Earthworks engineering: extraction

Published on 8 February 2008

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.

Scraper and pushdozer amongst loose materials (Photo: DTP Terrassement)

* 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.

In the foreground, bulldozer with ripping tooth (photo: DTP terrassement)

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 materials (Photo : DTP Terrassement)

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.