Mining_Methods_UnderGround_Mining - Mining and Blasting

Principles of raise boring
efficiency and safety
Raise boring is the process of me-
chanically boring, drilling or reaming
a vertical or inclined shaft or
raise between two or more levels.
Some 40 years ago, the world’s first
modern raise boring machine was
introduced by the Robbins Company.
It launched a revolution in
underground mining and construc-
tion, and the technique is now accepted
as the world standard for
mechanical raise excavation. New
products from Atlas Copco, such
as the BorPak, concepts such as
automatic operation and computerization,
and techniques such as
horizontal reaming, are creating
exciting new opportunities in the
underground environment. Atlas
Copco Robbins supplies the complete
raise boring package for all
situations, together with technical
and spares backup.
raise boring concept
The raise boring machine (RBM) is set
up at the surface or upper level of the
two levels to be connected, and a smalldiameter
pilot hole is drilled down to
the lower level using a string of drill
pipes and a tricone bit. A reamer is then
attached to the drill string at the lower
level, and the RBM provides the rotational
torque and pulling power to ream
back to the upper level. The cuttings
from the reamer fall to the lower level
for removal. Raise bore holes of over 6
m-diameter have been bored in medium
to soft rock, and single passes in hard
rock can be up to 1 km in length.
Advantages of raise boring are that
miners are not required to enter the ex-
cavation while it is underway, no explosives
are used, a smooth profile is obtained,
and manpower requirements are
reduced. Above all, an operation that
previously was classified as very dangerous
can now be routinely undertaken
as a safe and controlled activity.
Specific applications of bored raises
in mining are: transfer of material;
ventilation; personnel access; and ore
Robbins 73RH C derrick assembly layout.
Raise boring process.
raiSe BOring
underground mining methods 25