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2 DRAGLINE: Application. Further, the choice of stripping unit is influenced primarily by the system of mining, which is itself influenced by surface topography, nature and shape of coal seam, production requirement, nature and depth of overburden as well as reclamation considerations. The factors influencing most of the designers to go in for the deployment of Dragline are due to The flexibility of its operation. Greater digging depths (compared to a shovel of comparable cost). Greater range which can be well used for multi-seam working. It safeguards against spoil pile slides. Lowest maintenance Cost per cubic metre. High percentage of coal recovery. Its cheaper operational cost and Low ground pressure (less than 1kg/cm2) exerted makes it possible to move over dumps comfortably.

3 FORMULA FOR CALCULATING THE HEIGHT OF THE BENCH. t + tan x ( R - W / 4 ) H = S + tanx / tan y H= Height of the OB Bench. t= Thickness of the Seam. x= Angle of repose OB. y= Angle of High wall. S= Swell factor ( 1.25). R= Effective of Dragline. W= Width of the cut.

4 DRAGLINE OPERATION AT OPENCAST PROJECT - I ;R.G

5 DRAGLINE: Application. A BORE HOLE SECTION SHOWING THE INTERBURDENS

6 OPENCAST MINING WITH WALKING DRAGLINE. W WALKINGDRAGLINE

7 SALIENT FEATURES OF DRAGLINE 1. Make : Ramson & Rapier 2. Boom Length: 95.6 Mtrs. 3. Digging radius: 88 Mtrs. 4. Dumping Height : 39.6 Mtrs. 5. Bucket Capacity: 24 M³ 6. Base Dia: 16 Mtrs 7.Shoe Length/Width: 17 Mtrs./2.8 Mtrs. 8. Movement of Machine / Step:2.2 Mtrs 9. WT. Of Machine: 2000 Tonnes 10. Total HP:3500 HP ( Swing motors:3 No.s ; Hoist motors :2 No.s ; Drag motors :2No.s ; ) 11. Annual Target: 4.00 M. M³ 12. Material Handled since inception: M. M³ ( up to FEB-03 )

8 Use of Draglline: There are lot of controversies over the actual and best use of Dragline. Some experts say that the excavating capacity of traditional equipment for pre- stripping, should far exceed the excavating capacity of Dragline. Usually Dragline machine, being the last equipment to be used immediately above the bottom most coal seam, has got limited scope of enhancement on production, even by increase in the strength of conventional equipment. Initial development for deployment of Dragline has to be carried out by shovel-dumper combination and they are to be continued to be used for pre-stripping or removal of upper thin seams if any.

9 Use of Draglline: The other opinion emphasises and banks more on the operational cost of Dragline, the excavation cost with Dragline being minimum, tendency is always to fully use Dragline and therefore would prefer more excavation capacity in the form of more number of Draglines. To accommodate more number of Draglines, these experts like to either the property in a suitable way for unit work or combine two to three seams working with multiple Draglines or by having tandem application with wider cuts etc. Even though multiple seam operation is being effected by single Dragline, it may be remembered that, any mode of operation above the level of Dragline tub is inefficient. Mines have already come up with production reaching 10 million tonnes with as many as four Draglines of different sizes.

10 The advantages offset t he minimal disadvantages like 1) R equirement of bench preparation and 2 ) Higher capital cost 3 ) It's limitation to work only bottom most seams. Advantages: The greatest advantage of Dragline machine is that, its cost of overburden removal is the cheapest within its limitations. Though the machine is huge and requires special and stringent maintenance, it's operating cost per cubic metre works out cheaper than any other method. As earlier said, the machine also has its limitations and is ideally suited for flat thick seams with extensive property on strike direction and with uniform thickness of overburden. The presence of geological disturbances, multi direction dipping seams or steep seams complicate its field of operation.

11 Planning of Dragline Operation: Once the choice of the machine is made, its successful operation depends a lot on careful and efficient planning. Planning takes into account, apart from the best working of the machine, the correct and systematic deployment of other traditional equipment for pre stripping etc. Aspects which require close attention, at the planning stage itself include: Selection of proper machinery mix for allowing the Dragline, to have uninterrupted work. Initial planning of Dragline cuts and the sequence of operation. System for proper evacuation of the coal from the cuts.

12 Planning of Dragline Operation: Drainage, to conduct water away from coal extraction area and to prevent ponding. I.e., De-watering arrangements. Study of actual operational time of Dragline. Study of bank overburden removal and rehandling operations and to minimise rehandling. Fragmentation and blasting aspects to avoid hard digging conditions.

13 WORKING WITH DRAGLINE : Steps & Methods DRAGLINE CUTS PLAN

14 WORKING WITH DRAGLINE : Steps & Methods For any dragline operation two most important dimensions are operating radius and the dumping height, which describe the physical stacking capability of a particular machine, the operating radius is dependant on the positioning of the machine from the crest and decides the point of discharge/dumping. In other words, reach factor decides the exact place of dumping and can be obtained from the following relationship. Operating radius = Positioning + Reach factor. HTHT OR

15 WORKING WITH DRAGLINE : Steps & Methods For any dragline operation two most important dimensions are operating radius and the dumping height, which describe the physical stacking capability of a particular machine, the operating radius is dependant on the positioning of the machine from the crest and decides the point of discharge/dumping. In other words, reach factor decides the exact place of dumping and can be obtained from the following relationship. Operating radius = Positioning + Reach factor. HTHT OR

16 WORKING WITH DRAGLINE : Steps & Methods General Working Methods of Dragline:

17 WORKING WITH DRAGLINE : Steps & Methods GENERAL CROSS SECTION

18 WORKING WITH DRAGLINE : Steps & Methods

19 BLASTING - AN AID TO DRAGLINE WORKING:

20 BLASTING - AN AID TO DRAGLINE WORKING:

21 BLASTING - AN AID TO DRAGLINE WORKING:

22 BLASTING - AN AID TO DRAGLINE WORKING:

23 WORKING WITH DRAGLINE : Steps & Methods PLAN OF BOX CUT SECTION VIEW OF BOX CUT

24 Advantages of bench extended Method. Dagline has more room maneuver resulting in faster cycle times and safer operations. Scheduling easier as each slice takes longer complete. Higher production can be concentrated in a cut width along strike length. The extended bench offers a much safer position for Dragline to work from taken the original high wall. Coal recovery is more. Reduces the contamination of coal as it is easy to clean out the coal edge. Disadvantages are only to schedule.

25 DRAGLINE WORKING:

26 CONCLUSIONS: