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How do draglines remove overburden in surface coal mines?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
coal mine
coal mining Schematic diagram of an underground coal mine, showing surface facilities, access shafts, and room-and-pillar and longwall mining methods.

In surface coal mining, draglines are the most frequently utilized equipment for removing overburden. These machines operate by sitting on top of the overburden and digging the material directly in front of them.1

The process relies on a long, lattice-design boom that extends from the machine's cab at an angle of approximately 35°. A digging bucket is suspended from the end of this boom by a hoist cable. A separate dragline cable runs from the cab to the bucket; when the bucket is lowered, the operator pulls this cable, causing the bucket to dig into the earth. Once the bucket is loaded, the machine swings it to a disposal area and tips the contents.2

Compared to other equipment like power shovels, draglines offer greater flexibility, the ability to work on higher benches, and the capacity to disperse material over greater distances.1