ON SITE
T
he earth gave a brief rumble and
there was a muffled hum before
the gargantuan machine kicked
into life. The sun reflected off the
spaceship-like framework, held down by
several 12m long anchor bolts. Without
these, the monster cutter-head, driven by
a 35 tonne (t) gearbox, would pluck the
entire steel structure right out of
the ground.
A small group of investors and journalist
watched in awe as Master Drilling’s shaft
borer gradually ground itself into the baked
earth, and slowly started munching away
at some of the hardest rock on the planet.
It was only after the monstrosity started
spitting out grain sized rock chips, however,
that one realised the significance of that
moment. Nowhere else in the world,
never, has anything else like this been put
to the test. The trial run took place on a
farm near Fochville, the headquarters of
Master Drilling, the enigmatic South African
company that has drilled its way into the
annals of history before.
Blind shaft borers have been tested in soft
rock applications in other parts of the world,
but to drill a vertical shaft through norite as
hard as 320Mpa, would be a feat nobody else
has even attempted. Koos Jordaan, executive
director and technical director at Master
Drilling, says they chose the site specifically
because of its almost indestructible norite,
and excavating, during the initial test phase, a
shaft of only eight to 10m deep would prove
that it is indeed possible to sink a shafts of
more than 1000m deep and up to 11m in
diameter from the surface down, through
extremely hard rock.
Walking the talk
The idea is not new. Danie Pretorius, CEO
of Master Drilling, Jordaan and their team
at Master Drilling have been mulling it over
for a long time and they sold the concept to
delegates attending the Mining Indaba in Cape
Town three years ago. But back then, with
the mood suppressed and commodity prices
in the doldrums, it was, for most observers,
just an idea and concept, backed-up by a
meticulous scale model displayed in the
foyer of the Convention Centre. Regardless,
Pretorius and Jordaan, like they usually do,
walked the talk and three years later, with the
financial backing of the Industrial Development
Corporation (PIC), who is a 49% equity
partner, have brought that scale model to life,
albeit only the first phase of it.
The shaft borer’s main objective is to sink
a vertical shaft from surface quicker, safer
and cheaper than traditional shaft sinking
methods. Raiseboring a shaft from the bottom
up, has become the most popular method of
establishing a vertical shaft in modern times,
and it is the core service Master Drilling
offers. However, it requires capital investment
in the form of decline shafts to get the
raiseboring equipment to the bottom of the
intended vertical shaft so that the reamer
head can be fitted onto the drill and work its
way up from surface, which means it takes
longer, often at exorbitant costs.
On the other hand, the older, more
traditional methods of blasting out a shaft
requires a large workforce and is by nature
a costly, dangerous and time-consuming
undertaking. To thus sink a vertical shaft
from surface with less than a fifth of a
traditional crew, at only a fraction of the cost,
in double quick time, makes the blind sink
hardly a revolutionary idea, and if Master
Drilling actually pulls it off, it will take shaft
sinking to the next level and is sure to be a
game changer.
The group of mining analysts and
journalist at Master Drilling’s site outside
Fochville where the company put its
new shaft borer to the test.
www.equipmentandhire.co.za
JANUARY/FEBRUARY 2020
13