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ORE RESERVES AND MINERAL RESOURCES REVIEW |
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| CONVERTING
RESOURCES TO
RESERVES |
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Total Proved Ore Reserves increased from 809 million tonnes
in 2007 to 854 million tonnes in 2008 primarily due to higher
confidence in the ore bodies at Rustenburg and
Amandelbult mines’ UG2 deposits. Outside of
South Africa’s Bushveld Complex, Anglo
Platinum continued to explore in Brazil,
Canada, China, Russia and Zimbabwe
in 2008.
In line with Anglo Platinum’s
review and audit schedule,
the external Mineral
Resource and Ore Reserve
process review will next be
conducted during 2009. |
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| Bridgid Moyo is a transport assistant
who works underground at Union Mine.
Transport assistants direct the movement of
locomotives. |
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THE BUSHVELD COMPLEX |
The resources of platinum group metals (PGMs)
that result in Anglo Platinum’s major competitive
edge reside mostly in South Africa’s uniquely
large, mineral-endowed, layered igneous
intrusion known as the Bushveld Complex. This
complex remains the world’s largest source of
platinum, despite substantial exploration effort
and funding in other parts of the world to find a
body of rock that can match it.
Formed just over 2,000 million years ago, when
molten rock known as magma was injected into
the upper reaches of the earth’s crust from
chambers deep below, the Bushveld Complex is
an enormous, irregularly shaped saucer 350
kilometres across, with its central area deep
underground but it’s commercially valuable rim
exposed at or near the surface on its western,
eastern and northern sides, or ‘limbs’. At the outer
edges of each of the limbs, rocks known as
pyroxenites, norites, gabbros and chromitites are
found interlayered in a variety of combinations
that make up several readily identifiable zones
extending the length and breadth of the
complex. Within these zones are a number of
orebodies that yield a variety of minerals,
including chromite, titaniferous magnetite,
vanadium pentoxide, nickel, copper and, more
importantly for Anglo Platinum, the PGMs.
Within the sequences of rocks, there are three
distinct layers that contain concentrations of
PGMs at levels that are currently economic to
mine. Other layers in the Bushveld Complex
sequences also carry PGMs, but none of them
can currently be extracted on the basis of PGM
content alone. (Even where PGMs have been
produced as by-products, the quantities have
been insignificant in world terms.)
The principal PGM-bearing horizons being
exploited remain the Merensky Reef and the
Upper Group 2 (UG2) Reef, which occur around
the Eastern and Western Limbs of the complex,
while a third PGM-rich layer, the Platreef, is
found only on the Northern Limb, at the northeastern north-eastern
edge. In 2007, it was reported that there
are other deposits geologically similar to Platreef
in some respects, such as the Sheba’s Ridge
deposit as yet these have not, however, been
able to support the development of a mining
project and therefore are yet to be mined.
The Merensky Reef has been the principal
source of PGMs since it was first worked in 1925.
However, the other reefs have grown steadily in
importance. By 1999, the Merensky Reef
accounted for only 50% of all platinum-bearing
ore processed in South Africa. Exploitation of
the UG2 Reef began in the 1970s and has
steadily increased; in 1999, it was the source of
42% of ore processed. This is now thought to
have increased to more than 50% across the
complex. The UG2 is found at a vertical distance
of between 16 and 400 metres below the
Merensky Reef, depending on location. The
Platreef, mined briefly in the 1920s, was first
exploited on a large scale in 1993 and is
gradually becoming a significant contributor of
PGMs for Anglo Platinum.
Although narrow – the Merensky and UG2 reefs
are generally mined at a stoping width of less
than a metre – these tabular orebodies extend
laterally over hundreds of square kilometres,
resulting in extensive Mineral Resources, the
continuity of which, established over years of
exploration and mining, permits the long-range
extrapolation of data.
On the Northern Limb of the Bushveld, the
UG2 Reef is not developed on Anglo Platinum’s
properties. On the other hand, the Platreef,
which is substantially thicker than either the
Merensky Reef or the UG2, is well developed on
these properties. The term ‘Platreef’ describes
zones of mineralisation occurring in a variety of
rocks that range from normal pyroxenites to a
host of rock types that have arisen through the
contamination of Bushveld magma by
sediments from the underlying Transvaal
Supergroup. The thicknesses of Platreef are
such that they can support open-pit mining operations to depths well in excess of
200 metres at current prices and mining costs.
Significantly, they provide a much safer mining
environment than does underground mining.
The Merensky Reef and the Platreef yield
meaningful quantities of nickel and copper as
by-products of PGMs. The UG2 is relatively
devoid of nickel and copper, and although
chromitite in this reef has potential for economic
gain and in some areas is being exploited in this
way, we have not considered this when
measuring the contained monetary values for
Ore Reserve purposes. However, other non-significant
UG2 base metals have been
considered, and their value has been accounted
for in the relevant economic evaluations. |
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OVERVIEW OF
EXPLORATION |
Exploration 2008 |
The exploration department operated well
within the safety standards that were set at the
beginning of the year, and no significant
negative incidences were recorded.
