Grader, shovel, dragline

To form the subgrade earth digging equipment is also used such as drag line, shovel, etc. For preparing the sub grade the following machinery is used:

· Tractor

· Dozer

· Grader

·

· Drag line

· Trucks

· Rollers, etc.

A grader, also commonly referred to as a road grader, a blade or a motor grader, is a construction machine with a long blade used to create a flat surface during the grading process. Graders are commonly used in the construction and maintenance of dirt roads and gravel roads. In the construction of paved roads they are used to prepare the base course to create a wide flat surface for the asphalt to be placed on.

A shovel is used for digging and loading earth or fragmented rock and for mineral extraction.

An electric mining shovel is a bucket-equipped machine consisting of a revolving deck with a power plant, tracks, a counterweight, and a front attachment, such as a boom. The digging phase consists of crowding the dipper into the bank, hoisting the dipper to fill it, then, retracting the full dipper from the bank. The swinging phase occurs once the dipper is clear of the bank both vertically and horizontally. The operator controls the dipper through a planned swing path and dump height until it is suitably positioned over the haul unit. Dumping involves opening the dipper door to dump the load, while maintaining the correct dump height. Returning is when the dipper swings back to the bank, and involves lowering the dipper into the tuck position to close the dipper door.

The hydraulic mining shovel has been widely used for coal and rock loading since the 1970s.

A dragline excavator is a piece of equipment used in civil engineering and surface mining. In civil engineering the smaller types are used as pile driving rigs. Draglines are one the largest mobile equipment ever built on land, and weigh nearly 2000 metric tons, though specimens weighing up to 13,000 metric tons have also been constructed.

Source: http://www.heavyequipment.com/heavy-equipment/road-highways