Earthworks engineering: extraction
The materials from the excavations of a given project fall into various categories:
* Top soil and woodland humus : These are surface materials. They are stockpiled for later reuse in finishing.
These materials are extracted by means of scrapers or hydraulic shovels, or indeed a loader, once moved into heaps by a bulldozer.
* Loose soil (this is extracted without any prior preparation) :
This category covers a very wide range of materials from the softest type such as muds to more full-bodied soils such as fine chalks.
These materials are extracted with scrapers or a hydraulic shovel or loader.
In certain instances, if vehicular approach is impossible, draglines are used, which have a range of up to 50 metres.
Materials that can be ripped out (for these a ripper is needed; this is a ripper tooth mounted on a caterpillar vehicle or other high powered machine):
This intermediate category covers degraded rock materials which are generally located between rocky material proper and loose soil.
After being ripped out, these materials are extracted by a hydraulic shovel or loader.
Rocky material (these require mining techniques or a hydraulic hammer):
In this category are the hardest materials, in their original formation.
Once the mining process is complete, these materials are extracted by a hydraulic shovel or loader.