Extensive exploration activities on all Anglo
Platinum properties continued once again,
with a total of 470,050 metres of diamond
drilling completed in 2008. This very significant
effort is in line with the requirements for
Resources set by the Company’s project
portfolio for new developments and mine
planning, and the conversion of Resources to
Reserves where the latter occurs in proximity to
operations. Prospecting based on recently
issued prospecting permits is progressing in
line with the works programme schedules.
As was the case in 2007, the main focus of
exploration work in 2008 was risk mitigation
and the upgrading of resources where
appropriate. Anglo Platinum has an impressive
portfolio of announced and upcoming projects.
These are being assessed in line with internationally
recognised best practice, as
attested to by both in-house and international
third-party reviewers. Drilling remains a primary
tool in determining and evaluating resources,
and the extensive and structured drilling
programmes reflect this systematic approach
to generating value for the organisation.
Although some percussion drilling is used for
specific needs, diamond drilling, using mostly
BQ (48 mm) diameter coring, is used for some
99% of boreholes drilled. Only reef intersections
with 100% core recovery are used in the
geological models of resource grades.
Advances in the technology of three-dimensional
seismic surveys have been used
fully by the exploration team in recent years.
These surveys continue to be an invaluable tool
for supplementing borehole data, by providing
exceptional detail on the structural deformation
of the orebodies, which is not discernable from
borehole data alone. This ensures the correct
placement of shafts and other critical mining
infrastructure, particularly where orebodies are
at moderate to deep depths. Several additional
surveys are also in the planning stage and
will be implemented, subject to cost and
access considerations. Aeromagnetic surveys,
geophysical logging and borehole radar are also
used to supplement geological knowledge on
each of the prospects.
Where mine planning has reached an advanced
stage, a variety of additional drillhole and
surface to near-surface imaging tools are
employed, to determine the structure and
competency of the ground targeted for
development. In-drillhole and rock surface
remote sensing are integral components of this
risk-mitigation process: they have proved
highly cost beneficial over recent years.
Foreign exploration continued in 2008, with the
ongoing objective of finding, locating and
defining projects of value to the organisation.
This included projects in Brazil, Canada, China, Russia and Zimbabwe, with watching briefs in a
number of other promising geological provinces.
Our goal remains to be able to evaluate projects
swiftly and promote them promptly where
appropriate, with an information system in place
to promote these objectives.
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Russia: Two projects are being explored, with
differing styles of mineralisation. In the Urals, an
alluvial platinum target is reaching an advanced
stage, with appropriate documentation shortly to
be filed. If approved, this will permit exploratory
mining to validate exploration results. Several
other placer occurrences are under review
and being tested, each with a high potential
to become a resource evaluation target.
These deposits are dominated by platinum
mineralisation, with the metal occurring as ferroplatinum
alloy in nugget form and individual
nuggets comprised of around 90% platinum.
Concentrations of platinum in the ore are in the
order of a few grams per cubic metre.
In the Kola Peninsula, three large areas of
greenfields exploration remain our focus.
Where diamond drilling has been used as the
main tool for exploration, it has revealed
mineralised zones of considerable interest in
two areas to date. Geophysical surveys are
assisting in target generation and drillhole-siting
programmes.
Canada: The River Valley project progressed to
the level of a pre-feasibility study. This indicated
that, under present economic circumstances,
the deposit is not viable. The process of
acquiring a lease over the property was
concluded, which will facilitate its retention
until market conditions permit mining, or
permit a sale of the rights in future. Adjoining
ground evaluation and regional targeting – the
objective of our 2007 field season’s activity –
were followed up on in 2008, but no additional
potential was identified.
China: The extensive Panxi Rift in south-western Sizhuan Province has been the primary
geological target area in China, with the local
focal points of activity being a number of
specific intrusive complexes. The Emeishan
basalt suite of flood basalts is emplaced above
conducive and reactive country rocks, creating
a mineralisation environment similar to the one
Anglo Platinum is familiar with in South Africa.
A range of occurrences and anomalies were
identified. Some were considered worthy of an
application for a special prospecting licence.
These applications were under consideration
by the Chinese authorities during the year.
Unfortunately, drilling in the Danba project area
did not provide sufficient encouragement to
continue prospecting this deposit; work there
has been discontinued.
Brazil: Ongoing mapping and geophysically
targeted drilling progressed well during the 2008
field season, with target identification strategies
being successfully applied. The work remains
focused on a geological terrain conducive to the
development of chromite- and sulphide-associated
PGEs within igneous intrusives.
