Primary-crusher and recovery-plant
projects at Venetia
BATEMAN has been awarded a R232M EPCM contract by De Beers to design,
supply, install and commission a replacement primary crusher at the
Venetia diamond mine plant, with conveyors, a workshop and an electrical
substation. This project, to maintain the existing ore-crushing capacity
at the mine, is the latest in a series of projects in which BATEMAN
has been involved at the mine, situated 80 km west of Musina (formerly
Messina) in the Limpopo Province, RSA.
The main impetus for the project arose because the existing crusher,
located at the edge of the pit, will have to be dismantled and demolished
to permit the expansion of the pit to extend the mine's life. To maintain
uninterrupted production, a refurbished 1 500 t/h 54/74 Allis Chalmers
crusher, obtained from the Jwaneng mine in Botswana, will be installed
and commissioned at Venetia before the old one is shut down.
The current stockpile provides an available ore reserve for one day's
plant production only. As a result a by-pass facility will be included
in the overland ore-conveying system from the new crusher to provide
a future strategic-ore stockpile to minimise the impact upon production
if the feed from the crusher is interrupted. When the need arises,
a small section of the existing ore-feed conveyor will feed ore from
the strategic stockpile to the processing plant.
The new crusher system will have a duel tip arrangement to handle
trucks depositing 180 t loads of run-of-mine (ROM) ore into a bin
positioned over an apron feeder, which conveys the ROM to the crusher.
Any blockages in the tip will be cleared by an excavator and two rock
breakers, one above the bin and the second over the apron feeder,
will break or re-orientate any oversized rocks. The crusher operator,
with an unrestricted view of the material on the apron feeder and
the crusher, can prevent or remove any large pieces of tramp iron
or drill tubes from entering and blocking or damaging the crusher.
The crushed material discharges onto an apron feeder below the crusher
and is discharged onto a short sacrificial conveyor, so called because
its belt could be damaged by remnants of tramp iron discharged onto
it. A strong magnet at the head pulley of this conveyor removes any
magnetic tramp iron before dropping the ore onto the overland conveyor
to the stockpile feeding the processing plant.
The project was awarded in June 2004 and is subject to the partnership
agreement between BATEMAN and De Beers (see BATEMAN Globe, No. 39),
with work scheduled to be completed by March 2006. In a unique arrangement,
BATEMAN will assist the mine to operate the plant for one month after
hot commissioning and then provide a further 11 months guarantee period.
In terms of this agreement, BATEMAN could be paid a bonus based on
savings made in conducting the project.
As per the contract, BATEMAN will involve several sub-consultants
in the design, construction and commissioning, being Semane Consulting
Engineers (Pty) Ltd in the civil works, (LEBA) Versatex Trading 189
(Pty) Ltd in the electrical work and Nomatex cc in the instrumentation
and control work.
BATEMAN has been engaged in other projects at the Venetia mine to
expand production. A project completed in 2003 expanded the mine's
ROM production (see Globe No. 36) and, in March 2004, BATEMAN competed
a R6M project to expand the capacity of the high-security recovery
plant.
The project at the recovery plant resulted from a study commenced
by BATEMAN in July 2003. The key constraints to this project to increase
diamond recoveries were the need to maintain at least the current
throughput of diamonds through the plant and to fit the equipment
needed to expand output into very restricted spaces.
The four, new, high-performance x-ray machines were accommodated
in additional floors built into the existing maintenance well at the
one end of the building. This was done by prefabricating steel floors
and hoisting them sequentially into position in the well. An x-ray
machine in the existing building was repositioned.
The x-ray section's diamond-conveying system was completely overhauled
and new tube conveyors, a shaker conveyor and a completely new pneumatic
system, designed to Venetia's unique requirements, were installed.
Where possible, gravity was used to convey the diamonds. The feed
chutes in and out of the x-ray machines were specially designed and
carefully engineered to eliminate the possibility of vibration, which
could adversely affect the performance of these machines.
More information may be obtained from:
James Nieuwenhuys, General Manager, Diamonds,
on +27-11-899-2262 or email diamonds@batemanengineering.com
or
Vincent Diesel, Project Manager,
on +27-11-899-3213 or email diamonds@batemanengineering.com.
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Copyright BATEMAN 2004
