2000 Annual Report - Heron Resources Limited

2.0 Continued
Operations Review
Goongarrie South Resource Estimation
The drilling results from Goongarrie South have been exceptional, with extensive areas of drilling exceeding 15 Ni4Co% x m.
Two holes in particular within the Pamela Jean Zone were outstanding:
GSRC309
GSRC363
47 metres at 1.43% Ni and 0.23% Co
50 metres at 1.37% Ni and 0.20% Co (and open at depth)
This scale of metal enrichment is not documented elsewhere in the Eastern Goldfields Nickel Laterite province. Section interpretation
and resource estimation is in progress, with a current Inferred Mineral Resource of 63.0 million tonne at 1.08% Ni and
0.09% Co at a 0.75% Ni cut-off. Ore zone continuity is excellent.
A screen upgrade study has commenced on RC drill chip composites. As expected from drill chip logging, the Limonite Ore does
not upgrade, since it lacks silica. In contrast, with Siliceous Ore, there is a 47% screen reject at a -0.5mm screen size, for 43% Ni
upgrade and 37% Co upgrade, with 74% metal recoveries.
Of interest, gold mineralisation has been intersected in the course of Heron’s nickel laterite drilling, with the main Au-As anomaly at a
100ppb Au threshold extending over a 2.2km strike length. The gold anomalism occurs in saprock beneath the nickel laterite
mineralisation. Heron has completed a gold targeting plan, but as yet no gold drilling has been done. All resource drilling in the area
of the gold target has a standard precious metal assay suite run on the drill composites. This work is outside the Strategic Alliance.
Elsewhere in the Eastern Goldfields, gold anomalism is not recorded in association with lateritic nickel, reflecting an absence of iron
within laterite-hosting komatiites.
Goongarrie South Diamond Drill Core Grade Validation
A program of PQ Diamond Drilling was completed by Heron as part of a quality control audit and to provide material for detailed
metallurgy and density determinations. Heron completed 8 Diamond Drill holes for 406 metres. Core recovery was acceptable, with
only GSDD04 having to be abandoned in transported cover (re-drilled as GSDD008, which similarly failed to reach its full target depth).
Significant intercepts include:
Table 7 - GOONGARRIE SOUTH PROSPECT
Diamond Drilling Significant Intersections, 0.75% Ni Cut-off
Hole No. North East From To Interval Ni Co Ni4Co Ni4Co%*
m m m m m % % % x m
GSDD001 68,401 2,724 15 28 13 1.49 0.195 2.27 29.51
GSDD002 68,400 2,795 11 16 5 1.29 0.243 2.26 11.31
22 24 2 0.83 0.054 1.05 2.09
GSDD003 68,398 3,126 15 33 18 1.05 0.199 1.85 33.22
GSDD005 68,798 3,127 25 44 19 1.24 0.123 1.73 32.91
GSDD006 69,195 3,038 27 46 19 1.50 0.034 1.64 31.16
GSDD007 69,199 3,124 7 54 47 1.11 0.110 1.55 72.85
GSDD008 68,798 3,035 31 43 12 1.44 0.590 3.80 45.60
50 55 5 1.22 0.111 1.66 8.32
* ”Ni4Co% x m” for a drill intercept is the value of %Ni plus 4 times %Co of the interval multiplied by the intercept in metres.
In-situ Bulk Density measurements indicate a range of SGs from 1.0 to 3.0. The arithmetic mean SG is 1.9 (1.8 SG is used at Cawse),
but it is obvious that the SGs are extremely heterogeneous and will require detailed geology-based modelling.
To be conservative, the Goongarrie South and Scotia Dam SGs have been reduced from 1.8 (as per Cawse) to 1.6 (as per Kalpini).
Assay comparisons between a Diamond Drill hole and the adjacent RC drill hole are good, particularly within the supergene enriched
upper mineralised intervals. There is thus confidence in the predictability of the upper high grade ore. This ore will be the mainstay of
mining during the early project life. Within the lower ore zones, both lithological and assay correlations are less strong, reflecting
localised structural controls on grade distributions. Correlation problems with cobalt are recognised in the limited Diamond Drill holes
completed to date, with the RC drilling appearing to underestimate the cobalt grade when compared to the adjacent Diamond Drill
hole. This result is somewhat biased by the exceptionally high cobalt grades in Diamond Drill hole GSDD008.
Heron Resources NL Annual Report 2000 page 15