Zimbabwe: Resource definition and
quantification within and outside the Unki
resource block were completed during 2008.
Prospective resources additional to the Unki
resource were successfully defined. Exploration
activity has been maintained, pending the
finalisation of ongoing government negotiations.
In March 2008, an agreement was entered into
with the Government of Zimbabwe (GOZ) in
terms of which 31.3% of the PGM mining claims
have been released to GOZ in return for cash and
empowerment credits. The agreement is
expected to become effective during 2009.
Western Bushveld Joint Venture: In 2004,
Rustenburg Mine entered into a joint-venture
agreement with Platinum Group Metals RSA
Limited and Africa Wide Mineral Prospecting and Exploration (Proprietary) Limited, to
establish the Western Bushveld Joint Venture.
Wesizwe Platinum Limited acquired Africa Wide
Mineral Prospecting and Exploration in
September 2007. In mid-2008, the Western
Bushveld Joint Venture completed a bankable
feasibility study for its Project 1 area.
In December 2008, RPM entered into
agreement to sell its interest in the WBJV to
Wesizwe Platinum Limited. The parties are
currently in the process of fulfilling the
suspensive conditions of the agreement.
Sheba’s Ridge Joint Venture: Sheba’s Ridge
Joint Venture is a project owned jointly
between Ridge Mining (65%) and Anglo
Platinum (35%). Ridge Mining agreed to sell to
the Industrial Development Corporation of
South Africa a 26% interest in the joint venture in return for funding of R60 million to complete
a feasibility study on the project. Ridge Mining
has completed the feasibility study with the
exception of the process strategy. |
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Ron Hieber (Pr Sci Nat, FGSSA, MCIM)
Head: Exploration and Mineral Strategy
Johannesburg
5 February 2009 |
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CHANGES IN THE ORE RESERVES AND MINERAL RESOURCES
STATEMENT FOR 2008 |
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ORE RESERVE – MINERAL RESOURCE SUMMARY |
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2008 |
2007 |
Category |
Million
tonnes |
4E million
troy ounces |
Million
tonnes |
4E million
troy ounces |
| Total Ore Reserves |
1,478.3 |
197.5 |
1,453.3 |
194.1 |
| Proved Ore Reserves |
853.6 |
108.4 |
808.6 |
104.6 |
| Total Mineral Resources |
5,203.1 |
654.7 |
5,696.2 |
720.0 |
| Measured Mineral Resources |
607.8 |
92.0 |
621.8 |
91.1 |
| Measured and Indicated Mineral Resources |
2,221.1 |
280.6 |
2,188.6 |
280.8 |
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The total Ore Reserves increased primarily due to the conversion of additional Mineral Resources to Ore Reserves at:
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Amandelbult Mine (Merensky Reef and UG2 Reef ); and |
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Rustenburg MIne (Merensky Reef and UG2 Reef ). |
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This resulted in a 1.7% tonnage increase and a 1.8% 4E ounce increase. |
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The Proved Ore Reserves increased primarily due to higher confidence from:
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Rustenburg Mine (UG2 Reef ) where additional drilling and re-evaluation resulted in higher confidence and due to improved modifying
factors; and |
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Amandelbult Mine (UG2 Reef ) where additional drilling and re-evaluation resulted in higher confidence. |
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This resulted in a 5.6% tonnage increase and a 3.7% 4E ounce increase. |
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The total Mineral Resource tonnage (additional to the Ore Reserves) has decreased considerably, mainly due to the successful transaction
announced with Mvelaphanda Resources and the consequent exclusion of the Mineral Resources of the Booysendal project. This resulted in a
8.7% tonnage decrease and a 9.1% 4E ounce decrease in total Mineral Resources.
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The overall Measured and Indicated Mineral Resources changed marginally. The tonnage increases by 1.5% and the 4E ounce decreases by
0.1%.
For detailed statistics refer to Company statistics. |
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GLOSSARY FOR WATERFALL GRAPHS |
Opening balance: As at 31 December 2007.
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Production: The quantity of the commodity of interest delivered for beneficiation from underground or open-pit including material from
stockpiles (mine depletion during the financial year).
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Conversion: Process of converting Mineral Resources to Ore Reserves .
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| Conversion (reallocation): Process of ‘down-grading’ of Ore Reserves to Mineral Resources. |
Disposal: Reduced Ore Reserves/Mineral Resources due to new JV agreements (Transaction with Mvelaphanda Resources).
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New information: The effect of additional resource definition information which initiates an update to the geological models (facies, structural,
grade, geo-technical) and results in a new (reclassified) resource model.
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Exploration: Includes ore bodies not previously reported.
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4E grade: sum of platinum, palladium, rhodium and gold grades.
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MR: Merensky Reef.
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| Closing balance: As at 31 December 2008. |
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