This document provides information about Surface Miners (SMs). SMs directly cut rock with a rotating cutting drum, sizing the material and transferring it to conveyors. The key components of SMs are the mainframe, conveying unit, drive unit, crawler unit, and cutting unit. SMs can cut material continuously or in cycles by empty travel, turn back, or continuous mining methods. Material is loaded directly onto trucks or indirectly via windrowing or side casting. SMs provide advantages over drilling and blasting like selective mining and reduced costs, though they are best suited to homogeneous, flat deposits with low moisture content.

1. Nirbhay Kumar Sinha
Admn. No.-2013MT0130
MME
INDIAN SCHOOL OF MINES, DHANBAD

2. Introduction of SMs
 A Surface Miners (SMs) is basically a direct rock-cutting
machine.
 SMs have cutting drum usually fitted in the middle of
machine & sometimes in-front of the machine with TC
cutting peaks. They directly cut the rock by rotational
motion of the cutting drum.
 The cut material (less than 300mm, mostly less than
100mm) centrally transferred to the primary conveyor,
underneath the machine from where the material is
conveyed to the discharge conveyor which is slewing and
vertical lifting type, is directly loaded into either dump
trucks or into a series of belt conveyor for onward
transportation to the secondary crusher.

3.  Some SMs cut the material and stack them on the
mid-way run of the machine. This is known as
windrowing.
 In other method the material after being cut is side
casted with the help of boom conveyor.

4. SURFACE MINERS

5. The surface miner mainly consists
of 5 units:
Mainframe
Conveying Unit
Drive Unit
Crawler Unit
Cutting Unit

6. Mainframe
• It consists of operators
cabin, supporting
frames, Boom counter
weight, Slewing ring
etc.
•It consists of rigid,
metal-box welded
design with integrated
tanks for oil, diesel and
water.

7. 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.
•It is height adjustable
and can be swiveled
on both side.

8. 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.

9. Crawler Unit
• Based on the design it may be single pair crawler or
two pair crawler.
.

10. Cutting Unit
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.
It is flexibly
mounted to the
machine frame
through sliding
block.

11. 3) Spirals / Vanes
2) Flange
5) Edge cutter
1) Barrel
4) Toolholder
7) Cutter tool
It consist series of cutting peaks
spirally mounted on pick holders.
The cutting drum rotates in up
milling direction.

12. Working Cycle of SMs
Cycle completes in five stages:
1) Dumper positioning
2) Cutting and loading onto the conveyor
3) Conveyor loading the load on to dumper
4) Loaded dumper moves for unloading
5) Empty dumper replacing the loaded dumper
 First the dumper is positioned in such a way that its rear
end comes below the secondary conveyor then SMs cuts
the material and transfers to primary conveyor which
discharges the material onto secondary conveyor that in
turn loads the material onto the dumper. SMs moves
forward as it loads.

13.  Dumping is continued till the
SMs reaches the front end of
dumper body. When the
secondary conveyor is above the
front end of dumper body then
SMs operator gives a particular
signal to dumper driver so that he
drives the dumper forward till the
dumper’s rear end comes below
the secondary conveyor and then
SMs operator again gives distinct
signal to halt the dumper.
 Then the above process is
repeated on an average 3-4 times
to fill the dumper. As soon as the
dumper is filled empty dumper
replaces it and cycle is repeated.

14. The cutting drum
rotates in up
milling direction.
The cut material is
deflected to the
centre of the drum
by deflected
segments welded
on the drum.

15. From the centre of
drum, the primary
conveyor receives the
cut material & loads it
on to main conveyor
which can be height
adjustable & slewed over
90 degree to left & right.
The protection cover &
scraper blades are
located behind the
cutting drum.
The position of cutting
drum is continuously
sensed by sensors.

16. The depth of cut can
be adjusted directly
from the operators
cabin.
Gradient and levelling
is also sensed by
sensors.
A water spray system
suppresses the dust &
reduces wear and tear of
cutting tool.

17. Operator’s cabin is at front
side which is equipped with
heating and AC system &
complete control panel.
Machine is provided with
hour meter, engine
temperature meter, engine
rpm (Tachometer), oil
pressure gauge, hydraulic
pressure gauges- (system
control pressure, conveyor
pressure, track drive
pressure), battery charging
indicator, oil pressure of
cutting drum, filter
contamination warning
lights.

