Surface miner and its performance (1)

3. • Introduction
• Principle design of surface miner.
• Working principle of Surface miner.
• Performance of Surface miner.
• Summary.

4. ☻The conventional method of mining includes –
Drilling, Blasting, and Face loading.
☻ Even enough technology development took place to
take care of fly rock, still there is a problems. And the
second foremost is cost effective mining and also
quality control.
☻ To overcome the above problems, a series of research
and development led to the development of new
technology known as Blast free mining by SURFACE
MINER.

5. These jobs are no longer required:
Cleaning, levelling and bolder splitting
Surface Miners
Drilling Blasting Loading Crushing

6. ☻A significant improvement can be achieved in the following
area-
> Produce clean and high quality material.
> Deposit can be exploited fully.
> Reduction in transportation cost and production
process.
> Environmental friendly mining.
☻It also takes care of both safety part and economics in
mining
Some direct benefits are –
1. Mining with out blasting, therefore no need for drilling.
2. Insitu crushing & sizing before conveying on to the truck is
possible.

7. 3. Surface miners have a unique conveying system by
which the mined material is directly loaded onto the truck /
dumper.
4. The haul road preparation and maintenance in deposit are
reduced. Even some times its not required.
This system has special advantage of selective mining
Less coal loss and dilution.
Improved coal recovery especially in areas sensitive to
blasting.
Less stress and strain on trucks due to minimum impact of
the excavated material.
Primary crushing and fragmentation of coal reduces the
capacity requirements for coal washing / preparation
plants.

9. The surface miner mainly consists of 5 units:
1. Mainframe: It consists of operators cabin, supporting
frames, Boom counter weight, Slewing ring etc.
2. Conveying Unit: It consists of two stage conveyors,
one carries the material from the cutting drum and
discharges on the boom conveyor. This conveyor in turn
conveys it on to the trucks.
3. Drive Unit: It consists of a diesel operated engine
whose power is transmitted to the cutting drum via
robustic belts drive. And it consists of hydraulic system
to operate other units.
4. Crawler Unit: Based on the design it may be single pair
crawler or two pair crawler.

11. Central Cutting Drum is driven mechanically by a diesel
engine through belt drive

12. Cabin with all the controls
Crawler Tracks

13. ☻The most important
parameter is the cutting tool.
☻The selection of right cutting
tool is essential for good
cutting performance & high life,
since, it constitute a major
portion of operation cost of the
machine.
☻The cutting depth can be
regulated by automatic leveling
system mounted on the machine, the pre-selected cutting depth is main
-tained either automatically or manually.
5. Cutting Unit:

14. The milling processes used by surface miners are of two types:
Up-milling:
In this process, the milling drum rotates in the anti-clockwise direction
when seen from right-side, of the direction of advance of the machine.
During up-milling process, the milling drum, while cutting takes benefit of
the structural properties of the rock, like lamination, inherent cracks and
fractures, sedimentation, cleavage, etc. machines of companies like
Wirtgen, Bitelli, L&T, use this process. This process increases the
production of the machine as it uses the power developed by the engine
is used in a more efficient way.

15. Down-milling:
In this process, the milling drum rotates in the clockwise direction when
seen from right side, of the direction of advance of the machine. Down
milling is used in soft to medium hard material.

16. A diagram showing point of attack by Picks

17. Model Drum Width Cutting
Depth(max.)
No. of Picks
2100SM 2000mm 300mm 76
2200SM 2100mm 350mm 76
2200SM/3800 3800mm 250mm 200
SF202M 2000mm 200mm 84
KSM304 3000mm 400mm 105
KSM223 2200mm 300mm 76
TABLE SHOWING NUMBER OF PICKS IN DIFFERENT SURFACE MINERS

18. Belt Drive for Milling Drum: diagram

19. Picks:
Some of the picks used in the surface miners are:
Smaller diameter of tungsten carbide:
1. Low lifetime.
2. Good penetration.
3. High cutting.
4. Coarse gradation.
Large diameter tungsten carbide:
1. Long time.
2. Poor penetration.
3. Low cutting performance.
4. Fine gradation.

20. Tool holders:

21. 1. Machine with front boom cutting drum.
☻In these type of machines cutter drum fitted with picks is mounted on a
Boom, like road headers. Due to longer boom the cutting force of the
machine is limited.
BASED ON THE CUTTING PRINCIPLE AND POSITION OF THE DRUM,
THE SURFACE MINER IS CLASSIFIED IN THREE TYPES.

22. 2. Machine with front cutting wheel
☻In this types of m/c, several bucket wheels are arranged in tandem &
cutter picks are fitted on lip of each bucket to form the cutting drum,
which is positioned in front of the m/c, just like BWE.
☻The m/c can exert huge force in cutting both hard coal and rock as the
bucket wheel drum is close to the m/c and the reaction of cutting force is
directly transferred to the ground through a hydraulically loaded dozer blade
behind the bucket wheels.

23. 3.Machine with middle drum configuration
☻In these type of machines the cutting drum is positioned below the
machine in between the front and the rear crawlers, cutting picks are
fitted on a drum and having the depth of cut 500 to 600 mm
BASED ON THE CUTTING PRINCIPLE AND POSITION OF THE DRUM,
THE SURFACE MINER IS CLASSIFIED IN THREE TYPES.

25. Working Principle of Surface miner.
☻The surface miner is crawler-mounted machine having a
cutting drum located between two sets of crawlers and
positioned at the center of the machine.
☻The drum is lowered and raised by hydraulic system with
powerful hydraulic motors thereby varying the depth of cut
☻The material cut is loaded onto the primary and secondary
discharge conveyors for loading the same on to the
loading / transporting equipment.
☻The rear crawler travel at lower level than the front
crawlers to adjust to the required depth.

