Selective mining of minerals
Materials from deposits and mineral raw materials are used for a whole variety of purposes, as a raw material 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 are simply no longer up-to-date in mining, earthworks and rock construction. The WIRTGEN GROUP's answer: surface mining - with the mined material either loaded directly onto trucks or deposited in windrows.
Surface mining: Direct loading
One of the most important features of the WIRTGEN Surface Miners is their ability to load the cut material directly onto trucks. WIRTGEN Surface Miners are designed for front loading or rear loading, depending on the model concerned.
On the front-loading 2200 SM, the discharge belt is mounted at the front of the machine. It can be slewed to either side and the discharge height adjusted as required. Depending on the size of the truck, these machines load the trucks either from the rear or from the side. The operator of the Surface Miner has a clear view of the truck.
Other models, such as the 2500 SM and 4200 SM, are rear loaders and their discharge conveyor is 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.
Gently loading trucks with small-sized material
In all cases, the fine grained material cut by the WIRTGEN Surface Miner ensures that the truck body is loaded uniformly, continuously and completely. These loading characteristics allow the truck size to be selected as required. Trucks with aluminium bodies and increased payload can also be used under certain circumstances.
- No material re-handling
- Direct loading onto trucks is usually the most economical method if the material is to be transported over distances of more than approx. 1,640' (500 m).
Surface mining: Windrowing
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.
- No time lost waiting for trucks
- No belt wear / higher availability
- Higher production output than when loading with conveyors
- Larger lump sizes
- Greater selectivity when working steep and inclined seams
- Most economical method for transport distances of less than approx. 150 m when handled by wheeled loaders and approx. 500 m in scraper operation