60
CONSTRUCTION WORLD
OCTOBER
2014
Currently, a large majority of signage and information boards
reflect male iconography. “We would like to submit a motion to
Parliament for signs of equality,” says Kevin van Staden, Bagshaw
Footwear chief operating officer.
The Port Elizabeth safety footwear manufacturer recently launched its
new range of women’s stylish, yet functionally safe footwear which led
to the creation of the petition campaign. Bagshaw Footwear embraced
an opportunity in the market to empower women in the workplace by
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PRODUCTS AND SERVICES
The latest flagship civils project
to deploy this technology was
the Sedrun II shaft sunk for the
Gotthard Base Tunnel in Swit-
zerland, which had a depth of 800 m and a
finished diameter of 7 m. This high profile
shaft was bored, lined and installed in under
12 months. “The application of this tech-
nology for vertical service shafts in the civil
engineering environment is perfect,” Allan
Widlake, Murray & Roberts Cementation,
business development director, says.
Advance and primary shaft lining are
carried out simultaneously. With the aid of
laterally extendable hydraulic cylinders,
the machine braces itself before every
drilling stroke in the shaft steadying the
machine, allowing the thrust cylinders to
push the rotating cutterhead against the
borehole floor.
Hydraulic cylinders ensure precise
vertical alignment of the SBE to the
target axis by a laser aiming device.
The rotating anchor platform is located on
the drilling deck above the cutterhead, from
where anchors and steel mesh are put in
place by two powerful hydraulic drill rigs.
If required, a shotcrete unit on the SBE
secures the shaft wall immediately after
exposure of the rock outcrop. The operator
controls operations from the comfort and
safety of the machine’s interior.
Actual shaft sinking occurs in three
phases: First a pilot hole is created from the
top downwards in order to set the vertical
target axis. Once at the bottom, workers
in the cavern replace the drill bit with a
reamer in order to enlarge the pilot hole
from the bottom up, until the advance hole
diameter is achieved. Muck is loaded contin-
uously at the foot of the advance hole
and conveyed away. Thereafter the SBE
enlarges the advance hole from top to
bottom to the final diameter and installs
the primary lining of the shaft in parallel.
The only technical constraint of the achiev-
able shaft depth is the feasible length of the
advance hole undertaken by modern raise
boring machines.
The high precision in terms of verticality
and the circular shape of the shaft cross
section as well as the vibration free ground
treatment are further advantages of the next
generation SBE, compared to the conven-
tional shaft sinking method using drilling
and blasting as well as other mechanical
methods. The sinking cycle runs continu-
ously and is not interrupted by drill and blast
SHAFT BORING
system for civil engineering
The next generation Shaft Boring Machine for Shaft Enlargement
(SBE) developed by Murray & Roberts Cementation and Thyssen
Schachtbau, in conjunction with Herrenknecht, both of Germany,
is ideal for civil engineering as well as mining applications.
Allan Widlake, Murray & Roberts Cementation,
business development director.
New generation Shaft
Boring Extender (SBE) used
for the boring of shafts top
down with the use of an
advance hole. Stage used
for backup and final lining
of shaft not shown.
times or dispersal of explosion gases. This
new shaft boring technology not only boasts
high levels of efficiency but also increased
safety and ergonomic working conditions.
Various criteria were highlighted during
the development process. “We wanted to
keep it easy to maintain and user friendly,
with the most sophisticated electronics
confined to the laser guidance system.”
Once a unit has completed a particular
project, it can be disassembled and custom-
ised again for next project. Looking at lead
times from the manufacturing facility in
Germany, Widlake says that from a project
award to actual deployment of the machine
after the completion of the advance hole,
there is more than sufficient time to build a
new machine.
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SAFETY FOOTWEAR COMPANY PROPOSING CHANGE
Local safety footwear manufacturer,
Bagshaw Footwear, is proposing a
change to government legislation
through its online petition encouraging
altering standard safety signs to be
more gender neutral.
Continued on page 62
