Luzenac 20-pages - Rio Tinto

mineral resources
003
16 Luzenac
argets vs performance
> We extended Throw-Out technology to
our Talc de Luzenac France plant.
> We optimised our existing friction sorting
system at our Yellowstone mine in
the US and launched pilot studies in
France and Australia.
004 targets
> Extend friction sorting pilot study to
our Spanish operation, Luzenac SET.
> Prepare long-term mining plans
for all our North American mining
operations.
Making efficient use of our
mineral deposits
Sustainable development is often defined and discussed in terms of three
‘pillars’ of performance—environmental, social and economical. We must
bear in mind, however, that SD is principally about the wise management
of resources. As the world’s leading supplier of talc products, Luzenac has
a particular responsibility for the stewardship of its talc resources. It is our
job to get the most ‘value’ (economical, social and environmental) from
every tonne of rock we disturb and make the most thorough use of our talc
ore bodies. The activities described below are just some examples of how we
are doing this.
Microwave technologies
In collaboration with Rio Tinto Technical Services (RTTS) and its
Office of the Chief Technologist, Luzenac is currently assessing
innovative solutions to eliminate trace minerals responsible for
major ore discolorations.
These contaminants have a negative impact on recovery rates and
in extreme cases significant fractions of the orebody have to be
discarded. At our Trimouns mine in the French Pyrenees,
for example, some of the brighter talc ore is irremediably
contaminated by pyrites and there are minute graphite crystals
throughout the orebody.
Microwave technologies pioneered by a British university and
RTTS look promising because they can selectively destroy the
contaminant or enhance specific properties that can then be
exploited for efficient separation.
Throw Out
Demand for white products is constantly growing. Yet, year after
year, Talc de Luzenac France is forced to downgrade tonnes of
white industrial minerals for simple process reasons.
The purpose of the Throw Out project currently being led at our
French operation is to meet this growing demand for white talc
whilst respecting the natural balance of our mineral resources at
Trimouns mine.
Throw Out is a simple purification system enabling contaminants
such as pyrites, carbonates and quartz contained in the mineral to
be ejected during the pendular grinding process.
optimise
In 2003, we completed the initial test phase on the five
experimental Throw Out machines at our processing plant
and are now entering the product qualification validation
and industrial project phase.
Our French mill will eventually house ten Throw Out
machines linked to a centralised waste recovery system.
Small Particle Sorter
The Small Particle Sorter or SPS is a friction slide sorter
system that separates talc from chlorite and other sterile
products such as carbonates and pegmatites by friction
sorting fractions of between 20mm and 100mm.
The process follows an initial screening process to obtain
this fraction and which can, in some cases, lead to direct
recovery of marketable grades (less than 20mm).
The combined screening-SPS process is used to recover
marketable products from sterile sources, and purify
certain industrial ores.
SPS technology has been tried and tested by our North
American operations and is currently undergoing pilot
testing at our French and Australian operations.We are also
looking to extend this technology to our Spanish operation,
Luzenac SET. ¬