A PPT GIVING A DETAILED OVERVIEW OF THE HYDRAULIC DRILL JUMBO USED FOR DRILLING OPERATIONS IN UNDERGROUND MINES & IN TUNNELING APPLICATIONS.

1. HYDRAULIC DRILL
JUMBOS
A COMPREHENSIVE
PRESENTATION
Pinaki
M. S.
Roy
Rao

2. Background

In order to create an opening in a rock
mass DRILLING is the basic requirement.

3. Range & Selection of Drill Jumbos
……….for every Tunnel
section

4. Single Boom Jumbos

5. Two Boom Jumbos (8 - 45
sq.m.)

6. Two Boom with basket (8 - 90
sq.m.)

7. Three Boom/Three Boom with Basket
Boom
(upto 168 sq.m.)

8. Probing ahead

9. Drill Jumbo - Long Holes

10. 
Optional equipment

11. Basic
requirement
for rock drilling

16. Rock Drilling - Principle
Basic requirement :

18. Rock drill
mechanism
Impact
The piston transmits the
impact energy through
the drill steel to the hole
bottom. A valve directs
the compressed air /
hydraulic oil from one
side to the other of the
piston so that it moves up
and down.

19. Impact

20. Rock drill mechanism
Rotation
The drill steel is turned lightly with
each blow.
IN PNUEMATIC ROCK DRILLS :
The rotation is normally anti-clock
wise and normally made on the
return stroke of the piston.
The theoretical angle of rotation per
stroke is 36 degree. In practice it is
30 degree. The difference is due to
mating part.
IN HYDRAULIC ROCK DRILLS :
Hydraulic motor is normally used for
rotation. The rpm of the drill bit is
adjusted as per drill bit diameter.

21. Rock drill mechanism
Feed force
The feed force is created by hand in
case of hand held drills , Pusher leg
or hydraulic cylinder.
Proper feed force will give the best
penetration rate.
Improper feed force will cause:
 Loosening / damaging of thread.
 Overheating / low life of drill string.
 Diverted hole / poor pull in blasting.

22. Rock drill mechanism
Flushing
Flushing is done
normally by air or
water on all the rock
drills
used
in
underground, water
is used as flushing
media.
Optimum
flushing will provide
better
penetration
rate.

23. Factors which influence drilling rate







Type of rock
Air pressure/Hydraulic Pressure
Bit size
Bit condition
Flushing
Feed force
Wear of front of rotation chuck
bushing

24. Drifter - Heart of
Drilling Jumbo

25. New Generation Rock Drill

26. Components of Hydraulic
Drifter Shank Adapter









Flushing Head
Damping Piston
Stroke Selector
Piston
Rotation Gears
Cylinder
Accumulators
Hyd. Rotation Motor

27. Driver






Transmit rotation from Hyd.
Motor to Shank Adapter
Triangular in shaped
Housed in rotation chuck
Has internal splines
Made of bronze/Steel
Splines wear limit is half it
original width.

28. Stop Ring




Serves as retainer for Shank
Adapter
Stop Ring is extremely hard
and wear resistant
It is subject to impact
energy
Wear limit is 1 mm to the
front end of the splines

29. Damping Piston




Damping Piston protects the
Rock Drill from shock
waves (thru hydraulic
pressure)
Subject to powerful axial
shock waves.
It helps in absorbing reflex
shocks upto 20 tonnes.
Since it is pressed against
rot.chuck/shank adapter, it
tends to partially rotate.

30. Side Bolts



Two long side bolts hold
together the external parts of
the Rock Drill (front head,
cover, gear housing, interm.
part and cylinder
Third long side bolts
connect all above parts
except front head.
Two long side bolts have
have integral eccentric
lugs(for tightening)

31. Side Bolts



Tension of the side bolts
must be checked
regularly.
Rear dome nuts are
tightened as per the
recommended torque
Recommended to
change both the bolts
together.

32. Piston Guides



Front and Rear piston
guides located on either end
of the cylinder guides the
lateral movement of the
piston.
It prevents the piston lands
from touching the cylinder
Its has wear resistant quality
and also gives lowest
possible friction.

33. Impact Piston




The piston strikes the shank
adapter between 3000 –
3600 stokes per minute
Piston is supported by
piston guides.
Slim piston design transfer
optimum energy to the drill
string
Slim piston design also has
low stress on Rock Tools

34. Rotation Chuck Sleeve


Rotation Chuck sleeve
is a press fitted into the
rear of the Rotation
Chuck
It is made of high
quality bronze with high
resistance to wear and
friction

35. Rotation Chuck Bushing




The smaller front face of the
Rotation Chuck bushing
acts on the shank adapter.
Larger rear face is subject to
the thrust from the damping
piston.
Front face of the rotation
chuck bushing is subject to
steady wear.
Max. permissible wear on
the front face of the rotation
chuck bushing is 1 mm.

