus, hold all of the production records for seams less than 2 m (79 inches) thickness. Tiefa Coal Mining Group, with a 50% share in the joint venture project with Dongyi, owns four such systems already and has publicly indicated that the plow systems enable them to profitably mine thin seam reserves that otherwise would be uneconomic.
There was a time when the application of plows for longwall mining was limited by the type of coal to be cut. With Cat systems, this is no longer the case. Advancements in drive, control and transmission systems—with more powerful motors, stronger plow chain, increased plow speeds, higher advancing force provided by the roof supports, precise control of the cutting depth, and plow bit design improvements—all combine to allow Cat plows to be used for any coal hardness and with higher efficiency than other longwall extraction methods in low and medium seam heights.
As an example of the robust design and power of Cat plow systems, the gliding plow guide is welded to the face side of the armored face conveyor. Plow chains up to 42 mm can be used, allowing power installations up to 2 x 800 kW (2 x 1,080 hp). On older-style systems, the cutting depth was typically controlled by adjusting the shield advancing ram pressure. As a result, cutting depths varied with coal hardness. A modern Cat plow system can cut a precisely defined depth, regardless of coal hardness and seam structure.