26. Precise
cutting depth
Clean, level and
stable surface
Continuous
cutting
Crushed
aggregate
Direct
loading
Cut, crush, and load in a single operation with one machine

27. Method of working
MINING METHODS
• Wide bench method
• Block mining method
• Stepped cut method
Based on mode of travel
• Empty travel method.
• Turn back method.
• Continuous mining method.
Based on loading:
 Direct truck loading
 Indirect loading

28. 1231618
41424
102127
COAL SEAM
OB
SPOIL
STEPPED CUT METHOD
6
12
79
1315
19
22
25
1231921
41424
71827
COAL SEAM
OB
SPOIL
BLOCK MINING METHOD
6
9
1012
1315
16
22
25
12379
101418
192427
COAL SEAM
OB
SPOIL
WIDE BENCH METHOD

29. Empty travel method
☻In this method the machine starts cutting operation from
one end of the pit. After completion of the one full cut the
cutting drum is raised & it moves back to the starting end
without turning.
☻It travels empty while it moves backward and after
reaching the starting point the machine gets ready for the
fresh cut.
☻This method is applicable were the operating length is
less than 200 meters.

30. Empty travel method
Production travel
Empty travel

31. Turn back method
In this method, after completing the cut, the drum is raised
and the m/c turn for the fresh cut which is adjacent to the
previous cut. It is applicable where the length of face is
>200m.

32. Continuous mining method
Here, the machine moves with cutting the material and
while approaching the pit end, the m/c turns with gentle
angle without raising the drum.

33. BASED ON LOADING
LOADING
OPTIONS
DIRECT TRUCK
LOADING
INDIRECT
LOADING
WINDROW SIDE CASTFRONT LOADING REAR LOADING

34. DIRECT TRUCK LOADING

35. INDIRECT LOADING
Windrow

36. SIDE CAST

37. COMPARISON OF LOADING METHODS
ADVANTAGES DISADVANTAGES
Direct
loading
No re-handling of material
required
Where water percolation is more,
this system of loading will give
greater advantages.
Larger working area required for truck
Production affected by truck exchange
Belt wear
Side
cast
Blending of materials in the mine
Stockpile of material in the mine
No waiting for trucks
Restricted to 3-5 cuts
Belt wear
Material has to be re-handled
Material prone to absorb water when
lying on ground
Windrow
No waiting for trucks
No belt wear
Higher production rates
than conveyor loading
Coarser material
Better selectivity on steep
inclined seams
Larger working area required
Material has to be re-handled
Material prone to absorb water when
lying on ground

38. Following are the possible uses of surface miners:-
•Uses in mining sector: High purity of useful mineral, high cutting
performance, low price per tone.
1.Selective mining from thin seams of useful mineral.
2.Mining rock without blasting.
3.Producing small particle sizes during mining process.
•Uses in earth moving and construction: Production of precise, stable and
defined profiles in rock.
1.Production of stable embankments.
2.Production of defined surfaces.
3.Production and rehabilitation of traffic routes.
Main applications of surface miners:
•Selective Mining : one of the most important characteristics of the surface
miner is their ability to work highly selective. Thin distributed seams for
example, can be mined precisely and economically.
Advantages:
1.Enhanced ROM quality.
2.Improved exploitation of deposits.
3.Reduced stripping ratio.
4.Reduced processing after mining required.

39. •Material exploitation and crushing without blasting:
Since there is no drilling and blasting problems of vibrations and fly rock
are avoided. Blast free exploitation also ensures reduced noise and dust
development. Primary crushing stage can be omitted in surface mining
technology.
Advantages:
•Low investment costs in comparison to the range of equipment
necessary for conventional mining.
•Low operating cost due to less equipment and less personnel.
•Several working steps are realized by only one machine, leading to
easier co-ordination and process planning, dispatching and maintenance.
•Improved exploitation of deposit.
•Improved safety.

41. Performance of surface Miner
Factors affecting the performance of surface miner
Geological factors
☻Uniaxial Compressive strength
☻Abrasivity
☻Structure of the rock.
☻Binding material
☻Number of joints
☻RMR properties
Machine Factors
☻Engine rating/power
☻Width and diameter of cutting drum
☻Traveling speed of the machine
☻RPM of the drum
☻Cutting depth
☻Pick design
☻Loading option

42. • Cuttability of rock which depends on its:
Uni-axial compressive strength & tensile strength,
Abrasivity & Structure ( number and distance of
fractures) – depends on the formation to be cut
• Cutting depth & Travel Speed of the Surface Miner
while Cutting – depends on machine design
• Area available for operation
Larger the area, higher the productivity– depends
on size of mine & mine planning
Key factors to productivity

43. Effect of field length on productivity
Larger the cutting length, higher the productivity

44. Abrasivity
It has a direct correlation with number of picks consumed
during the operation.
Structure of the rock
It is easy to cut with surface miner in highly jointed and
fractured strata.
Binding material
It has a relation with pick consumption
Uniaxial Compressive strength
In general surface miners are capable of cutting rocks of hardness
b/w 10-80 MPa. Under certain circumstances (E.g. Highly fractured
material) even harder material can be cut economically.

45. Speed of cutting by SM2200 in different strata
17.03
18.83 19.32
24.13
0
5
10
15
20
25
30
shale coaly shale coal soft coal
speed(m/min)

46. Depth of cut by SM2200 in different strata
0.183
0.171 0.168
0.202
0
0.05
0.1
0.15
0.2
0.25
shale coaly shale coal soft coal
Depthofcut(m)

47. Production rate by SM2200 in different strata
1101.08 1145.07 1144.17
1730.76
0
200
400
600
800
1000
1200
1400
1600
1800
2000
shale coaly shale coal soft coal
Productionrate(t/h)