36. Flushing Head

37. Rock Drill - Reflex
Hydraulic Rock Drills normally work at 200
Bar Impact Pressure
Every Impact of the Rock Drill

Generates 20 Ton Reaction / Reflex from
Rock
Reflex 20 Ton
Drifter Impact

38. Drifter without Reflex
Dampener

39. Reflex kills the Drifter &
Mounting

40. Most effective Reflex
Dampener

42. CARE & MAINTENANCE
of
HYDRAULIC DRIFTERS

43. SAFETY REGULATIONS





Special attention must be paid to safety information
and especially to the warning symbol (triangle).
Never attempt maintenance of Rock Drill when the
hydraulic system is pressurised
Always use correct specification hoses, specially the
impact hose of rating SAE 100 R9R/4SH/4SP (4 layers,
spirally wound steel wire braided).
Use protective plugs when dismantling the Rock Drill
Always overhaul a Rock Drill in a Container or a clean
workshop

44. Start Up


Before starting up a new or a newly overhauled Rock
Drill:
 Connect up all hydraulic hoses
 Charge the Accumulators with Nitrogen gas to the
correct pressure
 Fill correct hydraulic and lubricating oil
 Adjust correct lubricating system
Tighten all threaded joints after first shift of operation

45. Every Shift




Check that Air & Lubricating oil come out
between the shank adapter and front guide
Check S/Adapter threads are not damaged
Keep an eye on the hydraulic hose vibration.
If they vibrate too much check the
Accumulators.
Check there is no leakage from the Rock
Drill. If flushing water leaks from the hole
in the front head, change the seals.

46. Every 40 Percussion Hour




Grease the Gear Housing
Tighten all threaded joints as per
specified torque.
Check for external leakage on the Rock
Drill. Replace the seals if leaking
Check condition of hydraulic hoses,
replace damaged/defective hoses.

47. Every 400 Percussion Hour

Recommended for complete
overhaul.

Overhauling to be done in a clean
and suitable workshop. Always use
Hydraulic Drifter Repair Tools.

48. Accumulators
Accumulators are fitted with
safety labels
 They should be charged with
Nitrogen gas only (other gas can
cause explosion)
 All new accumulators are not
charged


49. Charging the Accumulators






Remove the protective plugs
Open the valve nut and connect the charging hose
Open the gas valve on the cylinder
Charge the Accumulator to the collaring pressure
minus 30 bar. However the maximum pressure
should not exceed 110 bar
Tighten the valve nut and also close the cylinder
valve.
Remove the charging hose and fit back the
protective cap on the accumulator valve

50. Intake :
30 bar below
collaring pressure
Max - 110 bar
Return :
Not to be
charged
Accumulators
Damping :
20-25 bar

51. MAIN COMPONENTS OF DRILL
JUMBOS
•
•
•
•
•
CARRIER
BOOM
FEED
ROCK DRILL
POWER PACK

52. Carrier

53. Power train

54. Carrier System
CARE & MAINTENANCE

55. Engine – Air Filter
1.Clean every week
2.Change interval
normally
depends on
environment

56. Engine – Oil & Filter
Change interval
depends on
different
factors:
a. Quality of oil
b. Working temp
c. Environment

57. Engine – Fuel Filter
Change interval
normally
depends on
quality of fuel

58. Carrier Greasing
Grease every week.
Check once in every month whether
grease is passing through every point

59. Drive line : greasing
Grease every point
once in a week.
Only two stroke of
grease is
sufficient.
Use good quality
grease.
Check bolt torque
weekly

60. Coolant Level
Check
Coolant
level daily

61. Transmission Oil & Filter
Change interval
depends on
different
factors:
a. Quality of oil
b. Working temp
c. Environment

62. Transmission oil change
A - Filling
B - Drain
C - Filter
the oil when it is hot through
drain plug “B”.
e oil through port “A” up to “LOW”
mark on dipstick.
e the filter.
he engine at low idle to fill up the
converter and fill oil up to low mark.
he engine to heat up the oil at 80 deg. C
fill up to high level.

63. Differential
Check level
every week
Change
every 500
hours

64. Planetary hub
Check level
every week
Change
every 500
hours

65. Release Park brake
Loosen lock nut “A”
Screw in stud “B” to
the bottom.
To reset the park
brake screw out the
stud “B” to 47 mm.
Tighten the lock nut.

66. Service brake adjustment
Place the rig on jacks.
Open the lock nut “A” &
lock plate “B”.
Unscrew the adjusting
screw “C” anticlockwise to
take up any play. Continue
to turn until a torque of 40
Nm is attained.
Now screw the
adjusting screw “C”
clockwise 3 turns.
Refit lock plate “B”
& lock nut “A”.

67. Hydraulic Booms

68. B
A
C

71. Cross cut drilling

73. Hydraulic Booms

77. Rotation
unit

78. oom
B
Hydraulic
Syst em

79. Cylinder movement - Vertical

80. Cylinder movement - Horizontal

81. a
M
e
n
i
e
t
a
n
c
n

83. Adjustment - Feed cradle

84. Cradle clearance adjustment

85. Replacement of guide rail

86. In Conclusion….
Drilling is the backbone of all mining & tunneling
applications & thus the role of Electro Hydraulic
Drill Jumbos assumes critical proportions.
While these equipment are quite simple to operate
with built in ling term reliability, optimization of
drilling functions and high levels of availability is
only possible if correct maintenance and
operational directions are followed.
The presenters of this paper thankfully acknowledge the assistance from M/s Atlas
Copco & M/s Sandvik for their inputs during preparation.