New @ presentation on highwall mining.ppt

Contour mining of outcrop seam, hoghwall mining from trench and highwall mining from benches

1. .

4. What is Highwall Mining?
Equipment
Mining Methods

6. Mining a visible coal seam by making rectangular,
mainly parallel, unsupported drives, using an
unmanned cutter head and coal transport system,
controlled from a mining unit positioned outside
the drive, in front of the seam

7. Highwallmining is a proven primary method for
mining relatively flat coal seams lying at shallow
depth or coal seams available at highwallof open
cast.
An unmanned continuous miner is driven
underground and operated in front of the highwall
The miner stands on the pit floor or on the bench
directly in front of the exposed seam
It makes long parallel rectangular shaped drives into
the coal seam.
The remotely operated cutter module is pushed into
the seam by a string of pushbeams.
Coal is transported from coal face to surface by the
contra rotating augers housed inside the closed boxes
of push beams.

9. •Length base approx. 20.1
meters
•Width base approx. 9.2
meters
•Weight base approx. 190
tonnes
•Length of pushbeams–
6.27 meters –6 tonnes
each
•50 pushbeamsper miner
•Max. force in: approx. 170
tonnes, out: approx. 350
tonnes

10. •Four hydraulically
powered tracks articulate
over 90 degrees for
straight and cross travel
•Circle mode for accurate
heading
•Each track 1 meter
vertical movement for
adjusting seam dip and
floor contour
•Turning of each track is
achieved automatically

11. •Power chain for
•Electrical cables for cutter
•Hydraulic lines
•Closed circuit cooling water
lines for cutter motors
•Methane sensor cable
•Control cable
•Hoses protected by steel plates
and links
•Hose chain approximately 330
meters
•Automatically unwinds/winds
into/from channel on pushbeam

12. •Interchangeable, for seams 0.8
to approx. 4.62 meters
•Width 2.9 to 3.5 metres
•Automatically following seam
contour

13. Anchoring

14. Generator
Motor
Generator Set
Capacity
1550KW &
2000 KW

15. •Touch screen technology
•Automatic shearing, various
options
•Automatic sumping, various
options
•Straight holes due to rigid
string in horizontal direction
•Follows layers due to
flexibility in vertical direction
•Accurate heading is
important to ensure parallel
cuts

16. Mobility
•Public road transport:
Operational within three days
excluding travelling time.
•Optional:
Machine movers for longer hauls,
fully assembled
Example:
During 9 months one was moved to 7
different mining pits -some moves
over 6 kilometers in distance

17. Production
•Penetration 300 meters
•Dip of up to 12 degrees
•Monthly production typically
around 100,000 tonnes
•Operates with a 3 / 4 man crew
•Up to 70% recovery, subject to
-Coal compression
resistance
-Overburden load
-Seam height / Pillar
stability

19. Strength of Technology
1.Recovers coal otherwise lost
2.Safe: No man underground
3.Economical: Cheaper than U/G mining
4.Proven: 90 Machines working now
5.77 SHM make & 0thers 13 different make
6.Enclosed Pushbeams: No ash dilution
7.Screw Conveyors: Simple, can handle wet coal
8.Compact: Narrow bench or trench
9.Tracks: Easy travelling and positioning
10.Modular: Easy to relocate mine to mine

21. Mining Methods
•Contour Mining
•Trench Mining
•Bench mining
•Highwall Mining

22. Contour Mining
Outcrop of Seams

23. Trench Mining
Flat Seams

30. Highwall Mine Seam

32. Blast 2nd Bench

35. Highwall Mine Seam 2

37. Strip Seam 3

38. Strip Seam 3

40. Highwall Mine Seam 3

42. Highwall Mining
O/C Pit Limit

43. Where to be Applied:
1.Thin Seams
2.Beyond Strip Limit
3.Coal Blocked in Boundaries
5.Spoils, Roads, Power Lines
6.Villages

44. Highwall mining in the form of Auger mining
started in 1983 in USA.
ADDCAR system of highwallminer started in
1990.
Superior Highwall miners started manufacturing
Highwall miner in 1994.
Total coal production from highwallmining in
USA = 5o –55 million tonnesper annum.
Total population of highwallminer all over the
world in 2011 –90 Nos.
Population of SHM miner –77 Nos.
Highwall miner of other make –13 Nos.

