7
Geological
interpretation.
3D solids are created by flagging the principal rock types and structures defined during section interpretation.
The highest priority geological domains are the Garnet Gneiss, Dykes and Shears, as these are the most
visually distinctive units, are the least subjective when being logged. These are considered to have a high level
of confidence in interpretation. The Garnet Gneiss unit is an important unit, as it is generally found in the
hanging wall to the mineralisation and acts as a precursor to mineralisation, as well as being the dominant waste
rock unit. The dykes are locally important as they post-date mineralisation and are barren of gold mineralisation.
Modelling of the shears is critical to understanding geotechnical aspects and assessing the spatial controls on
the mineralisation. Measurements of structural data from drill core are used to generate 3D disks in Vulcan that
assist in correctly modelling the orientation of dykes and shears.
Modelled lithological boundaries and shears formed a framework for subsequent definition and triangulation of
mineralised lenses in the Tropicana and Havana zones. A 0.3g/t gold cut-off was applied with internal lower
grade zones (<3m) included in the model. The Tropicana mineralised zone was clipped at the saprock contact,
consistent with observations in diamond drill core. Havana zone mineralisation extends above the saprock
contact and 0.3g/t gold triangulations were clipped at the base of transported cover. Mineralisation envelopes
were projected down dip below the limit of assayed drill core and RC samples on average by 100m.
Interim solids were validated and refined using structural readings measured in drill core.
Dimensions.
The Open Pit Mineral Resource is reported within an A$1500 optimisation shell that is 4.7km long, up to 1km
wide, and up to 460m deep.
The Havana Deeps Underground Mineral Resource extends to a depth of approximately 1km below surface.
Estimation and
modelling techniques.
The Mineral Resource is reported from open pit and underground Mineral Resource models, estimated with
differing estimation techniques and with different cut-off grades applied to each model. The Open Pit Mineral
Resources have been estimated using the geostatistical technique of Uniform Conditioning using average drill
hole intercepts and are reported above a marginal (break-even) cut-off grade of 0.3g/t for Transported and
Saprolite material, and 0.4g/t for Transitional and Fresh material. The Havana Deeps Underground Mineral
Resource has been estimated at a cut-off grade of 1.73g/t using the geostatistical technique of Ordinary Kriging
using average drill hole intercepts. The cut-off grade calculation is based on an underground scoping study
completed in late 2010, and a gold price of US$2000 (A$1896).
3m down-hole composites are used for both estimates.
Gold is the only element modelled, as no other significant element has been detected in sampling to date which
would be deleterious to mine and mill performance.
The Open Pit estimate uses block sizes of 15m (X) by 30m (Y) by 10m (Z) with an SMU of 5m (X) by 7.5m (Y)
by 3.33m (Z).
The Underground estimate uses a block size of 15m (X) by 30m (Y) by 3.33m (Z).
Both Resource Estimates are compared to the input data using swath plots to check for bias in the estimation,
and to previous estimates.
No reconciliation data is currently available, although a trial grade control pattern of ~100m by 100m was drilled
during the BFS which provided confidence that the Mineral Resource Estimate was accurate in that volume.
Moisture.
Tonnage estimates are on a dry tonne basis.
Cut-off parameters.
The Open Pit Mineral Resources use a cut-off grade of 0.3g/t for Transported and Saprolite material, and 0.4g/t
for Transitional and Fresh material, based on contract mining costs and BFS-level estimates of processing and
administration costs, and a gold price of US$2000 (A$1896).
The Havana Deeps Underground Mineral Resource has been estimated at a cut-off grade of 1.73g/t. The cut-off
grade calculation is based on an underground scoping study completed in late 2010, and a gold price of
US$2000 (A$1896).
Mining factors or
assumptions.
Open Pit mining assumes selectivity of SMU’s of 5m (X) by 7.5m (Y) by 3.33m (Z), with no external dilution
accounted for in the Mineral Resource.
Underground mining is based on a modified Long-Hole Open Stope method, with 20m vertical intervals between
ore drives. No external dilution is included in the Mineral Resource Estimate.
Metallurgical factors
or assumptions.
Metallurgical recovery is taken into account in the optimisation of both Open Pit and Underground Resource
optimisations, with an average project recovery of 90.3% assumed, based on extensive metallurgical test work
completed as part of the Feasibility Study for the Havana Open Pit.
Bulk density.
Dry Bulk Density (DBD) determinations have been routinely collected on the mineralised zones in all DDH core
at one-metre intervals using water immersion methods. A coherent segment of core (>10cm length),
representative of the metre interval, is selected. The weight is measured dry, in air, then measured submerged
in water. Core was left to dry naturally on the core racks.
Dry Bulk Density has been estimated using Ordinary Kriging where sufficient data exist. In non-estimated areas,
the average measured value for that lithology and regolith type is used. Density values within units show little
variation.
Classification.
The estimates of the Mineral Resources presented in this Report have been carried out in accordance with the
principles and guidelines of the Australian Code for Reporting of Exploration Results, Mineral Resources and
Ore Reserves (JORC, 2004).