DRAGLINE MACHINE AT DHUDHICHUA PROJECT ,SINGRAULI

TAUHID MOHAMMAD ROLL NO:- 15MT000557

DEPARTMENT OF MINING MACHINERY ENGINEERING INDIAN SCHOOL OF MINES DHANBAD

intoduction• A dragline excavator is a piece of heavy equipment used in civil

engineering and surface mining.• Draglines fall into two broad categories: those that are based on

standard, lifting cranes, and the heavy units which have to be built on-site.

• Most crawler cranes, with an added winch drum on the front, can act as a dragline.

• These units (like other cranes) are designed to be dismantled and transported over the road on flatbed trailers. Draglines used in civil engineering are almost always of this smaller, crane type.

• These are used for road, port construction, pond and canal dredging, and as pile driving rigs. These types are built by crane manufacturers such as Link-Belt and Hyster.

• Draglines, unlike most equipment used in earth-moving, have remained relatively unchanged in design and control systems for almost 100 years. Over the last few years, some advances in dragline systems and methodologies have occurred.

LAYOUT OF DRAGLINE MACHINE

operation1.) In a typical cycle of excavation, the bucket is positioned above the material to be excavated. 2.)The bucket is then lowered and the dragrope is then drawn so that the bucket is dragged along the surface of the material. The bucket is then lifted by using the hoist rope3.). A swing operation is then performed to move the bucket to the place where the material is to be dumped. 4.)The dragrope is then released causing the bucket to tilt and empty. This is called a dump operation.

OVER VIEW WORKING OF DRAGLINE

Draglines in mining

• A large dragline system used in the open pit mining industry costs approximately 300 to 400 crore.

• A typical bucket has a volume ranging from 40 to 80 cubic yards (30 to 60 cubic metres), though extremely large buckets have ranged up to 168 cubic metres (5,900 cu ft).

• The length of the boom ranges from 45 to 100 metres (148 to 328 ft). In a single cycle, it can move up to 450 tonnes of material.

Schematic diagram of dragline

Walking mechanism• In all but the smallest of draglines, movement is accomplished

by "walking" using feet or pontoons, as caterpillar tracks place too much pressure on the ground, and have great difficulty under the immense weight of the dragline. Maximum speed is only at most a few metres per minute, since the feet must be repositioned for each step.

• If travelling medium distances, (about 30–100 km), a special dragline carrier can be brought in to transport the dragline. Above that distance, disassembly is generally required. But mining draglines due to their reach can work a large area from one position and do not need to constantly move along the face like smaller machines.

Limitations

• The primary limitations of draglines are their boom height and boom length, which limits where the dragline can dump the waste material.

• Another primary limitation is their dig depth, which is limited by the length of rope the dragline can utilize.

• Inherent with their construction, a dragline is most efficient excavating material below the level of their base. While a dragline can dig above itself, it does so inefficiently and is not suitable to load piled up material (as a rope shovel, or wheel loader can).

• Despite their limitations, and their extremely high capital cost, draglines remain popular with many mines, due to their reliability, and extremely low waste removal cost.

UDD

• UDD stands for Universal-Dig-Dump. It represents the first fundamental change to draglines for almost a century, since the invention of the 'miracle hitch'. Instead of using two ropes (the hoist rope and the drag rope) to manipulate the bucket, a UDD machine uses three ropes, two hoist and one drag.

• This allows the dragline operator to have much greater selectivity in when to pick up the bucket, and in how the bucket may be dumped. UDD machines generally have higher productivity than a standard dragline, but often have greater mechanical issues. Within the mining industry, there is still much debate as to whether UDD improvements justify their costs.

DEACK LAY OUT UNIT OF DRAGLINE

Deck layout of walking dragline:

MECHANISM IN DRAGLINE:

• SWINGING MECHANISM• HOIST MECHANISM• WALKING MECHANISM• DRAG MECHANISM

HOIST SYSTEM• Hoist system: The hoist generator (DC) delivers

power to the two hoist motor .These motors drive the two hoist drum through a gear box. two hoist ropes are separately wound on the surface of the drums.

• As the drum rotates in clockwise direction the bucket is hoisted while, during the counter clockwise rotation of drum ,the drum is lowered with the help of gravity

• These drums are provided with the hand brakes to stop and to control the movement of the bucket of the dragline

The dragline consists of the following components:

• · Base• · Revolving Frame and Slewing Machinery• · Bucket• · Bucket suspension system• · Boom• · Hoist and drag units• · Fair lead• · Walking Mechanism• · Superstructure

• The dragline comprises a main machinery house (rotating house), a main structure (A-frame, mast and boom), a bucket, a base and walking shoes.

• The rotating house rides upon the rollers mounted on the base. The revolving motion is achieved by swing pinions meshing with a large swing rack.

• The dragline is able to “walk” by means of large eccentrically driven walking shoes at the sides of the machine.

• Draglines are specified by the boom length and bucket capacity. A 24/96 dragline means the capacity of the bucket is 24 cubic meters and the boom length is 96 m.

Bucket Suspension• The dragline bucket is suspended from the

boom sheave by attaching to hoist rope and drag rope. The components of the bucket suspension system of a dragline .

• The bucket front arch has got two hooks or clevises at its two ends to fasten the drag chains. The drag chains converge in a drag yoke to which the end of the drag rope is fastened.

Dragline bucket