SURFACE EXCAVATION TECHNOLOGY & EQUIPMENT

- DRAGLINE WORKING

Venku

Mining Methods • Coal is mined by two main methods -

surface or ‘opencast’ mining and ‘underground’ mining.

• The choice of method is largely determined by the depth, geology of the coal deposit and other factors.

• The majority of the world's coal production is coming from Opencast mines.

• The scenario is also same in India.

Fixing of Mine Boundary • Boundaries are fixed based on the cost-

effectiveness.

Selection of Mining Equipment • Stripping Ratio• Life of the mine• Infrastructure available• Proposed annual output• Technology available

Different OC Machinery1. Dragline2. Shovel loading on dumper or tipping truck for transport3. Wheel-loader (also known as Pay loader or Front-end

Loader) for loading dumper or tipping truck for transport4. Bucket Wheel Excavator for loading belt for transport5. Surface Miner for coal loading on belt or dumper/tipping

truck6. Scraper7. Dozer with or without Ripper for making OB suitable for

lifting by a shovel8. Hydraulic Monitor (not used in India)9. In-pit crusher Technology10.Combination of the above machines

SHOVEL + DUMPER

1. Multi seam extraction

2. More flexibility

3. Can work in steep gradients upto 1 in 5

SHOVEL + DUMPER

SURFACE MINER

1. Selective mining.

2. Particularly suitable for coal having compressive strength below 250 kg/cm2.

3. Suitable in gradient of 1 in 10 and flatter.

SURFACE MINER

BUCKET WHEEL EXCAVATOR

1. Used mainly for lignite extraction.

2. Particularly suitable for coal having low compressive strength upto 100 kg/cm2.

BUCKET WHEEL EXCAVATOR

DRAGLINE1. Gradients flatter than 1 in 62. Seams should be free of faults & other

geological disturbances3. Deposits with Major Strike length4. Thick seams with more than 25m thick are

not suitable5. A hilly property is not suitable6. Property should have atleast 15 years life

DRAGLINE

DRAGLINE – Methods of Working– Simple casing method with or without

rehandling.– Extended bench method.– Horse shoe method/Across Pit method.– Continuous bench two pass method.– Tandem dragline working i.e., two

draglines working together, one dealing with part of the material dumped by the other.

Simple Casting

Extended Bench Method

S.No D/L Position

Excavating Cut Area m2 (solid)

Dump

1 P-1 1st Dig D’A’B’CFF’RST 480+192

YRQOU

Extended Bench Method with cast Blast

Horse Shoe Method

D/L Position

Operational position

Excavation Cut Area m2 (solid)

Dump

26M/81 R

Main Bench Position (MBP)

1st Dig ABCDEFGH 280+904 MPQRIS’SU

Spoil Bench Position (SBP)

1st Dig IJKL 332

Rehandle QPIS’ST+VV’NN’

513+17+152 MNOVWW’X’XY

Continuous Bench Two pass Method

Tandem Working of Draglines

Dragline Cut Dump Area m2 (solid)

10/70 ABCD abcd 285.020/90 CDEF

(Dig)kmnofci 570.0

Ijkl (R.H.) 9.6Ebf (R.H.) 1.0

D/L 10/70 is

150-200m ahead of D/L 20/90

Draglines in vertical tandem

Draglines in vertical tandem

Variables with Draglines

•Swing and boom angle of a dragline. •Increase or decrease of bucket size (within limits) with consequent decrease or increase of boom length. •Cut width and height of dragline bench.•Method of use of dragline/draglines.•More than one position of a dragline.•Adopting cast-blasting to the desired extent.

Technical specifications of Dragline (24 x 96)

- Boom length : 74 - 95 m- Boom angle : 30° - 38°- Bucket Capacity (nominal): 26 - 34 cu m- Dump height : 38 - 40 m- Digging depth : 44.3 - 53.4 m- Operating radius : 64.6 - 88.2 m- Walking speed : 0.24 kmph- Bearing Pressure : 0.95 kg/cm2

SPECIFICATIONS OF OC-I DRAGLINE

MAKE Ranson & RapierBucket Capacity M3 24Annual capacity mm3 3.31Boom Length Mtrs 95.6Operating Radius Mtrs 88Dumping Height Mtrs 39.6Base Dia Mtrs 16Shoe Length Mtrs 17Shoe Width Mtrs 2.8Movement of Machine Mtrs 2.2Weight of Machine Tonnes 2000Total H.P H.P. 3500

Specifications of OC-III DraglineMake BEML-MARIONModel 7820WORKING RANGE

Boom Length Feet 275 275 275 Pitch Dia Inches 90 90 90

Boom Angle Degrees 30 34 38Dumping Radius Feet 262 251 240Dumping Height Feet 102 118 134

Depth Feet 160 144 125BASE

Outside Dia-Nominal Feet 50 55Bearing Area Sq.ft 1965 2380

Bearing Pressure Psi 14 11.5

Production performanceAll figures in L.Cu.M.

Year  

OC-I Dragline OC-III DraglineOB OB OB OB OB OB

digging rehandling total digging rehandling totalDOC 26/11/1986 10/9/1994

1995-96 29.94 11.77 41.71 25.96 14.00 39.961996-97 32.07 12.55 44.62 24.56 13.33 37.891997-98 29.48 13.44 42.92 24.70 15.14 39.841998-99 26.14 9.77 35.91 21.98 11.20 33.181999-00 27.11 11.98 39.09 32.01 8.87 40.882000-01 29.23 14.17 43.40 33.80 10.81 44.612001-02 28.62 12.60 41.22 32.50 11.14 43.642002-03 29.02 12.56 41.58 32.10 10.24 42.342003-04 21.84 9.26 31.10 28.91 13.21 42.122004-05 21.95 11.01 32.96 28.98 12.21 41.19

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