18. Based on the cutting principle and position of the
drum, the surface miners is classified in three types:
1.Machine with middle drum configuration.
2. Machine with front boom cutting drum.
3. Machine with front cutting wheel.

19. 1.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.

20. 2. 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.

21. 3. Machine with front cutting wheel
☻In this types of m/c, several bucket wheels are arranged &
cutter picks are fitted on lip of each bucket to form the cutting drum,
which is positioned in front of the m/c.

22. Method of working
Based on mode of travel
 Empty travel method.
 Turn back method.
 Continuous mining method.
Based on loading:
 Direct truck loading
 Indirect loading

23. 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
with maximum
speed.

24. Empty travel method
☻When it moves
backward it travels
empty and after
reaching the starting
point the m/c gets
ready for the fresh
cut.
☻It makes only
straight cut.
☻This method is
applicable were the
operating length is
less than 200 meters.

25. Turn back method
•In this method, after
completing the cut, the
drum is raised and the
machine turn by 180 degree
for the fresh cut which is
adjacent to the previous cut.
•It is applicable were the
length of face is >200m.

26. 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.
•It eliminates the
unproductive time for
turning back and
empty travel back and
increases utilization
percentage of
machine.

27. • In this method SMs
travels in both
straight and
curvilinear cuts.
• Indian mines shows
that curvilinear cuts
increases the
productivity by 10-
15%.

28.  In this initially the
curvilinear paths
are cut
continuously by
SMs where a large
radius is available.
The central portion
of the deposit is
mined by straight
cuts.

29. BASED ON LOADING
LOADING
OPTIONS
DIRECT
TRUCK
LOADING
FRONT
LOADING
REAR
LOADING
INDIRECT
LOADING
WINDROW SIDE CAST

30. DIRECT TRUCK LOADING

31. INDIRECT LOADING
Windrow
In this method SMs cuts the rock and deposit it behind the
cutting drum and after that material is loaded to trucks or
dumpers with the help of payloader.

32. SIDE CAST
In this method SMs cuts the rock and deposit it beside the
machine and after that material is loaded to trucks or dumpers
with the help of payloader.

33. Merits of SMs
Extracts valuable minerals without drilling ,blasting
which leads to less operating cost.
Material is directly sized as it cut and can be loaded on
to the trucks, higher integrated conveyor system
directly-remove inpit crushing plant. Hence capital
investment is reduced much.
Selective mining can be done, beds or layers as thin as
15-50mm -increases the output and reduces
operational cost of processing plant.
Fulfills the environmental regulations for vibration,
noise, dust emissions easily.
Produces stable, clean and level surface. This protects
other site vehicles, particularly their tyres and saves
maintenance cost.

34. The material is mined, sized and loaded in single pass,
thereby substantially reducing machinery and
personnel requirements.
Work stoppage due to blasting is eliminated. Hence
better utilization of the machineries.
Effective supervision and management due to less
equipment.

35. Demerits of SMs
In case of high moisture content and sticky nature of
material, milling drum will get jammed & whole
system stops.
Sharp turns decrease the production of machine.
Initial cost of machine is high and may be around
200-300 crore, so more number of machines cannot be
deployed. Hence dependability on a single machine
increases and entire production comes to a halt if it
breaks down.

36. Deposit should be homogenous in term of
compressive strength.
It may not be economically suitable for smaller mines.
They are mostly suitable for flat deposits.

37. Physio-Mechanical Properties
Parameters Values
Moisture Content should not
exceed
8.0%
Compressive Strength
Should not exceed
60 MPa
Hardness of rock should not
exceed
3Mho
Depth of cut max. 300mm
Speed of SMs 6m/min.
Length of seam for mining 400-600 m
Width of seam 100m

38. SPECIFICATIONS OF SMs 2200Parameters Values
MAKE Writgen (Germany)
MILLING WIDTH 2200 mm
MILLING DEPTH 0 to 300 mm
ENGINE POWER 900 KW
NO. OF CUTTING TOOTH 76
TRAVELLING SPEED 5Kmph (max.)
GROUND CLEARANCE 90mm
THEORETICAL INCLINATION 37 %
PRIMARY & DISCHARGE CONVEYOR BELT
WIDTH
1100mm
MACHINE (L*B*H) 9600*2750*3000 mm