TauTona to take ‘deepest mine’ accolade
Gold producer AngloGold Ashanti will celebrate a historical moment
in July 2008 when its TauTona mine, in Carltonville, surpasses the
current record to become the deepest mine in the world.
The Below 120 Carbon Leader project will take TauTona to a depth of
3 902 m.
Currently, the deepest-mine accolade belongs to Savuka mine, in the
North West province, which descends to a depth of 3 774 km.
The TauTona project, which was initiated two years ago, has an
approved expenditure budget of R1,2-billion. On completion of the
mining area below 120 level, it is estimated that 1,2-million m2
will be mined and 26 km of develop- ment will be completed.
The Carbon Leader project will involve the sinking of the twin
decline shaft, which will take the mine down another five levels to
shaft bottom. This infrastructure will enable the mining of an
addi-tional 1,2-million m2 and yield about 72 t of gold.
Currently, TauTona’s narrow reef tabular orebody produces
about 550 000 oz of gold yearly. Current infrastructure is down to
3 600 m and in March 2007, the sinking of the twin decline shaft
will take TauTona to a depth of 3 902 m. With the introduction of
down-dip mining, the stoping date of the project has been moved
ahead to April 2008. Murray & Roberts have already excavated
the rock chamber and the man-and-material shaft, with civil work
under way. This will be followed by the winder installation of the
rock chamber. The sinking of the man-and-materials handling shaft
will be completed in December 2009 and the sinking process for the
rock shaft in March 2010. The 718,1-m-long man-and- material
decline, with a 350-kW double drum winder, will have a rope speed
of 3,5 m/s.
The Deilmann Haniel K313 decline loader will be used to sink the
declines. The Deilmann Haniel drill rig will be used to advance the
decline at a rate of three meters a blast.
Sinking and production will occur simultaneously owing to the
existence of interboxes on the reef elevation. This will allow ore
to be drawn into the shaft and hoisted to the 120 project site
while sinking is under way. This will bring financial returns for
AngloGold Ashanti, as gold will be recovered during the sinking
With 5 500 people employed at TauTona, those working on the project
area will have to travel an additional four kilometres horizontally
to reach their daily destination. It currently takes about an
hour-and-a-half to travel to the face and, as the project reaches
greater depths, travelling times will increase.
The existing shaft vertical system triple-deck cages carry about
120 people at a time. TauTona has a three-tier system of a main
shaft, subshaft and tertiary shaft. Management at Tau-Tona has
envisaged a new transport system that will maintain output at
current levels. The system, a gondola, will transport workers on
their decline down the mine. The gondola will have its own on-board
driver, conventional winder brakes and a special design brake for
use in emergencies.
The gondola personnel-carrying cassette will carry the same amount
of people ensuring a consistent flow of workers through the
four-shaft system. As personnel arrive at the Q shaft, the gondola
will depart and the next group of workers will arrive. Decline
equipment will also include a three-material car cassette, which is
attached to the main driver conveyance, thus allowing for the
transport of mate-rial bulk to the various levels when it is
required for production and sinking. Other advances have also been
made to ensure that production is maintained. The Hilti rock drills
will replace the air-driven rock drills on the existing Below 120
area. TauTona is currently in the pro-cess of rolling out all stope
panels that are being mined.
The average face advance is already 12 m. Three drillers and three
assistants will be used in each panel on the pre-Hilti while two
drillers and two assistants will be used on the post-Hilti.
Panel lengths are established at 28m and an increase in winch
operating speeds from 1,1 m/s to 1,3 m/s, having one back-fill
range for every two panels instead of one for every three panels
and the use of the Hilti electric drills on all stope faces.
At a depth of 3 902 m, virgin rock temperatures will increase from
the current 55 �C to 59 �C. Mining at greater depth induces higher
temperatures and upgraded fridge plants will be used to maintain
the mandatory 28 �C temperature.