46. Contra rotating augers housed inside the push beams are driven
by motor located on the mainframe of the m/c at surface
These augers inside the box establishes a ventilation circuit.
Foul air inside the coal face is brought out by the augers along
with the coal and fresh air goes over the top of the push beam.
Coal face environment is continuously monitored for
concentration of methane.
In the event methane percentage exceeds 0.75 it will be
displayed in operator’s screen. Operator will stop cutter head
operation , continue operation of the auger thus diluting
methane concentration
In case methane percentage exceeds 1.25% power supply to the
cutter head will be automatically cut off, but power to the auger
continues since the auger drive in it is positioned at surface.

47. Machine is fitted with FOG ( Fiber Optic
Gyro) navigation system.
Ensures the parallel drivages
automatically.
Machine is controlled by PLC, to avoid
human error .
Auger system is unique for the wet coal
transportation.
GPS ensures faster positioning of the
machine at desired angle of drivages.
An inbuilt device to measure the roll,
pitch, and Cutter head angle .

48. Operations are carried out by remote
control.
Operator’s cabin at 6 mtrheight and about
20 mtraway from Highwall.
No person is required to go inside the
drivages.
Persons are not exposed to hazards like roof
falls, gas, dust, irrespirable atmospheres,
etc.
Manpower requirement for the whole
operation is as low as 4 per shift.
One of the safest mining methods.

50. Electrical cables run inside a steel chain & chain is
placed in a protective slot on top of the push
beams. Steel chain protect the cable from
mechanical damage.
Cables inside the cutter module are laid under
steel cover of the cutter module.
LV cables which are not armoured are laid inside the
DGMS approved hydraulic hoses to provide
mechanical strength.

51. It contains:
Cables
Water Hoses
Hydraulic Hose

52. 7 types of cables used with the machine:
4 types of cables are already DGMS approved
Rest 3 Low Voltage cables conform to UL 13 & UL
758 standard
Types of cables used

53. Continuous monitoring of the methane by DGMS
approved methane Sensors
Intrinsically safe & fail safe in design
Methane sensor device interlocked with PLC control
system

54. Power to UG will be “ON” only if:
The Methane sensor is “ON”
Working properly
Methane level is below 1.25%
Protection Against Methane
Concentration

55. When Methane level:
=0.8% Operator get audio-visual alarm
>1.25% U/G part of the machine will be powered “OFF”
Protection Against Methane
Concentration
In case methane sensor switched off or is in fault mode all electrical
power sources including signal & control will be shut off (fail safe)

56. Sensor is encapsulated inside the hydraulic cylinder
The MTS sensor which is used for shear stroke is
actuated by 24V.
Selected cables are approved for 300V
Cable is laid through DGMS approved, steel
reinforced hydraulic hose as used in Indian Longwall
powered roof support operation working at a
pressure of 300 bar.
The cable entry to the shear cylinder is through FLP
CCG hose gland. The gland is approved by DGMS.

57. The machine is capable of making parallel drivages
without navigation system.
However, Fibre Optic Gyro (FOG) system has been
provided for auto Steer control

58. The steer actuator is a DGMS approved electro
magnetic solenoid valve.

59. Garland drain will be provided along the top of the
trenches and around the Highwall mining area.
Adequate pumping arrangement will be provided.
Un-interrupted power supply will be ensured by DG
set

60. Water spraying on the cutter head –at a flow rate of
19 litre per minute at a pressure of approx 20 Bar.
It is interlocked with power supply to the cutter head

61. Cutter motor is kept cooled by close loop water
circulation.
Cooler is also provided for the hydraulic oil

62. Entry of the drivages will be sealed off by non-
combustible overburden. After mining is complete in
the trench, it may be backfilled or may be treated
as water body.

63. The Methane monitoring system has already been
explained.
For dilution of methane concentration, ventilation
inside the drivage is established by the operation of
the two contra rotating auger.

64. The construction of the operator’s cabin protects
operator
Area of operation of the grounds man is below the
steel structure of the machine

65. From 1983 –2002
Total incidents reportable to NIOSH –
605 (auger /highwallmining operations )
9 Fatalities (3 fatalities due to ground fall )
460 nonfatal days lost injuries (NFDL)
130 no days lost injuries (NDL)

67. 1 (one) fatality –in 5 years (1998-2002)
among 1000 workers working daily
Fatality rate -0.02/200,000 employee
hours worked

68. .