Terraces are curving around the mining facility, even while they descend deep into the subterranean depths. This is open pit mining, an extraction method that uses a stepped layout to access great mineral resources. Copper extraction sites rely on this surface mining system, as does the coal industry. Come on, we’ll take a sneak peek at open pit mining. There’s no need for a mining lantern, so don’t dawdle.
Imagine the scale of this operation. These are the machines that occupy passages in record books. They’re gigantic, with their wheels casting shadows over nearby workers. Instead of shafts, the aforementioned terraces create wide thoroughfares, around which those diggers and overburden removers roam. The ore, be it copper or some other valuable resource, has to be located close to the surface for this extraction method to work. Once that condition is satisfied, though, the stepped terraces are cut into the hilly terrain.
Like the screening and conveying equipment lines working in a subterranean mining complex, these metal-framed rigs function as the heart of the operation. They’re built as a latticed superstructure, a machine base that uses a special wheel to scoop out the overburden. That mechanical wheel is edged with large buckets, which go to work on the slowly spinning wheel. As the lattice frame digs deep, the extracted dirt is sent over the top of the drum, where it’s inverted. A conveyor belt awaits the inverted buckets so that it can collect the dropped overburden and convey the material to the next stage of the operation.
Without the lattice boom, the scooped out discharge can’t go anywhere. The buckets have dumped the mineral-loaded rocks and dirt onto the moving backbone of the bucket-wheel excavator. From here, the fast-moving overburden load is transferred to a feed hopper, then to a crushing station, a series of conveyor belts, and the screening equipment. At this point, the equipment line looks like the machinery used in the underground scenarios we’ve described so many times, except it has a higher ingress protection rating. Underground, that IP grade protects against heavy dust clouds and humid conditions. Above ground, there’s less dust, but the moisture content in an open pit is potentially higher.
Expect the minerals in an open pit mine to be close to the surface. However, the scale of the operation moves from a long series of chambers and shafts to a wide area. That exposed region is covered with haulage vehicles, loaders, and bucket-wheeled excavators. Finally, the excavated materials are processed, so the processing equipment must be constructed to facilitate the high-volume streams that are discharged here.