2012 Annual Report (2 April 2013) - Grange Resources

2012 ANNUAL REPORT
13
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MINERAL RESOURCES AND ORE RESERVES - SAVAGE RIVER
OPERATIONS
The following tables show the Mineral Resources and Ore Reserves for the Savage River
operations as at 30 June 2012. Mining of ore through this period was focussed on high
grade supply from the Stage 1 area of North Pit. The increase in resources from 2011 is
due to the inclusion of the resource estimation for the Long Plains deposit (as announced
to the ASX on 30 August 2012).
Mineral Resources and Ore Reserves are categorised in accordance with the Australasian
Code for Exploration Results, Mineral Resources and Ore Reserves of December 2004
(JORC Code, 2004). Estimated Measured and Indicated Mineral Resources include
those Mineral Resources modified to produce the estimated Ore Reserves. Mineral
Resources which are not included in the Ore Reserves did not meet the required
economic viability hurdle at the time of last review.
Mineral Resources
A summary of the total Mineral Resources for Savage River as at 30 June 2012 (including
the mineral resource estimate for the Long Plains deposit that was announced to the ASX
on 30 August 2012) is as follows:
As at June 2012 As at June 2011
Tonnes Grade Tonnes Grade
(Mt) % DTR* (Mt) % DTR*
Measured 78.2 54.2 81.4 54.2
Indicated 135.7 53.5 131.5 53.5
Inferred 129.8 47.2 86.9 48.8
Total 343.7 51.3 299.8 52.3
* Davis Tube Recovery – a measure of recoverable magnetite
Ore Reserve
A summary of the ore reserve for Savage River as at 30 June 2012 is as follows:
As at June 2012 As at June 2011
Tonnes Grade Tonnes Grade
(Mt) % DTR* (Mt) % DTR*
Proved 44.6 52.2 47.6 51.6
Probable 64.8 52.1 66.3 51.4
Total 109.4 51.8 113.9 51.5
* Davis Tube Recovery – a measure of recoverable magnetite
The information in this release that relates to Exploration Results or Mineral Resources in relation to the
Savage River Project is based on information compiled by Mr Ben Maynard, who is a Member of the
Australasian Institute of Mining and Metallurgy and is a full time employee of Grange Resources Limited.
Mr Maynard has sufficient experience which is relevant to the style of mineralisation and type of deposit
under consideration and to the activity which he is undertaking to qualify as a Competent Person as
defined in the 2004 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral
Resources and Ore Reserves’. Mr Maynard consents to the inclusion in the release of the matters based
on his information in the form and context in which it appears.
The classification of Mineral Resources
was considered appropriate on the
basis of drill hole spacing, sample
interval, geological interpretation and
representativeness of assay data and was
based on a number of factors:
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The Measured and Indicated
Mineral Resources are inclusive of
those Mineral Resources modified
to produce the Ore Reserves. The
Inferred Mineral Resources are,
by definition, additional to the Ore
Reserves.
The estimation was constrained within
the interpreted geological domains.
The Ordinary Kriging (OK) and Inverse
Distance interpolation methods were
carried out on drilling data composited
to 2 metres as appropriate for the
different parts of the deposit. OK and
1 metre composites were used for
Long Plains.
Oxidised material was not included in
this statement of Mineral Resources.
Tonnages were estimated on a dry
basis.
Bulk density for samples taken from
diamond drill core has been physically
determined by the weight-in-air/
weight-in-water method. Samples are
unsealed during this process as most
material is competent and/or of low
porosity.
A lower cut-off grade of 15% DTR
was used in the calculation of both the
Mineral Resources and Ore Reserves.
The Ore Reserve was calculated using
a 1.087 dilution factor and a mining
recovery factor of 0.939. These factors
are based on periodic reconciliation
specific to mining areas.
A risk factor of 0.8 was applied to the
Centre Pit South reserve for potential
loss due to wall instability. Studies will
be undertaken to mitigate this risk.
The survey surface used for reporting
was the end-of-month June 2012
surface.