Rocky Gully Project
An RC drill program consisting of 21 planned holes commenced at the Company's Rocky Gully Nickel Project, located some 80km north-west of Albany, Western Australia. The primary target is a first order Versatile Time Domain Electromagnetic (VTEM) anomaly coincident with anomalous surface soil and laterite geochemistry and an aeromagnetic anomaly interpreted to represent a ultramafic intrusive. Surface sampling identified coherent anomalies of nickel to 836 ppm copper to 652 ppm and platinum and palladium to 8 ppb.
The rocks of the Albany-Fraser mobile belt are Proterozoic in age (1350-1140 Ma) which is the same age as the rocks hosting the Voisey Bay nickel sulphide deposit in Canada (1333 Ma) in a similar geological environment. In 2005 the Company identified the presence of potential ultramafic intrusives and weakly anomalous laterite geochemistry from review of historical reports and regional datasets. Over the next few years the company built up a land package of some 1200km² covering the prospective zones and identified up to 13 potential ultramafic intrusives.
In late 2008 Heron drilled some 5km southwest from the current target. This drilling identified disseminated primary magmatic nickel sulphides within a mafic-ultramafic intrusive, demonstrating the fertility of this area for nickel sulphide mineralisation.
With the potential targets covering such a large area, surface-based electromagnetic methods were not practical and an airborne VTEM survey was commissioned covering some 574 line kilometres over an area of 55km². While the previously drilled targets were identified as weak VTEM anomalies, the current drill target stood out as an order of magnitude better conductor. This combined with the anomalous surface geochemistry and the presence of an interpreted intrusive clearly make this a high priority drill target. Drilling will be completed in the coming quarter.
Kalpini Nickel Project
Two further diamond drillholes, KPDD0004-5, were completed for 665m at the Kalpini Nickel Project, located 70km north-east of Kalgoorlie. Both holes were targeting electromagnetic anomalies interpreted to be associated with nickel sulphide mineralisation along the footwall contact of the Emu Lake ultramafic horizon, in a similar stratigraphic position to where Xstrata Nickel Ltd and Emu Nickel Ltd have reported high grade nickel sulphide intercepts. The Kalpini project is situated in a similar geological setting as the rich Silver Swan mine to the northwest.
The first hole (KPDD0004) targeted a subtle downhole electromagnetic anomaly identified from hole KPDD0001. Drilling intersected six zones of disseminated iron sulphides in the footwall ultramafic unit between 95.5m and 270.6m down hole.
The second hole targeted and intersected an embayment-shaped feature identified in the detailed aeromagnetics over the eastern basal contact of the Emu Lake ultramafic unit. Minor stringer veins of pyrrhotite and chalcopyrite were intersected in felsic volcanic rocks stratigraphically directly below the ultramafic contact. These sulphides pre-date the ultramafic event and provide an excellent source of sulphur to facilitate the deposition of nickel sulphides within overlying flows. Six minor zones of magmatic disseminated sulphides consisting of pyrrhotite and minor chalcopyrite were intersected in the footwall ultramafic unit as well as one zone of stringer veins. The intersection of zones of disseminated and stringer mineralisation along the footwall contact of the Emu Lake ultramafic horizon is encouraging, which in combination with results reported previously by Xstrata Nickel Ltd and Emu Nickel Ltd on their adjacent tenements clearly demonstrates the nickel sulphide prospectivity of the belt. A soil-sampling program comprising 981 samples was conducted over the prospective horizon, along 11km of strike that Heron controls. This survey has identified two zones of anomalous surface geochemistry with nickel up to 1350 ppm, copper up to 124 ppm and platinum and palladium to 33 ppb, coincident with the footwall contact in areas previously not surveyed.
A surface moving loop electromagnetic survey comprising 137 stations over 12.5 line kilometres was completed targeting extensions of the basal contact. The Company is currently reviewing the results of the diamond drilling, regional soil geochemistry and surface electromagnetic surveys prior to conducting further drill testing.
Mt Zephyr Base Metal Project
A conductive anomaly over 400m of strike has been identified at the Mt Zephyr volcanogenic massive sulphide (VMS) Project, located 65km north west of Leonora.
Heron's exploration target is a high-grade VMS deposit similar to those being mined by Jabiru Metals Limited some 60km to the west of this prospect at Jaguar and their recent discovery at Bentley, in a very similar sequence of rocks.
Sulphide mineralisation associated with VMS style deposits is typically moderately conductive (conductivity is one of the parameters measured by EM surveys) and thus an anomaly of short strike associated with the target horizon is particularly interesting. Conductive zones of longer strike length may be related to stratigraphic conductors such as graphitic black shale horizons of no economic importance. This target with only a 400m strike length is not likely to be due to black shales.
The anomaly is located some 200m to the west of the historical "ESSO VMS Horizon" in an area of dominantly shallow colluvial cover.
Detailed mapping and geochemical sampling using the Niton handheld XRF analyser has identified subcrop within the colluvial plain of gossanous (the weathered product of sulphides) iron-rich rocks with elevated base metals further upgrading the prospectivity of this anomaly.
Drill testing is planned for early in the coming quarter. A total of four second-order EM anomalies were generated.
The ESSO VMS Horizon is an 8km long, north-westerly trending sequence of felsic volcanic rocks and related sediments with a number of VMS related copper, lead and zinc occurrences defined by mineral explorer ESSO in the 1980s.
Mt Zephyr Copper-Gold Project
Diamond Core ZRDD01 209 220m
Diamond Core ZRDD01 245 251m
Diamond core drilling intersected some 85m (from 190m depth) of strongly altered basaltic and granitic rocks associated with a discrete magnetic anomaly. The target is located in the far north of its Mt Zephyr Project area, some 80km north-east of Leonora. The alteration consists dominantly of magnetite and epidote with lesser, hematite, diopside and biotite. Such alteration can be described as "skarn-type" related to the high-temperature intrusion of the granitic unit. Some minor copper sulphides (chalcopyrite) were observed lower down in this zone at around 250m depth where biotite becomes the more dominant alteration phase.
The hole is being fast-tracked through the laboratory to provide gold, copper and other metal assays.
The first hole into this anomaly is an encouraging result and demonstrates that a potentially mineralising system is present. With other iron-oxide and skarn systems the economic mineralisation is often off-set from the main magnetic anomaly and therefore, the Company is currently fast tracking electromagnetic and gravity surveys to identify optimum follow-up drill positions.
