Delta - Indicated Drilling
The Delta Indicated Resource estimate is based on the results of
381 reverse circulation (RC) holes drilled in Delta
between October and December 2009 (see figure below).
Drillhole spacing was decreased to 125m between
lines and 100m between holes. Average in situ
densities were derived via direct measurement
from the diamond holes drilled in 2009 for
geometallurgical test work. Drillhole locations and
the extent of the resource model are also shown in the figure below.
The
resource consists of both hematite rich Channel
Iron Deposit (CID) mineralisation and goethite rich Bedded Iron Deposit (BID) mineralisation.
Compared to the Inferred Resource released
previously, the increased RC drilling density,
combined with the diamond drilling undertaken as
part of the geometallurgical test work, has enabled
a more detailed geological understanding of the
mineralisation.
On the basis of differences in physical and chemical
characteristics, the CID has been divided into four
discrete units and the BID into two units. In general, the four CID
units form a stratigraphic sequence, passing from
CID-1 to CID-4, with the iron grade increasing and the
contaminant concentrations decreasing with depth.
The underlying BID has been divided into a more
dominant goethite unit (BIDg) and a minor more
banded hematite unit with a goethitic overprint
(BIDh). However, not all units are present in any given
drillhole or on any given section. The BID material is
generally located beneath the CID material although
it does also outcrop at the margins of the channel.
These domains form the basis for the JORC
compliant resource estimate.
The ability to define and recognise these different
units has resulted in a more reliable interpretation of
the geological boundaries of the deposit. It has also
allowed a better definition of the distribution and
quality of different ore types.
Please see ASX Announcement of 8 February 2010 for more detailed information.
Delta Indicated and Inferred Mineral Resouce, showing location of drilling at Delta and JORC Resource classification.
Ajax
Drilling at Ajax commenced in May 2009, and a total of 93 holes for 3,180m has been drilled. Assay results have indicated good thicknesses of CID mineralisation, particularly along lines 7 and 8.
The majority of the mineralisation at Ajax is shallow and often near to the surface. Significant CID results include HRC827 with 24m @ 59% Fe; HRC848 with 18m @ 57.8% Fe; and HRC855 with 32m @ 61.1%Fe. Minor amounts of good quality BID were intersected with HRC858 the highlight, comprising 20m @ 57.2% Fe, 4.2% Al2O3 and 4.5% SiO2.
Blackjack
An additional 11 holes for 480m have been drilled in Blackjack. The majority of the holes were designed to better define the current resource; however, significant results were obtained at the western end of line 3, where two holes intersected BID thicknesses of 12m and 16m respectively within 10m of the surface.
This mineralisation is outside of the current estimated resource and remains open to the west.
Champion
A total of 34 additional holes have been drilled in Champion. The two mineralised zones of CID and BID were further delineated with infill holes and more confidence was added to the geology. Of particular interest were holes HRC513 and HRC518, located at the western end of lines 2 and 5 respectively. Both holes encountered BID mineralisation with an estimated 12m intersected in HRC518.
Delta
Additional drilling in Delta comprised 25 RC holes for 1,338m. This included all holes on line 1 which intersected good thicknesses of CID and clay rich Serenity-style mineralisation at depth. A number of holes were also drilled extending the northern end of line 2. Very good thicknesses of combined CID/BID of up to 58m were intersected in a number of these holes.
Other lines were also extended with the aim of testing for further BID mineralisation with excellent intersections. Two holes at the southern end of line 3, and holes at the northern end of lines 7 south and 7 north all intersected significant BID mineralisation.
Delta contains the highest tonnage of BID material of all the deposits identified on the Project and has the highest upside potential for increasing the BID resource. Drill testing of the BID extensions and additional BID targets formed an integral part of the drilling campaign to define an Indicated Resource at Delta.
Eagle
Drilling at Eagle in 2009 comprised 11 holes for 618m. Significant intersections of both CID and BID mineralisation were drilled as part of the northern extension to both lines 1 and 2 in the immediate vicinity of Blacksmith camp. These holes were drilled outside of the current resource estimate boundaries. Significant assay results include HRC115 with 18m @ 57.8%; HRC116 with 34m @ 57.5% Fe, including 10m @ 61.4% Fe, 1.8% Al2O3 and 2.6% SiO2; and HRC117 with 26m @ 55.1%.
Location of Indicated and Inferred Mineral Resources and 2010 Exploration Targets.
Future Exploration
2010 Drilling
Drilling in the 2010 campaign has commenced and was recently described in an ASX release dated 27 April 2010. It will initially focus on completing Indicated Resource drilling at Delta. Work will then involve exploring a combination of new CID, BID and hypogene hematite targets and extending zones of mineralisation outside the current resource. Drilling will also be carried out to increase the Indicated Resource outside the Delta deposit. The drilling campaign will remain flexible to allow for possible changes to highest priority work as the Prefeasibility Study progresses.
Mine planning studies
The latest resource estimate will be utilised in the mine planning portion of the Prefeasibility Study. Early testwork indicates that the majority of the orebody can be classified as “free dig” and that the majority of mining would be above the water table.
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