Petra Diamonds Limited
Annual Report and Accounts 2013
44
Performance Review
Resource and Exploration Management
The following table summarises the Reserves
and Resources status of the combined Petra Group
operations as at 30 June 2013:
Gross
Category
Tonnes
(millions)
Grade
(Cpht)
Contained
diamonds
(Mcts)
Reserves
Proved
1.8
39.1
0.71
Probable
127.3
42.1
53.66
Subtotal
129.1
42.1
54.36
Resources
Measured
14.7
8.4
1.24
Indicated
452.4
49.5 224.09
Inferred
1251.3
6.7
84.25
Sub-total
1,718.5
18.0 309.58
Exploration continues in Botswana and the careful management of Petra’s major
diamond resources will ensure sustainable, long-life mining operations for the Group.
Ensuring long-life operations
Resources
The Petra Group manages one of the world’s largest diamond
resources. This major resource implies that the potential mine
lives of Petra’s core assets could be considerably longer than
the current mine plans in place at each operation or could
support significantly higher production rates.
Gross Reserves and Resources
As at 30 June 2013, the Group’s gross diamond Resources
(inclusive of Reserves) had increased by 2.5% to 309.6 Mcts,
from 302.1 Mcts as at 30 June 2012. This is mainly due to an
increase in gross Resources at Finsch as a result of decreasing
the bottom cut-off used in the Resource estimation from
1.5mm to 1.0mm. This is in line with the decrease to the bottom
cut-off at the Finsch production plant, effected by Petra
during FY 2013, thereby serving to increase the grade
and recoverable carats over the life of the mine.
The Group’s gross diamond Reserves increased 14.3% to 54.4 Mcts
(30 June 2012: 47.6 Mcts), mainly due to an increase in gross
Reserves at Cullinan. This has resulted from the increased number
of new tunnels that have been brought into production and
the detailed mine plans being run through the PCBC block cave
scheduling and simulation software, thereby allowing for
a more representative Reserves figure to be calculated.
General notes on reporting criteria
1. Resources are reported inclusive of Reserves.
2. Tonnes are reported as millions; contained diamonds
are reported as per million carats.
3. Tonnes are metric tonnes and are rounded to the
nearest 100,000 tonnes; carats are rounded to the nearest
10,000 carats; rounding off of numbers may result
in minor computational discrepancies.
4. Resource tonnages and grades are reported exclusive
of external waste, unless where otherwise stated.
5. Reserve tonnages and grades are reported inclusive of
external waste, mining and geological losses and plant
modifying factors; reserve carats will generally be less than
resource carats on conversion and this has been taken into
account in the applicable statements.
6. Reserves and Resources have been reported in accordance
with the South African code for the reporting of mineral
reserves and mineral resources (SAMREC 2007).
7. The Petra 2013 Resource Statement is based on information
compiled internally within the Group under the guidance and
supervision of Jim Davidson, Pr. Sci. Nat. (reg. No.400031/06).
Jim Davidson has over 30 years’ relevant experience in the
diamond industry and is a full-time employee of Petra.
8. All Reserves and Resources have been independently reviewed
and verified by John Kilham, Pr. Sci. Nat. (reg. No. 400018/07),
a competent person with 33 years’ relevant experience in
the diamond mining industry, who was appointed as an
independent consultant by the Company for this purpose.
Jim Davidson
Technical Director
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