1. A raise borer is a machine used in underground mining, to
excavate a circular hole between two levels of a mine
without the use of explosives. Raise boring, as a technique
or system of driving raises (vertical or near vertical holes)
continues to gain in popularity due to its many important
advantages over conventional methods.
1. Diameter of pilot hole (mm)
2. Reaming Diameter
3. Drilling depth (m)
4. Drilling angle (°)
5. UCS of rock (MPa)
6. Drill rod diameter (inch)
7. Drill rod length (m)
8. Rotational speed (rpm)
9. Thrust Force (kN)
10. Mass drill rig (kg)
11. Power of drill rig
The raise borer is set up on the upper
level of the two levels to be connected,
On an evenly laid platform (typically a
concrete pad). A small-diameter hole
(pilot hole) is drilled to the level required; the
diameter of this hole is typically 230mm
- 445mm (9" - 17.5"), large enough to
accommodate the drill string. Once the
drill has broken into the opening on the
target level, the bit is removed and a
reamer head, of the required diameter of
the excavation, is attached to the drill string
and raised back towards the machine. The
drill cuttings from the reamer head fall to the
floor of the lower level. The finished raise has
smooth walls and may not require rock bolting or
other forms of ground support.
A Presentation on Raise Boring
machine
Introduction
Mechanism
Design criteria for raise boring machine
Drill rig
Power (driving) system
Control system
Drill string
Common drill pipe
Special-shaped joint
Pilot bit
Reamer head
Cutter
Stabilizer
Circulation system
Cooling system
Cutting removal system
Water supply
Power supply
Components
Types of Raise Boring Machine
1. Raise-Boring
In this system, the pilot hole is drilled
down to a lower level in the mine or civil
project. Once the pilot hole connects to
the lower access level in the rock, the drill
bit is removed and a reamer or raise head
is attached and the reamer is rotated and
pulled upwards. The broken rock falls to
the lower level by gravity. This system
operates with the drill string in tension
and this provides the most stable
platform.
2. Down-reaming
In this system, the pilot hole is drilled
downwards until it connects to a lower access
level. The drill string (all drill rods, stabilizers and
cutting bits) is retrieved and then a reamer is
pushed downwards. The cuttings flow down the
previously drilled pilot hole. This method uses
drill string in compression and usually stabilizers
must be installed to eliminate the potential of the
drill string buckling.
3. Box-Holing
The most difficult raise method,
known as BoxHole excavation, is to
drill a pilot hole to any level up from
the raise borer. Once the desired
length is achieved the drill string is
retrieved, and a reamer attached and
pushed upwards. The broken rock falls
down the enlarged hole onto a special
collection chute attached to the top
of the raise borer.
Advantages of raise boring machine
Raise boring offers several advantages over the conventional drill and blast method.
The most important are safety, speed, physical characteristics of the completed hole,
labor reduction and cost reduction.
The safety factor in raise drilling cannot be over emphasized.
No men are exposed to the danger of rock fall from freshly blasted ground or to the
continual use of explosives, with their fumes and inherent danger of misfires.
Raises can be safely drilled in ground.
A hole drilled by Raise Boring Machine can generally be completed in a fraction of
the time required for conventional methods.
The bored raise, with its firm undisturbed walls, is more adaptable to use as
ventilation and rock passes.
The advantage of smooth walls in ventilation raises is well known.
Raise boring will not only reduce labor requirements by achieving a higher advance
per day but, along with another technological advances, will have the tendency to
attract a higher level of skilled labor to the mining industry.
The raise boring machines are used in both civil engineering and mining applications for drilling
shafts for-
Ventilation,
Drainage,
Ore passes,
Back fills,
Hoisting,
Slot holes and
Penstocks for hydro power plants.
Uses of raise boring machine
Submitted to-
Dr. Mohammad Tofayal Ahmed
Associate Professor
Dr. Mohammad Forrukh Hossain Khan
Assistant Professor
Dept. of Petroleum and Mining Engineering
Jashore University of Science and Technology
Submitted By-
Group-2
Group Members
1. Md. Shahadot Hossain (150802)
2. Faruk Ahmed Patuary (150803)
3. Shamil Arfan Tuhin (140807)
Fig: Raise Boring Machine
The Raise Boring Machine has already proven itself
with high reliability. The mechanical excavation of
shafts using the raise boring method is ideal for
a variety of applications: Ventilation shafts, ore
and waste passes, hoisting shafts, supply
shafts (energy, water and air) and pressure
shafts for hydroelectric power plants, as
in the case described above.
Conclusion Referrences
1) https://en.wikipedia.org/wiki/Raise_borer
2) http://terratec.co/files/.pdf
3) https://www.researchgate.net/publication/
76152341 _Key_technologies_of_drilling_process_
with_raise_boring_method
4) https://www.tunnelonline.info/en/artikel/tunnel_
2011- 04_Vertical_Shaft_Construction_at_the_Pump_
Storage _Plant_Vianden_Luxembourg_1204398.html
Drill String
Reamer
Machine
Pilot Hole
Rock Cuttings
Joint
Jashore University of Science and
Technology
Department of Petroleum and Mining
Engineering
Course Title: Machineries and Maintenance
Laboratory
Course Code: 4104
