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.
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.
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.
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.
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.
Encofrado deslizante entre orugas
En el procedimiento de extendido entre orugas, unos camiones de aglomerado descargan el hormigón y lo colocan delante de la pavimentadora de encofrado deslizante. Cuando la anchura de extendido es muy grande, una excavadora u otra pavimentadora distribuyen previamente el material. A continuación, un sinfín de distribución, o bien, una cuchilla de distribución, dependiendo del modelo, extiende el material uniformemente en toda la anch de extendido. Durante la pasada, el robusto encofrado deslizante le proporciona la forma adecuada a la capa de hormigón. Unos vibradores eléctricos se hacen cargo, a la vez, de la perfecta compactación del material mediante vibraciones altamente frecuentes. Las anclas y los pasadores se insertan automáticamente en el hormigón aún no fraguado. Para finalizar, los alisadores transversales y longitudinales se hacen cargo de los últimos toques de la nueva carretera.
Side sliding formwork