Surface mining: Selective mining of payment minerals
The deposit material and the mineral raw material are used for a variety of purposes as the base for the construction or as energy source. But, how are they mined? What are the methods that permit that any kind of rock may be selectively and profitable extracted?
Drilling and blasting in mining operations, of rock and earth movement, are not simply “state of the art”. The surface mining offers an economical solution more efficient and respectful about the environment since it is able to cut, crush and load rock in one only step of work.
Direct loading
One of the most important characteristics of the WIRTGEN Surface Miners is its capacity of directly loading the material cut on the trucks. The WIRTGEN surface miners are designed for front or rear loading depending on the model in question.
Frontal loading
In the frontal loading 2200 SM, the unloading belt is mounted on the front section of the machine. You can turn to both sides and the unloading height is adjusted if necessary. Depending on the size of the truck, these machines load the trucks from the rear part or from the side part. The Surface Miner´s operator has a clear vision of the truck.
Rear loading
Other models, such as the 2500 SM and the 4200 SM, are rear loaders, being its unloading transporter mounted on the rear side of the machine. The transporter may turn about 90 degrees to both sides and the adjusted unloading height as the case may be. The Surface Miner´s operator may turn from his seat to the right or to the left to make sure that he has a clear vision of the truck.
Scaffolding
When you work in the yarn mood, the cut material is directly deposited at the rear of the machine without using the transport. This makes the cutting process to be independent from any other loading process (in trucks). However, the material must be subsequently re-handled by a frontal loader.
In many cases, the highest productivity reached by the scaffolding in comparison with the direct loading balances the additional costs incurred for the new material handling (for example, wheel loaders).
In addition, this method does not permit any belt wear and does not involve functioning expenses for the transporting system.
To deposit the material in the sideway
The innovative technology decreases the expenses for the machines and the staff and saves a considerable amount of time in comparison with the conventional methods. At the same time, it produces uniform, stable and embankment surfaces and permits the selective extraction of individual rock layers. And that is not all: the surface mining is a method of low dust level and low noise which does not produce harmful vibrations and therefore, it permits the effective mining of useful minerals near to residential areas or roads.
Cost reduction, quality increase and product efficiency
The extracted and crushed material is so small that may be processed in a profitable manner by requiring a minimal subsequent treatment. The mining of bauxite, phosphate, kimberlite or salt has become increasingly profitable and the surface mining may even mine hard limestone or granite with not confined compression resistance of up to 260 MPa with no blasting.
SLIDING FORMWORK
Encofrado deslizante entre orugas
When paving in inset application, the concrete is delivered by trucks and dumped ahead of the slipform paver. It is spread by an excavator or second paver when working with large paving widths. Depending on the paver model used, the material is then distributed evenly across the full paving width by a spreading auger or spreading plough. The robust paving mould slipforms the concrete pavement while travelling over the previously distributed concrete material. Electrical vibrators emitting high-frequency vibrations ensure optimum compaction of the concrete during the slipforming process. Tie bars and dowel bars are inserted into the freshly paved concrete automatically. Last but not least, a finishing beam and super-smoother put the finishing touches to the new pavement.
Side sliding formwork
