Deposit material and mineral raw material are used for a whole variety of purposes, as a basis for construction or as a source of energy. But how are they mined? Which methods allow rock of every kind to be mined selectively and cost-efficiently?
Drilling and blasting in mining, earthwork and rock operations are, quite simply, no longer “state-of-the-art”. Surface mining offers a far more economically efficient and environmentally friendly solution, as it is capable of cutting, crushing and loading rock in one single working pass.
One of the most important features of the WIRTGEN Surface Miners is their ability to load the cut material directly onto trucks.
The 2500 SM and 4200 SM are rear loaders, their discharge conveyor being mounted at the rear of the machine. The conveyor can be slewed about 90 degrees to either side and the discharge height adjusted as required. The operator of the Surface Miner can swivel his seat to the right or left to ensure that he has a clear view of the truck.
When working in windrowing mode, the cut material is deposited directly behind the machine without using the conveyor. This makes the cutting process independent of any loading processes (onto trucks). However, the material must subsequently be re-handled by a front loader.
In many cases, the higher productivity achieved by windrowing as compared with direct loading balances out the additional costs incurred for renewed handling of the material (e.g. by wheeled loaders). Moreover, this method does not give rise to any belt wear and does not incur operating costs for the conveyor system.
Sidecasting the material means that a stockpile is produced by dumping the material from several cuts on a pile via the belt. Depending on the slewing angle of the conveyor belt, material from 3 to 5 adjacent cuts can be piled up. Depending on the height of the resultant pile, the material can easily be picked up again by a front loader.
The innovative technology cuts expenses for machines and personnel and saves a considerable amount of time when compared to conventional methods. At the same time, it produces even, stable surfaces and embankments, and permits the selective mining of individual rock layers. And that’s not all: Surface mining is a low-dust, low-noise method that causes no damaging vibrations and therefore permits effective mining of useful minerals close to residential areas or roads.
The mined and crushed material is so small that it can be processed profitably, requiring minimum subsequent treatment. Mining bauxite, phosphate, kimberlite or salt has become increasingly profitable and the surface miner can even mine hard limestone or granite with unconfined compressive strengths of up to 260 MPa without blasting.