26
CONSTRUCTION WORLD
OCTOBER
2014
PROJECTS AND CONTRACTS
The Ingula Pumped Storage
Scheme is now in its seventh year
of construction and had it not
been for the tragic accident one
of the four 333 MW reversible pump turbines
would be undergoing commissioning at this
time. The Eskom project is located between
Ladysmith and Harrismith in the Little
Drakensberg, and will have a generating
capacity of 1 332 MW available during
periods of peak demand and to supplement
base load when necessary – for example
during outages or essential maintenance of
other generating plant.
Ingula is a peaking hydro power station
comprising an upper and a lower dam
or reservoir separated in elevation by
480m, an underground powerhouse located
116 storeys underground in two excavated
underground caverns and housing 4 x
333 MW Francis type pumps/turbines.
An underground labyrinth of intercon-
necting tunnels/waterways extends 6,5 km
and 3 km of access tunnels and a number
of shafts allow water to be released from
the upper Bedford Dam and delivered to
the turbines producing power, before being
captured in the lower Bramhoek Dam.
During off-peak times – at night for example
– the turbines are reversed pumping water
back from Bramhoek Dam to Bedford, in
readiness for the next peak event.
Recent progress
milestones
Construction senior supervisor, Jacques
du Plessis from consultants Royal Has-
koningDHV, one of the three firms of
consultants that make up the design and
construction supervision team, Braamhoek
Consultants Joint Venture, explains recent
progress milestones.
“Underground work is proceeding apace
with the concrete lining in the tailrace and
headrace tunnels completed, cavity and
consolidation tunnel grouting are about
75% complete and concrete slip forming
at one of two 91 m high surge chambers
recently commenced.
“All civil works in the transformer hall
have been completed and the machine hall
and underground control room are nearing
completion,” he explained.
“The first turbine shaft and runner were
taken underground recently, two gener-
ator transformers have been installed and
mechanical and electrical fit-out work is
underway. Above ground the operations and
maintenance building on the intake struc-
ture is nearing completion as is the stop log
storage facility at the outlet,” says Du Plessis.
The double-storey Administration Build-
ing, the basement of which has direct access
to the main tunnel leading to the under-
ground power station, has also recently
been completed.
In addition to office space, the building
accommodates
the
external
control
centre for the power station. Also recently
completed is the visitors centre, which
comprises a small office wing, a cinema,
various display halls, an auditorium and
facilities wings.
The surrounding area will be landscaped
with indigenous plants to minimise the
visual impact of the surface buildings.
Environmental
responsibility
“Amidst all this heavy engineering work,
Eskom is conscious of its environmental
responsibilities and in particular the site’s
bird life,” enthuses Du Plessis. More than
275 bird species have been sighted at
Ingula including all three crane species that
although rare, are regularly seen there.
“The endangered Southern Bald Ibis is
another resident of the conservation area
and thirty breeding pairs have been counted.
However, construction of the upper Bedford
Dam, completed in 2011, robbed them of
at Ingula
PROGRESS
The multi-billion rand Ingula
Pumped Storage Scheme, like
many around the world of this
magnitude and complexity
has suffered delays not least
the site closure ordered by
the Department of Labour
after last year’s tragic accident
that claimed the lives of
six construction workers.
However progress has been
made since the incident in
October last year on both
underground and on above
ground facilities.
>
An underground labyrinth of interconnecting tunnels/waterways extends 6,5 km and 3 km of
access tunnels.
Braamhoek Consultants
Joint Venture (BCJV)
comprises local consultants
GIBB, Royal HaskoningDHV
and Knight Piésold. It is
responsible for the overall
design and construction
supervision of many of the
packages within the greater
project.
