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The processing plant at Gem Diamonds’ Ghaghoo diamond
mine in the Central Kalahari, now on care and maintenance
till the start-up of the project (Photo: Gem Diamonds).
A visualisation of the Modular Tailings Treatment Plant (MTTP) at Jwaneng mine. The new facility will treat 2,4 Mt/a and produce 18
million carats over 20 years.
Access to the kimberlite orebody – covered by 80 m
of Kalahari sand – is being provided by a decline.
Mphusu said the sand portion of the decline – the so-
called ‘Sand Tunnel’ – was nearing completion with
(as of 10 June) 445 m of tunnel completed and only
14 m to go. The contractor responsible for the ‘Sand
Tunnel’, Redpath Mining, has deployed an hydrauli-
cally operated Open Face Tunnel Shield (OFTS) on
the contract, which is probably the first time a ma-
chine of this type has been employed in a decline
anywhere in Africa. Among other things, the shield
has been used to place the precast concrete segments
– around 7 650 of them, each weighing approximately
400 kg – used to line the tunnel.
Once the ‘Sand Tunnel’ is complete and the OFTS
removed (which should have taken place by the time
this article is published), Gem Diamonds will take
over the mining function for the remaining part of
Another view of the Ghaghoo plant with (in the foreground) the
Motor Control Centre (MCC) and the 100 t/h AG mill (photo: Gem
Diamonds).
the decline – the approximately 600 m long hard rock
section through basalt (the ‘Basalt Tunnel’). Mphusu
said the development fleet to be used by Gem – a drill
rig, loader and truck, all from Atlas Copco – was al-
ready on site and that completion of the Basalt Tun-
nel would take place by the end of Q1 2014.
Providing an update on the Ghaghoo plant, Mphu-
su said it had largely been completed earlier this
year and was now effectively on ‘care and mainte-
nance’ until the start-up of operations next year. De-
signed and built by Consulmet, the facility includes
a 100 t/h autogenous mill (only the second AG mill
in Botswana), a 65 t/h DMS section and a 2 t/h X-ray
recovery section.
The excavation of the ‘Sand Tunnel’, although suc-
